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Landscape Message: Sep 4, 2015

Sep 4, 2015
Issue: 
20

UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Green Industry professionals in the management of our collective landscape. Scouts compile and record environmental and phenological data for locations throughout Massachusetts to aid in the monitoring of plant and pest development, the planning of management strategies, and the creation of site-specific records for future reference.  Detailed reports from Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. UMass Extension has updated the following issue to provide timely management information and the latest regional news and environmental data.

The Landscape Message will be updated bi-weekly July-September. The next message will be available on September 18.  To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

Scouting Information by Region

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The weather appears to be stuck on hot, humid, and dry for the most part this reporting period. Dew points are frequently over 70, making it uncomfortable to do any physical work. There have been a few isolated thunderstorms coming through, giving Marstons Mills 0.45” on 8/22 with another 0.25” on the 23rd. Sandwich received 0.75” from that storm and Chatham again received the jackpot of 1.65”. The last rainfall recorded in the rain gauge in the Mills was 0.6” received on 8/26 and it has been dry since then. A brief cold front came through on the 27th, giving relief from the humidity but temperatures remain warm and dew points have crept back up into the sticky range. Hardy Crepe Myrtles are in full bloom, along with perennial hibiscus. Early fall asters are beginning to show color. Heptacodium miconioides is just beginning to bloom.

Pests/Problems: While there has been a bit of relief in the rain department, many plants still show that the dry summer as impacted them. Many trees and shrubs have brown margins on their leaves. Unirrigated lawns are still brown with patches of bright green crabgrass, which is drought tolerant! Insect activity has dropped off considerably. Few Japanese beetles can be seen and Oriental beetle appears to be finished for this year. Mites and leafhoppers are active on annuals and perennials. Wasp and hornet colonies are at their peak at this time of year. Black locust borer adults can be seen feeding on goldenrod pollen. Other than powdery mildew, disease activity has been slight this season. Mosquitoes are still biting and West Nile virus has been confirmed in the mosquito population in Hyannis. Deer ticks are less active at this time but will become more active when the weather cools off in late September/early October.

Southeast Region (Hanson)

General Conditions: August was a warm month with several days in the 90’s and most days in the 80’s. September has also started out warm and warm weather and no rain are in the forecast. Many days in August were also very humid. Hanson received 0.70 inches of rain over the last two weeks, not nearly enough, and soils are very dry. Rose-of-Sharon, Albizia julibrissin, Campsis radicans, Roses, Hydrangea paniculata, Hydrangea quercifolia, Caryopteris divaricata, Butterflybush, roses, Rudbeckia ‘Herbstonne', Rudbeckia subtomentosa ‘Henry Eilers’, Rudbeckia triloba, Rudbeckia ‘Goldsturm,’ Persicaria amplexicaulis, Ligularia sp., Campanula sp., Eupatorium sp., Corydalis lutea, Hosta sp., Heliopsis ‘Summer Sun’, Helianthus 'Lemon Queen', perennial Hibiscus, Lobelia syphilitica, Lobelia cardinalis, Lobelia hybrids, ornamental grasses, Coreopsis ‘Harvest Moon‘ and Phlox paniculata remain in bloom. Sedum sp. are beginning bloom. Veronicastrum and Echinacea purpurea and hybrids are ending bloom. Fruits of Kousa dogwood, Cornus controversa, hollies, crabapples, Staghorn sumac and Viburnums are beginning to add color to the landscape.

Pests/Problems: As mentioned in the last Landscape Message, dry soils remain the largest landscape concern. With high temperatures and no rain, soils are dry and warm. Soil temperatures in Hanson have remained in the low-mid 80’s for almost all of August. Hanson only received 2.60 inches of rain over the past 6 weeks and Bridgewater MA reported 1.79 inches of rain for the month of August. Most landscape plants are drought-stressed. Sufficient soil moisture in late summer-early fall is critical for plants as they go into fall dormancy. Plants need sufficient water right up until the time they go dormant and right now in many areas of southeastern MA, they are not receiving the moisture they need. Kousa dogwoods, Katsura, oak, maples, hosta, daylilies, etc., are some of the many plants showing signs of drought stress. Even weeds are wilting! Unirrigated lawns are turning brown. Some homeowners have complained about skunks and birds digging and damaging lawns. While grubs may be the culprit, there are other insects that may be present. Monitor lawns for chinch bugs and sod webworm. Sod webworm adult moths were observed in Hanson, on one lawn, and the moths were in high numbers. Birch sawfly (Arge pectoralis) was observed on paper birch. Like many other sawflies, birch sawflies congregate and feed along the leaf margins, leaving the mid-vein. These sawflies can strip a small tree of foliage unless managed. Remember, sawflies are not Lepidopteron caterpillars and Bacillus thuringiensis (Bt) will not work on sawflies. Earwigs, slugs and snails have been very active on a wide range of plants like hosta, Solomon’s seal, etc. While mosquito numbers remain low, West Nile Virus was found in Easton, Bridgewater and Kingston. Remember to use repellants. Continue to monitor for dogwood sawfly, viburnum leaf beetle, redheaded pine sawfly and introduced pine sawfly. The following insects remain active: Sunflower moth caterpillars, Pieris and other lacebugs, boxelder beetles, wasps, hornets, spider mites, leafhoppers and biting flies. Asiatic beetles, Oriental beetles and Japanese beetles appear to have finished for the year. Powdery mildew is noticeable on many plants, especially susceptible garden phlox, Monarda, Helianthus, and Cornus sp. Crabgrass is having an incredible year, as is prostrate spurge and clearweed. Goldenrod and ragweed remain in bloom.

North Shore Region (Beverly)

General Conditions: The conditions during this reporting period continued to be hot and humid. Rainfall occurred on only two days during this period. A thunderstorm passed through on Friday, August 21 and brought about 1.53 inches of rainfall. Another storm passed through on Monday, August 24 and brought about 0.14 inches of rainfall, bringing the total amount of precipitation during this period to 1.67 inches. Temperatures during this reporting period were in the high 80s during the day and high 60s during the night. There were no temperatures of 90 degrees and above reported. Woody plants seen in bloom include: Japanese pagoda tree (Sophora japonica), Silk tree or Mimosa (Albizia julibrissin), Oakleaf hydrangea (Hydrangea quercifolia), Butterfly bush (Buddleia davidii), Harlequin glorybower (Clerodendrum trichotomum), Blue mist shrub (Caryopteris x clandonensis), Russian Daphne (Daphne x transatlantica) and Woody clematis (Clematis stans). Herbaceous plants seen in bloom include: Bush clover (Lespedeza thunbergii), , Garden phlox (Phlox paniculata), hostas (Hosta spp.), Autumn joy sedums (Sedum spp.), Joy pye weed(Eutrochium purpureum), Sweet autumn clematis (Clematis paniculata), Rudbeckia (Rudbeckia hirta), Trumpet creeper (Campsis radicans), Morning glory (Ipomoea purpurea), Balloon flower (Platycodon grandiflorus), Japanese anemone (Anemone x hybrida), Yellow wax bells (Kirengeshoma palmata) and Water lily (Nymphaea odorata). Different kinds of annuals are also contributing more color in landscapes

Pests/Problems: Cedar apple rust (Gymnosporangium juniperi-virginianae) is still being observed on crabapples and powdery mildew (Microsphaera alni) is prevalent on lilac. Crabgrass and other weeds are thriving in the landscape. Goldenrod (Solidago canadensis) is in full bloom and providing a lot of color to roadsides. Mosquitoes have slowed down but they are still active at dawn and dusk. Ticks are also still active.

East Region (Boston)

General Conditions: Hot and dry conditions have prevailed over the past two weeks. We gained 308.5 growing degree days bringing us to 2398. we received 0.19” of precipitation, total precipitation for August was below average. Plants in bloom include: Aralia sp., Koelreuteria paniculata ‘Rose Lantern’ (cultivar of golden rain tree) and a large Rhus chinensis (Chinese sumac) that is active with honey bees and many other pollinators. Many perennials are flowering: Aster pilosus (fall aster), Helianthus tuberosus (Jerusalem artichoke), Lobelia cardinalis (cardinal flower), Silphium perfoliatum (cup plant) and many others. Adding color to the landscape is a wide variety of colorful fruit: Cotoneaster sp., Crataegus sp.(hawthorn), Malus sp. (crabapple), Prunus sp. (cherry), Rosa sp. (rose) and Sorbus sp. (mountain ash).

Pests/Problems: Dry soils continue to be a concern. Supplemental irrigation is required. In many locations the soil is dusty and repelling water. Many Quercus sp. (oaks) are dropping acorns of all sizes. Adult Viburnum Leaf Beetles were observed mating the week of August 24-28. Lacebugs and mites are active and prevalent throughout the landscape. Fruit is maturing on Ampelopsis sp. (porcelain berry), Celastrus sp. (bittersweet) and Cynanchum louiseae (black swallow-wort).

Metro West (Acton)

General Conditions: Summer isn’t over yet! The hot, humid and dry weather pattern has continued. Soils are dry. The Acton area gained 303 GDD during this two-week recording period and received 0.03” of rain. The Metro West area received a total of 1.24” of rain for the month of August, falling far short of 3.72", the thirty-year rainfall average for the month. Woody plants seen in bloom this week are Buddleia spp. (Butterfly Bush), Clethra alnifolia (Summersweet Clethra), Franklinia alatahama (Franklin Tree), Heptacodium miconioides (Seven-Son Flower), Hibiscus syriacus (Rose-of-Sharon), Hydrangea paniculata and its many cultivars including 'Tardiva', Rosa rugosa (Rugosa Rose), and R. 'Knockout' (The Knockout family of Roses). A woody vine in bloom is Clematis paniculata (Sweet Autumn Clematis). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Alcea rosea (Hollyhocks), Asclepias syriaca (Common Milkweed), A. tuberosa (Butterfly Weed), Aster spp. (New England Aster, New York Aster, Smoother Aster, White Wood Aster), Astilbe spp. (False spirea), Boltonia asteroids (Bolton’s Aster), Calamagrostis acutifolia 'Karl Foerster' (Feather Reed Grass), Ceratostigma plumbaginoides (Plumbago), Chasmanthium latifolium (Northern Sea Oats), Chelone lyonii (Pink Turtlehead), Cichorium intybus (Chicory), Coreopsis verticillata (Threadleaf Coreopsis), Daucus carota (Queen Anne's Lace), Echinacea purpurea (Coneflower), Eupatorium purpureum (Joe Pye Weed), Hemerocallis 'Stella D'Oro' (Daylily), H. spp. (Daylily), Hosta spp. (Plantain Lily), Liatris spicata (Spike Gayfeather), Malva alcea 'Fastigiata' (Hollyhock Mallow), Miscanthus sinensis (Maiden Grass), Patrinia gibbosa (Patrinia), Perovskia atriplicifolia (Russian Sage), Pennisetum alopecuroides 'Hameln' (Dwarf Fountain Grass), Phlox carolina (Carolina Phlox), C. paniculata (Phlox) and its many cultivars, Rudbeckia fulgida 'Goldsturm' (Black-Eyed Susan), Sedum ‘Rosy Glow’ (Stonecrop), and Solidago spp.(Goldenrod).

Pests/Problems: Lack of any amount of rainfall continues to be a problem. Signs of drought stress on woody plants are appearing in the form of leaf wilt, discoloration and drop and lawns are turning brown. Powdery mildew is rampant with the hot and humid weather and is evident on Monarda (Bee Balm), Phlox and Syringa (Lilac). The first and only Asian Longhorned beetle of the season thus far was caught in a trap within the Worcester County ALB regulated area on the August 14th in Worcester so continue to check your trees for oviposition sites, frass, exit holes and the beetle. Monitor the 13 host genera which are: Acer (Maple), Betula (Birch), Ulmus (Elm), Salix (Willow), Aesculus (Horsechestnut), Fraxinus (Ash), Platanus (Plane Tree), Populus (Poplar), Celtis (Hackberry), Sorbus (Mountain Ash), Albizia (Mimosa), Cercidiphyllum (Katsura) and Keolreuteria (Golden Raintree) for signs of this invasive pest.

Central Region (Boylston)

General Conditions: Hot & humid to start the new month of September. The lack of rain and heat are coupling to cause plant stress - roadside plants are now wilting, lawns are slipping into dormancy, and trees like Catalpa, maples, birch, and cherries are coloring early due to the dry conditions. In bloom this period are Anemone tomentosa ‘Robustissima’, Anemone x hybrida ‘Serenade’, Iris domestica, Callicarpa japonica and C. dichotoma, Hibiscus moscheutos, Phlox paniculata,Veronicastrum virginicum, Vernonia noveboracensis, Joe Pye Weed (Eupatorium sp.), many ornamental grasses are now at thier finest including Pennisetum alopecuroides ‘Hameln’, Miscanthus sinensis cultivars, and Panicum cultivars, Rudbeckia hirta, Rudbeckia triloba, Rudbeckia nitida, Rudbeckia subtomentosa ‘Henry Eiler’, Goldenrod (Solidago sp.), Perovskia atriplicifolia, Indigofera amblyantha, Aster linariifolius, Angelica gigas, Chrysanthemum ‘Clara Curtis’, Helenium autumnale, Clerodendrum trichotomum.  Pests/Problems: - and with the heat and humidity comes powdery mildew! Fireblight is still showing up on apple relatives. Dogwood Sawfly remains active but blister beetles, Japanese beetles are slowing down. Lack of rain continues to be our most pressing problem,

Pioneer Valley Region (Amherst)

General Conditions: This past reporting began with hot and humid weather, a continuation of conditions that ended our last report, with highs in the upper 80s and sweltering dew points in low 70s. Conditions cooled dramatically between 8/26 and 8/28 when highs reached only the upper 70s to low 80s and nighttime temperatures were comfortably in the 50s to low 60s. As we closed the door on August, the heat returned along with the high dewpoints. But, the decreasing solar intensity this time of year has taken the edge off this latest "heave wave". We are losing significant daylight as we march towards the autumn equinox. Heavy fog has blanketed the valley bottom during the morning hours for much of this reporting period. For trees that naturally grow in foggy locations, like balsam fir, this will hopefully ease some of the stress of the recent heat. From 8/1 to 8/31 we lost over 70 minutes of daylight, with the majority of that deficit coming at the end of the day. Supplemental watering in the dark has become the norm for this author. The valley experienced two rain events over this past reporting period. The first, on Friday 8/21 deposited up to 0.5" in Hampden, Hampshire and Franklin Counties, but the patchy distribution left many areas with only trace to 0.1" of rain. Significantly greater rainfall occurred on Tuesday 8/25. Greenfield was the recipient of over 2" of rain from multiple fast-moving cells that swept through the region. Accumulations tapered heading south, with Amherst recording ~1.5" and Springfield getting less than 0.15". Because of the wide variation in precipitation, some landscapes appear green and relatively vibrant while others are browning and drought-stressed.

Pests/Problems: Supplemental watering should continue in locations that have received less than 0.5” of rain over the past two weeks. High heat and humidity increases transpiration and can hasten drought stress. Scorch is common right now on red maple, katsura, stewartia, linden and many other landscape trees and shrubs with shallow root systems, restricted root zones, and those in decline from disease/insect infestations. Late in the season, many trees and shrubs are showing the wear and tear of the growing season, so expectations must be tempered. A fall fertilization may be recommended for recently transplanted and declining trees. A standard 10-10-10 fertilizer is a good choice for a wide array of woody plants but can burn surrounding turfgrass if applied too liberally. Sugar and red maples in decline are now showing their fall colors as they senesce early. This is a good time to scout for sugar maple borer, especially on trees known to be infected with Armillaria or other wood-decay fungi. Oval-shaped holes can be observed on large branches and the main trunk and may be accompanied by sawdust or sap. Lime applications around sugar maple can improve their vigor as they prefer basic soils. This can be a good time to prune dead shoots from apple and crabapple. A large fruit crop on many trees this season has weighed the branches down, making them more accessible. Spider mite damage is widespread on a variety of different landscape plants including andromeda, serviceberry, oak and spruce. The spruce spider mite is unlike many other spider mites in that it does not thrive in very hot weather. Therefore, once temperatures cool in September, expect increased activity from this pest. Hosts include spruce, fir, hemlock, and arborvitae, among others. For blue spruces suffering from stem cankering and needle cast, this is a compounding stress that will accelerate decline. Many declining blue spruces have no remaining needles from 2013 and needles produced in 2014 may soon become symptomatic from infection by Rhizosphaera. As such, what needles remain are vital to their survival and chemical control of mite populations may be necessary. Scout cherry and other hosts of the eastern tent caterpillar for egg masses. They are black, somewhat metallic, in color and are deposited in small masses encircling upper canopy shoots. Crushing these egg masses will significantly reduce the presence of this pest next spring. Japanese beetles are becoming difficult to find and the dry weather has kept mosquito populations down outside of forest settings. The scourge of the valley, Japanese knotweed, is still in full flower in many locations.

Berkshire Region (Great Barrington)

General Conditions: Interestingly, weather conditions recently are similar to that of last year during the same time frame. Temperatures are well above normal and relative humidity is high. Two heavy rainfalls have brought soil moisture levels up but high temperatures quickly depleted much of that moisture. Research has shown that September is a critical time to focus on soil moisture. Root systems are recovering from the stress of summer heat and low soil moisture. Without adequate water, regeneration of roots is limited. This in turn restricts the uptake of moisture by plants and makes them prone to winter desiccation. Monitor rainfall and soil moisture carefully this month and irrigate if soil moisture is deficient. Phlox, Rudbeckia, Echinacea, Eupatorium and many other late flowering perennials dominate landscapes and are putting on a very lush and colorful display. However, their dominance also masks the tattered appearance of plants which have passed their prime or suffer from pests, diseases, and poor maintenance. Sometimes it pays not to look too closely.

Pests/Problems: Premature leaf drop and/or fall coloration have been more common in recent weeks. These are always indicators of stress, whether it be abiotic or biotic. Clearly some the coloration has been due to heat scorch. During scouting, katsura, dogwood, and viburnums were the most common species observed to have been affected. Hickory tussock moth caterpillars are still active and feeding on leaves of a variety of trees, including maple. Another generation of oak lace bug (nymph stage) is feeding on bur oak. Aphids, scales, and other sap-sucking insects are active and feeding, judging from the preponderance of sooty mold observed on foliage of magnolia, tulip tree, and other woody species. One of the worst of these pests this year has been Magnolia Scale. The scale is now in the crawler stage and may be controlled with an application of summer horticultural oil. Euonymus scale is still in the crawler stage though some have settled. Fall browning on junipers is apparent, but pines and other needled evergreens are not yet showing this normal process in their annual growth cycle. Skunks are digging in lawns, a likely indication of grub infestation.

Environmental Data

The following growing-degree-day (GDD) and precipitation data was collected for an approximately two week period, August 20 through September 2. Soil temperature and phenological indicators were observed on or about September 2. Total accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our instruments for the 2015 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

Region/Location

GDD
(2-Week Gain)

GDD
(Total 2015 Accumulation)

Soil Temp
(°F at 4" depth)

Precipitation
(2-Week Gain in inches)

Cape Cod

330

2220

78

1.30

Southeast

286

2,007

80

0.70

North Shore

344

2184

75.5

1.67

East

338.5

2398

76

0.19

Metro West

303

2171.5

76

0.03

Central

279

1866

72

0.16

Pioneer Valley

309

2433

71

1.38

Berkshires

243

1919

70

2.79

AVERAGE

304

2150

75

1.03

n/a = information not available

Phenology

Phenological indicators are a visual tool for correlating plant development with pest development. The following are indicator plants and the stages of bloom observed for this period:

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT NAME (Botanic/ Common) CAPE S.E. N.S. EAST METRO W. CENT. P.V. BERK.
Heptacodium miconioides (Seven-Son Flower) begin begin begin begin begin begin begin *
Clematis paniculata (Sweet Autumn Clematis) begin begin begin/ full * begin * begin full
Sophora japonica (Japanese Pagodatree) full/end end end end end end end full/end
Polygonum cuspidatum (Japanese Knotweed) full/end full/end full full/end full/end full/end full/end full
* = no activity to report/information not available
  • CAPE COD REGION - Roberta Clark, UMass Extension Horticulturist for Barnstable County - Retired, reporting from Barnstable.
  • SOUTHEAST REGION - Deborah Swanson, UMass Extension Horticulturist for Plymouth County - Retired, reporting from Hanson.
  • NORTH SHORE REGION - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from the Long Hill Reservation, Beverly.
  • EAST REGION - Kit Ganshaw & Sue Pfeiffer, Horticulturists, reporting from the Arnold Arboretum, Jamaica Plain.
  • METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
  • CENTRAL REGION  -  Joann Vieira, Superintendent of Horticulture, reporting from the Tower Hill Botanic Garden, Boylston.
  • PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from UMass Amherst.
  • BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases & Insects

Stem cankering caused by Cytospora on Japanese maple (Acer palmatum). Tree is approximately 40-years-old and has girdling roots visible. Additionally, the tree has been stressed by repeated insect defoliation in the past and many branches now have brown leaves and desiccated shoots from Cytospora cankering.

Leaf spot caused by Entomosporium and stem cankering caused by Phomopsis and Botryosphaeria on English hawthorn (Crataegus laevigata). Tree is 155-years-old and resides at a National Park in the Commonwealth. Decline was noticed three years ago and at present, approximately half of the tree’s canopy is dead. The tree was planted very close a house on the site and has compacted soils from construction in the area.

Leaf blotch of apple (Malus domestica) caused by Marssonina coronariae. Tree is approximately 25-years-old and has been present at the site for nearly as long. Premature leaf shedding was first observed in July and has continued to increase in severity. In previous years the tree has appeared healthy. Marssonina can attack the fruit and foliage, creating grayish-brown spots that coalesce to consume significant areas of the foliage. Sapsucker injury is also present on the tree.

Armillaria root rot on Manchurian lilac (Syringa pubescens subsp. patula ‘Miss Kim’). Shrub is 15-years-old and has been present at the site for 10 years. A general decline was observed this growing season with sparse, undersized foliage that have a pale green appearance. Premature leaf shedding and desiccated twigs were also noted. An adjacent lilac also declined and died, most likely from the same disease. A near unrivaled plant pathogen, Armillaria is often observed but only rarely controlled.

Stem cankering on pitch pine (Pinus rigida) from Sirococcus and Phomopsis. The tree is mature, approximately 40’ tall with a diameter of 15”. Over the past several years, it has appeared to be in good health. The tree resides close to the ocean and is subject to salt spray. Sirococcus strobilinus attacks many different conifers andthrives in coastal settings where fog is common. Wounds from the pitch mass borer were also observed

Severe infestation of the juniper scale (Carulaspis juniperi) on Hinoki falsecypress (Chamaecyparis obtusa ‘Crippsii’). Tree is approximately 25 to 35-years-old and only recently was browning of terminal shoots observed throughout the top ¾ of the canopy. While typically not a major landscape pest, this particular tree was harboring a major infestation of this scale.

Suspected heat stress on Japanese stewartia (Stewartia pseudocamellia). Tree is 10-years-old and has been present at the site for eight years. Landscape conditions include full sun with supplemental water provided via overhead application. Beginning in 2012 (a very hot summer), leaf tips became scorched after periods of high heat. Only half of the canopy demonstrated the symptoms in 2014 but this year, the entire canopy has brown margins. No pests or pathogens were present on the submitted sample that could explain the symptoms.

For more detailed management information for woody plant diseases in the landscape, refer to UMass Extension's Professional Management Guide for Diseases of Trees and Shrubs.

Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass Amherst.

Weeds

Japanese knotweed is in flower and now is the time to manage this invasive plant. Use a 2% spray solution of glyphosate sprayed to the initiation of spray drip. Do not use herbicide formulations that contain diquat (RewardTM) or tank-mix pelargonic acid (ScytheTM) with the glyphosate. Diquat and pelagonic acid are contact herbicides and have the potential to decrease the efficacy of glyphosate. In areas near water, a formulation of glyphosate that is labeled for these areas should be used. Non-chemical products containing clove oil, citric acid, acetic acid or orange extract will not effectively control Japanese knotweed.

Poison ivy can be treated during the month of September. Glyphosate or triclopyr are the best herbicides for poison ivy control. Contact (ScytheTM, RewardTM) or the non-chemical/organic herbicide products will provide “burndown” activity only and will not adequately control poison ivy.

At this point in the season, summer annual weeds have become large. Many weeds have become very large and just spraying them will result in unsightly dead vegetation, so hand weeding may be necessary. However, spot spraying with a non-selective herbicide is usually a better strategy than hand-weeding because it does not break the mulch barrier. A determination on a site-by-site basis will need to be made.

Inspect areas of the landscape where new trees or shrubs, especially those that were field grown, have been planted early this season or last year. Look for perennial weeds that may be growing from the root ball. Canada thistle, mugwort, quackgrass, bindweed and horsenettle are some of the possible culprits.

Many landscape trees commonly produce vegetative suckers at their trunk base. Suckers are commonly seen on crabapples, pear, plum, linden, maple and sometimes oak. Honeylocust will also produce vegetative sprouts along the entire length of their trunk. It these sucker or sprouts are not controlled the landscape will be a contender for the “shabby landscape award”. Pruning is effective but very time consuming. Another option would be to use the product Scythe that contains pelargonic acid to remove these vegetative suckers and sprouts when they are very small. Very small means less than one inch in length. Pelargonic acid is a contact herbicide. If ScytheTM is applied to small suckers and sprouts the product will desiccate them and physical removal will not be required. Larger growth will first need to be physically removed and then ScytheTM can be used as a maintenance program. Products that contain glyphosate should not be used as glyphosate is a translocated herbicide.

Report by Randall Prostak, Weed Specialist, UMass Extension Landscape, Nursery and Urban Forestry Program.

Landscape Turf

Management Practices

Thinking ahead

The objective of any turf management program has always been to produce a satisfactory surface in terms of appearance and function. More recently, a central goal of a growing number of programs is to produce the highest degree of turf performance possible, while simultaneously reducing inputs to the lowest practical level and minimizing the potential for negative environmental impact. In a large number of instances, a little planning ahead and thoughtful implementation of proactive measures can be a catalyst for significantly lowering inputs and enhancing environmental protection. The concept is straightforward – invest a certain amount of energy and resources at a given point in time in order to reap comparatively larger benefits later. Here are a few detailed examples of this idea:

Promoting root system development in the spring: For cool-season grasses in New England, the period of favorable conditions in the spring is the principal time for root development. Focused management with a mind to protecting and promoting this root development (reasonable mowing height, measured fertility, deep and infrequent irrigation, etc) helps to encourage a robust root system heading into summer. The ‘window of opportunity’ in the spring is preciously short, and rising soil temperatures in summer lead to root dieback for even the most carefully and intensively managed systems. Hedging against this inevitable root dieback in the spring will help to increase resistance to wilting and dormancy (and any associated problems in terms of turf function and appearance), and will enable water savings during the driest months of the year on irrigated sites.

Using preventive pesticides: In some cases, using preventive pesticides is the smartest use pattern for problem pests, even within an IPM system. The usual, great examples are pre-emergence annual grass control and preventive control for white grubs. In the case of annual grass control, a single well-timed application in the spring can often reduce annual grass germination dramatically over the course of the season. Such applications do not necessarily preclude spring planting or repairs, as multiple options are currently available that are safe for use at the time of seeding. Each plant successfully controlled means one less plant that can potentially produce seed and contribute to the soil seed bank, leading to lower weed pressure in ensuing seasons. Alternatives to the preventive approach include post-emergence herbicides and hand pulling… both of which can be more labor intensive and typically more costly. Similar logic applies for preventive grub control. In areas with a history of grub control and for which there is reasonable expectation that damaging populations will occur within the current season, getting out ahead of a problem with preventive controls is often preferable to ‘curative’ options. Modern preventive controls are highly effective when applied and timed properly. In comparison, the traditional curative material, trichlorfon, tends to be less effective, can be more toxic to humans and non-target organisms, and is subject to greater application restrictions in some locales. The main goal of IPM is to reduce pesticide use to the lowest possible level, therefore certain preventive approaches within an IPM system make good sense.

Optimizing turfgrass selection: Matching turfgrasses to factors such as the growing environment, the use of the turf, and available resources for management are among the most important decisions that a turf manager makes. This is because species and cultivars with traits that are well matched to the most limiting factors on the site (drought stress, shade, disease pressure, or heavy traffic, for example) are less ‘needy’ in terms of maintenance, and are much more likely to perform as intended and sustain the desired level of appearance. Up the ante even further by planting or overseeding with endophytic grasses, which can discourage foliar-feeding insects such as chinch bugs and billbugs, leading to decreased management need, lower pesticide use, and overall better turf performance. The value is even clearer when you consider that turf cover has the potential to remain in place indefinitely, and repairs, renovation and re-construction because of poorly-adapted grasses are disruptive, costly and time consuming. A bit of extra care in selection from the outset when planting a new stand can enable efficiencies and savings for years to come.

  • This is particularly useful advice now that we are within the ideal period for planting projects in Southern New England… but it is dry out there! Pay particular attention to watering during the establishment phase, and use compatible mulches to help conserve moisture whenever and wherever possible.

Streamlining and implementing efficiencies into management can lead to substantial savings in terms of dollars, materials, time, labor and energy. Managing with attention to the environment, furthermore, can go a long way in protecting non-target organisms and conserving precious natural resources. A fundamental component of these efforts is looking at a long time horizon, doing your best to anticipate future challenges, and then determining what you can implement or change NOW to produce short term results as well as future dividends.

Report by Jason Lanier, Extension Educator, UMass Extension Agriculture and Landscape Program

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Diagnostic Services

A UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see Plant Diagnostics Laboratory

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site.   Alternatively, call the lab at (413) 545-2311.

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