Section 3: Weed Management

In this section:

Understanding weed life cycles

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 for turf weeds

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 for weed management

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.

Characteristics of turf herbicides

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

 

Weed management with herbicides

  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.  
      1. 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.
        Trade Name Active Ingredients
        2,4-D 1 2,4-DP (dichlorprop) carfentrazone clopyralid dicamba fluroxypyr MCPA 2 MCPP (mecoprop) pyraflufen-ethyl penoxsulam quinclorac sulfentrazone triclopyr

        2‐D

         

         

         

        X

         

         

         

         

         

         

         

         

        X

        3‐D

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        2,4‐D L.V. 4 Ester

        X

         

         

         

         

         

         

         

         

         

         

         

         

        2,4‐D L.V. 6 Ester

        X

         

         

         

         

         

         

         

         

         

         

         

         

        4‐Speed XT

        X

         

         

         

        X

         

         

         

        X

         

         

         

        X

        4‐Speed

        X

         

         

         

        X

         

         

        X

        X

         

         

         

         

        Banvel

         

         

         

         

        X

         

         

         

         

         

         

         

         

        Barrage HF

        X

         

         

         

         

         

         

         

         

         

         

         

         

        Battleship III

         

         

         

         

         

        X

        X

         

         

         

         

         

        X

        Brushmaster

        X

        X

         

         

        X

         

         

         

         

         

         

         

         

        Chaser

        X

         

         

         

         

         

         

         

         

         

         

         

        X

        Chaser 2 Amine

        X

         

         

         

         

         

         

         

         

         

         

         

        X

        Chaser Ultra

         

        X

         

         

         

        X

        X

         

         

         

         

         

         

        Chaser Ultra 2

        X

         

         

         

         

        X

        X

         

         

         

         

         

         

        Confront

         

         

         

        X

         

         

         

         

         

         

         

         

        X

        Cool Power

         

         

         

         

        X

         

        X

         

         

         

         

         

        X

        Dismiss

         

         

         

         

         

         

         

         

         

         

         

        X

         

        E‐2

        X

         

         

         

        X

        X

         

         

         

         

         

         

         

        Eliminate

         

         

         

         

        X

         

        X

         

         

         

         

         

        X

        Eliminate D

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Eliminate LO

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Escalade 2

        X

         

         

         

        X

        X

         

         

         

         

         

         

         

        Horsepower

         

         

         

         

        X

         

        X

         

         

         

         

         

        X

        Lockup

         

         

         

         

         

         

         

         

         

        X

         

         

         

        Lockup Extra

         

         

         

         

        X

         

         

         

         

        X

         

         

         

        Lockup Extra 2

        X

         

         

         

        X

         

         

         

         

        X

         

         

         

        Lontrel T&O

         

         

         

        X

         

         

         

         

         

         

         

         

         

        MCPP‐p 4 Amine

         

         

         

         

         

         

         

        X

         

         

         

         

         

        Mecomec (2.5, 4)

         

         

         

         

         

         

         

        X

         

         

         

         

         

        Momentum FX2

        X

         

         

         

         

        X

         

         

         

         

         

         

        X

        Momentum Q

        X

         

         

         

        X

         

         

         

         

         

        X

         

         

        Octane SC

         

         

         

         

         

         

         

         

        X

         

         

         

         

        OneTime

         

         

         

         

        X

         

         

        X

         

         

        X

         

         

        Pasture Pro

        X

         

         

         

         

         

         

         

         

         

         

         

         

        Power Zone

         

         

        X

         

        X

         

        X

        X

         

         

         

         

         

        Q4 Plus

        X

         

         

         

        X

         

         

         

         

         

        X

        X

         

        QuickSilver T&O

         

         

        X

         

         

         

         

         

         

         

         

         

         

        Quincept

        X

         

         

         

        X

         

         

         

         

         

        X

         

         

        RedZone 2

        X

         

         

         

        X

         

         

        X

        X

         

         

         

         

        Solitare

         

         

         

         

         

         

         

         

         

         

        X

        X

         

        Speed Zone

        X

         

        X

         

        X

         

         

        X

         

         

         

         

         

        Speedzone Southern

        X

         

        X

         

        X

         

         

        X

         

         

         

         

         

        Spoiler

        X

        X

         

         

         

         

         

        X

         

         

         

         

         

        SquareOne

         

         

        X

         

         

         

         

         

         

         

        X

         

         

        Strike 3

        X

        X

         

         

         

        X

         

         

         

         

         

         

         

        Surezone

        X

         

         

         

        X

         

         

        X

         

         

         

        X

         

        Surge

        X

         

         

         

        X

         

         

        X

         

         

         

        X

         

        Tailspin

         

         

         

         

         

        X

         

         

         

         

         

         

        X

        Three‐Way Ester II

         

         

         

         

        X

         

        X

         

         

         

         

         

        X

        Three‐Way Selective

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Threesome

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Triamine

        X

        X

         

         

         

         

         

        X

         

         

         

         

         

        Trimec (637, 992,

        1000 Low Odor,

        Classic, LAF,

        Southern)

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Trimec (Super)

        X

        X

         

         

        X

         

         

         

         

         

         

         

         

        Trimec Encore

         

         

         

         

        X

         

        X

        X

         

         

         

         

         

        Triplet (Low Odor, Sensitive SF)

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Tripower

         

         

         

         

        X

         

        X

        X

         

         

         

         

         

        Trupower (2 & 3)

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        Turflon‐D

        X

         

         

         

         

         

         

         

         

         

         

         

        X

        Turflon (Ester & Ester Ultra)

         

         

         

         

         

         

         

         

         

         

         

         

        X

        Turflon II Amine

        X

         

         

         

         

         

         

         

         

         

         

         

        X

        T‐Zone

        X

         

         

         

        X

         

         

         

         

         

         

        X

        X

        Vanquish

         

         

         

         

        X

         

         

         

         

         

         

         

         

        Vessel

        X

         

         

         

        X

         

         

        X

         

         

         

         

         

        WeeDestroy AM‐40

        X

         

         

         

         

         

         

         

         

         

         

         

         
        1 Products containing more than 20% 2,4‐D are classified as Restricted Use in Massachusetts.
        2 MCPA is regulated under the Public Drinking Water Supply Protection Regulations in Massachusetts.
        3 Sulfentrazone is regulated under the Public Drinking Water Supply Protection Regulations in Massachusetts

  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.