UMass Extension Landscape Message #22
August 27, 2004

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ENVIRONMENTAL DATA

The following growing degree day (GDD) and precipitation data was collected from August 12, through August 25, 2004. Soil temperature and phenological indicators were observed on August 25, 2004. Accumulated GDDs represent the heating units above the 50° F. baseline temperature collected via our mini-computers since the beginning of the current growing season. Please note that this data is particularly useful for pinpointing pest development at any time during the season.

Southeast - General conditions: Sunny days, cooler nights have been the norm. Hanson and the southeast region received some much needed rain over the past two weeks. Hanson received just over 5 inches. Soils are moderately moist. Many trees, like ash, oak, and red maple that were defoliated by caterpillars earlier this past spring, have not fully recovered and look poorly. Albizia julibrissin, Hydrangea paniculata, Hydrangea quercifolia (Oakleaf hydrangea), Liatris, Coreopsis 'Moonbeam', Joe-pye-weed, Rudbeckia trilobum, Rudbeckia 'Goldsturm', Echinacea purpurea, Corydalis lutea, Nepeta, Heliopsis 'Summer Sun', Lobelia cardinalis, Lobelia syphilitica, Lobelia hybrids, Hibiscus 'Copper King', Ironweed, and Phlox paniculata are in full bloom. Goldenrod and ragweed are beginning to bloom. Pollen from ragweed may cause allergies in some people but goldenrod is often mistakenly blamed. Viburnum trilobum fruit is starting to turn color (gold/red). Pests/Problems: Asiatic, Oriental and Japanese beetles are few and far between at this time. Earwigs, ticks, lily leaf beetle adults and larvae, spider mites, slugs, aphids, snails and mosquitoes are all active. Azalea lacebug is still active as is Pieris lacebug. Cedar-apple rust is evident on susceptible cultivars of apple and crab apple. Some crabapple trees have been defoliated by apple scab. Powdery mildew is prevalent on a wide range of plant material such as sycamore, garden phlox, lilac, dogwood, etc. Anthracnose is evident on sycamore, dogwood, maple and others. Wasps and hornets are plentiful. Black locust foliage is turning brown due to locust leaf miner. White fly was observed on azalea.

East - General Conditions: Some early fall color noted on some stressed trees near construction places and dry slopes.

Central - General Conditions: No report.

West - General Conditions: With the remnants of the two hurricanes and the recent cool front the rainfall has been plentiful in the Valley. The cool temperatures in the last several days were a boost for people doing some transplanting and seeding their lawns, too. Pests/Problems: Some sugar maples, katsuratrees, little-leaf linden to name a few trees that were stressed from previous years of drought are beginning to thin out and/or show early fall color. Powdery mildew continues to be visible on herbaceous and woody ornamentals such as phlox, zinnia, flowering dogwood, sycamore and lilac.

Berkshire - General Conditions: After a stretch of gray, soggy weather, the past week has been sunny and mild. Flower gardens continue to flourish and look as good as they have in many years. Nights have been cool, lows in upper 40s. Dense fog and heavy dew have characterized mornings.Pests/Problems: Powdery mildew and an assortment of leaf blights have marred the appearance of some perennials but overall, plants are thriving. Slugs, wasps and ticks are abundant. Other insect populations have been low.

PHENOLOGY

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

CAPE COD REGION - Roberta Clark, Horticulturist for Barnstable County, Barnstable.

SOUTHEAST REGION - Deborah Swanson, Horticulturist for UMass Extension in Plymouth County, Hanson

EAST REGION - James R. Allen, Horticulturist and Greenhouse Manager for UMass Biology Department, Boston

CENTRAL REGION - Joann Vieira, Superintendent of Horticulture, Tower Hill Botanic Garden, Boylston.

WESTERN REGION - Dan Gillman, Plant Pathologist, Urban Forestry Diagnostic Lab, UMass, Amherst.

BERKSHIRE REGION - Ronald Kujawski, Nursery Specialist, UMass Extension Agriculture & Landscape Program, Amherst.

WOODY ORNAMENTALS

INSECTS

Caterpillars

In general, products containing Bacillus thuringiensis (B.t. kurstaki) are very effective against the younger free-feeding caterpillars in the Lepidoptera only. Products that contain spinosad are generally very effective against caterpillars in the Lepidoptera and the Hymenoptera (wasp-like as adults). There are also many chemical insecticides that are labeled for caterpillars, which are pyrethroids, organo-phosphates, carbamates, and other classes.

Lepidoptera (moths):

• Mimosa Webworm caterpillars remain very active. The larvae tie foliage together in clumps and then skeletonizing the leaflets from within these 'pads' of leaves. Look for clumps of browned leaves. Treat with a spinosad product or one of the registered chemical insecticides. In some cases, this pest can affect every leaf on honeylocust and by late summer, the trees become very unattractive. Sometimes, the caterpillars become a nuisance on houses as they seek an over-wintering site.
  
• Juniper Webworm caterpillars remain active. They will tie foliage with silk and cause browning of the foliage. They will be active until the fall and then again next spring until they pupate. It is the second generation that is active now. Treat with a Bacillus thuringiensis var. kurstaki product or a product that contains spinosad. Chemical insecticides are also labeled for this pest. Upright junipers are often times more susceptible to this pest but they will be found attacking other junipers as well.
  
• Evidence of Pine False Webworm (Hymenoptera) and Pine Webworm (Lepidoptera) is very obvious now. Look for damaged needles and clusters of silk loaded with frass pellets. However, both of these pests should now be finished feeding for the year.
  
• Fall Webworm tents are very noticeable now. This pest has dozens of deciduous host species. The larvae feed from within the silken webs and expand the size of the tents, down the branch towards the trunk, as they feed. Injured foliage remains intact but is skeletonized and brown. This pest is mostly aesthetic and unsightly webs may remain through the winter. Individual webs can be pruned away now and destroyed. Feeding activity is almost finished for this year. Never burn webs while still on the tree! Treat with one of the many registered chemical insecticides or a spinosad product.
  
• Oak Skeletonizer injury and larvae become especially noticeable at this time of year. The tiny, yellow caterpillars can be seen hanging from long threads from oak. Larvae form cocoons that appear as a small grains of rice. In larger populations, oak leaves will have numerous individual skeletonized 'windows' on the foliage and leaves. This pest usually does not require control.

Hymenoptera (sawflies):

• Introduced Pine Sawfly remains active and may be found on the same host plants as the European Pine sawfly. Last year, this pest was quite prevalent in the eastern part of MA and caused much defoliation. Treat the young caterpillars with insecticidal soap or one of the products that contains spinosad. Chemical insecticides are also labeled for this pest.
  
• Red-headed Pine Sawfly is active. Mugo pine is a common host but other pines are susceptible. Spinosad products work well. Small infestations can be pruned away. This pest will feed well into the fall, usually up until the first good frost. It has the potential to be a very serious defoliator.

Beetles

In general, products containing spinosad are effective against the larvae (at least) of many free-feeding beetle, especially the Chrysomelids (leaf beetles) species. However, there are also many chemical insecticides that are labeled for beetles, which are pyrethroids, organo-phosphates, carbamates, and other classes.

Leaf Beetles:

• Lily Leaf Beetle - This pest remains active.
  
• Viburnum Leaf Beetle - is finished for this year.
  
• Imported Willow Leaf Beetle remains active. The small, round blue-black adults will chew ragged notches in the margins of foliage but it is the larvae that create the bulk of the injury. These small, black, elongate larvae are now active. They line up on the leaf surface and skeletonize. There are multiple generations per year and they will remain active until September. By August, entire trees can appear to have been swept by fire; all of the leaves will be intact but dead and brown from total skeletonizing. Treat with a spinosad product or with one of the many registered chemical insecticides.

Scarab Beetles:

• Japanese Beetle adults are still active but their numbers are beginning to lessen. Visit the archive and see the Turf Management section in previous messages for additional management information.

Piercing-Sucking

In general, imidacloprid applied systemically is very effective on most, with the exception of spider mites. Horticultural oil or insecticidal soap, especially against the immature stages, is usually very effective.

Lacebugs:

• Andromeda Lacebug remains very active throughout MA. Inspect the undersides of foliage for their presence. Systemic imidacloprid products work well. If contact pesticides (mechanical mode of action) such as summer oil sprays or insecticidal soap are utilized, they need to be targeted to the foliage undersides. Japanese andromeda in sunnier growing sites will experience greater problems with this pest.
  
• Azalea Lacebug remains active. Like Andromeda Lacebug, this pest is active all summer and capable of creating much stippling (chlorosis) of the foliage. Drought conditions and sunnier growing sites tend to favor this pest.
  
• Sycamore Lacebug remains active. Although common to Sycamore, it can be especially destructive to English White Oak. Active all summer, it can lead to serious chlorosis of the host plant.

Aphids:

• Assorted Aphid Species are active on many different hosts. Inspect plants carefully for building populations. Catalpa, rose, lindens, and many others are common hosts for aphids. Severe sooty mold problems are beginning to appear from the copious amounts of honeydew that these insects produce. Treat with insecticidal soap sprays, an imidacloprid product, a summer oil spray, or with one of the many registered chemical insecticides. Catalpa Aphid and Tuliptree Aphid, in particular, are reaching peak numbers now and can be problematic.

Adelgids:

• Hemlock Woolly Adelgid can still be treated with horticultural oil even though this pest is now dormant. The young instar nymphs have settled on the stems at the base of the needles and will not move or feed again until about mid-October. However, they can still be managed with horticultural oil sprays. To know if they are alive or not, inspect them under magnification (a microscope, if possible) and gently poke them with a sharp needle. If they are dried and brittle, then they are already dead. If they exude a small amount of liquid, then they are most likely alive and dormant. If the use of systemic imidacloprid is desired, wait either until the third or fourth week in August for application or once regular rain or irrigation is available along with cooler temperatures.

Other Piercing-Sucking Insects:

• Sharpshooter Leafhopper (aka Red-banded Leafhopper) is now very prevalent. Although found on various host plants, they cause their injury particularly to rhododendrons. By feeding on the newest foliage, they cause stunting and curling of the foliage. These will be active until the first good frost. Although they don't kill host plants, their feeding can reduce the aesthetic value of plants, especially those in nurseries.
  
• Aster Leafhopper (aka Six-spotted Leafhopper) is very active. This pale-yellow leafhopper can be easily seen jumping and flying, usually in large numbers, on a variety of plant species. At this point in time, their feeding may cause injury to the developing flower buds of chrysanthemum among other species. They are capable of vectoring Aster Yellows to plants, which generally appears as chlorosis, stunting and/or distortion of foliage. This problem is less likely to occur now. Monitor for activity and feeding injury. Treat, only if necessary, with one of the labeled chemical insecticides.
  
• Spider Mites - Several growth regulator products are available that offer high levels of control; mostly for population numbers that are low to moderate in size. Most are so specific that they kill spider mites but not the beneficial predatory mites. Some even posses ovicidal (egg-killing) qualities. Horticultural oil sprays can also be very effective. Many insecticides and miticides are specifically labeled for spider mites as well.
  
• Two-spotted Spider Mite remains very active. This species has a wide host range. It is also a 'warm-season' spider mite, which means that it will remain active all season long and be very prolific once the very hot and dry season approaches. Begin to monitor now and continue monitoring throughout the growing season for increasing population numbers. Treat if numbers become too high and (especially) if predator mite population numbers are too low. Horticultural oil sprays (summer rate) can be very effective as well as the other labeled pesticides for mites. Treat only if necessary. Deciduous plants, such as winged euonymus (E. alatus), will develop very chlorotic foliage and may even drop its leaves when high populations occur.
  
• Honeylocust Spider Mite remains active. In some cases, foliage is becoming quite chlorotic. Inspect the undersides of affected foliage for these tiny mites and treat if necessary.
  
• Spruce Spider Mite is dormant but will return soon.

Leafminers

• Arborvitae Leafminer larvae are mining foliage. Browning of mined foliage will not appear until January or February.
  
• Locust Leafminer on Black Locust continues to be very active and its injury is now very noticeable. Adults skeletonize the foliage while the larvae mine. The next generation of adult beetles are active and mating now. Treatments now may not be warranted; it may be too late. In many cases, untreated trees are appearing 'fire-swept' with bronzed leaves.

Scale Insects

In general, horticultural oil sprays work well against most armored scale species, especially when they are in the crawler stage. Imidacloprid™ does not work well on armored scales but is much more effective against many soft scales.

Armored (hard) Scales:

• Monitor for Pine Needle Scale on mugo and Scots pines, in particular.
  
• Monitor junipers for Juniper Scale.
  
• Monitor different euonymus for the Euonymus Scale.

Continue to monitor scale species at the appropriate time of the season for crawlers and treat again at that time, if necessary.

Soft Scales:

• The Tuliptree Scale is very noticeable now. The large, brown 'gumdrop-shaped' coverings of the dead females may harbor up to 3000 eggs each. This pest produces huge amounts of honeydew and now sooty mold problems will be quite obvious. Treatments at this time are challenging.
  
• Taxus Mealybug (technically not a scale but a close relative) can be found actively feeding on the inner branches of Taxus. This pest also is responsible for much sooty mold. In high numbers, it can seriously stunt plant growth. Move foliage aside to inspect the inner branches.

Gall Formers

• Maple Gouty Vein Gall has been rather widely reported this year. Sugar and red maples are the primary hosts (mostly sugar). This tiny fly (a midge) attacks foliage as it is emerging and stimulates gall formation along the main veins of the leaf, usually on the undersides. These galls are initially green but may turn red as they mature. In some cases, there are so many galls per leaf that foliage becomes stunted and distorted. However, the injury is aesthetic. There are no controls nor are they necessary.

Wood Attackers

• White-Spotted Pine Sawyer adult beetle remains active. This species is only attracted to previously weakened pines and is not considered to be a pest. However, it looks very much like the Asian Long-Horned Beetle (ALB), which is not yet known to exist in MA. The adults of ALB are a very shiny black with crisp white spots. Their antennal segments alternate between white and black segments. The WSPS also has the same type of antennae but, its body coloration is more of a dull grey and has a varying number of dull white spots. Visit the web site listed here for more details: http://www.na.fs.fed.us/spfo/alb (the main Forest Service page for ALB). Under the heading for Information, select publications; then open the link to the fact sheet titled "Asian Longhorned Beetle vs. Whitespotted Sawyer."
  
• Monitor previously stressed plants (drought, soil compaction, etc.) for signs of invasion of wood borers. Bronze Birch Borer is one such invader. Water infested trees during drought periods. Insecticide injections may be effective in some cases. The adults of BBB are seeking new host plants for egg-laying. Even though they only emerge over a few weeks time, the adults can remain active through August. It is recommended that susceptible birches not be pruned during this time, especially if they have been previously weakened. Pruning (wounding) releases plant chemicals that attract BBB females. The Two-lined Chestnut Borer, which is a close relative of the BBB, is also very active in previously stressed oaks and birches. Inspect for declining health and 'D'-shaped exit holes.
  
• Conifer Bark Beetles, such as the Black Turpentine Beetle, invade stressed trees. Inspect for pitch tubes and streaks of pitch on the bark. These are signs of an already weak tree. Water during times of drought.
  
• Tunneling larvae of Rhododendron Borer will expel sawdust but this early signal can be hidden by dense foliage. Often, an infestation is not noticed until much later in the summer when individual shoots wilt and suddenly die. Adults can be treated with a chemical insecticide. New tunnels, if possible to find, can be treated with beneficial nematode sprays.

Nuisance Pests

• Many wasp, bee and hornet species [Hymenoptera] are increasing in numbers. Be aware of their potential presence, especially when around plant material, in order to avoid their stings.
  
• Western Conifer Seedbug populations are building and can be found on the seeds (cones) of conifers. These do not harm conifers in the Northeast. However, as populations build, the adults become a nuisance in late autumn as they seek shelter in homes. Inspect all screening now on windows, doors and attic vents. Repair if necessary. Also, inspect and repair caulking around the same areas.

Reported by Robert Childs, Entomologist, UMass Extension Landscape, Nursery and Urban Forestry Program, Amherst

DISEASES

Horsechestnut (Guignardia) leaf blotch - As summer progresses the scattered, irregular-shaped orange-brown blotches are becoming larger, but it is too late for chemical intervention this season. Collect and dispose of leaves as they fall.

Powdery mildews - These fungi are visible as a dusty, gray-to-white coating on phlox, lilac, dogwood, and sycamore leaves as well as rose leaves and flower buds. In addition to having this dusty coating, infected immature leaves become yellowed, puckered and stunted. Powdery mildews grow superficially over both leaf surfaces as well as green shoots. They are obligate parasites and derive sustenance only from living host plants. They do this using minute, tube-like structures (haustoria) that penetrate the epidermal cells and draw out material they need to survive. On some leaves spherical, black fruiting structures (cleistothecia) are visible with a hand lens on the underside of leaves in the dusty, gray mycelia. If control is desired, apply fungicide sprays at intervals specified on the label when the white dusty spots first appear in late spring next year. Fungicides labeled to protect foliage on susceptible plants are listed in the UMass Extension Management Guide for Woody Ornamentals.

Black spot on rose - Black spot can be ugly and destructive to highly susceptible roses. Black, rounded spots develop on infected leaves and rose hips. Infected first-year canes have lesions that are reddish colored initially and then turn black. Black, pin-head sized fruiting structures develop in the center of the spots. Repeated black spot infection cycles will occur during wet periods throughout the remainder of the growing season. Eventually, spotted leaves turn yellow and drop off prematurely. Plants that sustain considerable leaf loss fail to thrive and are more prone to winter damage. Prune and destroy all infected leaves and canes. Avoid wetting foliage during irrigation. If overhead irrigation cannot be avoided, water before midday to reduce period of time leaves are wet. If replacement is an option, many beautiful, resistant varieties are available. Apply fungicide sprays at intervals specified on the label to protect healthy foliage. Nothing can be done to disinfect spotted leaves. Fungicides labeled to protect foliage on susceptible plants are listed in the UMass Extension Management Guide for Woody Ornamentals.

Gymnosporangium (several different species of the fungus) rust is visible as red-orange-yellow blister-like spots on susceptible hawthorn, apple and crab apple leaves. From mid summer to autumn, spores are wind-carried from the broadleaf host leaves; and when conditions are wet, they infect green shoots and needles of junipers. Pea-sized to two inches in diameter brown galls, as well as fissures in the bark are visible on susceptible juniper needles and twigs between 12 and 20 months after infection. The best long-term approach to manage this disease is to grow Gymnosporangium rust resistant apple, hawthorn and juniper cultivars. Also, prune dormant galls on junipers infected with the cedar-apple form of Gymnosporangium rust during the summer, fall, winter and early spring (before orange jelly-like horns form). The time to apply fungicides to protect high value apples from cedar-apple rust has passed for this season. Fungicide protection of susceptible junipers is of little benefit; but if it were desired, it would be from mid August through September.

Dogwood anthracnose infections are evident on susceptible flowering dogwood (and even some resistant Kousa dogwood). Infected trees have scattered leaves exhibiting irregularly shaped gray-brown areas with purplish-brown margins. This can be a difficult disease to control due to the abundance of inoculum that over-winters on twigs and fallen leaves. In addition, heat and water stressed flowering dogwood sustain more extensive branch dieback than those trees that have more vigor. If this is a recurring problem, consider replacing the tree with a resistant tree. On susceptible specimen trees consider a late summer fungicide application to protect the new flower buds from infection if the weather is cool and wet.

Sudden Oak Death (SOD) - The fungus Phytophthora ramorum causes SOD. It is a severe disease of oak and tanoak in certain Pacific Northwest fog forest areas. In 2004 Phytophthora ramorum has been found in nurseries in California, Oregon and Washington. These detections demonstrate that the pathogen is not necessarily limited to the moist coastal regions of northern California and southern Oregon. All of these nurseries distribute nursery stock nationwide, including Massachusetts. Canada has identified three infested nurseries in British Columbia; one of which is a production nursery that shipped potentially infected plants to 19 nurseries in CA, OR and WA.

This pathogen has a wide range of host plants, including rhododendron, viburnum and camellia, which are potential 'carriers' of the fungus when plants are transported. The damage on non-oak hosts involves minor leaf spotting and twig dieback. However, infections on these non-oak hosts may contribute to a rapid build-up of the fungus in an area, serving therefore as a reservoir of inoculum. All of the details of how the fungus spreads have not been worked out, but these reservoir plants may play an important role.

SOD (Phytophthora ramorum) surveys in nurseries and forest areas around the state are well underway. Agencies involved include the Massachusetts Department of Agricultural Resources (MDAR), Massachusetts Department of Conservation and Recreation (MDCR), and USDA Animal and Plant Health Inspection Service (APHIS) with UMass Amherst providing the lab and staff to perform the assays. To date, Phytophthora ramorum has not been found in Massachusetts, but nearby states in which it has been positively identified include Pennsylvania (indoors), New York and New Jersey.

Trace forward and national surveys continue as APHIS PPQ determines the distribution of P. ramorum. The total number of confirmed positive locales from the trace forward, national, and other survey finds is 157 in 21 states. The breakdown per state is: AL (3), AR (1), AZ (1), CA (53), CO (1), FL (6), GA (18), LA (5), MD (2), NC (9), NJ (1), NM (1), NY (1), OK (1), OR (10), PA (indoor), SC (3), TN (2), TX (11), VA (2) and WA (25). It is important to note that only three are from residential landscape situations, two in Georgia and one in South Carolina, as well as one environs find on Long Island, NY.

As of August 19, 2004, the participating states have surveyed 1,898 sites and have collected 36,615 samples; 19 sites are confirmed positives. The US Forest Service P. ramorum nursery perimeter and general forest surveys continue; all sampling results are negative to date. As of July 22, the US Forest Service has conducted 26 nursery perimeter and 13 general forest surveys.

On July 2 APHIS Plant Protection and Quarantine (PPQ) confirmed the presence of Phytophthora ramorum in Nassau County, NY. A joint PPQ, US Forest Service, NY Department of Agriculture team collected sample in the county after PPQ received information from a member of the public. The team collected the positive sample from a mature red oak tree located in a 192 acre forested county park. Further surveys are underway to identify other possible infected plants and infested sites. PPQ is currently working on determining the most appropriate regulatory response to the find.

For more information about SOD and Phytophthora ramorum check out the Massachusetts Introduced Pests Outreach Project web site at www.massnrc.org/pests/ . From the home page, hit the Search for Pest Info button; then enter the keywords 'sudden oak death' in the search box. Follow the link to the fact sheet.

Landscape, Nursery, and Urban Forestry Diagnostic Lab Report

The following are some of the interesting disease/abiotic disorder samples received at the UMass Extension Landscape, Nursery, and Urban Forestry Diagnostic Lab in Amherst during the period August 9 through August 20, 2004:

• Boxwood - hedge planted 3 years ago has not thrived, and this spring/summer most plants have scattered areas of yellow-brown leaves and branch dieback; soil pH < 5/winter damage/Nectria canker/worsened by Volutella blight.
• Hickory - extensive leaf spotting and premature loss; Gnomonia leaf spot.
• Eastern red cedar - browning and blackened shoot tips scattered through several mature trees; Cercospora blight.
• European mountain ash - most of several large branches in a mature tree died back this summer; Valsa canker secondary to both bacterial fire blight (Erwinia amylovora) + severe water shortage in previous years.
• Sugar maple - leaves with brown blotches and leaf loss in mid-July; both Kabatiella and Discula forms of maple anthracnose.
• American elms - several large branches with wilted and yellowed leaves in late July; Dutch elm disease (7 cases)/Botryodiplodia canker (1 case)/Dothiorella canker (2 cases).

Reported by Dan Gillman, Plant Pathologist, based in the Urban Forestry Diagnostic Lab at UMass, Amherst, Mass

TURFGRASS

Diseases: No report: Visit the Landscape Message Archive for previous messages.

Insects:

Fall Armyworms? I just received a telephone call from a turf manager indicating he had found large numbers of caterpillars moving on a putting green in central Massachusetts. Cautions... I have not seen any specimens from this outbreak but the description that was given over the telephone sounds like it might be the fall armyworm (Spodoptera frugiperda). I should receive some specimens early next week to "confirm or deny" this diagnosis. Just in case, here is some information about fall armyworms.

The fall armyworm occurs occasionally in the Northeast and usually is sporadic. In other words, some folks may be inundated while others will not see any. The insect is very vulnerable to cold temperatures so it overwinters in extreme south Florida or even further south, in Central America. The description of the caterpillar (from Turfgrass Insects of the United States and Canada by Vittum, et. al.): "The general color of the FAW caterpillar ranges from pinkish to yellowish, greenish, and dull gray to almost black. There is a faint, narrow, pale mid dorsal stripe. The top of the cranium has a light-colored inverted AY." What we often see is two tones of yellowish or tannish broad stripes running the length of the body, with black spots scattered throughout the body. Full grown caterpillars are over an inch long.

Young caterpillars feed on the undersurface of leaf blades, leaving thin "windows" or layers of epidermis. Older caterpillars eat the entire leaf area, sometimes leaving cut leaf particles strewn around and producing a "ragged" appearance.

The good news is that if these really are fall armyworms, we probably will only see one generation of them. If you happen to notice large numbers of caterpillars that match the above description and they are no longer than a half inch, you may get some relief by applying a pyrethroid or Dursban™ in areas where those products are labeled. Once the caterpillars are an inch long, insecticides are not likely to be effective and the caterpillars will be pupating soon anyway.

Please let us know if you see any caterpillars that match this description and remember that I have not yet confirmed the diagnosis. I just want to give you a "heads up" the fall armyworms might be in the area.

(Also note that I saw a couple variegated cutworms on a velvet bentgrass putting green in southeastern Massachusetts earlier this week. They sometimes can be seen feeding on the surface on cloudy days, of which there have been plenty this year! Variegated cutworms have a more pinkish tinge to them and have some diagonal "stripes" on their backs and can be 1.5 inches long.)

Pat Vittum, Professor and Extension Entomologist, UMass, Amherst, Mass.

Weeds: No report. Visit the Landscape Message archive for previous messages.

IMPORTANT INFORMATIONAL RESOURCES

Two UMass Extension Web Sites are specially designed to provide Green Industry professionals with resources, upcoming educational programs and events, and other relevant information. The Internet address for the Landscape, Nursery, and Urban Forestry Program is http://www.umassgreeninfo.org. The Turf Program address is http://www.umassturf.org .

UMass Extension’s Management Guide for Woody Ornamentals is NOW available! Remember to use the Professional Management Guide for Insects, Diseases and Weeds of Trees and Shrubs in New England 2003-2004 as a reference tool along with this message. The guide is a 130-page guide to provide arborists, tree wardens, and green industry professionals with current information on the materials and products available to manage pests of woody plants in New England, updated every two years by the University of Massachusetts Extension's Landscape, Nursery and Urban Forestry Program. Send orders (checks payable to UMass) to UMass Extension Bookstore, Draper Hall, 40 Campus Center Way, Amherst, MA 01003. You can also order with a credit card by calling the Extension Bookstore at 413-545-2717. The cost is $26 (plus $5 shipping) for Part I: Professional Management Guide for Insects, Diseases, and Weeds of Trees and Shrubs in New England; $12 (plus $5 shipping)for Part II: Strategies for Plant Health Management of Woody Ornamentals; or $40 (plus $5 shipping) for both Parts I and II and the inscribed 3-ring binder to hold them. For more details or to order online, go to the Publications Section of this web site.

UMass Extension’s Turf Management Guide and IPM Facts: For more information about the pests mentioned in this message, you will need to refer to the following publications: the Professional Guide for IPM in Turf for Massachusetts, 2003-2004 edition and Turf IPM Facts . Call (413) 545-2717 to order these publications from the UMASS Extension Bookstore.

DIAGNOSTIC SERVICES

UMass Laboratory Diagnoses for Turf and Landscape Problems: Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. The UMass Extension Urban Forestry Diagnostic Laboratory is available to serve commercial landscape contractors, turf managers, arborists, nurseries, and other green industry professionals. It provides woody plant disease analysis, woody plant and turf insect identification, turfgrass identification, landscape and turf weed identification and offers a report of pest management strategies that are research based, economically sound, and environmentally appropriate for the situation. Send specimens and payment made payable to the University of Massachusetts to Urban Forestry Diagnostic Lab, 160 Holdsworth Way, Holdsworth Natural Resources Center, UMass, Amherst, MA 01003. The fee for a woody plant disease analysis is $50.00. All insect, weed, and turfgrass identification samples are $25.00 each. For complete information and instructions on how to send specimens, visit the Urban Forestry Diagnostic Lab page.

Turfgrass disease samples should be directed to the UMass Turf Disease Diagnostic Lab . This service is available ONLY to green industry professionals such as landscapers, lawn care companies, and golf course managers. For more info specifically on turf disease diagnostics, visit the Disease Diagnostics page at www.umassturf.org .

NEXT UPDATE: The next issue will be available on Friday September 10, 2004.

This message is produced by the UMASS Extension, Landscape, Nursery and Urban Forestry Program. The copy is prepared by Anna Greene from data and reports provided by the staff and faculty of the UMass Landscape, Nursery and Urban Forestry Program and the UMASS Extension Turfgrass Program as well as cooperating horticultural, green industry, and other professionals from the field. The text is adapted for access via the Internet by Jason Lanier and made available to subscribers via electronic transmittal by Ellen Weeks.

DISCLAIMER. This message is intended for commercial use. UMASS Extension assumes no liability for recommendations. The use of trade names does not imply endorsement. Similarly, there may be other products you prefer to use.

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