A weed is defined as a plant out of place, or a plant growing where it is not desired. Weeds compete with turfgrasses for light, water, soil nutrients and space. In a turf, weeds disrupt uniformity and are often considered to be aesthetically unpleasing. With a few exceptions, weeds will not provide year-round vegetative cover. A year-round turf cover is especially beneficial to prevent erosion and runoff, and in areas that might receive moderate to heavy use during the non-growing season. Weeds in athletic fields can adversely affect playability and athlete safety.

Weeds of turf are most often categorized by their life cycle. The most important thing one can learn about a specific weed is its life cycle. Knowledge of the life cycle is valuable when attempting to manage a specific weed because not all strategies are appropriate for all life cycles. Also, the timing of when a specific control strategy is implemented will vary based on a weed’s life cycle. A weed can be a summer annual, winter annual, biennial or perennial (Tables 9 and 10).

Annual weeds

Annual weeds reproduce by seed and complete their life cycle in one year. The annual life cycle is further divided into summer annual weeds and winter annual weeds. Summer annual weeds germinate in spring or early summer, grow vegetatively, flower and produce seed and die in late summer or fall. Examples of summer annual weeds include crabgrass, yellow foxtail, goosegrass, barnyardgrass, ragweed, purslane, spotted spurge, pigweed, carpetweed and prostrate knotweed. Winter annual weeds germinate in late summer and fall. They grow vegetatively and go dormant with the arrival of cold weather. In the spring they continue to grow vegetatively early and then switch to a reproductive phrase during which they flower and produce seed. After flowering, they die with the onset of warm weather. Winter annual weeds can be just as problematic and troublesome as summer annual weeds. Examples of winter annual weeds include shepherd’s-purse, common chickweed, sticky chickweed, annual bluegrass, henbit, pineappleweed, spring whitlowgrass and corn speedwell.

Biennial weeds

Biennial weeds reproduce by seed and complete their life cycle in two years. Biennial weeds germinate in spring to early summer and grow vegetatively forming a leaf rosette at the end of the first growing season. After over-wintering as a rosette, the biennial weed resumes growth, flowers, produces seed and completes the life cycle in the second growing season. Examples of biennial weeds are common mullein, burdock, bull thistle, wild carrot and garlic mustard.

Perennial weeds

Perennial weeds live for three or more years and reproduce by seed and vegetative propagules including roots, rhizomes, stolons, tubers, and bulbs. Dandelion, broadleaf plantain, narrowleaf plantain, broadleaf dock, false dandelion, spotted cat’s ear and fall dandelion are examples of simple perennials and reproduce by seed. Spreading perennials reproduce by seed and vegetative propagules and can form sizable clonal patches in turf. Examples of spreading perennials are quackgrass, red sorrel, creeping woodsorrel, Canada thistle and ground ivy. Other perennials such as wild garlic and star-of-bethlehem arise from bulbs. Yellow nutsedge arises from small tubers called nutlets.

Table 9. Life cycles of common broadleaf turf weeds

Common name	Scientific name	Life cycle
alyssum, hoary	Berteroa incana	perennial
bedstraw, catchweed	Galium aparine	winter annual
bedstraw, smooth	Galium mollugo	perennial
beggarticks, devil’s	Bidens frondosa	summer annual
bittercress	Cardamine hirsuta	winter annual
bittercress, cuckoo	Cardamine pratensis	perennial
bluets	Houstonia caerulea	perennial
buttercup, bulbous	Ranunculus bulbosus	perennial
buttercup, creeping	Ranunculus repens	perennial
carpetweed	Mollugo verticillata	summer annual
carrot, wild	Daucus carota	perennial
cat’s ear	Hypochaeris radicata	perennial
celandine, lesser	Ranunculus ficaria	perennial
chickweed, common	Stellaria media	winter annual
chickweed, mouse-ear	Cerastium vulgatum	perennial
chickweed, sticky	Cerastium viscosum	winter annual
chicory	Cichorium intybus	perennial
cinquefoil, old field	Potentilla simplex	perennial
cinquefoil, silvery	Potentilla argentea	perennial
clearweed	Pilea pumila	summer annual
clover, alsike	Trifolium hybridum	perennial
clover, rabbitfoot	Trifolium arvense	summer annual
clover, red	Trifolium pratense	perennial
clover, white	Trifolium repens	perennial
common lambsquarters	Chenopodium album	summer annual
copper-leaf, rhombic	Acalypha rhomboidea	summer annual
daisy, oxeye	Chrysanthemum leucanthemum	perennial
dandelion	Taraxacum officinale	perennial
dandelion, fall	Leontodon autumnalis	perennial
deadnettle, red	Lamium purpureum	winter annual
deptford pink	Dianthus armeria	perennial
dock, broadleaf	Rumex obtusifolius	perennial
dock, curly	Rumex crispus	perennial
evening primrose, common	Oenothera biennis	biennial
fleabane, annual	Erigeron annuus	winter annual/biennial
fleabane, poor-robin	Erigeron pulchellus	perennial
galinsoga, hairy	Galinsoga ciliata	summer annual
garlic, wild	Allium vineale	perennial
ground ivy	Glechoma hederacea	perennial
groundsel, common	Senecio vulgaris	summer annual
hawksbeard, narrowleaf	Crepis tectorum	summer annual
hawkweed, orange	Hieracium aurantiacum	perennial
hawkweed, yellow	Hieracium pretense	perennial
healall	Prunella vulgaris	perennial
hedge bindweed	Calystegia sepium	perennial
henbit	Lamium amplexicaule	winter annual
horseweed	Conyza canadensis	winter annual
jimsonweed	Datura stramonium	summer annual
knawel	Scleranthus annuus	winter annual
knotweed, prostrate	Polygonum aviculare	summer annual
maiden pink	Dianthus deltoids	perennial
mallow, common	Malva neglecta	annual/biennial
medic, black	Medicago lupulina	annual
moneywort	Lysimachia nummularia	perennial
mouse-ear cress	Arabidopsis thaliana	winter annual
mugwort	Artemisia vulgaris	perennial
nightshade, eastern black	Solanum ptycanthum	summer annual
pearlwort, birdseye	Sagina procumbens	perennial
pepperweed, virginia	Lepidium virginicum	summer or winter annual
pigweed, prostrate	Amaranthus lividus	summer annual
pigweed, redroot	Amaranthus retroflexus	summer annual
pimpernel, scarlet	Anagallis arvensis	summer annual
pineappleweed	Matricaria matricariodes	winter annual
plantain, broadleaf	Plantago major	perennial
plantain, narrowleaf	Plantago lanceolata	perennial
pokeweed, common	Phytolacca americana	perennial
purslane, common	Portulaca oleracea	summer annual
pussytoes, field	Antennaria neglecta	perennial
ragweed, common	Ambrosia artemisiifolia	summer annual
ragweed, giant	Ambrosia trifida	summer annual
rocket, yellow	Barbarea vulgaris	biennial
sandspurry, red	Spergularia rubra	summer annual
shepherd’s-purse	Capsella bursa-pastoris	winter annual
smartweed, ladysthumb	Polygonum persicaria	summer annual
smartweed, Pennsylvania	Polygonum pensylvanicum	summer annual
sorrel, red/sheep	Rumex acetosella	perennial
sowthistle, annual	Sonchus oleraceus	summer annual
sowthistle, perennial	Sonchus arvensis	perennial
sowthistle, spiny	Sonchus asper	summer annual
speedwell, common	Veronica officinalis	perennial
speedwell, corn	Veronica arvensis	winter annual
speedwell, purslane	Veronica peregrina	winter annual
speedwell, thymeleaf	Veronica serpyllifolia	perennial
spurge, spotted	Euphorbia maculata	summer annual
star-of-bethlehem	Ornithogalum umbellatum	perennial
stitchwort	Stellaria graminea	perennial
strawberry, wild	Fragaria virginiana	perennial
thistle, Canada	Cirsium arvense	perennial
thymeleaf sandwort	Arenaria serpyllifolia	winter annual
toadflax, oldfield	Linaria canadensis	summer annual
toadflax, yellow	Linaria vulgaris	perennial
tower mustard	Arabis glabra	biennial
trefoil, birdsfoot	Lotus corniculatus	perennial
velvetleaf	Abutilon theophrasti	summer annual
violet, wild	Viola spp.	perennial
white cockle	Silene alba	perennial
whitlowgrass, spring	Draba verna	winter annual
woodsorrel, creeping	Oxalis corniculata	perennial
yarrow	Achillea millefolium	perennial
yellow woodsorrel	Oxalis stricta	perennial

Table 10. Life cycles of common grass and grass-like turf weeds

Common name	Scientific name	Life cycle
barnyardgrass	Echinochloa crus-galli	summer annual
bentgrass, creeping	Agrostis stolonifera	perennial
bluegrass roughstalk	Poa trivialis	perennial
bluegrass, annual	Poa annua	winter annual/perennial
bluegrass, bulbous	Poa bulbosa	perennial
brome, downy	Bromus tectorum	winter annual
crabgrass, smooth or small	Digitaria ischaemum	summer annual
crabgrass, large or hairy	Digitaria sanguinalis	summer annual
fescue, tall	Festuca arundinacea	perennial
foxtail, giant	Setaria faberi	summer annual
foxtail, yellow	Setaria glauca	summer annual
goosegrass	Eleusine indica	summer annual
lovegrass, purple	Eragrotis spectabilis	perennial
nimblewill	Muhlenbergia schreberi	perennial
nutsedge, yellow	Cyperus esculentus	perennial
orchardgrass	Dactylis glomerata	perennial
panicum, fall	Panicum dichotomiflorum	summer annual
paspalum	Paspalum setaceum	perennial
quackgrass	Elytrigia repens	summer annual
rush, path	Juncus tenuis	perennial
sandbur, longspine	Cenchrus longispinus	summer annual
stiltgrass, Japanese	Microstegium vimineum	summer annual
stinkgrass (lovegrass)	Eragrostis cilianensis	summer annual
timothy	Phleum pratense	perennial
witchgrass	Panicum capillare	summer annual
zoysiagrass	Zoysia japonica	perennial

 

Scouting and monitoring are important components of an effective integrated management program for turf weeds. Monitoring should be done every time a turf manager is on a particular site, in addition to an all-inclusive, in-depth scouting event carried out in late summer or early fall.

The turf manager should use a back and forth or zig-zag pattern when scouting for weeds, being sure to cover all distinctly different and/or known problem areas. Special attention should be given to areas of thin turf and possible causes, as well as newly introduced weeds and historically problematic weeds that are not controlled with the current management program. All weed species present and their respective life cycles should be recorded. Observations can be recorded on a site map or listed on a sheet with location identified. Regular scouting and accurate weed identification enables a turf manager to plan and implement an appropriate management approach and to evaluate the long-term effectiveness of control strategies.

Indicator weeds

There is an old adage that states “Weeds are the result of a poor turf, not the cause of a poor turf”. Weed infestation often suggests that there are one or more underlying factors contributing to poor turf health and vigor. A comprehensive list of all weeds should be developed as a turf manager scouts a specific turf site; however there are certain weed species that should be scrutinized more carefully. These weed species, often referred to as “indicator weeds” or “diagnostic weeds”, are particularly competitive when environmental conditions are not optimal for turfgrass growth. The occurrence of indicator weeds can be used as a starting point in identifying those factors that may contribute to poor turf. Identifying and correcting those factors can tip the competitive balance in favor of the turfgrass while minimizing, and in some cases eliminating, many weed infestations.

Red sorrel and bluets are common inhabitants of acid soils, whereas broadleaf plantain may be more abundant at high soil pH. Crabgrass and many other annual weeds require light for germination and thrive in turf areas that are thin as a result of low fertility. White clover and birdsfoot trefoil are also common in low fertility situations and may indicate the need for fertilization. Prostrate knotweed, goosegrass, pineappleweed and path rush commonly occur where the soil has become compacted. Excessive irrigation and/or poorly drained soils may result in an increase in the occurrence of algae, moss, annual bluegrass, creeping bentgrass and yellow nutsedge. Some weeds such as ground ivy, common speedwell and moss are able to thrive in shaded conditions.

Turf managers should not assume that just because these weeds are present that a specific problem exists. For example, red sorrel can grow at high pH and ground ivy may persist in turf areas that receive full sun. While the use of “indicator weeds” is not a fool proof method, it can be a valuable tool in the assessment of potential problems at a turf site.

Cultural practices are a vital component within an effective management program for turf weeds. Successfully executed cultural practices can result in a healthier, denser turf which increases the overall competitive nature of the stand and decreases the severity of many weed infestations. Some weed infestations can be significantly reduced or even eliminated with the use of appropriate and well-timed cultural practices.

Mowing

Many weeds require light for germination and establishment. Increasing the mowing height within the range for the particular species or mix of species present will result in a decrease in the amount of light reaching the soil surface and can reduce weed germination and establishment. This is particularly important in the spring and early summer during the peak germination period of annual grassy weeds. Decreasing the height of cut and collecting clippings that contain seedheads during the late summer and early fall can be effective in reducing the amount of viable seed that is added to the weed seed bank.

Fertility

Fertility, as with mowing height, can play a major role in the reducing the amount of light that penetrates the turf canopy and reaches the soil surface. Fertilization programs should supply adequate and balanced nutrition to yield a dense turf. Avoid high levels of fertility during the summer months when cool-season turfgrasses are less competitive. If heavy summer weed pressure has thinned turf, an application of fertilizer in late summer or early fall will support turf recovery. Fertilization after herbicide applications can aid in the filling of canopy voids left by dying weeds.

Aeration

Compaction is a major contributor to thin turf and the encroachment of weeds. An effective aeration program will alleviate compaction and increase overall turf health and density. However, aeration methods that bring soil to the surface can reposition weed seeds, which were once too deep to germinate, to a location where germination and establishment are favored. The alleviation of compaction in conjunction with overseeding of desirable grasses can reduce and in some cases eliminate weeds such as goosegrass, pathrush, pineappleweed and prostrate knotweed.

Irrigation

Many annual weeds, including crabgrass, are warm-season species. Warm-season species are capable of growing very well during the hot, dry periods characteristic of summer. Turfgrass species utilized in the northeast are cool-season species and, without adequate moisture from rainfall or irrigation, become dormant during the summer. During periods when the growth of cool-season turfgrass species has slowed or ceased as a result of low soil moisture and high temperatures, warm-season annual weeds become very competitive in otherwise healthy, dense turf. If some weed encroachment is not acceptable, irrigation should be applied in the absence of summer rainfall to maintain turf growth and prevent summer dormancy. Special attention should be focused on areas that are prone to drought including elevated areas, south and southwest facing slopes and areas adjacent to hardscapes such as sidewalks and driveways. If there is annual weed pressure and the turf at a site is going to be allowed to go dormant during the summer months, the option also exists to apply a preemergence herbicide in the spring. If turf has thinned due to drought dormancy, overseeding with desirable turfgrass species should be done in late summer/early fall when cooler temperatures and rainfall return.

The over-watering of turf areas can also contribute to weed encroachment. Weeds such as annual bluegrass, creeping bentgrass, and yellow nutsedge can be more problematic on over-irrigated sites. On poorly-drained sites, the installation of a drainage system may be warranted to decrease naturally-existing excessive soil moisture.

Turf Renovation and Establishment

Turf renovation and establishment projects carried out in the spring and early summer without the use of a preemergence herbicide fail more often than not due to annual weed pressure. Summer annual weed pressure is minimal when turf renovation and establishment is initiated in the late summer and early fall. Warm-season annual weeds that germinate later in the season seldom reach a size that deters turf establishment and die with the onset of cold weather. Special attention should be paid to winter annual weed encroachment in such areas, however.

When planning a turf renovation, choose turfgrass species and cultivars that are best suited for the site conditions and expected turf use. Aggressive cultivars should be considered when available. Encourage rapid establishment by providing adequate fertility at seeding. Maintain good soil moisture during the germination and early establishment period. Overseeding can be a valuable tool in restoring sites where turf thinning has resulted from insufficient annual weed control. Openings in the turf as a result of insect damage, diseases and excessive wear are prone to weed encroachment. Overseeding is frequently useful to repair such damage and regain turf density.

In turf management, the two most basic categories of herbicides are preemergence and postemergence. Preemergence materials are applied preventively, that is prior to germination, to control weeds that have not yet appeared. Postemergence materials are applied to existing, actively growing weeds.  Some herbicides have both preemergence and postemergence activity. With such materials, appropriate application timing can be dictated by the target weed(s), distinct characteristics of the herbicide, or specific management goals.

Herbicides can be more finely categorized into chemical classes, which indicate the mode or mechanism of action of each compound. The particular mode of action influences whether a material is effective against broadleaf weeds, grassy weeds, or a more specific collection of species. Many individual modes of action offer selective control of weeds within desirable turf, while others provide non-selective control more appropriate for spot treatment and renovation situations.

Refer to Table 12 below to cross reference trade names with active ingredients.

Table 11. Characteristics of turf herbicide active ingredients registered for use in Massachusetts.

amicarbazone Chemical class Mode of action Application timing triaolinone inhibits photosynthesis postemergence Controls annual bluegrass, crabgrass, bittercress, carpetweed, henbit, field pennycress, common chickweed, sticky chickweed, Virgina pepperweed, purslane, shepherd’s-purse, spurge, and oldfield toadflax.

benefin Chemical class Mode of action Application timing dinitroaniline interferes with cell division preemergence Controls crabgrass, goosegrass, annual bluegrass, yellow foxtail and many annual broadleaf weeds.

bensulide Chemical class Mode of action Application timing organophosphate interferes with cell division and inhibits rooting. preemergence Controls annual bluegrass, crabgrass, goosegrass, henbit, lambsquarters, and yellow foxtail. Provides excellent control of annual bluegrass. Strongly adsorbed to soil, potential for leaching is very low.

bentazon Chemical class Mode of action Application timing benzothiadiazole inhibits photosynthesis, causes cell membrane destruction postemergence Controls primarily yellow nutsedge; will provide control of broadleaf weeds including Canada thistle, groundsel, ladysthumb, lambquarters, Pennsylvania smartweed, purslane, shepard’s purse and yellow woodsorrel. Controls primarily yellow nutsedge; will provide control of broadleaf weeds including Canada thistle, groundsel, ladysthumb, lambquarters, Pennsylvania smartweed, purslane, shepard’s purse and yellow woodsorrel. Contact herbicide. Some temporary turf discoloration may occur. The addition of a surfactant is required for application. Bentazon is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

bispyribac-sodium Chemical class Mode of action Application timing pyrimidinyloxybenoic inhibition of amino acid synthesis postemergence Controls annual bluegrass and roughstalk bluegrass in creeping bentgrass and perennial ryegrass, also broadleaf plantain, common chickweed, dandelion, henbit, narrowleaf plantain, white clover and yellow woodsorrel. May injure Kentucky bluegrass, especially some cultivars. Labeled for use only on golf courses and sod fields.

carfentrazone Chemical class Mode of action Application timing protox inhibitor inhibits chlorophyll production, results in rapid destruction of cell membranes postemergence Controls a wide range of broadleaf weeds. Often formulated in pre-mixed combinations with other broadleaf herbicides. Does not provide good control of perennial broadleaves when applied alone. Provides good moss control. Does not persist in soil and has no leaching potential.

chlorsulfuron Chemical class Mode of action Application timing sulfonylurea inhibition of amino acid synthesis postemergence Controls tall fescue, annual ryegrass and perennial ryegrass in Kentucky bluegrass, fine fescue and bentgrass; also buttercup, cinquefoil, common chickweed, common mallow, henbit, mouse-ear chickweed, pineappleweed, prostrate knotweed, purslane, shepards-purse, white clover, wild garlic and wild violet.

clopyralid Chemical class Mode of action Application timing pyridine disrupts growth by mimicking naturally occurring plant hormones. postemergence Broad spectrum; controls many broadleaves, particularly effective on members of the aster family (dandelion and hawkweed) and bean family (clover, black medic and birdsfoot trefoil). Translocated within the plant. Herbicide products that contain clopyralid are Restricted Use on residential turf. Turf clippings from treated areas should not be collected for mulching and composting or sent to a recycling facility. Use caution near ornamentals, including aster, daisy, coneflower, liatris, redbud, and honeylocust. Clopyralid is weakly adsorbed to soil and has a moderate leaching potential.

corn gluten meal Chemical class Mode of action Application timing not classified inhibition of root growth at germination. preemergence Labeled for the control of crabgrass species. Corn gluten meal is a by-product of the wet-milling of corn grain for the production of corn starch and corn syrup. Because of its high protein content (about 60% by weight), its historic use has been as an animal feed. Its associated nitrogen concentration of about 9 to 10% N makes it a fertilizer. The carrier of the nitrogen is the proteinaceous fraction of the corn grain; several dipeptides in this fraction comprise the active ingredient that imparts some preemergence herbicidal activity. Research suggests that the herbicidal activity is greater in dry environments than in areas where soil moisture for plant growth is adequate. Product application rates for turf are 10 to 20 lbs of corn gluten meal per 1000 ft2 applied twice a year (equal to approximately 2 to 4 lbs of N per 1000 ft2 per year) with some products suggesting higher rates. Studies conducted at the University of Massachusetts indicate that crabgrass control using corn gluten provided no advantage over maintaining a properly fertilized lawn regardless of whether the fertilizer material used was organic or synthetic. Corn gluten is considered to be organic.

dicamba Chemical class Mode of action Application timing benzoic acid disrupts growth by mimicking naturally occurring plant hormones. postemergence Controls many broadleaf weeds, especially red sorrel, dandelion, violets, plantains, chickweed, ground ivy, buttercup and woodsorrel. Formulated alone and in premixed combinations with other broadleaf herbicides. Susceptible weeds curl and twist soon after application. Drift to desirable plants, particularly flowers, ornamentals, and other broadleaf plants should be prevented. Dicamba leaches readily into the soil and is soil active, therefore applications within the drip line of trees should be avoided.

dimethenamid Chemical class Mode of action Application timing chloroacetanilide/chloroacetamide inhibits very long chain fatty acid synthesis preemergence Controls annual bluegrass, crabgrass, downy brome, yellow foxtail, fall panicum, sandbur, bittercress, carpetweed, lambsquarters, pigweed, puslane, common ragweed, shepherd’s-purse, spurge, willowherb, kyllinga and yellow nutsedge. Dimethenamid is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

dithiopyr Chemical class Mode of action Application timing pyridine inhibits cell division. preemergence Controls annual grasses, including annual bluegrass, barnyardgrass, crabgrass, downy brome, yellow foxtail and sandbur. Also provides preemergence control of several broadleaf weeds including bittercress, carpetweed, henbit, black medic, pineappleweed, purslane, shepard’s-purse, corn speedwell, spurge, yellow woodsorrel and creeping woodsorrel. Enters the plant through shoots and roots. Also provides early postemergence crabgrass control when applied before the 3-leaf growth stage.

ethofumesate Chemical class Mode of action Application timing not classified unkown, evidence suggests inhibition of leaf wax formation. preemergence and postemergence Utilized primarily in turf for postemergence control of annual bluegrass. Absorbed by emerging roots and shoots, and is translocated to leaves. Postemergence applications are somewhat poorly absorbed by leaves with thick, well-developed cuticles. Also provides preemergence control of barnyardgrass, common chickweed, crabgrass, purslane and yellow foxtail, and some yellow nutsedge suppression. Ethofumesate is not prone to leaching.

fenoxaprop-ethyl Chemical class Mode of action Application timing aryloxyphenoxyprionate inhibits biosynthesis of fatty acids in sensitive plants postemergence Controls annual grassy weeds, especially large and smooth crabgrass, goosegrass, barnyardgrass, yellow foxtail, sandbur and Japanese stiltgrass. Application rate depends on weed growth stage. Some broadleaf herbicides when tank-mixed with or applied within a certain period of time can reduce the efficacy of fenoxprop as a result of herbicide antagonism. Can be tank-mixed with preemergence crabgrass herbicides to obtain residual control. Drought stress can significantly reduce efficacy. No soil activity.

ferric-HEDTA Chemical class Mode of action Application timing not classified iron toxicity postemergence Ferric-HEDTA is a selective broadleaf herbicide. It is effective at cooler temperatures, rain-fast in a short period of time and results can be seen in as little as 24 to 48 hours. Ferric-HEDTA is quickly absorbed by the leaf tissue and transported down to the root. The leaf tissue turns black or brown and death the of the weed follows.

forasulam Chemical class Mode of action Application timing sulfonanalide inhibits biosynthesis of certain essential amino acids postemergence Controls bedstraw, common chickweed, mouse-ear chickweed, white clover, dandelion, dandelion, fleabane, groundsel, prostrate knotweed, shepherd’s-purse and spurge.

fluroxypyr Chemical class Mode of action Application timing pyridine disrupts growth by mimicking naturally occurring plant hormones. postemergence Broad-spectrum material, especially effective for chickweed, cinquefoil, creeping woodsorrel, dandelion, ground ivy, henbit, plantain, purslane, white clover, wild strawberry, and yellow woodsorrel. Either formulated alone and in pre-mixed combinations with other broadleaf herbicides. Absorbed by roots and shoots and is strongly translocated within the plant. Induces an epinastic (leaf curling) response and death occurs in days or weeks.

glufosinate-ammonium Chemical class Mode of action Application timing not classified causes metabolic changes that disrupt photosynthesis. postemergence Glufosinate-ammonium is a non-selective herbicide. Not translocated. Often poor to fair control of some perennial weeds. No soil activity.

glyphosate Chemical class Mode of action Application timing phosphonoglycine inhibits biosynthesis of certain essential amino acids postemergence Glyphosate is a non-selective herbicide. Strongly translocated and therefore very effective for perennial weeds. Symptoms include yellowing, starting with the youngest plant tissue, and progressing toward the oldest. Binds strongly to soil and does not leach. Glyphosate is not soil active.

halosulfuron Chemical class Mode of action Application timing sulfonylurea inhibits biosynthesis of certain essential amino acids postemergence Halosulfuron is utilized in cool-season turf primarily for the control of yellow nutsedge. Yellow nutsedge is best treated in the three- to eight-leaf stage of growth. The addition of a non-ionic surfactant is required. Halosulfuron is degraded by microbial activity in the soil and has a low potential for leaching.

isoxaben Chemical class Mode of action Application timing amide inhibits the biosynthesis of cellulose, disrupts root and hypocotyl development. preemergence Controls a wide range of broadleaf weeds including black medic, carpetweed, dandelion, henbit, plantain, purslane, red sorrel, spurge, white clover, and yellow woodsorrel. The only compound available exclusively for preemergence control of broadleaf weeds in cool-season turf.

mesotrione Chemical class Mode of action Application timing triketone disrupts carotenoid synthesis. preemergence and postemergence When applied postemergence, mesotrione controls many broadleaf weeds including broadleaf plantain, carpetweed, common chickweed, clover, henbit, horseweed, purslane, purslane speedwell and yellow woodsorrel. Will provide postemergence control of creeping bentgrass, nimblewill, and yellow nutsedge as well. Also indicated for preemergence control of barnyardgrass, crabgrass, yellow foxtail and broadleaf annual weeds. Can be applied at the time of cool-season turf establishment for preemergence control. Symptoms in susceptible weeds include bleaching followed by necrosis. Mesotrione is a synthetic analogue of the alleochemical leptospermone, which is produced by the roots of the “bottle brush” plant (Callistemon citrinus). Classified as a Reduced Risk pesticide by the US Environmental Protection Agency (EPA), for information visit https://www.epa.gov/.

oxadiazon Chemical class Mode of action Application timing protox inhibitor inhibits chlorophyll production, results in rapid destruction of cell membranes. preemergence Primarily controls annual grasses (barnyardgrass, crabgrass and goosegrass) but also controls several broadleaf weeds (bittercress, carpetweed, smartweed, spurge, yellow woodsorrel). Strongly adsorbed by soil colloids and therefore is not prone to leaching.

pendimethalin Chemical class Mode of action Application timing dinitroaniline interferes with cell division preemergence Primarily used for preemergence control of crabgrass and other annual grasses including barnyardgrass, annual bluegrass, yellow foxtail, goosegrass and sandbur.  Also controls several broadleaf weeds including carpetweed, common chickweed, henbit, prostrate knotweed, purslane, spurge and yellow woodsorrel. Pendimethalin is not prone to leaching

penoxsulam Chemical class Mode of action Application timing sulfonamide inhibits biosynthesis of certain essential amino acids. postemergence Controls bittercress, broadleaf plantain, chickweed, dandelion, ground ivy, white clover and yellow wood sorrel. Formulated alone and in combination with other selective herbicides on fertilizers and straight granules. Accepted for review and registration under the Reduced Risk Pesticide Initiative of the US Environmental Protection Agency (EPA), for information visit https://www.epa.gov/.

phenoxy herbicides (2,4-D, 2,4-DP/dichlorprop, MCPA, MCPP/mecoprop) Chemical class Mode of action Application timing growth regulator disrupt growth by mimicking naturally occurring plant hormones. postemergence The phenoxy herbicides control a wide range of broadleaf weeds. Systemic herbicides, but relatively slow acting. General symptoms on susceptible weeds include the twisting and curling of leaves and stems soon after application. Avoid application in hot weather. Products containing 20% or more 2, 4-D are classified as Restricted Use in Massachusetts. MCPA is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

prodiamine Chemical class Mode of action Application timing dinitroaniline interferes with cell division. preemergence Provides preemergence control of crabgrass, goosegrass, annual bluegrass and other annual grasses. Also controls several broadleaf weeds including carpetweed, chickweed, henbit, purslane, spurge and yellow woodsorrel. Low water solubility and is strongly adsorbed to soil, therefore not prone to leaching.

pyraflufen-ethyl Chemical class Mode of action Application timing phenylpyrazole inhibits chlorophyll production, results in rapid destruction of cell membranes. postemergence Controls carpetweed, chickweed, curly dock, dandelion, pineappleweed, purple deadnettle, purslane, round mallow, smartweed and spurge. Contact herbicide. Formulated alone and in premixed combinations with other broadleaf herbicides.

quinclorac Chemical class Mode of action Application timing quinoline carboxylic acid unknown, thought to inhibit cell wall biosynthesis and mimic natural plant hormones. preemergence and postemergence When applied postemergence, provides control of crabgrass, yellow foxtail, barnyardgrass, white clover, black medic, dandelion and speedwell. Also provides preemergence control of crabgrass and other annual grasses. Does not control goosegrass. Absorbed by foliage and roots and is translocated throughout the plant. Formulated alone and in premixed combinations with other broadleaf herbicides. Postemergence treatments require addition of a methylated seed oil, crop oil concentrate or high quality surfactant for best control. Can be used before or after seeding or overseeding of cool-season turfgrasses for the control of crabgrass and other annual grasses. This compound should be used to control crabgrass before the 2-tiller and after the 5-tiller stage of growth.

siduron Chemical class Mode of action Application timing substituted urea root growth inhibitor; disrupts cell division. preemergence Controls barnyardgrass, crabgrass, downy brome, and yellow foxtail. Does not control annual bluegrass, chickweed, clover, goosegrass and plantain. Either formulated alone or on turf starter fertilizers. Unlike many other preemergence herbicides, siduron can be applied at time of seeding, on seedling turf and on sod to be harvested.

sulfentrazone Chemical class Mode of action Application timing protox inhibitor inhibits chlorophyll production, results in rapid destruction of cell membranes. preemergence and postemergence Provides postemergence control of broadleaf weeds including carpetweed, common chickweed, mouse-ear chickweed, dandelion, henbit, lambquarters, narrowleaf plantain, Pennsylvania smartweed, purslane, spurge, star-of-bethelem, speedwell, yellow woodsorrel and creeping woodsorrel. Can be used to control or suppress yellow nutsedge and kyllinga. Formulated alone and in premixed combinations with other broadleaf herbicides. Sulfentrazone is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

topramezone Chemical class Mode of action Application timing pyrazolones disrupts carotenoid synthesis. postemergence Provides effective control of barnyardgrass, large and smooth crabgrass, yellow foxtail,  fall panicum and Japanese stiltgrass. Very effective on goosegrass.

triclopyr Chemical class Mode of action Application timing pyridine disrupts growth by mimicking naturally occurring plant hormones. postemergence Provides effective control of poison ivy, ground ivy, wild violets, and other difficult-to-control perennial weeds. Absorbed by roots and shoots and readily translocated throughout the plant. Formulated alone and in premixed combinations with other broadleaf herbicides. The potential for leaching decreases with increasing soil organic matter and when conditions are favorable for soil microbial activity.

Table 12. Common herbicide products and their active ingredients

Herbicide product	Active ingredient(s)
Acclaim Extra	fenoxaprop-p-ethyl
Armor Tech CGC (40 & 40WP)	dithiopyr
Armor Tech Quin Pro 75DF	quinclorac
Balan 2.5G	benefin
Barricade (4FL, 65WG, on-fertilizer formulations)	prodiamine
Basagran T&O	bentazon
Bensumec 4LF	bensulide
Calvalcade PQ	prodiamine and quinclorac
Cavalcade 65WDG	prodiamine
Defendor	florasulam
Dimension (2EW, EC, Ultra 40WP, on-fertilizer formulations)	dithiopyr
Dismiss	sulfentrazone
Drive (75DF, XLR8)	quinclorac
Echelon 4SC	prodiamine and sulfentrazone
Eject 75DF	quinclorac
Fiesta	ferric HEDTA
Finale	glufosinate
Gallery	isoxaben
Guardrail 65WDG	prodiamine
Halosulfuron Pro	halosulfuron
Jewel	oxadiazon
Kade 65 WDG	prodiamine
Knighthawk	prodiamine
Manage	halosulfuron
Pendulum (2G, 3.3EC, AquaCap)	pendimethalin
PoaConstrictor	ethofumesate
Pre-M (3.3EC, Aqua-Cap, on-fertilizer formulations)	pendimethalin
Pre-San Granular (7G, 12.5G)	bensulide
PrimeraOne Prodiamine 65WDG	prodiamine
PrimeraOne Quinclorac 75DF	quinclorac
PrimeraOne Prodiamine 65WDG	prodiamine
Proclipse 65WDG	prodiamine
Prograss	ethofumesate
Prograss SC	ethofumesate
Pylex	topramezone
Quali-Pro Dithiopyr 40WSB	dithiopyr
Quali-Pro Prodiamine 65WDG	prodiamine
Quali-Pro Quinclorac 75DF	quinclorac
Quin Pro	quinclorac
Resolute (4L, 65WDG)	prodiamine
Resolute (65WG, 4L)	prodiamine
Ronstar (50WSP, FLO, G)	oxadiazon
Ronstar G	oxadiazon
Scythe	pelargonic acid
SedgeHammer	halosulfuron
SedgeHammer+	halosulfuron
Stonewall 65WDG	prodiamine
Stonewall RQ	prodiamine and quinclorac
Team (2G, Pro)	benefin and trifluralin
Tenacity	mesotrione
Tower	dimethanamid
Tupersan	siduron
Velocity SG	bispyribac-sodium
Xonerate	amicarbazone

 

1. Crabgrass and other annual grassy weeds

   The first step in managing crabgrass and other annual grassy weeds, including yellow foxtail and goosegrass, is to insure that the cultural practices previously mentioned in this section are being completed on a routine basis. Fundamental cultural practices including mowing, fertilization, irrigation, and aeration when done correctly can significantly decrease annual grassy weed infestations. Cultural practices alone will seldom control crabgrass and other annual grassy weeds completely and there is commonly a need for herbicides to produce results that are commercially acceptable. An effective crabgrass management program utilizes a preemergence herbicide, followed by a postemergence herbicide as needed in the case of less than acceptable preemergence performance or the need to control “escapes”. With the exception of sites in which there are low populations of crabgrass and other annual grasses, postemergence herbicides should not be relied on as the sole control measure. In some situations, preemergence application can be split with 50% of the use rate being applied during the normal application window and the remaining 50% applied 4 to 6 weeks later.
   1. Preemergence materials
      Preemergence herbicides for the control of crabgrass and other annual grasses are applied in early spring. Applications in most areas of Massachusetts should be completed before Forsythia flowers drop or by approximately the first week in May, depending on prevailing weather conditions. Preemergence herbicides are available in sprayable and on-fertilizer formulations. These products need to be watered in to be activated and with the exception of very few materials (e.g. siduron, mesotrione), reseeding of turf cannot be done for three to four months after application. Refer to the product label for specific instructions in regard to safe reseeding intervals. Many annual broadleaf weeds can also be managed with preemergence herbicides.
       

      Active Ingredient	Trade Name(s)	Comments
      benefin	Balan 2.5G, Team 2G (combination with trifluralin), on-fertilizer formulations
      bensulide	Bensumec 4LF, Pre-San Granular (7G, 12.5G), on-fertilizer formulations
      corn gluten meal	Many formulations available	Corn gluten products are 9-10% N by weight and should be factored into fertility program.
      dithiopyr	Armortech CGC 40, Crab and Spurge Preventer, Dimension (2EW, EC, Ultra 2SC, Ultra 40WP, Ultra WSP), Dynamo 40WSP, Lifeguard, Quali-Pro Dithiopyr 40WSB, on-fertilizer formulations
      dimethenamid	Tower
      mesotrione	Tenacity	Can be used at the time of seeding or overseeding of cool-season turf.
      oxadiazon	Ronstar (50WSP, FLO, G) Quali-Pro Oxadiazon 2G, Starfighter (3.17F, 2G), on-fertilizer formulations
      pendimethalin	Pendulum (2G, 3.3EC, AquaCap), Pre-M 3.3EC, on-fertilizer formulations (Halts, Pre-M)
      prodiamine	Barricade (4FL, 65WG), Cavalcade 65WDG, Echelon 45SC (combination with sulfentrazone, Guardrail 65WDG, Knighthawk, Quaili-Pro Prodiamine 65WDG, Stonewall 65WDG, Primeone Prodiamine 65WDG, Proclipse (4F, 65WDG), Resolute 65WDG, on-fertilizer formulations
      quinclorac	Armortech Quin Pro 75DF, Eject 75DF, Drive (75DF, XLR8), PrimeraOne Quinclorac 75DF, Quali-Pro Quinclorac 75DF	Can be used before or after seeding or over-seeding of cool-season turfgrasses for the control of crabgrass and other annual grasses.
      siduron	Tupersan (50WP, 4.6G), on-fertilizer formulations	Can be used at the time of seeding or overseeding of cool-season turf.

   2. Postemergence materials
      Another strategy for managing crabgrass and other annual grasses is the use of postemergence herbicides. The most effective and economical control programs use a preemergence herbicide and a postemergence herbicide, if needed, to clean-up weed escapes.
       

      Active Ingredient	Trade Name(s)	Comments
      fenoxaprop-ethyl	Acclaim Extra
      dithiopyr	Armortech CGC 40, Crab and Spurge Preventer, Dimension (2EW, EC, Ultra 2SC, Ultra 40WP, Ultra WSP), Dynamo 40WSP, Lifeguard, Quali-Pro Dithiopyr 40WSB, on-fertilizer formulations
      quinclorac	Armortech Quin Pro 75DF, Eject 75DF, Drive (75DF, XLR8), PrimeraOne Quinclorac 75DF, Quali-Pro Quinclorac 75DF, plus several combinations with broadleaf herbicides.	Can be used before or after seeding or over-seeding of cool-season turfgrasses for the control of crabgrass and other annual grasses.
      mesotrione	Tenacity

2. Broadleaf Weeds

   1. Preemergence materials
      Preemergence herbicide application for the control of broadleaf weeds in turf is not a common practice. Most often these weeds are controlled with postemergence broadleaf herbicides discussed in section 2B below. There are, however, some situations in which preemergence herbicides can be incorporated into an effective weed management program. Preemergence herbicides used for the control of crabgrass and other annual grass weeds (section 1A above) will effectively control many annual broadleaf weeds. The herbicides isoxaben and mesotrione are labeled for the preemergence control of many annual and perennial broadleaf weeds. These products need to be applied before weeds germinate.
       

      Active Ingredient	Trade Name(s)	Comments
      isoxaben	Gallery	The only material available exclusively for preemergence control of broadleaf weeds in cool-season turf.
      benefin, bensulide, dithiopyr, mesotrione, oxadiazon, pendimethalin, prodiamine, siduron	Several preemergence herbicides used for the control of crabgrass and other annual grass weeds will effectively control many annual broadleaf weeds – see Section IA above.

   2. Postemergence
      Annual and perennial broadleaf turf weeds can be managed with postemergence herbicides. Sprayable formulations are the most common but granular and on-fertilizer formulations are also available. Broadleaf weeds can be treated at any time of the growing season as long as weeds and cool-season turfgrasses are actively growing. Applications are best done in the fall and spring, avoiding periods when cool-season turfgrasses are heat and/or drought stressed. Winter annual broadleaf weeds that occur in late summer and fall turf seedlings can be controlled with broadleaf herbicides after the turf has received a minimum of three mowings. Postemergence broadleaf herbicides include the phenoxy herbicides (2,4-D, 2,4-DP/dichlorprop, MCPA, MCPP/mecoprop), carfentrazone, clopyralid, dicamba, fluroxapyr, quinclorac, penoxsulam, pyraflufen-ethyl, sulfentrazone and triclopyr. Broadleaf herbicide products are formulated as a single herbicide or in combinations of two, three or four herbicides, as summarized in Table 13:
      
      Table 13. Active ingredients in commercially-available postemergence herbicide products.
      Click to download Table 13

3. Yellow Nutsedge

   Yellow nutsedge is one of the most difficult to control weeds in turf. Applications for yellow nutsedge should be made soon after spring and early summer emergence with application completed before the summer solstice. Heavy infestations can be treated with glyphosate.

   Active Ingredient	Trade Name(s)	Comments
   bentazon	Basagran T&O, Nutgrass Nihilator	2 applications commonly needed. Bentazon is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.
   dimethanamid	Tower	Preemergence material for application where perennial stands of yellow nutsedge are known to exist.
   halosulfuron	Manage, SedgeHammer, Halosulfuron Pro	Addition of a non-ionic surfactant is required.
   mesotrione	Tenacity
   sulfentrazone	Dismiss, Q4 Plus, Surge, Eschelon 4SC (combination with pendimethalin)	Sulfentrazone is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.

4. Annual Bluegrass

   Annual bluegrass is a winter annual with perennial biotypes being common in certain turf situations. Annual bluegrass germination occurs primarily in very late summer and fall. Ethofumesate and bispyribac-sodium are labeled for selective postemergence control in certain cool season turfgrass species. Annual bluegrass can be controlled with preemergence crabgrass herbicides when those materials are applied in late summer and fall before germination.

   Active Ingredient	Trade Name(s)	Comments
   ethofumesate	Prograss, Poa Constrictor	Applications are best made in the fall and 2 to 3 repeat applications at 3 to 4 week intervals may be needed.
   bispyribac-sodium	Velocity SP, Velocity SG	Labeled for use only on golf courses and sod fields.
   benefin, bensulide, dithiopyr, mesotrione (suppresses growth), prodiamine, pendimethalin	Several preemergence herbicides used for the control of crabgrass and other annual grass weeds will effectively control or suppress annual bluegrass – see Section IA above.

5. Non-selective herbicides for turf renovation

   Non-selective herbicides are used to kill existing turfgrass, weeds and other vegetation before turf renovation. Using any of these herbicides for the spot-treatment of existing weeds in established turf is not recommended as turf injury or death will occur in the treated areas. The herbicide glyphosate is strongly translocated and therefore is the best option of the non-selective herbicides for use prior to turf renovation. Glufosinate is not as strongly translocated as glyphosate and therefore can be weak on perennial weeds. Glufosinate can be used when the weed population is comprised of only annual weeds. Pelargonic acid, acetic acid, citric acid, clove oil and d-limonene are contact in nature and will not control perennial weeds making them inappropriate to use in turf renovation.

   Active Ingredient	Trade Name(s)	Comments
   glufosinate	Finale	May be weak on perennial weeds.
   glyphosate	Roundup Pro Max, GlyphoMate 41, many others
   pelargonic acid	Scythe	Not appropriate for turf renovation.
   acetic acid, citric acid, clove oil, d-limonene	various materials formulated alone or in combination	Not appropriate for turf renovation.

6. Selective perennial grass control

   Turf areas are often plagued by undesirables: cool-season and warm-season perennial grasses that disrupt uniformity and can result in an unacceptable turf. These grasses include creeping bentgrass, nimblewill, orchardgrass, paspalum, purpletop, quackgrass, tall fescue, timothy and zoysiagrass. A few herbicides are labeled for the selective control of certain grasses, however, most often the area is best treated with glyphosate and reestablished by seeding or sodding.
    

   Active Ingredient	Trade Name(s)	Comments
   chlorosulfuron	Corsair	Controls tall fescue, perennial ryegrass and annual ryegrass.
   glyphosate	Roundup Pro Max, GlyphoMate 41, many others	Spot or broadcast treatment on all species.
   mesotrione	Tenacity	Controls creeping bentgrass and nimblewill.
   metsulfuron	Manor, MSM	Controls perennial ryegrass.

 

White grubs

Several species of grubs occur in New England. The most widespread species is the Japanese beetle. The European chafer is found in several locations in eastern and western Massachusetts (especially “inside” Route 495, and along the coast as far north as mid-coast Maine). The Oriental beetle is active in Connecticut, Rhode Island, coastal Massachusetts, and along the Connecticut River Valley. As a general rule European chafers and Oriental beetles are harder to manage than Japanese beetles. In addition, there have been a few occasions where Asiatic garden beetles have caused damage, although the damage from this species is usually most severe in less well maintained turf.

Management of white grubs is most efficient when the specific population causing turf damage is identified. Because some insecticides are less effective against Oriental beetle or European chafer, species identification has become increasingly important for management decisions. Identification of a white grub is made based on its raster pattern. A raster is the pattern of bristles on the underside of the last abdominal segment of the grub. Refer to Figure 1 for illustrations of the various grub rasters.

Damage - Damage from white grubs initially resembles drought stress, with general thinning and/or yellowing of turf. In some circumstances, skunks, raccoons or birds may tear apart turf in infested areas to feed on grubs near the surface, often dramatically increasing the extent of the damge.

Scouting - Use a shovel or spade to cut three sides of a square in the turf anywhere from 6” to 12” on a side, 3” to 4” deep. Flip the sod back on the uncut (fourth) side, turf side down, and use a hand trowel to dislodge soil in the soil/thatch interface. Alternatively, you can use a golf course cup cutter (4.25” diameter) to collect soil samples. The cream colored grubs will be very visible against the dark soil background. Place grubs in a container and count them after removing all of them from the sample area. Convert the area to square feet (e.g., 6” sides = 0.25 sq. ft.). Note that a standard golf course cup cutter is equivalent to 0.1 sq. ft. Take several samples and then calculate the average number of grubs found. For ease in averaging, make all sampling cuts the same size.

Note that weather and soil moisture conditions will affect grub behavior and movement. In very dry or very warm conditions, grubs will move deeper in the soil profile (so sampling holes must be dug deeper). In very moist conditions, grubs will either be closer to the surface or will move laterally to higher or better draining locations.

In the autumn or in early spring, grubs respond directly to soil temperatures. European chafers tend to remain in the root zone later in the fall and return to the root zone earlier in the spring than other species of grubs. Japanese beetles and Oriental beetles tend to respond to daily temperature fluctuations. On warm days in late fall or early spring, the grubs will move up into the root zone and feed, while on cold days or after very cold nights, grubs will remain several inches below the soil surface.

Figure 1. Raster patterns of turf-infesting grubs (drawings not to scale).

Adapted from Haruo Tashiro: Turfgrass Insects Of The United States And Canada. Copyright (©) 1987 by Cornell University. Used by permission of the publisher, Comstock Publishing Associates, a division of Cornell University Press.

Black turfgrass ataenius

The black turfgrass ataenius (BTA) is a small species of white grub. The BTA life cycle is quite different from other grubs. It spends the winter in the adult stage, and females lay eggs in late spring. These eggs hatch into small grubs that feed throughout the month of June and into early July. In many years the grubs pupate and the new adults lay eggs in late July for a second generation. Black turfgrass ataenius is only a pest of concern on golf courses and other very low-mown sports turf (i.e. tennis, croquet) in New England.

Damage - Damage resembles that of other white grubs. Roots can be destroyed and damaged turf may peel back easily. Damage sometimes is more severe in areas with high levels of soil organic matter.

Scouting - Grubs can be found by taking a soil sample, cutting a small section of turf to a depth of 2” to 4” and inspecting the soil for tiny (less than 0.5”) grubs. Adults often are seen on the surface of putting greens, especially on warm sunny days in the spring. To scout for adults, force them to the surface with a soapy flush (irritating drench).

Chinch bugs

The hairy chinch bug (Blissus hirtus), the most common species in the Northeast, prefers ryegrass and fescues but will attack other lawn grasses as well. Adult chinch bugs are about 1/5-inch long and black with white markings on the wings. Nymphs (immature stages) have the same general shape as the adult but lack wings and often have red or orange markings.

Damage - Damage is often confused with drought stress, and normally occurs during July and early August. Injury (wilted or browned out areas) is most severe in sandy soils and in sunny areas. Small patches gradually coalesce into large areas of wilted or dead turf. Chinch bug-damaged turf may not recover in September when other turf comes out of drought dormancy.

Scouting - Use a cup cutter or similar device to remove cores of turf about 4” to 6” in diameter, place the cores in a bucket, and fill the bucket with water. Wait about five minutes. Chinch bugs (and big-eyed bugs, a beneficial insect) will float to the surface of the water. Chinch bugs can also often be observed directly by inspecting the foliage and thatch.

Sod webworms and cutworms

Sod webworms and cutworms are moths that cause damage to turf in the caterpillar stage of their development. In webworms, the color pattern varies with the species and plant source, but most are greenish, grayish, or brownish, and usually have dark spots scattered along the body. The black cutworm, the most common cutworm species in New England, is normally dark gray or nearly black but may have a hint of green in the stripes. Webworms are more likely to cause damage in lawn settings, while cutworms are more frequently encountered on golf courses and other closely-mown turf areas.

Damage - Damage usually begins as small discrete brown patches which can coalesce into larger areas of damage. A finger inspection of the infested area will sometimes reveal sod webworm burrows lined with green frass (insect excrement). Cutworms are often active around aerification holes on golf course greens.

Scouting - Prepare an irritating drench by mixing one fluid ounce of lemon scented dish detergent in one to two gallons of water in a pail. Spread this solution over an area about 2’x2’. Wait three to five minutes. Webworms and cutworms (and earthworms) will be irritated by the soapy solution and will crawl to the surface of the turf area. Note: The soapy solution can burn turf, so on sunny days, and on bentgrass or Poa annua turf, rinse the sample area with clear water after you have completed the insect count.

Annual bluegrass (Hyperodes) weevils 


The annual bluegrass weevil (Listronotus maculicollis, also sometimes referred to as the Hyperodes weevil) is a significant golf course pest in many parts of the Northeast and Mid-Atlantic states. Annual bluegrass weevil is only a pest of concern on golf courses and other very low-mown sports turf (i.e. tennis, croquet), and is not found in higher-cut turf. The insect overwinters in the adult stage. Adults emerge in the spring and migrate from overwintering sites to lay eggs in turfgrass leaf sheaths (almost exclusively annual bluegrass). Following egg hatch, feeding of the tiny larvae becomes increasingly more aggressive up until pupation and the final transition to the adult stage. The annual bluegrass weevil may complete two or three generations per year in New England.

Damage - The most severe damage normally occurs from early June through mid-August, with moderate damage possible at other times of the summer as well. Damage begins as small yellow patches, often along the edges of fairways or on collars around greens, and spreads into large areas. Severely damaged areas take on a water-soaked appearance. Damage is most often restricted to short cuts (fairways and shorter) of annual bluegrass. However, field observations have confirmed that annual bluegrass weevils will feed on creeping bentgrass under certain conditions.

Scouting - Use a cup cutter or similar device to collect cores of 4” to 6” diameter. Loosely break up the soil in the cores and place the loosened soil and all plant matter in a dish pan or similar plastic container. Fill the container with lukewarm water and wait about five minutes. Weevils in all stages of development (except eggs) will float to the surface of the water, where they can be counted. You can also use a saturated salt solution to force larvae to the surface of the water. Large larvae and pupae are visible in turf samples without using flotation techniques. A leaf blower can be reversed and used to vacuum adults from an infested area. Insert a gauze bag in the end of the tube to collect the insects.

Bluegrass billbugs


Bluegrass billbugs can cause serious damage to lawns, particularly those which are predominantly bluegrass. They occur sporadically in New England. Billbug adults are black beetles with very elongated “snouts.” The total body length is about 1/4-to 3/8 -inch and the tail end is somewhat pointed. Despite the name, bluegrass billbugs will feed and even thrive on most cool season turf species.

Damage - Look for evidence of damage along the edges of paved areas in mid- to late July. Bluegrass billbug infested areas begin to wilt but do not respond to watering. As larvae feed in the stems and on the roots, damaged turf can be tugged loose with very little force. Infested areas will brown out entirely in a matter of several days. Damage is usually most severe in July and August. Damaged turf often does not recover in September and renovation may be necessary.

Scouting - Larvae can be found by digging into the root/thatch interface with a hand trowel and inspecting the area. Accumulations of “sawdust-like” material (billbug excrement) will be found in the thatch.

Invasive craneflies


The European cranefly (Tipula paludosa) is an invasive species that has become a pest in western New York and southern Ontario (Niagara Peninsula). The common (or marsh) cranefly (Tipula oleracea) is another invasive species that has become established in western New York and Long Island. T. oleracea has been recently reported from several areas in Massachusetts, including Martha’s Vineyard, Cape Cod, and several suburbs south and west of Boston. Adults (which resemble large mosquitoes) emerge in late August or September. Females lay 200 to 300 black eggs near the soil surface. Small larvae feed from October through February, (when temperatures are mild). Larvae normally feed in the top inch of the soil, feeding on roots and root hairs. Larvae can be found within 3 inches of the surface, even in the winter months (larvae wriggle to the surface and can be seen projecting out of the turf. They pupate mid-March to mid-April. New adults emerge, lay eggs, and the resulting larvae feed through the summer months. They pupate in mid- to late-August, and adults emerge in September to complete the cycle.

Damage - Damage may resemble grub damage, especially in higher cut turf, because the larvae destroy roots. Animals and birds may cause turf damage while foraging for the larvae, as is also frequently the case with white grubs. On closely-mown turf, such as tees and greens, the damage might resemble cutworm feeding or aerification holes with the edges nibbled away.

Scouting - Watch for flights of ‘large mosquitoes’ in the spring and late summer. For larvae, take a soil sample (a cup cutter plug to a depth of about six inches often works well) and break the soil apart. The larvae are olive green to dark brown and quite active, often within the top inch of soil or in the thatch. Larvae can occasionally be seen at the surface feeding on turfgrass foliage on warm, humid nights.

Ants


Ants can be beneficial because they are often predators of other insects.

Damage - Several species of ants occur in turf and can disrupt the surface when building mounds. The turfgrass ant (Lasius neoniger) forms numerous mounds of 0.5” to 2.0” diameter on closely mown turfgrass, such as golf course fairways. These mounds are unsightly and can dull or damage mower blades. In the process of building tunnels, ants can break off roots and root hairs or increase desiccation of the soil.

Scouting - Rough estimates of ant activity can be obtained by counting the number of mounds in a given area.

Insect threshold levels

The key to any Integrated Pest Management program is the identification of response (or “action”) threshold levels. There is no single magic number which will be appropriate for all turf situations. Thresholds are given as first approximations only, and should be used only as guides.

Several agronomic factors will have a direct effect on the number of insects a turf area can tolerate. Some of these factors include the species of turfgrass, the height of cut, availability of irrigation (and resulting soil moisture distribution), use patterns (including traffic and other sources of compaction), and the fertility program. The thresholds presented in Table 14 are for unirrigated turf and are provided as guidelines only. In most cases, irrigated turf can sustain higher insect populations without showing stress.

Actual response thresholds will depend on the overall vigor of the turf being managed, the use of the turf, the presence of secondary pests such as skunks and raccoons, and the quality expected.

Table 14. Approximate threshold levels* for turfgrass insect pests.

INSECT	Approximate threshold per sq. ft.
Japanese beetle	8 to 15 larvae
Oriental beetle	8 to 15 larvae
Masked chafer	8 to 15 larvae
European chafer	3 to 8 larvae
Asiatic garden beetle	12 to 20 larvae
May beetle (Phyllophaga)	2 to 4 larvae
Black turfgrass ataenius	15 to 80 larvae
Annual bluegrass weevil	10 to 80 larvae
Bluegrass billbug	No good estimate available
Chinch bug	30 to 50 nymphs
Sod webworm, cutworm	No good estimate available
* Please note that actual threshold levels will vary based on site conditions, management practices, and/or turf use.

 

Paenibacillus popilliae


Milky disease (sometimes called “milky spore”) is caused by a bacterium, Paenibacillus popilliae, which occurs naturally in soil and affects the digestive system of Japanese beetle grubs. According to tests conducted in New Jersey, there is no evidence that milky disease is effective against other species of grubs. It is relatively nontoxic to people and other “non-target” organisms.

Milky disease is somewhat inconsistent in the Northeast. More turf managers have reported success with milky spore in the sandy soils of southeastern Massachusetts than in other areas. In any case, the milky disease organism may take several months to become effective; in some cases it may remain effective for three to five years. The discovery of “milky looking” grubs while monitoring may indicate that a milky spore application has taken hold. However, sporadic natural infestations of milky disease do occur, so the mere presence of milky grubs does not necessarily indicate that an application will be effective or consistent. Studies conducted in Kentucky indicate that there is no evidence that commercial preparations of P. popilliae increase the incidence of milky disease significantly in field populations.

Bacillus thuringiensis (Bt)

Bacillus thuringiensis (Bt) is a bacterium that causes disease in several kinds of insects. Recently several new strains of Bt have been identified that are quite specific in the kinds of insects they attack. Because they are more specific, they can be used in a turf setting without disrupting some of the natural enemies, such as predator beetles and mites, which are present.

The strain which is effective against caterpillars (particularly cutworms and sod webworms) is known as the “kurstaki” strain, and is available commercially (some products are not registered for turf use, so check the label carefully before purchasing or using any formulations). The material is formulated to be applied to the turf with a hydraulic sprayer. As with several of the biological control agents currently available, Bt kurstaki is most effective when directed against small stages of caterpillars (less than 0.25” long). Bt kurstaki will not kill caterpillars immediately after exposure, but it will paralyze the gut and digestive system very quickly after the insect ingests the material, so feeding activity stops soon after exposure. Currently, there are no published field trials available reporting the effectiveness of Bt kurstaki for caterpillar control in turf.

A newer strain of Bt (japanensis, or ‘buibui’) appears very promising based on field trials targeting Oriental beetle and Japanese beetle grubs, but looks less effective against European chafers and Asiatic garden beetles. It must be applied when grubs are just beginning to hatch (usually early to mid-August). This strain is not currently under commercial development.

Beauveria bassiana


Beauveria bassiana is a fungus that occurs naturally in New England turfgrass, and is favored by wet conditions in the spring. The fungus is a natural enemy of chinchbugs. B. bassiana is sometimes available commercially, but no field trials have been conducted (and published) to determine whether commercial applications will reduce pest populations.

Entomopathogenic nematodes

Entomopathogenic nematodes are small, microscopic worms which attack insects. Certain species of these nematodes have proven to be quite effective against some of the surface feeding insects (cutworms, sod webworms). The preparations, consisting of live organisms, must be handled more carefully than traditional insecticides. For example, they are temperature-sensitive, so the containers must be stored in areas that will not get too hot (above 80° to 85°) and will not freeze.

Entomopathogenic nematodes can be applied through standard hydraulic sprayers (although very fine filters should be removed). However, these nematodes are very sensitive to desiccation. To maximize their effectiveness, nematodes should be applied in early morning or late afternoon (not between 10 a.m. and 2 p.m.) and should be watered in immediately. In addition, nematodes are most effective when the target insects are small.

There are several species of nematodes which are commercially available in the United States at this time. Steinernema carpocapsae is available as several trade names. Studies throughout the Northeast indicate that this species of nematode is not particularly effective against white grubs, but it can be effective against caterpillars in turf (sod webworms and cutworms). Many turf managers do not rely on nematodes for caterpillar control, however, because they tend to be inconsistent. If nematodes are used to target caterpillars, they must be applied when caterpillars are small (less than 0.25 inch long), and must be watered in with at least 0.25 inch water.

Several field studies have been conducted over the past five years, testing the effectiveness of entomopathogenic nematodes against annual bluegrass weevils (ABW). The results have been inconclusive — occasionally there appears to be a reduction in larval populations in the first generation, but the “window of opportunity” (when larvae are susceptible) appears to be about five to seven days each spring. The nematode showing the most promise is Steinernema carpocapsae, but more field testing must be completed before golf course superintendents can be confident using nematodes for ABW control.

Heterorhabditis bacteriophora (HB) is also available under many different trade names, and field trials in Massachusetts indicate that it can reduce white grub populations when used properly. However, studies conducted at Rutgers University indicate that HB is much more effective against Japanese beetle grubs than other species of grubs. When targeting grubs, nematodes must be applied when grubs are present but still small (often mid August to early September) and must be watered in with at least 0.25 inch of water.

Neem

Azadirachtin is a derivative of the neem tree, which grows in India and other tropical settings. The compound repels several kinds of insects and often causes them to stop feeding. Neem also acts as an insect growth regulator on some insects, preventing them from molting normally from one stage to the next. There is an indication that the neem compounds may sometimes reduce populations of the surface feeders (cutworms and sod webworms). Some commercial applicators report that applications of azadirachtin have been inconsistent. Also, some azadirachtin formulations are very viscous and difficult to handle in a sprayer.

Spinosad

Spinosad (Conserve) is a synthetic preparation of a soil actinomycete which is often categorized as a biological control material, even though it is synthetic and produced in large facilities. It has provided significant control of larval populations of annual bluegrass weevil in the first generation in several field trials. It must be applied as the larvae are emerging from the stems, before they reach their largest (fourth and fifth) instars. Spinosad is also very effective against caterpillars in both turf and landscape setings.

Beneficial insects in the turf setting

If a turf manager were to take a cup cutter sample from a turf area which had not been treated with insecticides for a year or two, and extracted all of the insects and other arthropods from that sample, that manager would be amazed at the diversity of arthropod life in the sample. There are countless beneficial insects and close cousins active in the thatch and upper root zone, decomposing organic matter or preying on other insects. Some of the predatory arthropods include ground beetles (most of which feed on insect eggs and small soft bodied insects, such as small caterpillars or aphids), predatory mites, spiders, and ants. Some of the decomposers include springtails (often in huge numbers), saprophytic nematodes, symphylans, and some mites. While we do not yet fully understand the role of each of these creatures, we do know that their role is crucial to thatch management, and to the overall health of the turf.

Unfortunately, some of the insecticides that are currently used in turf settings are “broad spectrum” materials, which means they kill a wide range of insects and other arthropods, including many beneficial insects. If these broad spectrum insecticides are used regularly, the balance of beneficial insects may change over time, so that fewer of the predators or decomposers remain active. As a result, pest populations can build up more rapidly following an application, because some of the natural enemies have been destroyed and are no longer available to provide a natural level of control of the target pest.

It is critical, therefore, that insecticide applications should be made only when sampling has demonstrated that a pest population has reached the threshold level, and only to areas for which infestation has been confirmed through careful monitoring.

Big-eyed bugs are naturally occurring predators that can be found in many New England turf settings. They are very effective predators of chinchbugs, but unfortunately they look very similar to chinchbugs (except for big bulging eyes), so sometimes insecticide applications are made that reduce big-eyed bug populations. These predators are not available commercially.

Endophytic turfgrass cultivars

Endophytic cultivars have within the seed and plant itself a beneficial fungus called an endophyte. The fungus is unable to live outside of the seed or plant, and so it depends upon the plant for its survival. The plant also benefits from its association with the fungus. Endophyte-enhanced cultivars tend to be vigorous even under conditions of stress such as minimal fertilization and irrigation, and exhibit a level of resistance to foliar feeding insects such as sod webworms, and in particular chinchbugs and billbugs. Endophytes impart no tolerance or resistance to root feeding insects such as white grubs. Furthermore, cultivars which contain endophytes may vary in their susceptibility or in their resistance to disease. This factor is not as clear cut as insect resistance, and will vary by cultivar as well as by disease.

At present there are some endophytic cultivars of perennial ryegrass, tall fescue, creeping red fescue, hard fescue and chewings fescue available. When repairing lawns and other areas that have been damaged by surface feeding insects such as chinchbugs, billbugs, or sod webworms, select endophytic cultivars of appropriate turfgrasses whenever possible. Keep in mind that the percent of endophyte infection in a cultivar may differ by seed lot. Also, the level of endophyte in old or improperly stored seed will decrease as the fungus loses viability. Check with a reputable seed supplier for cultivars with endophyte, as well as for level of endophyte in a particular seed lot.

Endophytic turfgrass cultivars should not be used where animals may graze. The alkaloids produced by the endophyte and the interaction of the endophyte with the plant not only impart some degree of insect resistance to the plant, but also have the potential to sicken animals that may feed upon the plant.

Some turf insecticides act very quickly while others take much longer to kill the target insect. In addition, some materials persist for several weeks and remain active, while others break down in a matter of a few days. Of the insecticides listed in these guidelines, a few work quite quickly (within one to three days) and break down within one to two weeks. These materials, often used for ‘curative’ applications, include: acephate (Orthene), and trichlorfon (Dylox). Some of the synthetic pyrethroids, like cyfluthrin (Tempo) and bifenthrin (Talstar) begin to act quickly but will persist longer if they penetrate the thatch and/or are applied to the soil.

Very few of the turf insecticides currently available for use in Massachusetts are intermediate in their “speed of efficacy” and persistence. These materials will often take three to seven days to begin to affect the target insects, but normally will remain active for three to five weeks, and sometimes even longer. Several “intermediate” materials have been taken off the market in the last few years, one that remains is carbaryl (Sevin).

Some insecticides, such as imidacloprid (Merit) or chlorantraniliprole (Acelepryn), are used for preventive insect control in areas that have a history of damage.  This use pattern is common for white grub management, but care must be taken to ensure that the material is in place and fully active when the grubs are in the most susceptible stage. These materials vary in how quickly they become active, but then normally remain active for several weeks or even months.
Please note that some listed materials have been somewhat inconsistent in their performance while others have provided similar levels of control through the years. Be sure to obtain current label information before using any insecticide.

Using insecticides preventively in an IPM program

Insecticides usually have either preventive or curative action against the pest for which they are used. Preventive materials are applied before a noticeable pest population develops. Curative materials are typically applied after populations reach a damaging level.

There are many components to an IPM program, including monitoring for pest activity, establishing tolerance levels, and considering cultural and biological management strategies whenever possible. One of the key tenets of IPM is to apply pesticides when a pest population exceeds a threshold level and only when all other avenues of control have been exhausted. In certain instances, however, preventive pesticide applications may be preferred to the alternative of waiting until a problem develops.  Part of the process in selecting and applying pesticides in an IPM program is to use application methods and materials that minimize the potential for environmental disruption.

For example, several turf insecticides [including the neonicotinoids and chlorantraniliprole (Acelepryn)] provide preventive protection against white grubs and are much less toxic than the older organophosphate materials that were used for many years. There are few cultural practices or effective biological control agents available that provide reliable control of white grub populations. Furthermore, in Massachusetts the use of the most effective curative material, trichlorfon (Dylox), is not allowed on school properties as specified in the Children and Families Protection Act (see the Pesticide Regulations section of this guide for more information). The only option for effective management of high populations of white grubs in this circumstance is preventive application with a neonicotinoid or chlorantraniliprole.

To be justified in an IPM plan, preventive insecticide applications must be based on scouting or other documentation of the potential for damaging populations from the previous season or seasons.

Insecticide resistance


There are several chemical classes of insecticides available to turf managers. Recently some turf insects (most notably, the annual bluegrass weevil) have developed resistance to certain chemical classes (in the case of the weevil, resistance to pyrethroids). This means that applications of certain products made now at rates that were effective several years ago do not kill as many insects. One of the most effective ways to delay the development of resistance is to avoid using insecticides in the same chemical class repeatedly. In most cases, you must also avoid using chemicals with the same mode of action. The Insecticide Resistance Action Committee (www.irac-online.org) has assigned “IRAC” numbers for each chemical class, and many chemical companies are putting these numbers on labels to make it easier for turf managers to incorporate this information into their decisions on chemical inventories. For example, any insecticide in the neonicotinoid class (e.g., Merit or Meridian or Arena) will have a black box with a white “4A” indicating the IRAC chemical subgroup. Carbamates (class 1A) and organophosphates (class 1B) are in the same group but listed separately because while the chemistry of the two classes of insecticides is different, the mode of action (cholinesterase inhibition) is the same.

The following information on insecticide characteristics will help turf managers avoid using the same chemical class repeatedly. Trade names referenced here are the first trade name under which the product was available in turf. Note that for some chemicals, there are many additional trade names not listed here.

Table 15. Characteristics of turf insecticides registered for use in Massachusetts.

ABW = annual bluegrass weevil; BTA = black turfgrass ataenius; ECF = European crane fly

Chemical class: ORGANOPHOSPHATE OR CARBAMATE			IRAC class: carbamate – 1A; organophosphate – 1B
Most are “older” chemicals and, as cholinesterase inhibitors, tend to be more acutely toxic to vertebrates than some of the newer compounds. There is a lot of variation in field characteristics: Some are soluble in water while others are not; some are systemic while some are not; some are quite persistent while some are not. For example, trichlorfon (Dylox) and acephate (Orthene) are very soluble in water and can break down quickly when water pH is above 7.5. Neither is very persistent in field conditions. Most other insecticides in these classes are being phased out of the turf market.
Common name	Trade name	Partial list of insects on label		Notes
acephate	Orthene	caterpillars, chinchbugs
carbaryl	Sevin	caterpillars, many beetle adults, chinchbugs, ECF		Very toxic to honeybees and other bees
chlorpyrifos	Dursban	billbug adults, caterpillars, chinchbugs, ECF		Golf course only. Actively being phased out of the market and available only as generic formulations.
trichlorfon	Dylox	white grubs		Works quickly, breaks down quickly. Susceptible to rapid breakdown with water pH above 7.0-7.2
Chemical class: PYRETHROID			IRAC class: 3
Every pyrethroid available for use on turf is virtually insoluble in water and is bound quickly to organic matter. As a result, pyrethroids are effective against insects that are active in the thatch (e.g., annual bluegrass weevil adults, black turfgrass ataenius adults, bluegrass billbug adults, caterpillars, chinchbugs, European crane fly). ABW has developed resistance to pyrethroids in some locations, particularly between Hartford, CT and metropolitan NY. Most pyrethroids begin working three to five days after application (sometimes more quickly) and remain active for three to five weeks (sometimes longer). Labels on pyrethroids sometimes change, and there may be additional products labeled for turf that are not listed here. Most pyrethroids are toxic to fish and aquatic invertebrates, and some are also toxic to bees that are exposed to direct treatments on flowering crops and weeds. Some of the pyrethroids that are used in New England are listed below. Many pyrethroids have gone “off patent” so there are many other products available with different trade names.
Common name	Trade name	Partial list of insects on label		Notes
bifenthrin	Talstar	ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF
cyfluthrin	Tempo	ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF
lambda-cyhalothrin	Scimitar	ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF
deltamethrin	Deltagard	ants, ABW adults, BTA adults, billbugs, caterpillars, chinchbugs, ECF
Chemical class: NEONICOTINOID			IRAC class: 4A
There are four neonicotinoids currently available in turf, and all of them are systemic through the roots.  Imidacloprid works much more slowly than most of the other insecticides available for turf. However, it appears to remain active for several weeks, and even a few months in some cases. Two of the neonicotinoids (chlothianidin and thiamethoxam) are also absorbed directly into leaf tissue to some degree. As a result they tend to work a little more quickly than imidacloprid and appear to be active on a slightly wider range of turf insects. None of the neonicotinoids are effective against Asiatic garden beetles. Neonicotinoids often take several days to start working, but remain active for several weeks or months (depending on the time of year they are applied). Even though imidacloprid has been on the turf market for more than 10 years, there have been no reports of resistance in any turf insects yet. There have been some implications that use of imidacloprid might be a contributing factor to colony collapse disorder in honeybees, but there are also many other possible explanations for that disorder. Care should be taken when using any neonicotinoid to avoid applications when honeybees are foraging, such as when clover or ground ivy is in bloom. In addition, some labels indicate products are toxic to aquatic invertebrates.
Common name	Trade name	Partial list of insects on label		Notes
chlothianidin	Arena	ABW, BTA, caterpillars, billbugs, white grubs
dinotefuran	Zylam			More soluble than the others, optimum use patterns still being identified. Dinotefuran is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.
imidacloprid	Merit	ABW, BTA, billbugs, white grubs		Merit went “off patent” in 2007
thiamethoxam	Meridian	ABW, BTA, caterpillars, billbugs, white grubs		Thiamethoxam is regulated under the Public Drinking Water Supply Protection Regulations in MA, see the Pesticide Regulations section of this guide for details.
Chemical class: COMBINATION PRODUCTS			IRAC class: neonicotinoid, 4A; pyrethroid, 3
Three products are now available for commercial applicators that combine a neonicotinoid and a pyrethroid. The combination provides protection against soil insects (neonicotinoid) and surface feeders (pyrethroid). Optimal timing of application depends on what the primary insect target is at a given site. (For example, if white grubs are the primary target, applications should be made just as adults become active and start laying eggs. If billbugs are the primary target, applications could be made in late May or early June to target adults as they become active.)
Trade name	Contents	Partial list of insects on label		Notes
Allectus	Merit and Talstar	ABW, BTA, billbugs, caterpillars, chinchbugs, ECF, European chafer, Japanese beetle, and oriental beetle.		available only to commercial applicators
Aloft	Proprietary blend of chlothianidin and bifenthrin	ABW, BTA, billbugs, caterpillars, chinchbugs, ECF, European chafer, Japanese beetle, and oriental beetle.		available only to commercial applicators
Maxide	Meridian and Scimitar	ABW, BTA, billbugs, caterpillars, chinchbugs, ECF, European chafer, Japanese beetle, and oriental beetle.		available for general use
Other generic combination products are also available.
Chemical class: OXADIAZINE			IRAC class: 22
There is only one product currently available in turf that is in the oxadiazine class: indoxacarb. This class has a very low mammalian toxicity and a new mode of action. It works by blocking the movement of sodium ions into nerve cells. Product labels have the same precautionary language as pyrethroids regarding toxicity to fish and aquatic invertebrates, as well as foraging honeybees. Indoxacarb is particularly effective against caterpillars and is most effective when applications are made targeting eggs and small caterpillars.
Common name	Trade name	Partial list of insects on label		Notes
indoxacarb	Provaunt	ABW larvae, caterpillars
indoxacarb	Advion	turfgrass ants (bait formulation)
Chemical class: ANTHRANILIC DIAMIDE			IRAC class: 28
This new chemical class has a totally new mode of action and has such low mammalian toxicity, the EPA did not require the registrant to include a signal word on the label. It received federal registration in April 2008 and at least one formulation has been registered in each of the New England states. The label describes chlorantraniliprole as toxic to aquatic invertebrates, but it is relatively insoluble so it is less likely to move to surface water than some other products. It is not toxic to bees, ants, or wasps. It is extremely effective against all the white grub species we encounter in New England, but should be applied before early to mid June to achieve maximum effectiveness against grubs. Spring applications of chlorantraniliprole will not affect grubs that are present in the spring.
Common Name	Trade name	Partial list of insects on label		Notes
chlorantraniliprole	Acelepryn	ABW, BTA, billbugs, caterpillars, white grubs
Chemical class: SPINOSYN			IRAC class: 5
This group is represented by spinosad (Conserve), which is derived from a soil actinomycete. The label describes it as highly toxic to bees and to mollusks. Effective against many caterpillars, including sod webworms, cutworms, and armyworms (as well as caterpillars in the landscape). Also a good larvacide for annual bluegrass weevil.
Common name	Trade name	Partial list of insects on label		Notes
spinosad	Conserve	ABW larvae, caterpillars		Apply against ABW larvae when larvae have just begun to emerge from the stem

 

Table 16: Labeled insecticides and ideal application timing for common turf insect pests in New England.

Insect	Insecticide	Ideal Timing	Comments
White grubs (Japanese beetle, European chafer, Oriental beetle, Asiatic garden beetle, etc.)	carbaryl (Sevin)	when grubs are present	Sometimes inconsistent, sensitive to high pH. Very toxic to honey bees. Not available for use on school grounds in Massachusetts.
	chlothianidin (Arena)	when adults are laying eggs	A neonicotinoid, not effective against Asiatic garden beetle (AGB). May have some curative properties in late summer applications.
	chlorantraniliprole (Acelepryn)	mid April to early June	Not effective against grubs present in spring.
	imidacloprid (Merit)	when adults are laying eggs	Merit went off patent in 2007, many generic forms now available. A neonicotinoid, not effective against AGB. Not effective against grubs present in spring
	thiamethoxam (Meridian)	when adults are laying eggs	A neonicotinoid, not effective against AGB
	trichlorfon (Dylox)	when grubs are present	Best option to control grubs in spring. Can be used into mid September most years. Sensitive to high pH. Not available for use on school grounds in Massachusetts.
	Allectus	when adults are laying eggs	combination product – Merit + Talstar (not effective against AGB)
	Aloft	when adults are laying eggs	combination product – proprietary blend of chlothianidin and bifenthrin (not effective against AGB). May have some curative properties in late summer applications.
	Maxide	when adults are laying eggs	combination product – Meridian + Scimitar (not effective against AGB)
Scouting: Scout for adult activity in mid-July to mid-August by scouting nearby foliage and/or use black light traps for European chafers. Scout for larvae in late summer or early spring with soil samples. Check the root/thatch interface for presence of grubs in late July to late August. Treatment: Treat when adults are laying eggs (mid-June to early August) if using a neonicotinoid. Treat between mid-August and mid-September to moist soil if grub population averages at least 5 to 10 grubs per square foot if using an intermediate or fast-acting material. Water in (at least 0.25”) immediately after application, but avoid puddling. If population was not controlled in late summer, apply spring control as soon as grubs are near surface (normally in April). Note that some materials have been inconsistent while others have performed consistently well over the years.
Insect	Insecticide	Ideal Timing	Comments
Annual bluegrass weevil (Hyperodes weevil)	bifenthrin (Talstar)	Forsythia half green, half gold to dogwood full bloom
	chlorantraniliprole (Acelepryn)	Two weeks after Forsythia half green, half gold	Also controls white grubs and caterpillars
	chlorpyrifos (Dursban)	Forsythia half green, half gold	Golf course use only. Generic formulations only.
	cyfluthrin (Tempo)	Forsythia half green, half gold to dogwood full bloom
	lambda-cyhalothrin (Battle, Scimitar)	Forsythia half green, half gold to dogwood full bloom
	deltamethrin (Deltagard)	Forsythia half green, half gold to dogwood full bloom
	indoxacarb (Provaunt)	when larvae first emerge (Rhododendron catawbiense full bloom)	May need to make two applications. Also effective against caterpillars.
	spinosad (Conserve)	when small larvae present (Rhododendron catawbiense full bloom)
	trichlorfon (Dylox)	when small larvae present (Rhododendron catawbiense full bloom)
Scouting: Scout for adult activity in mid- to late April with soapy flush. Monitor for larval activity in late May through June with soil samples, flotation, and visual inspection of thatch layer or collect samples, submerge in saline solution. Treatment: When targeting adults, treat between Forsythia and flowering dogwood “full bloom” (usually late April to mid-May). Treat for second generation if necessary during first two weeks of July. Water lightly (0.05” to 0.1”). Most applications are best targeted against adults as they begin to lay eggs or against young larvae. When targeting larvae, treat at Rhododendron catawbiense full bloom. Many annual bluegrass weevil (ABW) populations in the Northeast have developed resistance to pyrethroids. While not every population is resistant, golf course superintendents should try to minimize their reliance on pyrethroids whenever possible. Cultural strategies that may help reduce larval populations or minimize damage include converting Poa annua to creeping bentgrass, raising the height of cut where possible, and removing pine litter from nearby white pines. Monitor the areas where ABW are active and target larvae with one of the larval treatments as soon as they are observed.
Insect	Insecticide	Ideal Timing	Comments
Black turfgrass ataenius adults	bifenthrin (Talstar)	Forsythia half green, half gold to dogwood full bloom
	chlorpyrifos (Dursban)	Forsythia half green, half gold to dogwood full bloom	Golf course use only. Generic formulations only.
	cyfluthrin (Tempo)	Forsythia half green, half gold to dogwood full bloom
	lambda-cyhalothrin (Battle, Scimitar)	Forsythia half green, half gold to dogwood full bloom
	deltamethrin (Deltagard)	Forsythia half green, half gold to dogwood full bloom
Black turfgrass ataenius grubs	chlothianidin (Arena)	mid May to early June
	imidacloprid (Merit)	mid May to early June
	thiamethoxam (Meridian)	mid May to early June
	trichlorfon (Dylox)	when larvae present (often late June)
	Allectus	late April to early June	combination product – Merit + Talstar
	Aloft	late April to early June	combination product – Arena + generic bifenthrin
Scouting: Look for adults, sometimes in very large numbers, on putting greens in April (or use a soapy flush to force them to the surface). Large numbers of adults do not necessarily lead to heavy grub populations. Monitor for grubs from mid-May through mid-August by soil sampling. Treatment: If treating for adults (before egg laying), apply Dursban or a pyrethroid between Forsythia full bloom and dogwood full bloom, (late April to mid-May) and again two weeks later. Water in lightly (0.05” to 0.1”). Use this approach only in areas where BTA populations have been unusually high in previous years, to avoid treating areas that do not have populations high enough to warrant control. If treating for larvae, apply a material which will penetrate the thatch when horse chestnut or Van Houette spirea are in full bloom, (usually early June). Water in with at least 0.15” to 0.3” of water immediately after application. Imidacloprid or chlothianidin can be applied preventively, but should not be applied earlier than early June if white grubs are also a problem.
Insect	Insecticide	Ideal Timing	Comments
Chinch bug	bifenthrin (Talstar)	June - July
	chlorpyrifos (Dursban)	June - July	Golf course use only. Generic formulations only
	cyfluthrin (Tempo)	June - July
	lambda-cyhalothrin (Battle, Scimitar)	June - July
	deltamethrin (Deltagard)	June - July
	Allectus	June to mid July	combination product – Merit + Talstar
	Aloft	June to mid July	combination product – Arena + generic bifenthrin
	Maxide	June to mid July	combination product – Meridian + Scimitar
Scouting: Scout for adult activity in May and early June, for immature stages throughout summer. In addition, chinch bugs move steadily in the thatch and can be seen by using fingers to spread the turf. Treatment: Populations are commonly highest in fine fescues and turf stands with thick thatch. Use endophyte containing cultivars when available; avoid drought conditions. Apply in June; water in lightly (less than 0.1”) after application. In some cases, a second application two to three weeks later may be needed.
Insect	Insecticide	Ideal Timing	Comments
Cutworm	bifenthrin (Talstar)	when damage appears
	carbaryl (Sevin)	when damage appears	Very toxic to honey bees. Not available for use on school grounds in Massachusetts. Repeat applications may be needed, especially after heavy rain.
	chlorantraniliprole (Acelepryn)	mid May to mid June	Several weeks of protection when applied at high label rate.
	chlorpyrifos (Dursban)	when damage appears	Golf course only. Generic formulations only.
	cyfluthrin (Tempo)	when damage appears
	deltamethrin (Deltagard)	when damage appears
	indoxacarb (Provaunt)	June – July	Often provides several weeks protection.
	lambda-cyhalothrin (Battle, Scimitar)	when damage appears
	Spinosad (Conserve)	when damage appears
	Allectus	June to mid July	combination product – Merit + Talstar
	Aloft	June to mid July	combination product – proprietary blend of chlothianidin and bifenthrin.
	Maxide	June – July	combination product – Meridian + Scimitar
Scouting: Monitor adult activity with black light traps. Apply insecticides two to three weeks after peak flights. Scout for caterpillars (late in the day or early in the morning) with soapy flushes. Treatment: Most cutworms are nocturnal, so treatments are most effective if applied late in the day. Water lightly (less than 0.10”). On golf courses inspect aerification holes throughout summer. Damage often becomes most noticeable shortly after aerification, particularly in late summer. Apply two to three weeks after peak moth flight.
Insect	Insecticide	Ideal Timing	Comments
Sod webworm	bifenthrin (Talstar)	when damage appears
	carbaryl (Sevin)	when damage appears	Very toxic to honey bees. Repeat applications may be needed, especially after heavy rain. Not available for use on school grounds in Massachusetts.
	chlorantraniliprole (Acelepryn)	mid May to mid June	Several weeks of protection when applied at high label rate.
	chlorpyrifos (Dursban)	when damage appears	Golf course use only. Generic formulations only.
	cyfluthrin (Tempo)	when damage appears
	lambda-cyhalothrin (Battle, Scimitar)	when damage appears
	deltamethrin (Deltagard)	when damage appears
	indoxacarb (Provaunt)	June – July
	Spinosad (Conserve)	June – July
	Allectus	June – July	combination product – Merit + Talstar
	Aloft	June – July	combination product – proprietary blend of chlothianindin and bifenthrin
	Maxide	June – July	combination product – Meridian + Scimitar
Scouting: Monitor adult activity by inspecting turf surface at twilight looking for small “tube moths” flitting just above the canopy. Scout for caterpillars with soapy flushes. Treatment: Check for sod webworm activity: look for small green pellets in upper thatch or flush an area with soapy water. Watch for webworm moths flying at twilight. Apply controls 10 to 14 days after number of moths declines sharply. Repeat applications may be necessary. Treat as late in day as possible. Water lightly (0.10”); do not mow for one to three days after application.
Insect	Insecticide	Ideal Timing	Comments
Invasive craneflies, preventive	bifenthrin (Talstar)	mid September to mid October	Apply when larvae are mostly first and second instars.
	carbaryl (Sevin)	mid September to mid October	Very toxic to honey bees. Apply when larvae are mostly first and second instars. Not available for use on school grounds in Massachusetts.
	chlorantraniliprole (Acelepryn)	mid September to mid October	Preliminary trials look promising.
	chlothianidin (Arena)	mid September to mid October	Apply when larvae are mostly first and second instars.
	indoxacarb (Provaunt)	mid September to mid October	Apply when larvae are mostly first and second instars.
	Aloft	mid September to mid October	combination product – proprietary blend of chlothianidin and bifenthrin
Invasive craneflies, curative	chlothianidin (Arena)	when larvae are small	Apply when larvae are mostly third instars.
	indoxacarb (Provaunt)	when larvae are small	Apply when larvae are feeding actively in spring.
	Aloft	when larvae are small	combination product – proprietary blend of chlothianidin and bifenthrin
Scouting: “Common” cranefly (Tipula oleracea) larvae occasionally can be seen at the surface feeding on foliage on warm, humid nights. Check for larval activity by taking soil samples (cup cutter plugs), dislodging the soil and looking for the dark-colored larvae. In late summer look for pupal skins that jut out from the surface. Also watch for adults flying just above the turf surface or landing on walls of buildings. Treatment: Normally the larvae survive best in areas that have high soil moisture during the fall and spring. Withholding irrigation during the time when females are laying eggs may reduce larval survival. There are two approaches for controlling cranefly larvae. Preventive applications are made when larvae are first and second instars (usually mid September to mid October), while curative applications are made when larvae are third and fourth instars (usually mid March to mid April). Water lightly to moderately (0.05 to 0.15 inch) to move product into the thatch and enhance contact with the larvae. A second generation occurs with egg laying in April or May and larvae feeding from mid May through late August.
Insect	Insecticide	Ideal Timing	Comments
Turfgrass ants (Lasius neoniger)	bifenthrin (Talstar)	when new mounds appear
	chlothianidin (Arena)	when new mounds appear	Studies in other states indicate spring applications can provide control for several weeks
	chlorpyrifos (Dursban)	when new mounds appear	Golf course use only. Generic formulations only.
	cyfluthrin (Tempo)	when new mounds appear
	lambda-cyhalothrin (Battle, Scimitar)	when new mounds appear
	deltamethrin (Deltagard)	when new mounds appear
	hydramethylnon (Maxforce)	when new mounds appear	Bait – do not water in
	imidacloprid (Merit)	when new mounds appear	Studies in other states indicate spring applications can provide control for several weeks
	indoxacarb (Advion)	when new mounds appear	Bait – do not water in
	Aloft	when new mounds appear or in mid to late August	combination product – proprietary blend of chlothianidin and bifenthrin. Bifenthrin provides quick relief, chlothianidin provides longer coverage
Scouting: Scout for turfgrass ants by watching for new mounds on the surface. Treatment: Turfgrass ants produce mounds on turf that are unsightly and can dull mower blades. The traditional approach has been to apply a pyrethroid or chlorpyrifos to the new mounds as soon as they appear (typically late April or early May). These surface applications kill many of the workers and weaken the colony but the only way to eliminate a colony is to kill the queen. The most effective way to eliminate the queen is to use a bait formulation, which workers will carry to the brood chamber. Baits should not be watered in, while surface applications can be watered in lightly (less than 0.10 inch).

 

Table 17. Insect treatment calendar.

Insect treatment		Mar				Apr				May				Jun				Jul				Aug				Sep				Oct
One year grubs: Japanese beetle, European chafer, masked chafer, Oriental beetle, Asiatic garden beetle
2 or 3 year grubs: May or June beetles. Best time is July of year the eggs are laid. Second best time is spring after eggs are laid.
Hyperodes weevil
Black turfgrass ataenius (adult)
Black turfgrass ataenius (larvae)
Chinch bugs
Billbugs
Sod webworms
Cutworms
Ants
periods where damage is most likely to occur   best time to treat (specific timing depends upon material selection)   second best time to treat (specific timing depends upon material selection)

 

The following key is patterned after Shurtleff (1987) in “Controlling Turfgrass Pests” but has been adapted to turfgrass diseases common in Massachusetts. The four sections include COLD, COOL/WARM, and HOT temperature diseases as well as problems not generally related to temperature.

Technical terminology has been minimized. The word “mycelium” (or hyphae) refers to the web-like growth of fungi on turf when wet. “Black specks” are the spore containers produced by a few of the disease causing fungi. “Sclerotia” are dark, pinhead-sized or slightly larger masses of mycelium that some fungi produce as survival structures.

How to use this key

Decide first the temperature when symptoms first appeared. Then read the subsections to decide which best describes the problem. Symptoms of diseases are often quite different on lawns than on highly maintained, low-mown turf such as putting greens. The most common diseases are indicated by a star (★).The diagnosis of turf diseases can be difficult even in the laboratory. Use this key only as a general guide. For information about disease diagnostic services available from UMass, refer to the UMass Extension Plant Diagnostic Lab at ag.umass.edu/services/plant-diagnostics-laboratory.

Section I. Cold Weather (32–45°F) Diseases and Disorders A. Irregular patterns or streaks in turf. Bleached or dead grass, especially in wind-swept areas free of snow with deeply frozen soil. WINTER DESICCATION New leaves killed back, often in yellow to white patches following freezing temperatures. SPRING FROST B. Turf killed (rotted or straw-colored) in wettest areas. May follow drainage patterns. WATER AND ICE DAMAGE Distinct circular patches of dead grass from 1” to 3” across. Wet grass is often covered with white to bright pink mycelium; NO sclerotia present. « MICRODOCHIUM PATCH (PINK SNOW MOLD) Wet grass covered with white to gray or bluish-gray lint-like mycelium; small yellow to dark brown or reddish sclerotia often present in or on grass leaves. « TYPHULA BLIGHT (GRAY OR SPECKLED SNOW MOLD) Section II. Cool-to-Warm Weather (45–75°F) Diseases A. Circular patches or rings in turf after grass greens up in spring. Yellow patches or “tufts” usually less than 1” across. Plants easily pulled from turf. DOWNY MILDEW (YELLOW TUFT) Sunken, straw-colored patches, 1” to 6” across. May be covered with dense white mycelium in moist weather. Whitish tan leaf spots with brown, reddish brown or purplish borders. ★ DOLLAR SPOT Turf wilted, killed, rotted or straw-colored. Often in poorly drained areas. PYTHIUM ROOT ROT Leaves yellowing and wilting; tiny black, spiny fungal hairs in tufts may be evident with a hand lens. ★ ANTHRACNOSE (CROWN/BASAL ROT) Patches from 1” to 3’ across. A prolonged cool rain commonly following melting snow. Wet grass is often covered with white to bright pink mycelium or may be greasy to coppery in color. ★ MICRODOCHIUM PATCH (PINK SNOW MOLD) Patches usually with green centers. Yellow to straw colored, sunken in high cut turf. Wet grass not covered with mycelium. ★ YELLOW PATCH (COOL WEATHER BROWN PATCH) Initially yellow, then reddish brown or bronzed, and finally sunken, tan rings. Centers often invaded by weeds. Most commonly found in cool, moist, coastal areas; most common in bentgrass. « TAKE-ALL PATCH Patches, rings, arcs, “frog-eyes” about 6” to 8” across, enlarging later. Most common in Kentucky bluegrass sod two to four years old and annual bluegrass. ★ NECROTIC RING SPOT Rings or arcs up to 15’ or more across; often with outer ring of dark green grass; may be mushrooms in rings; often dead turf on highly managed areas in golf course. ★ FAIRY RING B. Irregular patterns (usually) in turf. Colored fungus or spores on leaf surfaces; leaf spots not usually evident. White to gray powdery mycelium and spores on leaf surfaces; found mostly in shade. ★ POWDERY MILDEW Gray to black streaks of black powdery spores in leaves; leaves shred into ribbons and curl. Grass may later die in irregular patches or a general thinning; usually in turf three or more years old. LEAF SMUTS Pink to reddish and mycelium flecks on leaves; red thread-like growths beyond leaf tips; appears tan in patches; most common in low nitrogen turf. ★ RED THREAD/PINK PATCH Bright yellow, orange, or reddish-brown pustules of powdery spores on leaf blades; mostly late summer, usually on slow growing and low fertility turf. ★ RUSTS Slimy, superficial whitish gray to yellow fungus-like material in the early stages; turns powdery later. SLIME MOLDS Irregular patches of turf lacking distinct fungal signs. Increased leaf senescing on annual bluegrass (indicated by tan patches) or purpling of bentgrass on putting green height turf. Turf may also be off-color, thin or slow-growing in variably-sized patches. PYTHIUM ROOT DYSFUNCTION Leaves distinctly spotted or with tip blight. Oval to eye-shaped, dark-bordered spots. In warm weather, turf may look thin and weak (melting-out). ★ LEAF SPOTS AND BLIGHTS/MELTING OUT Section III. Hot Weather (over 75°F) Diseases Occur from late spring to late summer. Possibilities from previous sections Circular patterns in turf: Dollar Spot Necrotic Ring Spot Irregular Areas: Rusts Slime Molds A. Circular patterns in turf. Straw colored patches often 6” to 8” across, but can be larger; centers often remain green. Most common on Kentucky bluegrass sod two to four years old and in annual bluegrass. Symptoms often appear in hot weather after heavy rains. Symptoms identical to necrotic ring spot. ★ SUMMER PATCH Patches up to 2’ to 3’ across; light brown; grass blades usually not matted. Patches appear during wet periods. Gray mycelium may be visible in moist conditions; most common on bentgrass greens (look for “smoke ring”) and tall fescue lawns (distinct tan or chocolate brown lesions on leaf blades). ★ BROWN PATCH Tan leaf spots without darker borders. Grass leaves matted and slimy. Copious amounts of dense gray/white mycelium in moist weather. ★ PYTHIUM BLIGHT Yellow/golden brown rings (3” to 12” in diameter) on annual bluegrass putting greens. Rare on creeping bentgrass. Rings may have scalloped appearance and enlarge over time. BROWN RING PATCH (WAITEA PATCH) Circular patches (1” to 2” diameter). Tan dead tissues with reddish-brown borders on young, sand-based bentgrass putting greens. BENTGRASS DEAD SPOT Circular copper or salmon colored patches less than 3” in diameter, during humid weather. Most common on golf course putting greens. COPPER SPOT B. Irregular patterns of weak, thin, dormant or dead grass. Large areas appear dry, then wilt, and turn brown. Turf is yellowish, then reddish brown. Leaves spotted to blighted. Tiny black, spiny fungal hairs in tufts on blades evident with hand lens. Most common in compacted, stressed turf. Most common on annual bluegrass golf course putting greens. ★ ANTHRACNOSE (CROWN/BASAL ROT) Oval or eye-shaped leaf spots with dark margins, mostly on Kentucky bluegrass. « LEAF SPOTS/BLIGHTS/MELTING OUT Irregular gray to brown leaf spots with dark margins and yellow halo. Mostly on perennial ryegrass and tall fescue. GRAY LEAF SPOT Recently seeded areas have irregular, empty areas due to poor germination. Dying and dead seedlings have dark or black coloration. DAMPING-OFF, SEED ROT Irregularly thinning turf, soil surface with has green or black coating that is slimy to the touch. ALGAE Irregularly thinning turf, soil surface has a thick, silvery green mat. MOSSES Section IV. Other Causes of Poor Turf Usually Independent of Temperature. A. Turf gradually becomes pale green to golden yellow and grows slowly; stand often thins out. Definite leaf lesions or mottling present. AIR or SOIL POLLUTION Yellow streaks may form parallel to the leaf veins. IRON or NITROGEN DEFICIENCY B. Turf suddenly appears scorched. Usually in patches, bands or streaks. CHEMICAL BURN or MOWER BURN Bands, streaks, or irregular patterns; grass is stimulated at margins. FERTILIZER BURN Ring of dark green grass at margins; patches up to about 1’ across. DOG INJURY Entire turf area or patches over slight elevations or mowing corners are yellow to brown. SCALPING INJURY Leaf tips are shredded; appear gray, then tan. DULL MOWER INJURY C. Round to irregular patches of dead or dormant grass; often follows dry periods. BURIED DEBRIS, INSECT INJURY or THICK THATCH D. Turf bare or thinned; often in traffic areas, dense shade, waterlogged soil, etc. Greenish to brown scum that later forms a black crust. ALGAE Small green plants that grow on soil in slight mounds. MOSS Soil hard in heavily tracked paths, under swings, etc. COMPACTION E. Turf dry, bluish green (footprints visible), wilts may later turn brown. DROUGHT, WILT or IMPROPER WATERING

 

Though it can be challenging to maintain intensively-managed turfgrass without fungicides, good cultural practices will reduce the need for fungicide applications and make necessary applications more effective. In fact, effective and well-timed cultural practices may minimize or eliminate the need for fungicide applications in lawns and other less intensely maintained turfgrass areas.

Starting right 


Prepare the site well. Remove stumps, construction materials and other debris. Improve drainage where necessary, and fill in low areas. Test soil pH and adjust to 6.0 to 7.0 if required. Break up soil clumps to provide a uniform area for seed or sod.

Choose seed or sod carefully (see Turfgrass Selection: Species and Cultivars). Inspect sod for diseases or other problems. Choose high quality, pathogen-free seed. Many disease resistant cultivars are now available and should be included in blends and mixtures. Genetic variability in turfgrasses will reduce the chance for epidemics that kill or damage large areas of turf.

General landscaping decisions can have significant impacts on turf health. Pruning of tree branches may increase light penetration to allow better turfgrass growth. Trees, shrubs, and other plantings should be placed to allow good air circulation, so turf will dry quickly after rain or dew. In very shady areas, shade-tolerant turfgrass cultivars or other groundcovers should be planted.

Seed should be planted only in well prepared soil with good drainage when temperatures stay in the range to allow rapid germination and establishment. Keep soil and seed moist, but do not over-water.

Routine Care

Fertilizers - Apply according to current recommendations and based on a soil test. Excess nitrogen will cause succulent growth that is more susceptible to disease. Avoid nitrogen applications (especially water soluble/quick-release fertilizers) during leaf spot season early in spring, during hot, humid weather, and just before dormancy in fall, which may leave turf more susceptible to snow molds and winter injury. Be sure, however, to meet the minimum nitrogen requirement for the turfgrass species and use as some diseases (e.g. red thread, rusts, and dollar spot) are encouraged when nitrogen is deficient.

Herbicides - Herbicides can stress turfgrasses and make them more susceptible to diseases. Apply carefully according to label directions and with attention to environmental conditions.

Some herbicides may have fungistatic effect and provide some degree of disease control. Noting fungistatic occurrences may be useful for reducing the amount of fungicide applied, by applying fungicides in combination with fungistatic herbicides.

Liming - Adjust pH according to soil test recommendations. Disease occurrence may increase at pH extremes (too high or too low). Lime applied late in autumn can increase Microdochium patch (pink snow mold) incidence and high pH can predipose turf to take-all patch infection during the spring. 



Mowing - Mowing wounds turfgrasses and can spread pathogens (disease-causing organisms). Minimize wounding and shredding of grass blades by keeping mower blades sharp and adjusted properly. If possible, mow when the turf is dry. Mow as high as possible for species and the turf use, using the maximum mowing height in hot weather. Avoid mowing more than one-third of the total height at each cutting to reduce stress to the root system. Mowing in autumn until turf stops growing can help to reduce damage from snow molds.

Watering - Water is necessary for good plant growth, but too much water floods open spaces in the soil, depriving roots of oxygen. Disease-causing fungi reproduce by spores that, like seeds, need water to germinate and infect turf. Dry turfgrass blades reduce disease by reducing infection. Deep and infrequent watering is strongly preferred to shallow, frequent watering to minimize leaf wetness and to encourage an extensive root system. Every effort should be made to not extend the duration of time blades are wet from dew or irrigation. Do not water in late afternoon or early evening. Night irrigation after dew appears may help conserve water, but is not recommended on hot, humid nights because it can increase some diseases (Figure 2). Avoid light, frequent sprinklings (syringing) except to prevent wilting in close-cut or shallow rooted turf and during hot, dry weather. In certain situations, keeping upper soil layers moist may help to reduce the occurrence of necrotic ring spot and summer patch.

Figure 2. When NOT to water turf

 

Thatch - Thatch is mostly composed of partially decayed above- and below-ground lateral stem tissue (stolons and rhizomes). A thin layer is beneficial in most turf situations. When thatch is more than 1/2” thick, it reduces nutrient and water absorption and harbors insect pests and disease pathogens. Prevent excessive thatch formation by providing adequate fertility in combination with aeration, verticutting and topdressing when needed. Mechanical removal of thatch is disruptive and should be accomplished in spring and late summer when time and conditions will allow for sufficient turf recovery.

Compaction - Several diseases (e.g. necrotic ring spot, summer patch, or athracnose basal rot) are worse in areas with compacted soil. Core aeration can help relieve soil compaction and improve turf quality. On some sites, traffic management may also be appropriate to minimize soil compaction.

Targeted cultural practices

Some sites have a history of disease problems, while others exist in a growing environment conducive to certain diseases.  For some pathogens, targeted cultural practices can go a long way towards preventing disease occurrence, reducing severity of disease when it does occur, and promoting recovery from damage. Table 18 details cultural management strategies for some of the most common turf diseases encountered in the Northeast.

Table 18. Cultural management strategies for common turf diseases.

Disease (Pathogens)	Turfgrass Hosts*	Season	Cultural Management Strategies
Algae, Mosses	all turfgrasses	Apr – Nov	Improve fertility and drainage. Alleviate compaction. Modify shade-causing agents to increase light penetration.
Anthracnose (Crown/Basal Rot) Colletotrichum cereale	bentgrasses, annual bluegrass	Mar – Sept	Provide adequate N fertility. Avoid stress from too little or too much water and compaction. Raise mowing height.
Bentgrass Dead Spot Ophiosphaerella agrostis	bentgrasses less than 6 years old on sand-based root zones.	June – Sept	Add N. Rake out and reseed.
Brown Patch Rhizoctonia solani	all turfgrasses, tall fescue, bentgrasses, perennial ryegrass	July – Sept	In hot weather, avoid excess N and excess water. Avoid night watering. Remove dew from putting greens.
Brown Ring Patch (Waitea Patch) Waitea circinata	annual bluegrass, rough bluegrass, creeping bentgrass	Dec – July	Apply adequate N for rapid recovery from damage. Dethatch and improve drainage. Symptoms can often be masked with N or iron.
Copper Spot Gloeocercospora sorghi	bentgrasses	June – Sept	Avoid excess N. Minimize leaf wetness. Plant resistant cultivars.
Damping-off, Seed Rot several fungi including Pythium spp., Fusarium and Rhizoctonia solani	all turfgrasses	Apr – Oct	Ensure careful seedbed preparation. Use good quality seed. Maintain soil moisture but avoid overwatering.
Dollar Spot Sclerotinia homoeocarpa	all turfgrasses, bentgrasses, annual bluegrass	June – Sept	Avoid N deficiency and water stress. Minimize leaf wetness. Relieve compaction and excess thatch. Raise mowing height.
Downy Mildew (Yellow Tuft) Sclerophthora macrospora	all turfgrasses	May – Sept	Avoid excess N and excess watering. Iron sulfate may mask symptoms. Improve drainage.
Fairy Ring (various fungi)	all turfgrasses	April – Nov	Mask symptoms with N or iron. Core aerate and water. Fumigate or remove soil in severe cases.
Gray Leaf Spot Pyricularia grisea	perennial ryegrass, tall fescue	July – Nov	Avoid excess N. Minimize leaf wetness. Reduce shade, lower mowing height.
Leaf Smuts Ustilago striiformis	bentgrasses, Kentucky bluegrass	April – Nov	Avoid excess N in spring. Avoid water stress. Plant resistant cultivars. Collect clippings and discard.
Leaf Spots and Blights/ Melting Out “Helminthosporium” spp. Ascochyta, Bipolaris, Curvularia, Drechslera, Nigrospora, Septoria, Leptosphaerulina	all turfgrasses, Kentucky bluegrass, bentgrasses, fine fescues	April – Oct	Avoid excess N, especially in spring. Raise mowing height. Minimize leaf wetness. Plant resistant cultivars.
Necrotic Ring Spot Ophiosphaerella korrae	Kentucky bluegrass, esp. sod (3-4 yrs old), fine fescues, annual bluegrass	June – Sept	Avoid water and fertility stress. Avoid compaction and excess thatch. Utilize slow release N sources.
Powdery Mildew Blumeria graminis	Kentucky bluegrass, fine fescues	July – Sept	Reduce shade and increase air circulation. Avoid excess N.
Pythium Blight Pythium spp.	all turfgrasses, perennial ryegrass, bentgrasses	June – Aug	Avoid excess N and night watering in hot weather. Do not mow when wet or when disease is active. Improve drainage and air circulation.
Pythium Root Dysfunction Pythium volutum	creeping bentgrass	Sept – June	Avoid excess N. Improve drainage. Aerate Regularly.
Pythium Root Rot Pythium spp.	all turfgrasses, bentgrasses and annual bluegrass in sand greens	Mar – Nov	Improve drainage. Increase soil organic matter.
Red Thread Laetisaria fuciformis and Pink Patch Limonomyces roseipellis	all turfgrasses, perennial ryegrass, fine fescues	April – Oct in mild, wet weather	Avoid N deficiency, water stress, and low pH. Minimize leaf wetness. Water deeply and infrequently. Improve light penetration and air circulation.
Rusts Puccinia spp.	all turfgrasses, Kentucky bluegrass, perennial ryegrass	July – Oct	Avoid N deficiency and water stress. Minimize leaf wetness. Plant resistant cultivars. Reduce thatch. Raise mowing height and collect clippings. Water deeply and infrequently.
Slime Molds various organisms	all turfgrasses	June – Sept	Mow or hose away. Fungicide applications are not necessary.
Snow Molds: Pink Snow Mold (Microdochium Patch) Microdochium nivale and Gray or Speckled Snow Mold (Typhula Blight) Typhula spp.	all turfgrasses, bentgrasses	Nov – April	Avoid lush growth in fall. Continue mowing until autumn growth ceases. Avoid prolonged snow cover; do not allow excessive piling of snow on turf and reduce drifting with placement of snow fences. Fertilize lightly in spring to promote re-growth.
Summer Patch Magnaporthe poae	fine fescues, annual bluegrass, Kentucky bluegrass	July – Sept	Avoid water stress and overwatering. Avoid compaction. Maintain adequate fertility. Lower pH in top inch of soil. Raise mowing height. Utilize slow release forms of N. Apply 2 lb/A MnSO4 annually in spring.
Take-all Patch Gaeumannomyces graminis var. avenae	bentgrasses	Mar – June Sept – Nov	Avoid heavy lime applications. Lower pH in top inch of soil. Improve drainage. Apply acidifying fertilizers.
Yellow Patch (Cool Weather Brown Patch) Rhizoctonia cerealis	bentgrasses, Kentucky bluegrasses, perennial ryegrass	Nov – April	Avoid excess N. Minimize leaf wetness. Improve drainage and air circulation.
* The most susceptible turfgrass species are in bold italics.

 

At this time, many research programs are investigating biological controls for turf diseases. The two main areas of emphasis are the use of organic composts and the use of specific microbes that inhibit disease-causing fungi. There are some new commercial products for the biological control of turf diseases that consist of specific microbes, and many potential products are currently under study. Several organic composts have exhibited some suppression of certain diseases, but much more research is needed before recommendations can be made. Such composts are thought to contain microbial populations that inhibit disease-causing fungi. Different composts inhibit certain diseases but not others; other composts do not appear to suppress disease at all.

Genetic resistance can also be considered a form of biological control because certain turfgrass cultivars are resistant to or tolerant of some diseases. Selection of disease-resistant cultivars or disease-immune species is a priority in many turfgrass breeding programs. If a certain disease is a continuing problem, it can be helpful to investigate the availability of new disease-resistant cultivars that can be used for over-seeding or reestablishment of damaged areas. See Turfgrass Selection: Species and Cultivars for information on disease tolerant cultivars that are well-adapted to Massachusetts conditions.

There is little doubt that the use of biological control products and improved genetic resistance will become a more significant part of turfgrass disease management in the near future. However, these new alternatives will work best as part of an integrated disease management program that includes a strong cultural approach to reduce stress factors and minimize opportunities for infection by pathogenic fungi.

Most common turfgrass diseases are caused by fungi. Fungicides kill or inhibit the growth of fungi.

There are two general categories of fungicides:

• contact/protectant
• penetrant

Contact/protectant fungicides remain on the outside of the plant and protect the plant from new infection. They must be applied at comparatively short intervals that can range from 5 to 14 days, because the fungicides are degraded by ultraviolet light, washed from the leaf surface by irrigation or rain, or mowed away. These fungicides do not have curative activity and new growth is not protected. Thorough coverage of plant tissue is critical to successful protection. Examples of contact/protectant fungicides commonly used in turf include captan, chlorothalonil, chloroneb, etridiazole, fluazinam, fludioxonil, mancozeb, maneb, PCNB, and thiram. 


Penetrant fungicides are absorbed into plant tissue and may provide some curative action. The duration of control afforded by penetrant fungicides is often much longer than that offered by contact fungicides, and some redistribution into new tissue may occur as the plant grows. Application intervals vary, but often range from 14 to 21 days and longer. According to specific topical modes of action, penetrant/systemic fungicides can be further divided into three sub-categories:

• Localized penetrants form a protective barrier on the plant surface and permeate into the leaf in the area where deposition occurred. These fungicides have some curative activity, but do not move upward or downward inside the plant. Examples include iprodione, polyoxin D zinc, trifloxystrobin, and vinclozolin.

• Acropetal penetrants form a protective barrier on the plant, permeate into the plant, and move upward in the plant’s xylem. These fungicides have protective activity including new growth, and have good curative activity. Examples include azoxystrobin, fenarimol, mefenoxam, and triadimefon.

• Systemic penetrants form a protective barrier on the plant, permeate into the plant, move upward in the plant’s xylem, and move downward in the plant’s phloem. These fungicides have protective activity including new growth, and have good curative activity. Of the currently available penetrant/systemic fungicides, only fosetyl-Al (Aliette Signature) is truly systemic and moves both upward and downward in the plant.

Refer to Table 20 for a list of available fungicide materials and their respective topical modes of action.

Fungicide resistance

Some fungicides are site specific in their mode-of-action. This means that it takes very little genetic change on the part of a fungus for resistance to occur. Resistance may result in poor disease control, meaning that higher application rates or shorter intervals are needed to maintain healthy turf, or complete control failure. Resistance may develop suddenly or gradually depending on the fungicide involved. Once resistance has developed in a fungal population, it may last for a long time or gradually disappear if the fungicide is no longer used, depending on the fungicide and site-specific factors. Resistance is common for some diseases, but not observed for others. Fungicide resistance has been documented for anthracnose, dollar spot, Microdochium patch, gray leaf spot, and Pythium blight. 


The best strategy is to try to prevent, or at least delay, resistance. All penetrant fungicides are at risk for resistance development due to their “single-site” mode-of-action. Contact/protectant fungicides are unlikely to result in resistance because most of them have “multi-site” modes-of-action with the exception of fludioxonil (Medallion) and a few others which have a “single-site” mode-of-action. There are multiple chemical groups with different biochemical modes-of-action for broad-spectrum disease control in turfgrass that are at risk for resistance. Fungicide resistance has already been reported in five of these groups (Benzimidazole, Dicarboximide, Demethylation Inhibitor (DMI), Strobilurin (QoI) and Phenylamide). 


Table 19. Turfgrass pathogens and chemical classes with documented fungicide resistance.

Turfgrass Disease (causal agent)	Resistance to chemical classes (see Table 20)
	Benzimidazole	Dicarboximide	DMI	QoI	Phenylamide
Anthracnose (Colletotrichum cereale)	X		X	X
Dollar spot (Sclerotinia homoeocarpa)	X	X	X
Gray leaf spot (Pyricularia grisea)				X
Microdochium patch/pink snow mold (Microdochium nivale)		X
Pythium blight (Pythium aphanidermatum)					X

Mix or alternate between different site-specific chemical groups or with multi-site contact/protectant fungicides, indicated by different FRAC (Fungicide Resistance Action Committee) code numbers, to prevent or delay the development of resistance. Changing fungicides by brand or trade name will not prevent resistance if the active ingredient or chemical group is the same. Fungicide labels list the active ingredient(s) in smaller letters below the brand name. Be especially careful when using combination (pre-mixed) products, which may include fungicides subject to resistance prevention strategies. Tables 20-22 list fungicide materials along with their corresponding FRAC codes for ease of reference.

Guidelines to prevent or delay resistance to turf fungicides Minimize disease conditions Employ good cultural practices. Choose resistant turfgrass cultivars or species. Make proper fungicide choices Be sure of the problem. Decide if it warrants treatment. Read the label, calibrate, and apply properly. Know the material Read the label to determine the active ingredient. Is repeated use likely to lead to resistance (i.e. does it have a single-site mode-of-action)? Determine the fungicide group to which it belongs. Mix or alternate between fungicide groups with single-site mode-of-action or with contact/protectant fungicides. Do not use fungicides with the same FRAC (Fungicide Resistance Action Committee) code number in combination or rotation. Make sure all pesticides being applied in tank-mixtures are compatible prior to mixing.

Table 20. Chemical classes, trade names and topical modes of action of fungicides registered for use on turf.

Common Name	FRAC 1	Group Name	Trade Name(s)	Topical mode of action 2
azoxystrobin	11	Strobilurin (QoI)	Heritage (50WG, TL, G)	Acropetal Penetrant
boscalid	7	Succinate Dehydrogenase Inhibitor	Emerald 70EG	Acropetal Penetrant
captan	M4	Phthamlimides	Captan (50W, 50WP, 4L), Captec 4L	Contact
chloroneb	14	Aromatic Hydrocarbon	Terraneb SP, Teremec SP, Andersons Fungicide V, Proturf Fungicide V	Contact
chlorothalonil 3	M5	Chloronitrile	Andersons 5% Daconil 5G, ArmorTech (825 DF, CLT 720), Concorde SST 6F, Daconil (5G, 2787, Zn, Ultrex, WeatherStik), Echo 720F, Ensign 720, Equus 500ZN, Manicure (6FL, Ultra), Lebanon Daconil 5G, Legend, Pegasus (6L, DFX, HPX)	Contact
cyazofamid	21	Quinone inside Inhibitors (QiI)	Segway	Localized Penetrant
etridiazol (ethazole)	14	Aromatic Hydrocarbon	Koban, Terrazole 35WP, Truban	Contact
fluazinam	29	Uncoupler of oxidative phosphorylation	Secure	Contact
fludioxonil	12	Phenylpyrrole	Medallion (WDG, WP)	Contact
fluoxastrobin	11	Strobilurin (QoI)	Fame 480SC	Acropetal Penetrant
flutolanil	7	Succinate Dehydrogenase Inhibitor	ProStar 70WP, Moncut 70-DF	Acropetal Penetrant
fluxapyroxad	7	Succinate Dehydrogenase Inhibitor	Xzemplar	Acropetal Penetrant
fosetyl-Al (Aluminum tris)	33	Phosphonate	Autograph, Chipco Aliette, Chipco Signature, Chipco Signature Xtra, Lesco Prodigy Signature, Viceroy 70DF	Systemic Penetrant
iprodione	2	Dicarboximide	Andersons Fungicide X, ArmorTech IP 233, Chipco 26 GT, Chipco 26019, Iprodione Pro, Lesco 18 Plus, Proturf Fungicide X, Raven	Localized Penetrant
isofetamid	7	Succinate Dehydrogenase Inhibitor	Kabuto	Acropetal Penetrant
mancozeb	M3	Dithiocarbamate	Dithane 75DF, Fore Rainshield 80WP, Junction, Lesco Mancozeb DG, Lesco 4 Flowable Mancozeb, Manzate Pro-Stick 200, Protect DF, WingMan (4L, DF)	Contact
mandestrobin	11	Strobilurin (QoI)	Pinpoint	Acropetal Penetrant
maneb	M3	Dithiocarbamate	Maneb 80WP, Maneb 75DF, Pentathalon (LF, DF)	Contact
mefenoxam	4	Phenylamide	Andersons Pythium Control, Mefanoxam, Subdue MAXX	Acropetal Penetrant
metalaxyl	4	Phenylamide	Subdue 2E, Subdue GR, Subdue WSP, Apron (seed treatment), Vireo MEC	Acropetal Penetrant
metconazole	3	Demethylation Inhibitor	Tourney	Acropetal Penetrant
myclobutanil	3	Demethylation Inhibitor	Andersons Golden Eagle, Eagle 20EW, Siskin	Acropetal Penetrant
PCNB (pentachloronitrobenzene or quintozene)	14	Aromatic Hydrocarbon	Andersons FFII 15.4G, Defend 4F, Engage 75W, Fluid Fungicide II, Lesco Revere 4000 4F (10G), Parflo 4F, PCNB 12.5G, Penstar 75WP, Terraclor 400F (75WP), Turfcide 400F (10G)	Contact
penthiopyrad	7	Succinate Dehydrogenase Inhibitor	Velista	Acropetal Penetrant
phosphite (salts)	33	Phosphonate	Appear, Alude 5.2F, Biophos, Fiata Stessguard, Fosphite, Jetphiter, Magellan, Phostrol, Reliant, ReSyst 5F, Vital 4L	Systemic Penetrant
polyoxin D zinc salt	19	Polyoxin	Endorse 2.5WP, Affirm 11.3WDG	Localized Penetrant
propamocarb	28	Carbamate	Banol 6S	Localized Penetrant
propiconazole	3	Demethylation Inhibitor	ArmorTech PPZ 143, Banner GL, Banner MAXX II, Kestrel, Lesco Spectator, Procon-Z, ProPensity, Propiconazole Pro 1.3MEC, PropiMax, Strider	Acropetal Penetrant
pyraclostrobin	11	Strobilurin (QoI)	Insignia Intrinsic SC, Insignia	Localized Penetrant
tebuconazole	3	Demethylation Inhibitor	Clearscape, Mirage Stressguard, Tebuconazole 3.6F, Torque, Skylark,	Acropetal Penetrant
thiophanate-methyl	1	Benzimidazole	Allban, Andersons Systemic Fungicide 2.3G, ArmorTech TM 462, Cleary's 3336 (F, WP, DG lite, G, GC, Pro-Pak, Plus), Fungo (Flo, 50WSB), Lesco T-Storm 2G, Systec, T-Bird (4.5L, WDG), Tee-Off 4.5F, T-Methyl SPC 50 WSB, TM (4, SF, 85WDG)	Acropetal Penetrant
thiram	M3	Dithiocarbamate	Defiant 75WDG, Thiram, Spotrete F	Contact
triadimefon	3	Demethylation Inhibitor	Accost 1G, Bayleton (50WSP, Flo), Andersons Fungicide VII 0.59G, Andersons 1% Bayleton 1G, Lebanon Bayleton 1G	Acropetal Penetrant
trifloxystrobin	11	Strobilurin (QoI)	Compass 50WDG	Localized Penetrant
triticonazole 5	3	Demethylation Inhibitor	Trinity, Chipco Triton (70WDG, Flo)	Acropetal Penetrant
vinclozolin	2	Dicarboximide	Curalan 4F, Touché EG	Localized Penetrant
1 Fungicide Resistance Action Committee (FRAC) Code: fungicides with the same FRAC code have the same mode of action. M-codes indicate multi-site chemicals with low risk of resistance development. It is recommended to rotate applications by FRAC code and not to make sequential applications of fungicides with the same FRAC code. 2 See above text for information on topical mode of action. 3 Use of chlorothalonil is regulated in Massachusetts under the Public Drinking Water Supply protection regulations, see the Pesticide Regulations section of this guide for details. 4 Phosphite (salts) is also commonly referred to as phosphorus acid or phosphonate. 5 Use of triticonazole is regulated in Massachusetts under the Public Drinking Water Supply protection regulations, see the Pesticide Regulations section of this guide for details.
Updated October 2017

Table 21. Pre-mixed fungicide products registered for use on turf.

Pre-mixed Products (Common Name)	FRAC 1	Trade Name(s)
azoxystrobin + chlorothalonil 2	11 + M5	Renown
azoxystrobin + difenconazole	11 + 3	Briskway
azoxystrobin + propiconazole	11 + 3	Headway, Headway G, Contend B
Benzovindulflupyr + difenconazole	3 + 7	Contend A
chlorothalonil 2 + acibenzolar-S-methyl	M5 + P1	Daconil Action
chlorothalonil 2 + propiconazole	M5 + 3	Concert II, Echo Propiconazole Turf Fungicide
chlorothalonil 2 + tebuconazole	M5 + 3	E-Scape ETQ
chlorothalonil 2+ thiophanate-methyl	M5 + 1	Broadside, ConSyst, Peregrine, TM/C WDG, Spectro
chlorothalonil 2 + fludioxonil + propiconazole	M5 + 12 + 3	Instrata
chlorothalonil 2 + iprodione + tebuconazole + thiophanate-methyl	M5 + 3 + 3 + 1	Enclave
fluoxastrobin + chlorothalonil 2	11 + M5	Fame C
fluoxastrobin + tebuconazole	11 + 3	Fame T
fluopyram + trifloxystrobin	7 +11	Exteris
iprodione + trifloxystrobin	2 + 11	Interface Stressguard
mancozeb + copper hydroxide	M3 + M1	Junction
mancozeb + myclobutanil	M3 + 3	MANhandle
propamocarb + fluopicolide	28 + 43	Stellar
pyraclostrobin + boscalid	11 + 7	Honor
pyraclostrobin + fluxapyroxad	11 + 7	Lexicon
pyraclostrobin + triticonazole 3	11 + 3	Pillar G Intrinsic
thiophanate-methyl + chloroneb	1 + 14	Proturf Fungicide IX
thiophanate-methyl + flutolanil	1 + 7	SysStar
thiophanate-methyl + iprodione	1 + 2	ArmorTech TMI 20/20, 26/36 Fungicide, Dovetail, Lesco Twosome, Proturf Fluid Fungicide
thiophanate-methyl + mancozeb	1 + M3	Duosan (WP, WSB)
triadimefon + flutolanil	3 + 7	Prostar Plus
triadimefon + trifloxystrobin	3 + 11	Armada
triadimefon + trifloxystrobin + stress guard	3 + 11	Tartan Stressguard
1 Fungicide Resistance Action Committee (FRAC) Code: fungicides with the same FRAC code have the same mode of action. M-codes indicate multi-site chemicals with low risk of resistance development. It is recommended to rotate applications by FRAC code and not to make sequential applications of fungicides with the same FRAC code. 2 Use of chlorothalonil is regulated in Massachusetts under the Public Drinking Water Supply protection regulation, see the Pesticide Regulations section of this guide for details. 3 Use of triticonazole is regulated in Massachusetts under the Public Drinking Water Supply protection regulations, see the Pesticide Regulations section of this guide for details.
Updated October 2017

To get the most from a fungicide application within an IPM program, it is important to proceed in an informed and intelligent manner. Keep in mind that fungal pathogens of plants are dependent on a susceptible host and specific, favorable environmental conditions in order to cause disease. Planting resistant turfgrass cultivars (see Turfgrass Selection: Species and Cultivars) and modifying the growing environment to help reduce disease will make fungicides more effective. The most important aspect of disease control is correct identification of your target pest. It is imperative to be certain of the identity of the pathogen prior to any fungicide application. If in doubt, send a turf sample to the UMass Extension Plant Diagnostic Lab (ag.umass.edu/services/plant-diagnostics-laboratory). Knowing the pathogen allows you to know which grass species are susceptible or resistant, the optimum conditions for disease development, and the sensitivity of the pathogen to specific fungicides.

If you experience reduced efficacy or complete failure from fungicide applications to control dollar spot and athracnose, the UMass Pathology Lab offers both in vitro and molecular assays to assess potential fungicide resistance in the disease population.  See the Fungicide Resistance Assay page of this web site for information.

Table 22. Commonly used turf fungicides and the diseases they are labeled to control or suppress.

Click to download Table 22

In the Northeastern United States, high populations of nematodes in turf areas are generally restricted to golf greens as opposed to golf fairways, athletic fields, and lawn areas. Golf greens provide an ideal environment for nematodes. Root zones are commonly 75% to 95% sand which provides ideal pore spaces for oxygen, water and nematode mobility, and greens are watered frequently. Plant parasitic nematodes are found in all soils where plants grow but damage does not occur unless high populations develop. Golf greens can support high nematode populations and damage is exacerbated by other stresses brought about by environmental conditions, cultural practices and play.

Nematodes injure turfgrass roots either by feeding or burrowing through tissues. Depending on the host and the nematode involved, symptoms on roots include: inhibition of root elongation, swollen tips, galls, lesions, and shortened stubby roots. In most cases root symptoms are not obvious. Symptoms occurring above-ground result from root dysfunction and are not unique to nematodes. Patchy areas of wilting, thinning and decline occur where nematode populations are excessively high. Lance nematodes can result in patches of dead grass similar to fungal patch diseases. Above-ground symptoms are of little value in diagnosing nematode problems in turf. An accurate assessment of the pathogenic potential of nematodes can only be determined by a nematode assay.

Extraction of nematodes from soil is an imperfect process and only provides an estimation of the total population. Repeated extractions from the same soil sample will yield different results. It is not important exactly how many nematodes are recovered from the soil. Populations above thresholds are potentially a problem, while low populations are not. Moderate to high populations of nematodes should be considered within the context of other stresses and diseases present at the time.

Nematode population distribution

Nematodes are unequally distributed in the soil both vertically and horizontally. In the horizontal plane, nematodes have a clumped distribution. Figure 3 shows the number of nematodes in individual soil cores taken at one foot intervals in a transect across a putting green. The average number of nematodes in the example is 51. With regard to vertical distribution, population densities of various species differ according to the depth at which the sample was taken. Some tend to be concentrated in the upper portion of the soil profile. For example, a sample taken at a 2” depth may have twice the concentration of stunt nematodes as the same sample taken at 4”. Other nematodes may be more evenly distributed through the 4” depth.

Time of year

During winter months nematode populations decline. As the turf resumes growth, nematodes begin feeding. The reproductive potential of nematodes increases as the soil temperature rises. In Massachusetts, populations peak anytime from mid-June through mid- to late July. An additional peak of activity may occur later in the season.

For More Information
For further information about turf nematode assays and assay fees, refer to the UMass Extension Plant Diagnostic Lab at ag.umass.edu/services/plant-diagnostics-laboratory.

Assay procedure

It is not possible to extract all of the nematodes from a soil sample. Also, extraction techniques vary from one laboratory to another and some techniques are more efficient than others for recovering certain species.

Collecting a soil sample

Nematode populations are estimated most accurately with a composite sample. Use a 3/4” to 1” diameter soil probe, or something similar, and sample to a depth of 3 to 4” throughout the site. If a patch of dead turf is present, take 6 or 7 cores from within the patch, and for comparison, take 8 to 10 cores in a circle about 1 foot from the damage.

When damage is evident, collect 20 to 25 subsamples from throughout the affected area and bulk them. For comparison, a composite sample should also be taken from an adjacent, healthy appearing area.

When no damage is evident the entire green can be sampled by collecting 15 to 20 samples and bulking them as one. However, if the same green is sampled again, the assay results may be different solely because of the unequal distribution of nematodes. Also, there may be “hot spots” were nematode populations are high. When the intention is to monitor nematode populations over the course of the year, or from season to season, choose an area no larger than 500 sq. ft. Return to the same area later for additional samples. Collect 15 to 20 cores from within the designated area and bulk them.

The soil (at least one-half pint) should be placed in a container, such as a plastic bag, to prevent desiccation. Clearly identify the sample number on the outside of the container. After collection, refrigerate or deliver to The UMass Extension Plant Diagnostic Lab as soon as possible (ag.umass.edu/services/plant-diagnostics-laboratory).

Figure 3. Horizontal distribution of nematodes in a sample putting green
Golf greens provide an ideal environment for nematodes. Root zones are commonly 75% to 95% sand which provides ideal pore spaces for oxygen, water and nematode mobility.

Important note

Due to fluctuations in population levels over the course of the season, a single-sample evaluation for nematodes can be misleading, particularly if the results indicate populations below “threshold levels.” A more comprehensive evaluation the following year is recommended as a follow-up. Collect samples as outlined above starting in early June and re-sampling every four to five weeks until mid- to late September.

Threshold levels (nematode population levels which justify the implementation of control measures) are dependent on the variables described above. At this time there is very little experimental data to establish threshold levels for golf greens in Massachusetts and New England. The numbers listed in Table 23 are based on research from other states as well as from case history information and survey results compiled in our region. These numbers are meant to serve as a guide only and are subject to change.

Table 23. Guide to approximate threshold levels for nematodes in turf for the Northeast.

Nematode	No. / 100cc soil *
needle	100
lance	400
stunt	800
spiral	1,500
ring	1,500
lesion	100
cyst juveniles	500
root-knot juveniles	500
stubby root	100
sting	20
* Note: These threshold levels were developed when a nematicide capable of stopping nematode populations from developing further was commercially available. The thresholds listed here are not meant to imply that damage would occur at these levels. Some stress may occur at these levels, but at 2x or 3x these numbers damage would likely be evident.

Assessing damage caused by nematodes

High populations of certain species of nematodes may indicate that the root system has become debilitated to a significant extent. However, this information should be evaluated in context with past and prevailing circumstances. For example, all of the following factors are important in the development of a diagnosis and recommendation: species and numbers of nematodes present; depth at which the sample was taken; turfgrass species composition; depth of root system; soil texture; symptoms and extent of damage; potential contamination of the environment by a nematicide; and presence of other stresses to turf.

The decision to use nematicides must be carefully evaluated. The simple presence of plant parasitic nematodes does not warrant chemical application. Furthermore, when high populations of nematodes occur in the absence of appreciable damage to turf, it is difficult to justify applications. Nematicides should not be used where contamination of water may occur.

Fenamiphos (Nemacur), the only nematicide both effective on and labeled for control of nematodes on tees and greens, is a restricted use material. In addition, it is one of the pesticides on the Massachusetts Groundwater Protection List. Fenamiphos is being phased out of the market and existing stocks can be used only until October 6, 2017. Turf managers who wish to apply this material should refer to the Pesticide Regulations section of this guide.

Alternatives to nematicides

There currently are no cultural practices that will significantly reduce nematode populations. Any practices that encourage root growth and increase plant health, however, will help turf tolerate nematodes. Several biological controls and other “novel products” are available; however, field trials of these products have not been promising.

The Federal Government regulates pesticides through the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). FIFRA empowers the Environmental Protection Agency (EPA) to register pesticides and to regulate their use. FIFRA also allows for individual states to have primary enforcement responsibility for pesticide use within their borders

The Massachusetts Department of Agricultural Resources (MDAR) Pesticide Program regulates the use of pesticides in this state according to the 1978 Massachusetts Pesticide Control Act (Chapter 132 B of the Mass. General Laws). State regulations 333 CMR 1.00-14.00 have been promulgated pursuant to this law.

A brief overview of the specific parts of the regulation governing the application of pesticides by turf managers and in some instances other pesticide applicators follows. It is incumbent upon pesticide applicators to become familiar with the details of all aspects of the Pesticide Regulations, not just those listed here. For additional information on pesticide regulations, contact the Massachusetts Department of Agricultural Resources Pesticide Program (see contact information in the side bar of this page).

To obtain a complete copy of the regulations, contact the MDAR Pesticide Program or the UMass Extension Pesticide Education Program. The regulations are also available for download at the MDAR Pesticide Program web site.

For More Information
UMass Extension Pesticide Education Program Agricultural Engineering Building University of Massachusetts Amherst, MA 01003 (413) 545-1044 www.umass.edu/pested Massachusetts Department of Agricultural Resources Pesticide Program 251 Causeway Street, Suite 500 Boston, MA 02114-2151 (617) 626-1720 http://www.mass.gov/eea/agencies/agr/pesticides/

Licensing and certification

The process of licensing and certification for those individuals who apply pesticides is conducted by the MDAR Pesticide Program under Massachusetts Pesticide Regulations 333 CMR 10.00. Applicators applying pesticides to the property of another or areas to which the public has access, both indoors and outdoors, must be licensed. Applicators must be certified in order to buy restricted use pesticides. Complete information on the procedures and exams for licensing and certification, as well as recertification and insurance requirements are detailed in the Pesticide Examination and License Information Bulletin, available annually from the MDAR Pesticide Program.

The UMass Extension Pesticide Education Program conducts regular workshops and trainings designed to assist applicators in preparation for licensing and certification exams. Study materials are also available for purchase. For additional information on Massachusetts pesticide applicator licensing and training visit the Pesticide License Information page of this web site.

Notification and posting for turf pesticide applications to residential and public or private non-residential properties

333 CMR 13.06 requires turf pesticide applicators provide to the entity with which they contract or the manager or superintendent of the contracting entity information about pesticides used, safety measures for humans and the environment, and specific application information. Provisions for pre-notification of application are covered in this regulation. It further requires that turf pesticide applicators post approved signs on properties prior to treatment and that signs remain in place for 24-72 hours. Further information on this regulation should be obtained from the MDAR Pesticide Program.

Record keeping

Regulation 333 CMR 10.14 requires that all licensed and certified commercial applicators or their employers keep true and accurate operational records on each application of a pesticide. The same regulation authorizes the Massachusetts Department of Agricultural Resources to require annual records and reports of the information maintained in accordance with the regulation. Record keeping forms and/or a listing of specific information required is available from the MDAR Pesticide Program.

Legislation (The Act Protecting Children and Families from Harmful Pesticides — Chapter 85 of the Acts of 2000) that amends the Massachusetts Pesticide Control Act (Chapter 132B of the M.G.L.) took effect on November 1, 2000. This regulation is commonly known as the Children and Families Protection Act.

This legislation primarily addresses the use of pesticides in schools, day care centers, and school-age childcare programs. Other sections of the legislation include but are not limited to: notification and posting requirements, pesticide use along rights-of- way, applicator competency evaluation, and Integrated Pest Management (IPM) plans. Ultimately, the intent of the legislation is to encourage the use of IPM and to minimize pesticide exposure, especially to children and facility employees.

Who is responsible? Those persons who perform, contract, and/or administratively oversee pest management services for schools, day care centers, and school-age child care programs play significant roles in ensuring compliance regulation. Additional parties involved may include utility companies and state agencies.

The MDAR Pesticide Program is responsible for the implementation of this legislation. Detailed information about how to comply with the Children and Families Protection Act can be obtained from the MDAR Pesticide Program. For turf managers that must develop an IPM plan under the requirements of the Children and Families Protection Act, UMass Extension has published Integrated Pest Management Protocols for Turf on School Properties and Sports Fields. This manual is a tool that specifies the steps required for development and implementation of a comprehensive IPM plan. For additional information see the Printed Publications page of this web site.

The Massachusetts Department of Agricultural Resources (MDAR) Public Drinking Water Supply Protection Regulations (State Regulation 333 CMR 12.00, enacted 1/1/1992) are intended to prevent non-point source contamination of public drinking water supply wells from pesticide products on the Massachusetts Groundwater Protection List. Updated annually, the Groundwater Protection List identifies specific pesticide active ingredients that could potentially impact groundwater due to their chemical characteristics and toxicological profile.

Geographic sites protected under the regulations are referred to as primary recharge areas. For pesticide regulatory purposes, a primary recharge area is considered to be either an Interim Wellhead Protection Area (IWPA) or a “Zone II” for wells that have pumping rates of over 100,000 gallons per day (gpd). The Drinking Water Supply Protection Regulations do not apply to wells that pump less than 100,000 gpd.

If a management decision has been made to use one of the pesticides listed on the Groundwater Protection List, then it is the responsibility of the applicator to be aware if the site is within an IWPA or Zone II area, and to act accordingly. For general guidelines about how to comply with the Massachusetts Public Drinking Water Supply Protection Regulations, consult the flowchart in Figure 4 below.

Table 24. Massachusetts Groundwater Protection List (current as of April 1, 2018)

Herbicides		Insecticides	Fungicides
Acetochlor Acifluorfen Alachlor Aldicarb Atrazine Bentazon* Bromacil Cyanazine Chlorthal-dimethyl (DCPA) Dimethanamid*	Diuron Flufenacet Fluthiacet-methyl MCPA* Metolachlor Metribuzin PCP Pronamide Propazine Simazine Sulfentrazone*	Aldicarb Carbofuran Dinotefuran* Disulfoton Fonofos Lindane Methoxyfenozide PCP Propoxur Terbufos Thiamethoxam*	Chlorothalonil* Cyflufenamid Cyproconazole Folpet Kresoxim-methyl Triticonazole* Sedaxane
			Nematicides
			Fenamiphos*

* Denotes active ingredient labeled for cool-season turf use

Figure 4. Do the Massachusetts Public Drinking Water Supply Protection Regulations Apply to You? 1. Do you plan to make a pesticide application within a Zone II or Interim Wellhead Protection Area (IWPA)? For instructions on how to determine if your application will fall within a Zone II or an IWPA, contact the MDAR Pesticide Program at (617) 626-1771, or visit https://www.mass.gov/pesticides-and-water-supply-protection If NO, then STOP. You do not need to be concerned about the regulations. If YES, then proceed to Question 2.   2. Does the pesticide product that you intend to use contain any of the active ingredients listed on the current Massachusetts Groundwater Protection List? If NO, then STOP. You do not need to be concerned about the regulations. If YES, then proceed to question 3.   3. Are there any viable alternatives to the pesticide that you intend to use? If YES,  then STOP and use the alternative. If NO, then proceed to Question 4.   4. Will the pesticide product be applied to an area which has greater than 50% foliar cover? If YES, then you must confirm the non-viability of alternatives, you must apply the pesticide as part of an Integrated Pest Management (IPM) program approved by MDAR, and you must submit a Groundwater Protection Program Notification Form to MDAR within 10 days of the end of the calendar month in which the pesticide is applied. If NO (meaning that the pesticide product that you intend to use is soil-applied, or will be applied to an area with less than 50% foliar cover), then you must confirm the non-viability of alternatives, you must apply the pesticide as part of a MDAR approved Integrated Pest Management (IPM) program, and you must verify that a Pesticide Management Plan (PMP) for that use pattern has been approved by MDAR.   For further information on MDAR notification requirements, MDAR approved Integrated Pest Management (IPM) programs and/or a Pesticide Management Plan (PMP), contact the MDAR Pesticide Program at (617) 626-1771.

Turf pesticides on the Massachusetts Groundwater Protection List

Herbicides

Bentazon (Basagran) is used primarily for the control of yellow nutsedge in turf. Possible alternatives to bentazon include halosulfuron and mesotrione. For more information about bentazon, see the Characteristics of Turf Herbicides section of this guide.

Dimethanamid (Tower) is used primarily for the preemergence control of yellow nutsedge in turf.  No other material is currently labeled for preemergence yellow nutsedge control.  Postemergence control with halosulfuron or mesotrione is an alternative option.  For more information about dimethanamid, see the Characteristics of Turf Herbicides section of this guide.

MCPA (several trade names) is a component of several combination products labeled for postemergence control of broadleaf weeds in turf. MCPP has gained favor over MCPA for many formulations in recent years because of higher activity. Thus, viable alternatives are readily available. For more information about MCPA, see the Characteristics of Turf Herbicides section of this guide.

Sulfentrazone (several trade names) is used primarily for postemergence management of a range of broadleaf weeds in turf. It is formulated alone or in combination with additional herbicides. Possible alternatives to sulfentrazone include halosulfuron and mesotrione. See the Characteristics of Turf Herbicides section of this guide for additional information about sulfentrazone.

Fungicides

Chlorothalonil (Daconil and several other trade names) is labeled for use on several major turfgrass diseases in the Northeastern U.S, including anthracnose, brown patch, copper spot, dollar spot, Microdochium patch (pink snow mold), Helminthosporium leaf spot disease, red thread, rusts, and Typhula blight (gray or speckled snow mold). Many alternative fungicides are available for these diseases (see Table 22 in the Disease Management with Fungicides section of this guide). The primary disadvantage of many of the alternative compounds, however, is the potential for fungicide resistance development with repeated use. Because resistance has not been reported for chlorothalonil, it is an important rotation and tank-mix product for resistance management programs (refer to the Characteristics of Turf Fungicides section of this guide for a discussion of fungicide resistance). Also, the broad spectrum activity of chlorothalonil is part of its value as a fungicide. This value is reflected in the relatively frequent use of chlorothalonil on turf, despite decreased residual control compared to penetrant fungicides. Many of the alternative products do not have the same broad spectrum of activity.

Unfortunately, cultural management may not be sufficient to protect turf in stressful conditions, especially when weather conditions are conducive to the development of a particular disease, and in particular on golf greens and tees. In a good IPM program, no fungicide application should be considered for a specific disease problem without considering secondary problems. Before it is determined that use of an alternative to chlorothalonil will be a sound decision, it is necessary to consider all disease problems in an area and in a particular season. Often, determining a viable alternative is a complex task involving more than a single disease evaluation. At this time, there is no viable alternative to chlorothalonil plus a penetrant fungicide for control of anthracnose on putting greens. See Figure 5 for special considerations about the application of chlorothalonil for anthracnose in Massachusetts.

Figure 5. Guidelines for the use of chlorothalonil for anthracnose on putting greens in Massachusetts. Obtain a diagnosis, at least once, from a diagnostic lab and keep the report in your records. Information for submitting samples to the UMass Extension Plant Diagnostic Lab can be found at ag.umass.edu/services/plant-diagnostics-laboratory.   File the Notification Form with MDAR within 10 days of the end of each calendar month in which chlorothalonil is applied (you also must record all applications of chlorothalonil on the IPM Program form listed below). The proper Notification Form can be obtained by contacting the MDAR Pesticide Program at (617) 626-1720 or visiting http://www.mass.gov/eea/agencies/agr/pesticides/.   Obtain a copy of the UMass Extension fact sheet “Why is it so Difficult to Control Anthracnose?” The fact sheet is available on the MDAR web site or on the UMass Extension Turf Program web site at ag.umass.edu/turf/fact-sheets/why-is-it-so-difficult-to-control-anthracnose.   Manage anthracnose using the MDAR approved Turf Anthracnose Management Approved IPM Program and maintain the required records with your pesticide application records. A copy of the program can be obtained by contacting the MDAR Pesticide Program at (617) 626-1720 or visiting http://www.mass.gov/eea/agencies/agr/pesticides/.

Triticonazole (Trinity, Triton) provides good control of a number of turf diseases including anthracnose, dollar spot, necrotic ring spot, red thread, brown patch, and take-all patch. Triticonazole is one of the demethylation inhibitor (DMI) fungicides. If you make a decision to use triticonazole, but are located in a Zone II or IWPA area, several alternatives in the DMI class are available. Alternatives include propiconazole, fenarimol, metconazole, triadimefon, and myclobutanil. Refer to Table 22 in the Disease Management with Fungicides section of this guide for additional information.

Insecticides

Dinotefuran (Zylam) is one of several insecticide compounds in the neonicotinoid class. While it is used more commonly in landscape settings, it is now being marketed for control of annual bluegrass weevils on golf courses. If you wish to control ABW in a Zone II or IWPA area, there are several alternatives to dinotefuran.  These include a pyrethroid to target adults; or indoxacarb, spinosad, chlorantraniliprole, or trichlorfon to target larvae.

Thiamethoxam (Meridian) is another insecticide in the neonicotinoid class. Insects on the label include annual bluegrass weevil, black turfgrass ataenius, caterpillars, billbugs, and white grubs. If you wish to make an application for any of these target insects in a Zone II or IWPA area, you should be able to substitute another neonicotinoid. For example, imidacloprid or chlothianidin are viable alternatives and are both somewhat less soluble than thiamethoxam. If the primary target is white grubs, chlorantraniliprole would also be an alternative. See the Insect Management with Insecticides section of this guide for additional information.

Nematicides

Fenamiphos (Nemacur) is a nematicide and is labeled for use on golf course greens (bentgrass) where virtually all nematode problems on turf occur. Fenamiphos has been gradually phased out of the turf market, but any existing stocks can still be used until October 6, 2017. As such, fenamiphos is a highly toxic material and should be used only after high nematode populations have been confirmed by a diagnostic lab (for the UMass Extension Plant Diagnostic Lab, see ag.umass.edu/services/plant-diagnostics-laboratory).

Considerable testing underway at this time seeks to identify viable alternatives to fenamiphos, but an effective replacement has yet to be found. Cultural practices that encourage root system health and development are strongly recommended as a first line of defense against nematode pressure. Cultural management may help to mitigate damage from low nematode populations, but unfortunately may not be sufficient for golf greens with high populations.