UMass Extension Landscape Message #14
June 4, 2004

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ENVIRONMENTAL DATA

The following growing degree day (GDD) and precipitation data was collected from May 27 through June 2, 2004. Soil temperature and phenological indicators were observed on June 2, 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: Cool, damp weather continues to be the norm and Hanson received some much needed rain over the past week. Soil temperatures have gone up to 58° F. Soils in Hanson are slightly moist. White pine male flowers are in full bloom and the pollen is everywhere. Tuliptree, Goldenchain Tree, Rutgers' hybrid dogwoods, Miss Kim Lilac, Cornus kousa (Kousa Dogwood), Chionanthus virginicus, bearded iris, siberian iris, Doronicum, Corydalis lutea, Dicentra spectabilis, Dicentra eximia, Aquilegia, (Columbine), Vinca, Tiarella, Phlox divaricata, and Trillium are in full bloom. Phlox stolonifera, Pulmonaria, tree peony, burning bush and oriental bittersweet are past bloom. Herbaceous peonies and early Clematis are starting to bloom. Most Hydrangea macrophylla probably will not bloom this year due to winter cold and injury. Although, many Rhododendrons suffered winter injury, there are a great number that look absolutely terrific, even the less hardy Dexter hybrids! Pests/problems: Many trees are fully or partially defoliated due to caterpillar activity. Winter moth caterpillars have started to pupate and are about finished for the year. The Hanson office continues to receive calls from the southeast region relating to forest tent and tent caterpillars. Like last year, this seems to be the "Year of the Caterpillar." Asiatic garden beetles, aphids, boxwood psyllid, cottony camellia scale on Taxus, oak sawfly, lily leaf beetle, hemlock woolly adelgid, gypsy moth caterpillar, mosquitoes, ticks, and forest tent caterpillars are all active. Plymouth County Extension does not spray for mosquitoes. The number to call for Plymouth County residents is 781-585-5450. Black spot has been observed on roses.

East - General Conditions: Cool and rainy. Pests/Problems: Lily leaf beetle larvae continue to feed and adults are present and laying eggs too. White grubs found in soil around flower beds - beetle not identified.

Central - General Conditions: No report..

West - General Conditions: Lush and green continues to be the look of the landscape in the Pioneer Valley. Iris, columbine, Catawba rhododendron, pansies and newly planted bedding plants are the showpieces in the gardens. Pests/Problems: However, closer inspection shows evidence of disease and a lot of assorted caterpillar feeding activity (see Insect Section below). Diseases that are current include those discussed below, but also Swiss needle cast on Douglasfir and fire blight on Callery pear.

Berkshire - General Conditions: A pattern of moist weather has settled in over the past two weeks. For the most part the rains have been gentle and with a few exceptions have amounted to less than one-half an inch per day. This has been ideal for planting trees and shrubs. Pests/Problems: The first appearance of Viburnum Leaf Beetle (VLB) in Massachusetts has been confirmed. The beetle larvae were found in Great Barrington on a couple of specimens of Viburnum trifolium. Anyone working in Berkshire County should be alert to the presence of this pest of native and non-native viburnums. See the VLB fact sheet for a description and information on life cycle. Please report any sightings to Bob Childs (413-545-1053) or Ron Kujawski (413-528-8267).

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):

• Winter Moth - Continued monitoring indicates very high population levels for this pest this year. For most areas, the larval period (caterpillar = feeding stage) is now complete and they have dropped from the trees and are pupating. No more injury will occur this year from this pest.

• Fall Cankerworm - Initially thought to be in low numbers in coastal areas, it is now being found in large numbers in many of the same areas as winter moth. It is mostly on oaks but it is also being found on other deciduous species. This pest will remain active for another 1-2 weeks. It has 3 pairs of prolegs but the first pair (most anterior) is about half the size of the other two pairs. In low to moderate size populations, this caterpillar is green. However, when in high densities, it becomes very dark (black). This year, depending on the areas of infestation, we are finding both color types, even within the same town.
  
• Eastern Tent Caterpillar has finished feeding but its unsightly webs remain in Malus and Prunus species. Although defoliation is very apparent in some areas, no further damage will occur. Some of the caterpillars may still be found, usually off of the primary host plant. They are either seeking a pupation site or are parasitized.
  
• Forest Tent Caterpillar remains active as is quite physically large now. When in large numbers they are serious defoliators of hardwoods, especially oaks. Southeastern MA (Lakeville, Taunton, Freetown, in particular) will most likely experience heavy defoliation once again this year. Although, they are in noticeable numbers across the state and throughout much of southern New England. They will remain active for another 1-2 weeks.
  
• Larch Casebearer Caterpillars have pupated. Adult moths will be active in another 2-3 weeks.
  
• Gypsy Moth caterpillars, although limited this year in numbers, continue to feed and are at the instar stages where their characteristic markings are very identifiable. Populations of this pest remain low in much of the state. In most areas, this pest is now between the third and fourth instar stage and it is too late to treat with a B.t. product. Look for the yellow markings on the head capsule, which indicates at least the fourth instar stage. Prior to this stage, the head capsule is all black. Once the yellow appears, it is too late for B.t.
  
• Fruitworms (Green) remain active. There are many species of these that sometimes appear in large numbers and create damage on such hosts as maples, beech, fruit trees, and many other deciduous hosts. They are now much larger than winter moth. Do not confuse them with Winter Moth. Fruitworms generally have 5 pairs of prolegs and develop a white stripe down the length of their backs. They also achieve a much greater physical size than winter moth. Treat if found in large numbers. Most likely, it's too late for B.t.
  
• Euonymus Caterpillar is active. This small, pale yellow lepidopteran caterpillar with black spots attacks many varieties of euonymus from shrub-form to tree-form. They produce much silk but act as free feeders by moving throughout the entire plant. By mid-June, affected plants may be defoliated and covered in a fine veil of silk. Treat with Bacillus thurngiensis 'Kurstaki' or a spinosad product or with one of the many registered chemical insecticides.

Hymenoptera (sawflies):

• European Pine Sawfly - Caterpillars now are near full size in much of the state and are dropping to the soil to pupate. They will not appear again until next spring. Injury to such hosts as mugo pine is severe in many areas.
  
• 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 the young caterpillars with insecticidal soap or one of the products that contains spinosad.
  
• Azalea Sawfly - This pale green caterpillar is virtually the same color as its host foliage; primarily that of 'Mollis' and 'Exbury varieties' of deciduous azaleas. These caterpillars feed mostly at the leaf margins and consume leaves right down to the mid vein, which they do not consume. Look for clusters on main veins and now leaf blade; most likely, upon very close inspection, this pest will be found. It is extremely cryptic in coloration and a challenge to find. However, its injury is very identifiable. Treat with a spinosad product when found. This pest is only active for a few weeks in the spring but is capable of severe defoliation. In many areas, infested azaleas are already displaying heavy defoliation from this pest. In many parts of the state, this caterpillar may have already finished its feeding period and will not appear again until next year.
  
• Rose Slug Sawfly remains active. This is another sawfly caterpillar that is only active for a short while but capable of creating much unwanted injury. These rather small, pale green caterpillars feed on the upper leaf surface (mostly) by scraping away the leaf surface (skeletonizing). Such areas first appear as a 'window-paning' effect but later turn brown as tissue dies. Treat with a spinosad product when found.
  
• Oak Sawfly are 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. Spinosad products are effective if deemed necessary.
  
• Birch Sawfly species are 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.

Beetles

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

Leaf Beetles:

• Lily Leaf Beetle - Adults of this bright red beetle continue to feed and lay eggs. Eggs are hatching and tiny larvae are feeding. 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 carefully for bare twigs that have a 'sandpaper' feel to them; this could be an indication of an egg-laying site. Monitor for the larvae that are free-feeders and cause much defoliation injury to viburnum. In areas where Winter moth is active, do not confuse that injury with that of the viburnum leaf beetle. Visit the following Cornell web site to become more familiar with this pest: http://www.hort.cornell.edu/vlb
  
• Imported Willow Leaf Beetle is 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:

• European Chafer adults are active. These rather large beetles congregate at night on woody plants, sometimes by the hundreds or thousands. Primarily clustering for mating purposes, they can also create much injury to foliage by feeding. Large ragged notches, and no insects being present during the day, may indicate a problem with this insect. Inspect the plant at night with a flashlight. Treat with a chemical insecticide if necessary.
  
• 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 are pupating and the rust-colored beetles will be active within a few weeks. The grubs of this pest cause marginal 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.

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 in warmer regions of 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 will be active very soon, if not already in warmer parts of the state. 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 will be active soon. 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:

• Honeylocust Plantbug remains active. Although, foliage of host plants is almost fully emerged and this pest may no longer be of concern. Continue monitoring by gently shaking branches over a white piece of paper and inspecting with a hand lens. If deemed necessary, apply an application of insecticidal soap or one of the registered chemical insecticides. In many areas, the new growth emerged quickly enough this year to avoid being injured much by this pest.
  
• Tarnished Plantbug is active. This small, brown insect with pale yellow markings has a wide host plant range that includes shrubs and annuals. It's 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.

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. Avoid oil sprays on newly emerging tender foliage. There is strong evidence that much winter mortality occurred (as high as 80-90%) and inspections should be made prior to applications to determine if they are necessary.

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 white piece of 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.

Eriophyid Mites:

• Hemlock Eriophyid Mite (not a spider mite). This tiny, peg-shaped, four-legged mite feeds openly upon needle surfaces. Inspect for its presence. It will remain active into early June. Plants with high levels of infestation become chlorotic. Treat with a horticultural oil spray when necessary.

Psyllids:

• Boxwood Psyllid - This pest remains active but is quickly reaching the end of its feeding cycle for this year. Monitor those boxwoods with cupped foliage for activity of this pest. Maturing nymphs also produce fine strands of wax fibers that are very noticeable right now and aid in monitoring. Cupping of new foliage has already occurred.

Leafminers

• Native Holly Leafminer remains active in the mines as a larva, mostly in American Holly. Pupation is beginning. Hang yellow sticky cards in affected plants to monitor for adult emergence. Treat when they appear with a registered chemical insecticide.

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.

Oystershell Scale and Euonymus Scale will have crawlers soon, which is an ideal time to treat with an oil spray. Monitor infested branches with black electrical tape (sticky side out) to determine when crawlers have emerged from under the adult female scale covering.

Continue to monitor each 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.
  
• 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.

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

• 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 (WSPS) adult beetles are 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 0f 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/pubs/alb_wss/alb_wss.htm ,
  http://www.na.fs.fed.us/spfo/alb (the main Forest Service page for ALB)
  
• Monitor previously stressed plants (drought, soil compaction, etc.) for signs of invasion. Bronze Birch Borer is one such invader. Water infested trees during drought periods. Insecticide injections may be effective in some cases. Now that Black Locust has bloomed (a good phenological indicator), 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 a sign of an already weak tree. Water during times of drought.
  
• Dogwood Borer - Continue to monitor for new infestations (adults will become active soon) 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.

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

DISEASES

Leaf spot and shoot blight (including anthracnose) diseases are widespread this year because of the extended periods of rainy weather. The best time to initiate protective fungicide applications to nursery and specimen woody landscape plants that are known to be susceptible to these diseases has passed. However, if they were started earlier this spring, it is important to repeat the treatments at the labeled intervals to maintain the protection until the foliage matures or drier weather conditions prevail.

Cedar-apple rust is visible as orange-yellow 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-inch 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 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 showing up on red and pin oak leaves as faint, yellow-green spots. Puckering is minimal but noticeable, if you look closely. This is a not a serious problem in our area. If a severe outbreak is occurring on specimen trees, note that for future reference. Chemical control activities should be started just before buds open next spring.

Apple scab 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. To maintain scab-susceptible crabapples in the landscape in which infection has already occurred, consider using systemic fungicides. These fungicides act to prevent new infections that develop on newly emerging leaves. Systemic fungicide applications will not restore distorted, discolored crabapple leaves to health. They can reduce the incidence of apple scab as the season goes on if they are applied soon, before the extent of infection is too severe, and protection is maintained at labeled intervals. Alternate every second or third systemic fungicide spray with a broad-spectrum fungicide to reduce problems with fungicide resistance. 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 resistant varieties of crabapple.

Susceptible flowering dogwood have scattered leaves exhibiting irregularly shaped gray areas with purplish 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 during wet springs, apply fungicides as buds open, after bracts have fallen and again four weeks later.

Sycamore and oak anthracnose diseases are evident now as dark-green to dark-brown curling leaves and shoots. Anthracnose is widespread on early leaves and shoots this year due to the abundance of inoculum on over-wintering twigs and fallen leaves, as well as the consistently wet weather. These diseases cause some premature leaf loss, but that is not going to seriously an otherwise healthy tree. In the fall fine prune infected twigs and collect and dispose of fallen leaves. Promote drying of foliage by pruning and spacing plants to increase the penetration of sunlight and air circulation in and around plants.

The wet conditions, along with development of immature scale-leaves/needles are favorable for infection of juniper by Phomopsis tip blight. Juniper shoots that are tan-gray with pinhead sized, black fruiting bodies are producing spores at this time. New growth that becomes infected this spring with Phomopsis tip blight will turn green-yellow, then brown and die within a few weeks of infection. Management begins with the removal and disposal of infected shoot tips to reduce inoculum. Cut an inch or so below the boundary between dead and healthy tissue. Now is the time to initiate fungicide control of juniper tip blight to improve plant appearance. Grow junipers in an open, sunny location to promote drying of foliage, that are adapted to the site and that have resistant to tip blight.

There were recent news reports about Sudden Oak Death (SOD), caused by the fungus Phytophthora ramorum. SOD 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. To date, Phytophthora ramorum has not been found in Massachusetts, though it has been positively identified in Florida and Georgia. The Massachusetts Department of Agricultural Resources (MDAR) is monitoring this situation carefully. A number of surveys are planned by MDAR, the United States Department of Agriculture (USDA) Forest Service, and the USDA Animal and Plant Health Inspection Service (APHIS) nationwide and in Massachusetts to check for the presence of Phytophthora ramorum in nurseries and natural forest areas.

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 the environment serving, therefore, as a reservoir of inoculum, which in turn infects woody tissues of oaks and tanoak trees.

Surveys continue in several states as a national survey is getting underway. APHIS-PPQ is determining the distribution of Phytophthora ramorum. 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 facilities, 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: http://www.massnrc.org/pests/ and hit the 'Search for Pest Info' button for pictures and more details.

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 May 24 through May 28, 2004:

• Red maple 'Fairview Flame' - Approximately10-year-old trees growing in nursery field with scattered dead, weeping areas on the stem; Cryptosporiopsis canker/fungus infected egg laying holes made by narrow-winged tree cricket last fall.
• Taxus species - yellow-to-brown branches and twigs on well-established hedge growing 8' back from curbside; winter drying, heavy snow load and deicing salt damage worsened by secondary Botryosphaeria cankers.
• Red pine -decline and death of groups of 30-year-old plantation trees, Heterobasidion annosum root and butt rot.

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: A sampling of some white grubs were recently collected from Berkshire County (western Massachusetts). It was observed that most of the European chafer grubs had stopped feeding. Some had already moved into that elusive "pre-pupa" stage, where they begin to change shape a little bit. Almost all of the grubs had stopped feeding, and looked a little yellower than usually. This simply means that they will be pupating soon, and adults should be emerging about on schedule or slightly earlier than the usual mid-June.Japanese beetle grubs appeared to be on scheduleCstill feeding and looking very healthy. They should be feeding for another couple weeks before they go through the process of emptying their digestive system of indigestible food and preparing to pupate.

Reported by Pat Vittum, Professor and Extension Turf Entomologist, UMass, Amherst, Mass

Weeds: Now is the time for the following activities:

• Continue actively monitoring for crabgrass and other annual grass weeds. Crabgrass stage of growth ranges from 1-2 leaf in denser turfs to 1-2 tiller in thinner turfs and warmer areas of the landscape. Follow postemergence product label for application timing based on growth stage.
• Postemergence broadleaf herbicide can continue. Cool and cloudy weather may slow herbicide actively.
• Monitor landscape beds for annual weeds that may be germinating in areas where mulch is thin. Larger weed should be treated with glyphosate since hand-weeding will often result in mulch disturbance. Small seedlings can be covered with mulch.
• Many winter annuals are now going to seed; remove before seed shatter.
• Inspect areas of landscape where new trees or shrubs, especially those that were field grown, have been planted in the last year. Look for perennial weeds that may be growing from the root ball. Canada thistle, mugwort and quackgrass are possible culprits.

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 . By special arrangement, the UMass Turfgrass Disease Diagnostic Lab is now open at Marquette University. This lab provides diagnostic services for turfgrass professionals in CT, MA, ME, NH, NY, RI, VT. 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 June 11 , 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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