UMass Extension Landscape Message #18
July 2, 2004

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ENVIRONMENTAL DATA

The following growing degree day (GDD) and precipitation data was collected from June 24 through June 30, 2004. Soil temperature and phenological indicators were observed on June 30, 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: Hanson has not received very much rain this month. Soils are dry and many established plants are wilting. Remind clients to water newly planted trees, shrubs, perennials and also trees that were defoliated by caterpillars. For many trees in Plymouth County, this is the second year in a row that they were defoliated. Plants in window boxes and containers are requiring water on a daily basis. Hydrangea paniculata 'Praecox', Hydrangea macrophylla 'Blue Billows', Clematis, landscape roses, Rosa rugosa, Spirea, Potentilla, Campanula sp., daylilies, Nepeta sp., Foxglove, Corydalis lutea, Thalictrum and Astilbe are in full bloom. Pests/Problems: Asiatic garden beetles, earwigs, aphids, four-lined plantbug, polydrusus weevil, white-spotted sawyer beetle, oak sawfly, lily leaf beetles and larvae, mosquitoes, ticks, wasps and hornets are all active. Anthracnose is showing up on dogwood, maples, and sycamore. Black spot has been observed on roses. Sod webworm adult moths are active on turf. Red thread is showing up on lawns. Plymouth County Extension does not spray for mosquitoes. The number to call for Plymouth County residents is 781-585-5450.

East - General Conditions: No report.

Central - General Conditions: Dry!

West - General Conditions: There were scattered episodes of rain and the temperatures have been cool, but the soil is drying out. The rich green color is fading in the lawns, though the gardens are thriving. Pests/Problems: Dogwood anthracnose, apple scab, Entomosporium leaf spot on hawthorn, Gymnosporangium rusts on crab apple and some hawthorn, and Guignardia leaf blotch on horsechestnut are all in evidence on susceptible trees. A disease that is just beginning to show up in the Valley is powdery mildew on flowering dogwood, roses and London planetree. Now is the time to begin management on high value plants (See the Woody Ornamental Disease section below).

Berkshire - General Conditions: No report.

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.

The spring of 2004 resulted in many caterpillar species being active, often in unprecedented numbers. This phenomenon made local and eventually national news. For more information, visit: http://www.cnn.com/2004/US/Northeast/06/23/caterpillar.crescendo.ap/index.html

Lepidoptera (moths):

• Fall Cankerworm - has pupated and is finished feeding for this year.
  
• Forest Tent Caterpillar (FTC) - has pupated and has finished feeding for this year. White-colored cocoons are quite prevalent and moths will merge over the next 2-3 weeks. No controls are warranted.
  
• Gypsy Moth caterpillars are now quite large and feeding voraciously. One mature larva is capable of consuming many leaves in one day. Pupation will begin soon.
  
• Mimosa Webworm adult moths will be active soon and depositing eggs on foliage of Honeylocust, in particular. The larvae will become active by mid-July and will start feeding by tying 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.

Hymenoptera (sawflies):

• Introduced Pine Sawfly will be active soon 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 then young caterpillars with insecticidal soap or one of the products that contains spinosad.
  
• Oak Sawfly species remain very active. In general, they are usually found in small numbers feeding by scraping the foliage, which leads to a "window-paning" effect. In large numbers, they can be serious defoliators. These are more prevalent this year than it has been in past years. Spinosad products are effective if deemed necessary.
  
• Birch Sawfly species remain active. They will appear in clusters on foliage of many species of birch. Treat with a spinosad product when found. Small individual clusters can be pruned away and destroyed by hand.
  
• Mountain Ash Sawfly is now active. Continue to monitor for this yellow caterpillar with black spots that feeds in clusters. Small infestations can be pruned away and destroyed. Larger infestations can be treated with a spinosad product. This pest consumes all but the main vein of the host plant foliage and is capable of creating serious levels of defoliation.

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 - Adults of this bright red beetle are not now very commonly found. However, the larvae are quite large and feeding. As larvae feed, they pile their own excrement on their backs thus giving them a very unattractive appearance. Monitor for their appearance on true lilies, fritillaria, and Solomon seal. Recent feedback from pest control practitioners suggests that NEEM products may not achieve the desired results for management of this pest. Spinosad products and many different chemical insecticides are labeled for this pest.
  
• Viburnum Leaf Beetle - has finally been found in MA in the town of Great Barrington (Berkshire County) not far from the NY border. Larvae are active now and creating much injury. Inspect viburnum for defoliation injury, which should be quite noticeable now. Pupation will occur in about 1-2 more weeks. Treat with a spinosad product or one of the registered chemical insecticides. Visit the following Cornell web site to become more familiar with this pest: http://www.hort.cornell.edu/vlb
  
• 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:

• Adult Rose Chafer Adult beetles are active. Monitor roses for the presence of these tan and somewhat slender scarab beetles. Treat if necessary.
  
• Asiatic Garden Beetle adults are now emerging. These rust-colored beetles will be active for a month, or so. The grubs of this pest cause minimal injury to turf but the adults can appear in great numbers, feed at night between first dark (approx 9:00 PM) until about midnight. Adults feed on many hosts including garden plants, annuals, perennials and others. Their feeding can range from notched foliage to heavy defoliation. Inspect at the feeding time with a flashlight; treat if necessary.
  
• Japanese Beetle adults began to emerge from the soil in warmer parts of the state last week. Although limited in numbers right now, an ever-increasing number of new adults will emerge per day over the next month. They are strong fliers and individual beetles may live for 2-3 weeks. Very soon, there will be large numbers of this pest actively feeding. They have a rather wide host range. Refer to the Turf Section below for more specific details.

Weevils (Snout Beetles):

• Polydrusus Weevil - These small and often bright green weevils are active on a variety of deciduous host plants. They will remain active well into July. They mostly create injury by notching the margins of the foliage, often to an extreme. Treat with a chemical insecticide when found in abundance. Spinosad products might be affective.
  
• White Pine Weevil injury is now very noticeable. Then insect, however, is long gone. Affected shoots, mostly of white pine, are very brown and dead. Prune out dead leaders.

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 nymphs are active throughout MA. Inspect the undersides of foliage for their presence. Systemic imidacloprid products work well. If contact (mechanical mode of action) pesticides, 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 is 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 is 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.

Plantbugs:

• Tarnished Plantbug is active. This small, brown insect with pale yellow markings has a wide host plant range that includes shrubs and annuals.
  
• Four-lined Plantbug is active. Its feeding causes brown dead patches to appear on foliage that resemble disease caused by pathogens. If much spotting occurs, controls may be necessary. This insect is active for much of the summer. At first appearance, it almost looks beetle-like with its dark body and yellow stripes.

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. Treat with insecticidal soap sprays, an Imidacloprid™ product, a summer oil spray or with one of the many registered chemical insecticides.

Adelgids:

• Hemlock Woolly Adelgid can still be treated with horticultural oil but monitor plants carefully for their stage of development. This pest will become dormant within the next 2-3 weeks. The young instar nymphs will settle on the stems at the base of the needles and not move or feed again until about mid-October. However, they can still be managed with horticultural oil sprays.

Other Piercing-Sucking Insects:

• 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.
  
• Spruce Spider Mite remains active. Inspect by gently shaking branches over a piece of white paper and then inspect with a hand lens. Monitor weekly to establish if population numbers increase significantly. Note the numbers of predatory mites present. Treat if necessary.
  
• Two-spotted Spider Mite is 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.

Root & Shoot Feeders

• White Pine Weevil damage is now noticeable. The affected new terminal shoots have wilted and died.

Leafminers

• Arborvitae Leafminer adult moths are mostly finished with mating and egg-laying. The female deposits individual eggs on the undersides of foliage and the tiny caterpillars hatch from the egg and chew their way into the foliage out near the tips. In a couple of weeks, inspect the undersides of foliage (with magnification) for new entry holes. The larvae will feed within the foliage all summer and into the fall but browning will not occur until January or February and is often attributed to winter injury. Control measures at this time are very limited.
  
• Locust Leafminer on Black Locust has been active for a while and its injury is starting to appear. Adults skeletonize the foliage while the larvae mine. The next generation of adult beetles are active and mating now. Treat with a spinosad product or with one of the registered chemical insecticides to break the cycle of re-infestation. In many cases, untreated trees will appear to be fire-swept by August as all of the foliage is killed.

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.
  
• Pine Needle Scale crawlers will be emerging soon.

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

Soft Scales:

• Monitor yews and certain hollies for the Cottony Camellia Scale (aka: Cottony Taxus Scale). Treat the active nymphs with a summer oil spray. This pest creates much honeydew that generates much sooty mold. We have received many reports about this pest, this year, from central and southern CT, especially. Coastal areas of MA are also experiencing injury from this pest.
  
• Begin to monitor azaleas for the Azalea Bark Scale. Inspect inner branches for nymphs and sooty mold. Treat with a summer oil spray if necessary.
  
• 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

Many different galls have appeared on various host plants; most are insignificant in terms of plant injury.

• Felt patch galls, caused by certain Eriophyid mites, are commonly found on maples, beech, and other hosts. Although usually a tan color they can sometimes be a spectacular pink color and raise much alarm. They are harmless
  
• 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.
  
• Aphid-induced galls are common on certain elms. These large pouch-like galls are often very numerous. There are no controls for these nor are any deemed necessary.
  
• Galls on oaks - Mostly stimulated by Cynipid wasp species, the majority of these are harmless. However, if found on the stems, they can be quite serious. Unfortunately, there are no effective controls for the ones on stems. The vast majority of these will be found on foliage and control measures are not warranted nor effective.

Wood Attackers

• White-Spotted Pine Sawyer adult beetles 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 is they have been previously weakened. Pruning (wounding) releases plant chemicals that attract BBB females.
  
• 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. .
  
• Dogwood Borer - Continue to monitor for new infestations (adults are active) and continue to avoid any wounding of the tree trunks with mowing equipment and string trimmers, which encourages infestations of this pest. If necessary, monitor for adult emergence with pheromone traps.
  
• Rhododendron Borer adult moths are active. Pheromone traps are available for this clear-winged moth species. Adult females lay individual eggs usually near the base of shoots of rhododendron. Tunneling larvae will expel sawdust but this is often hidden due to dense foliage. Often, 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.

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

DISEASES

Horsechestnut (Guignardia) leaf blotch - scattered, irregular-shaped orange-brown blotches are visible on infected leaves. They are primarily affecting lower, inside leaves, and less than 10% of the total leaf area. As the summer progresses the impact of the disease may be more noticeable, but chemical intervention for this season is of little benefit.

Powdery mildews - these fungi are now visible as a dusty, gray to white coating on phlox, dogwood, sycamore and rose leaves, to name a few. 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. Later this summer spherical, black fruiting structures (cleistothecia) will be 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. 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 are developing 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 mid day to reduce period of time leaves are wet. Many beautiful, resistant varieties are available. Apply fungicide sprays at intervals specified on the label. Fungicides labeled to protect foliage on susceptible plants are listed in the UMass Extension Management Guide for Woody Ornamentals.

Botrytis blight is noticeable as a gray moldy blight of flowers, leaves and shoots in herbaceous perennial gardens. Cool temperatures and shaded conditions enhance the damage by this fungus. To manage Botrytis blight, remove dead plant material that the fungus uses as a beachhead for the development of more inoculum. Irrigate before mid-afternoon so foliage dries off before nightfall. With the advent of warmer, drier weather there is little benefit to fungicide applications. But next spring, if cool and wet conditions prevail, fungicides help to protect succulent growth on high value plants from becoming infected.

Cedar-apple rust is visible as orange-yellow blister-like spots on susceptible hawthorn, apple and crab apple leaves. By mid-summer tiny yellow-white tubes will extend from the underside of infected leaves. From mid-summer to autumn, spores are wind-carried from the apple leaves and, when conditions are wet, they infect green shoots and needles of junipers. Pea-sized to 2" diameter round, brown galls develop 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 cedar-apple rust resistant apple and juniper varieties. Also, prune dormant galls on juniper during the summer, fall, winter and early spring (before jelly-like horns form). Avoid growing susceptible junipers close to apples. The time to apply fungicides to protect high value apples from cedar-apple rust has passed for this spring. Fungicide protection of eastern red cedar and Rocky mountain junipers is seldom performed, but if it were desired, it would be from mid-August through September.

The minute red-purple spots of hawthorn (Entomosporium) leaf spot are visible on leaves and causing some yellowing and defoliation of susceptible hawthorn. Now that the fungus is established, it regularly produces spores; and with recurring wet periods the disease spreads via these secondary infection cycles. A long-term management strategy to consider is replacement of susceptible hawthorns with resistant trees. Otherwise, preventative fungicides must be applied as buds open or when the first rains begin after the leaves start to develop in the spring; these should be repeated at labeled intervals several times until early summer. There is little benefit from chemical controls of this disease when they are started this late in the season.

Oak leaf blister is apparent on red and pin oak leaves as faint, yellow-green spots that are beginning to turn brown. Puckering is minimal but evident, if you look closely. This is a not a serious disease problem in our area. If a severe outbreak is occurring on specimen trees, note that for future reference. Fungicide control activities should be started just before buds open next spring.

Apple scab lesions lesions are visible on susceptible crab apple leaves. Many leaves are curling or cupping where lesions developed before the leaves were mature, and the dead leaf tissue constricted leaf expansion. Within weeks after infection the olive green fruiting bodies produce new spores. New infections can occur essentially the entire growing season during wet and mild conditions. Fungicide protection at this point in the season is of little benefit. Prune to increase sunlight penetration and air circulation, which promotes rapid drying of wet foliage. If apple scab is a chronic problem and replacement is an option, consider planting a resistant variety of crabapple near the susceptible one. Once it are well established the susceptible tree can be removed and management of this disease is much easier.

Susceptible flowering dogwood have scattered leaves exhibiting irregularly shaped gray areas with purplish-brown margins of dogwood anthracnose infections. 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 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 variety. 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.

The official Massachusetts Department of Agricultural Resources (MDAR), Massachusetts Department of Conservation and Recreation (MDCR), and USDA Animal and Plant Health Inspection Service (APHIS) Sudden Oak Death (SOD) survey in nurseries and forest areas around the state has begun. To date, Phytophthora ramorum has not been found in Massachusetts, but nearby states in which it has been positively identified include Pennsylvania and New Jersey.

The fungus Phytophthora ramorum causes SOD. It is a severe disease of oak and tanoak in certain Pacific Northwest fog forest areas. In March 2004 Phytophthora ramorum was found in two large ornamental nurseries in southern California. This detection demonstrates that the pathogen is not necessarily limited to the moist coastal regions of northern California and southern Oregon. At least one of the two nurseries distributes nursery stock nationwide, including Massachusetts.

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.

P. ramorum has been confirmed in plants traced forward from the initially positive California wholesale nursery in 97 facilities in14 states. The numbers of nurseries or garden centers with positive P. ramorum samples from the wholesaler by state are: California (38), Alabama (1), Florida (5), Washington (6), Oregon (9), Texas (5), Colorado (1), Georgia (13), Louisiana (5), Maryland (1), North Carolina (9), New Mexico (1), Tennessee (2), and Virginia (1).

The number of confirmed positive nurseries or garden centers from the national, and other surveys is 118 in 14 states. Fourteen states continue to impose quarantine regulations over and above those ordered by PPQ on California, and in some cases Oregon, Washington or British Columbia.

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 June 21 through June 25, 2004:

• Sugar maple - 12-year-old tree that was trans planted four years ago had about 2/3 of its branches leaf out and now a few adjacent branches that leafed out are browning; Valsa canker.
• Japanese maple - well established tree leaved out normally but in early June several branches wilted and died; Verticillium wilt.
• Norway maple - scattered branches on a 40 year old tree have a few yellow-brown blotches on the leaves; Kabatiella form of maple anthracnose.
• London planetree - many 1 year transplants of 3/4" to 1" caliper trees in a nursery began to leaf out this spring and died; no disease/winter freeze damage to roots and basal stem.

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:

White grubs.
We have had a few reports of Japanese beetle adults flying, particularly in areas around New York City. We normally expect to see adults around July 4th here in Amherst, and I suspect they will be pretty close to "on time" this summer. So far the white grub development is expected to be very close to "normal" this summer. One factor that could change that would be an extended dry period. If we do experience a stretch of several weeks without measurable rainfall, we can expect female beetles to delay egg laying until soil moisture conditions improve.

The good news for the short term is that grub activity that plagued some of you throughout the spring is over in most places. Most of the grubs that have not already pupated have stopped feeding.

Caterpillars
Dave Shetlar (Ohio State) mentioned in a recent e-mail newsletter that he had seen large numbers of armyworm moths in central Ohio. This is the first report I have had of armyworm activity this year. It is way too early to panic in New England. The moths that have been reported in Ohio may or may not make their way to New England. But it would be appropriate to keep your eyes especially tuned to possible armyworm activity. Remember that armyworm caterpillars are often nocturnal but when the caterpillars reach outbreak populations, they are also active in the day. Armyworm caterpillars are a very dark base color (often described as black or navy blue), have a two-toned brown head capsule that looks "honey-combed" and have a black splotch at the base of each fleshy leg (proleg) on the abdomen.

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

Weeds:

In many areas crabgrass plants are getting large enough were effective control may be difficult. Check growth stage before postemergence applications.

There have been several calls about large numbers of ash and maple seedlings in landscape beds. Glyphosate will provide effective control; however depending on the size of the seedlings, the dead plants can be unsightly. Hand-pulling is another option as long as there is no mulch disturbance and soil scattered on the mulch surface. Several years ago I observed a unique control strategy using an electric hedge trimmer. The landscape contractor slid the trimmer just above the mulch surface clipping the seedlings about 1/4 inch. He commented that this was the way to go since it does not disturb the mulch and clipped seedlings can be easily removed.

Randall Prostak, Weed Specialist, UMass Extension Landscape, Nursery, and Urban Forestry Program, Amherst, Mass.

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 . 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 July 16, 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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