UMass Extension Landscape Message #15
June 10, 2005

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The LANDSCAPE MESSAGE is an educational tool intended to guide Massachusetts Green Industry Professionals in identifying pests in the landscape, monitoring their development, planning management strategies, and creating site-specific records for present and future management reference. This issue has been updated to provide timely pest management information and the latest regional news and environmental data throughout Massachusetts. The next issue of the LANDSCAPE MESSAGE will be available next week on Friday, June 17, 2005 . Missed a previous message? Visit the Landscape Message Archive.

ENVIRONMENTAL DATA

The following growing degree day (GDD) and precipitation data was collected for the one-week period from June 1 through June 8, 2005. Soil temperature and phenological indicators were observed on June 8, 2005. Accumulated GDDs represent the heating units above the 50° F baseline temperature collected via our instruments since the beginning of the current growing season. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

The statewide GDD averages for this period are as follows: Total = 333; GDD/week = 119; GDD/day = 17

REGIONAL NOTES

Cape Cod Region (Barnstable) - General conditions: The past week was mild and dry for a pleasant change. Plant development is progressing nicely, with early summer perennials coming into bloom. Areas with sandy soils are actually a bit dry and newly planted material should be on a regular watering schedule. Pests/Problems: Winter moth caterpillars are rapidly developing and many areas have defoliated trees. If the warm weather continues, they will be spinning down to the ground to pupate in a very short time. Forest tent caterpillar is still feeding and may follow winter moth onto partially defoliated trees. Parts of the Cape also have gypsy moth caterpillars. Lily leaf beetle adults and 1st, 2nd, and 3rd instar are actively feeding on Asiatic and Oriental lilies. Adult Asiatic garden beetles have emerged and are feeding at night on annuals and other herbaceous material. Queen carpenter ants are flying. Mosquito populations are extremely high, making working outdoors a pain. Deer tick nymphs are active; do thorough tick checks each day. Sycamore anthracnose is evident on emerging foliage. Maple anthracnose had come into the clinic. Apple scab and cedar-apple rust can be seen on susceptible crabs. Red thread is active on turf.

Southeast Region (Hanson) - General Conditions: Warm, humid weather has been the norm for the past week. Hanson received no rain and soils are warm and starting to dry out. Many plants are wilting. Many trees, fully or partially defoliated due to caterpillar activity, are starting or struggling to put out new growth. Water is critical to trees at this time. With no rain, a good deep soaking over the root zone, once a week, is warranted. Tuliptree, doublefile viburnum and other viburnums, Rutgers hybrid dogwoods, kousa dogwood, goldenchain tree, (Laburnum sp.), Kerria, hybrid lilacs, Wisteria, Phlox stolonifera, Corydalis lutea, Dicentra eximia, Dicentra spectabilis, bearded iris, Solomon's seal, columbine, Geranium sp., Lunaria, Euphorbia sp., Siberian Iris, early daylilies, Pulmonaria, Polemonium, Phlox divaricata, Phlox subulata, Primula, Trillium, Vinca minor and ajuga are in full bloom. Helleborus foetidus, Arisaema, Tiarella, Lily-of-the-Valley, Epimedium, and tree peony are past bloom. Pests/Problems: 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. Staff from Arborcare/Ropes and Saddles report that the geographic region of tent caterpillar continues to spread in the southeast region, especially in the SW Freetown/Assonet areas. Many of the caterpillars appear to be dying from disease. Buttery-yellow caterpillars, which we believe to be the mustard sallow or the pale mustard sallow, are feeding on witchhazel 'Arnold Promise'. This caterpillar was first observed last year. The Plymouth Extension office has received numerous calls on ants appearing outdoors. Many of these are the large black, winged reproductives of carpenter ants. Other ant calls refer to numerous ant hills in lawns. Aphids, cottony camellia scale on Taxus, carpenter bees, 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. Clover is in full bloom

East Region (Boston) - General Conditions: No report.

Central Region (Boylston) - General Conditions: No report.

Pioneer Valley Region (Amherst) - General Conditions:The daily temperatures have been quite variable from below normal to within the past few days, very warm. There has been less rainfall but the soil moisture level is adequate as evidenced by the green lawns and flourishing gardens. However, young trees and shrubs should be watered if the warm weather continues and the rainfall remains as episodic as it has been.

Berkshire Region (Great Barrington) - General Conditions: Dry conditions prevail and upper two inches of soil are dry, yet plant growth is vigorous and showing no signs of water stress. Pests/Problems. Insects observed during the past week include: eastern and forest tent caterpillars, leaf rollers on oaks and crabapples, leaf hoppers on willow, European pine sawfly, pine spittlebug (abundant), cankerworms on assorted deciduous trees. Deer ticks, slugs, wasps and carpenter bees are also prominent.

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 Agroecology Program, Great Barrington.

WOODY ORNAMENTALS

INSECTS

The sudden, yet greatly delayed, onset of warm summer weather has greatly accelerated both insect and plant development. However, we are still behind the norm for GDD accumulations statewide. Winter moth is virtually finished feeding in much of its Massachusetts range. Forest tent caterpillar and some gypsy caterpillars are beginning to be killed by natural causes (fungi, virus, etc.) but much defoliation has already occurred in many areas.

Gypsy Moth - This pest is active in larger numbers than it has been for a few years. However, the now naturally occurring fungus - Entomophaga maimaiga - should be very prevalent this year due to the wet conditions. It is expected to have a significant role in reducing gypsy moth numbers once again. If treatments are deemed necessary, then Bacillus thuringiensis var. kurstaki (B. t. k.) or a product containing spinosad or a tebuzenozide product, e.g., Confirm™, an insect growth regulator (IGR) or one of the registered pyrethroid insecticides should work well. Even though gypsy moth is noticeable throughout the state, it is at much higher levels in the Boxborough area and down through much of southeastern Massachusetts.

Winter Moth - Locations from Boston down through Plymouth County and much of southeastern Massachusetts are now seeing the end of the larval (feeding) period and the beginning of pupation. This caterpillar is now mostly finished feeding for this year. Treatments are no longer necessary. Note: A new fact sheet entitled 'Identifying and Managing the Life Stages of Winter Moth' (Operophtera brumata)' shows a gallery of winter moth photo images and is now available on this web site.

Forest Tent Caterpillar (FTC) - This caterpillar mostly prefers oaks but can be a pest on maples, crabapples and other deciduous hosts. Once again, they have appeared in large numbers in portions of southeastern Massachusetts and are showing increasing numbers statewide. This caterpillar is now quite large, and B. t. is now ineffective for its control. New York state is once again reporting big numbers for this pest this year. In 2004, forest tent caterpillar began pupation around the first of June in Massachusetts. By being much cooler this year, this pest will remain actively feeding for another 1-2 weeks this year. In eastern Massachusetts, there appears to have been a staggered hatch of FTC this year and the range in physical size of this pest on individual trees is quite dramatic. As noted earlier, FTC is starting to be affected by naturally-occurring pathogens in some areas.

Eastern Tent Caterpillar - Common to Malus and Prunus species, this native defoliator was present in high numbers last year across much of the northeast. Where we typically only see one web, we are noticing a dozen or more in one tree this year. Webs are now at full size and feeding has ceased in most areas of the state. Most caterpillars that still remain are most likely parasitized or affected with a pathogen. Trying to kill them with insecticide is not necessary. Also, killing a parasitized caterpillar only serves to kill the beneficial organism within it.

Fall Cankerworm - This native pest is still present in high numbers, especially in eastern Massachusetts. Parts of Plymouth county have very high numbers of this insect right now. It can be found primarily on oaks but it has a rather wide deciduous host range. Now that winter moth is disappearing from the scene, this insect is becoming more noticeable. Treat with a B. t. k. product or spinosad or tebufenozide or with one of the registered pyrethroid insecticides.

Fruitworms - These caterpillars have five pairs of prolegs and are green.. They are free-feeders and have been increasing in numbers over the past 2-3 years. Oaks, maples and many other deciduous hosts are attacked. They are currently still quite small but will increase in size dramatically within the next few weeks. Treat the same way as the other Lepidoptera.

Euonymus Caterpillar - This pest can be found on a number of different deciduous euonymus species. It is a pale yellow caterpillar with black spots that makes much silk on the host plant. In large numbers, it can be a serious defoliator. Treat the same way as the other lepidopteran caterpillars.

Hymenopteran Caterpillars (Sawflies):

European Pine Sawfly - This voracious caterpillar is now quite large and injury is very apparent. Treat with a spinosad product or with one of the registered pyrethroid insecticides. This pest is almost finished feeding for this year. However, at this stage, it can cause large amounts of defoliation within days if not treated

Azalea Sawfly - the larval stage is now active on deciduous azaleas, such as 'Exbury' and 'Mollis' varieties. This pale green caterpillar is virtually the same color as the foliage of its host and feeds along the leaf margins, making it very hard to see despite it being in plain sight. Monitor for foliage that has nothing remaining but the main vein of the leaf. Look very closely for this cryptic caterpillar. They are capable of defoliating individual plants within a few weeks. Treat with a spinosad product or with one of the registered pyrethroid insecticides. Younger larvae can be treated with an insecticidal soap spray.

Birch sawfly caterpillars are active. They can be easily observed lined up along the leaf margins. They will feed down to the midrib of the foliage. When disturbed, they will writhe in a defensive posture. Treat with a spinosad product or with one of the registered pyrethroid insecticides. Younger larvae can be treated with an insecticidal soap spray.

Maple petiole borer - this petiole-mining sawfly causes an area of the leaf petiole to become shrunken and blackened. Then, during winds or rainy periods, usually around this time of the year, the affected leaves will drop to the ground. Hundreds of leaves may be lost from one tree. Raking and destroying the fallen leaves does no good in terms of controlling this insect; the larvae stay within the piece of the petiole that is still attached to the tree. Within weeks, these petioles (with the caterpillar) will drop unnoticed to the ground. Although appearing to be serious, it is not a problem for the tree. It happens once per year and only a tiny fraction of foliage is lost. There are no controls nor are any deemed necessary. Sugar maple is the primary host.

Beetles:

Viburnum Leaf Beetle - Inspect all viburnum plants (those that are established in the landscape and nursery, as well as those which are newly arriving) for the presence of this unwanted pest. The indicators of its presence at this time of the year will be bare twigs that have a ‘sandpaper’ texture, a sign of the over-wintering eggs. Larvae are active now. Visit the Cornell web site, http://www.hort.cornell.edu/vlb/index.html , for current information on this pest. Report any new findings in MA to Robert Childs, rchilds@psis.umass.edu, 413-545-1053.

Lily Leaf Beetle - The bright red adults are now actively mating and the females have been laying eggs. In all areas of the state, eggs are hatching and tiny larvae are feeding. Inspect foliage for notching (adult feeding) and for “window-paning,” effects that are initially caused by the larvae feeding from the leaf undersides. The eggs are laid in irregular lines, about one inch long, on the leaf undersides. Initially, the eggs are tan in color but soon darken and turn a deep red prior to hatching. This is a pest of all true lilies (not daylilies), fritillaria, Solomon’s-seal and others. It is a devastating pest to true lilies. Neem-based products, when applied every 10-14 days, can be effective against the larvae when they begin to appear. Other than that, certain pyrethroid insecticides may be necessary.

Piercing-Sucking Pests:

Boxwood Psyllid - This pest is near the end of its activity for this year in much of the state. Even if it is found to be active in certain areas, the injury has already occurred in the form of cupped foliage. Treat with a registered pyrethroid insecticide when found in damaging numbers. Cupped foliage may stay on the plant for 2-3 years.

Spider Mites - Inspect the needles and stems of conifers now for the presence of spruce spider mite. One of the growth regulator miticide products may be useful in managing this pest. Continue to monitor on a weekly basis for any building populations. Horticultural oil sprays (at the summer rate) can also be effective.

Hemlock Woolly Adelgid (HWA) - This pest experienced a phenomenal reduction in population numbers during the winter of 2003/2004. However, by being milder, this past winter did not have the regulating effect on HWA as did the previous one. The next generation of eggs are about to appear. In certain areas, HWA is showing strong signs of rebounding from the winter mortality of two years ago. Monitor for increasing numbers and treat with horticultural oil (when plant phenology allows) and/or whenever the correct weather conditions prevail. Systemic imidacloprid products can also be of benefit.

Mealybugs - begin to inspect the inner branches for taxus mealybug. Treat when found. In most areas of Massachusetts they are quite active now.

Honeylocust Plantbug - Monitor for the presence of this pest by shaking branches over a piece of paper and inspecting the paper with a hand lens for nymphs. These nymphs are very small right now and are pale green in color. When found in excessive numbers, treat with an insecticidal soap spray or with one of the registered chemical insecticides. In warmer areas, honeylocust foliage has expanded enough to no longer warrant concern over this pest.

Andromeda lacebug will be active soon. The eggs of this pest have overwintered embedded in the host plant tissue. Inspect leaf undersides of Japanese andromeda for the activity of this pest. Treat the plant with a soil applied systemic treatment of imidacloprid or spray the leaf undersides with an insecticidal soap. Pyrethroid insecticides are also labeled for this pest.

Scale Insects:

Armored Scales - A group of scale insects characterized by a hard, convex covering over their bodies, such as pine needle scale, euonymus scale, juniper scale and white prunicola scale can be monitored now. Treat with a horticultural oil spray (summer rate) when plant phenology and correct weather conditions prevail. Pine needle scale has a new batch of crawlers that are settling now to feed.

Soft Scales - Tuliptree scale and azalea bark scale can be monitored now. Look for sooty mold on the host plants. In the case of tuliptree scale (found on tuliptree and magnolia), one can also find the large, dark brown coverings on the stems. Azalea bark scale will appear white and cottony and will mostly be found in branch axils along the main trunk. Treat with a horticultural oil spray or systemic imidacloprid. These can be difficult to manage and may require future monitoring and treatments.

Azalea bark scale is active. Inspect the intersections of branches with the main stems for the cottony-white females with egg-sacs. Wait for the crawlers to emerge (soon) and treat with a horticultural oil spray at the summer rate or a spinosad product or with a cyfluthrin product.

European fruit lecanium scale has many hosts. Inspect for the large, dark brown female scale coverings from last year that will appear lined up on the stems. This is another soft scale that is problematic to control. Wait for the crawlers to emerge (late June into early July) and treat with a horticultural oil spray at the summer rate or a spinosad product or with a cyfluthrin product.

Leaf Miners:

Birch Leaf Miner (BLM) - This pest now has well-established mines within the foliage and treatments now are most likely not feasible.

Arborvitae Leafminer - The adults will emerge with 2-3 weeks in much of the state. This leafminer (a moth as an adult) is not attracted to yellow sticky cards. Inspect foliage for browned tips and exit holes. Gently shake branches to dislodge the tiny, off-white moths. Treat with a pyrethroid insecticide or a spinosad product to kill the newly hatching caterpillars. Eggs are laid on the foliage and the larvae must chew their way into the leaf, which usually occurs on the leaf underside.

Wood Borers:

Dogwood Borer - The adult moth will become active very soon. Pheromone traps are available for this pest. Keep flowering dogwood trees free of wounds from mowers and line trimmers, which encourage invasion by this insect. Treat infested trees in August with a trunk/branch spray of entomopathogenic (beneficial) nematodes.

Bronze Birch Borer - This wood boring beetle requires a previously weakened tree for successful colonization. Keep birches healthy by watering during drought, mulching and avoiding soil compaction. Some advise that birches not be pruned from June into September to avoid releasing plant volatiles that may attack female beetles. However, healthy trees should be able to withstand pruning at this time and still naturally defend itself against this pest.

Other Insects:

Birch Catkin Bug - This bug will become active soon. This pest overwinters as an adult. Upon emerging in the spring, it mates and lays eggs in newly forming catkins. Nymphs feed on the developing seeds. This pest does not harm plants; it consumes seeds. However, they often occur in large numbers and accidentally find their way onto people and into homes where they become a nuisance. When catkins fall to the ground, they will contain the developing bugs. Mowing over these catkins crushes the insect within and releases their foul smelling odor. When found exposed on the host plant in large numbers, treat with a registered pyrethroid insecticide, if necessary.

Squirrels have been active by clipping off foliage that holds seeds. In some cases, dozens to hundreds of shoots can be found lying on the ground beneath a tree. Maples, ash, spruce and other seed-bearing trees are susceptible. There are no legal controls nor are they usually necessary.

Carpenter ant reproductives are very active statewide right now. The future queens of new colonies are 3/4” to 1” in length, black in color, have 2 pairs of membranous wings (with the front pair being larger than the hind pair), and elbowed antennae. They will look very wasp-like but the elbowed antennae and the spike (pedicel) between the thorax and abdomen, makes them ants and not wasps. They will be seeking moist wood where they can establish a new colony.

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

DISEASES

Botrytis blight is noticeable as a gray moldy blight of flowers, leaves and shoots in herbaceous perennial gardens, as well as on some young woody plants with dense foliage. 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 needles dry off before nightfall. Consider fungicide applications to protect succulent growth on high value plants from becoming infected. Fungicides labeled include: chlorothalonil, chlorothalonil plus fenarimol, copper sulfate pentahydrate, ferbam, fosetyl-Al, iprodione, mancozeb, thiophanate methyl, triflumizole, thiophanate methyl plus chlorothalonil, thiophanate methyl plus flutolanil, and PCNB. Repeat applications at labeled intervals until warm, drier weather prevails and Botrytis blight is less able to infect plants.

Cedar-apple rust is visible as orange-yellow spots on susceptible hawthorn, apple and crab apple leaves. By mid-summer tiny yellow-white tube-like fruiting structures 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 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.

Horsechestnut (Guignardia) leaf blotch is just beginning to become evident, as scattered, irregular-shaped orange-brown blotches on infected leaves. They are primarily affecting lower, inside leaves, and less than 10% of the total leaf area. However, as the summer progresses the impact of the disease may be more noticeable, but chemical intervention at this time for this season is of little benefit. Likewise, it has been noted that horsechestnut that suffer repeated severe infections continue to grow vigorously in spite of Guignardia leaf blotch.

Powdery mildew fungi are now barely visible as a dusty, gray to white spots on horsechestnut leaves. Other plants that are typically infected such as phlox, dogwood, sycamore and rose are not showing signs of powdery mildew yet in the Amherst area. Once established on plants, powdery mildews grow superficially on both upper and lower leaf surfaces as well as green shoots and flower buds. 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. Generally, the damage caused by powdery mildew is of minor consequence to healthy plants and does not warrant chemical control if unsightliness is not a critical concern. If chemical control is desired there are a number of unconventional applied materials that are labeled to protect susceptible plants. They include summer horticultural oil, commercial baking soda preparations (sodium bicarbonate and potassium bicarbonate), anti‑transpirants, as well as a number of conventional fungicides. Chemical spray programs are most effective when begun just as symptoms of powdery mildew begin to show. Once powdery mildew is extensive on the plant, there is little benefit from chemical control that season. Applications need to coat both surfaces of all susceptible plant parts to prevent infection. Spray on a regular schedule, and repeat more often during warm, humid weather.

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 fungal disease 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 is minimally visible on susceptible crabapple leaves. The heavy, prolonged rainy periods appear to have suppressed early scab infections. 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. Now is a favorable time to maintain scab-susceptible crabapples in the landscape in which infection has just begun with fungicides. These fungicides act primarily to prevent new infections, especially those infections that would develop on newly emerging leaves. Systemic fungicides 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 the development of fungicide resistance by the apple scab fungus. Prune to increase sunlight penetration and air circulation to promote rapid drying of wet foliage. If apple scab is a chronic problem, consider planting resistant varieties of crabapple if replacement is an option. This fall remove and destroy fallen leaves in the vicinity of the tree to reduce primary inoculum available for initial infections next spring.

Sycamore, maple, oak and ash anthracnose. Sycamore, maple, and oak anthracnose are evident now as dark-green to dark-brown curling leaves and shoots, while ash anthracnose is apparent as young green leaves with tiny brown spots falling from the trees. 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 affect 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.

Phomopsis tip blight. The current wet conditions, along with the 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.

Dogwood anthracnose fruiting structures are apparent on trees where there are buds that did not open and twigs and branches that died back. Water shortage, heat stress, compacted soils and winter damage weaken trees and increase the severity of the disease. Dogwoods receiving good cultural care are better able to limit the extent of dogwood anthracnose damage. Water during dry periods and maintain 2-4 inches of composted bark mulch over as much of the root area as possible. Prune off and dispose of diseased twigs and branches to reduce anthracnose inoculum that is in the tree and is readily splashed to nearby leaves and shoots. Four fungicide applications are usually needed to control dogwood anthracnose on susceptible trees during wet seasons. Begin now (as buds break open), when bracts have fallen, and four weeks later as well as in late summer if there is wet weather after flower buds form. If this is a persistent problem, consider planting one of the many resistant cultivars of C. florida and C. kousa now commercially available.

Ramorum Blight, also known as Sudden Oak Death (SOD). Since 1995, oaks and tanoaks have been dying in the coastal counties of California. Since then, other types of plants have been found to be infected or associated with this disease, referred to as Sudden Oak Death, ramorum leaf blight or ramorum dieback, or by regulation as Phytophthora ramorum. SOD was first seen in 1995 in Mill Valley ( Marin County) on tanoak. Since that time, the disease has been confirmed on various native hosts in fourteen coastal California counties (Marin, Santa Cruz, Sonoma, Napa, San Mateo, Monterey, Santa Clara, Mendocino, Solano, Alameda, Contra Costa, Humboldt, Lake and San Francisco) and in Curry County, Oregon. Research being conducted by the Agriculture Research Service, US Forest Service, universities and others is under way to better identify hosts, methods of detection and effective treatments. Currently, 64 plants are regulated, two of which at the genus level (Camellia and Rhododendron). There are no chemical treatments currently available to eliminate the disease in nursery stock.

Status of Phytophthora ramorum Monitoring Surveys. The 2005 National Nursery Survey is underway. Ten states have reported on their progress. As of May 5, 2005, 221 sites have been surveyed and 1744 samples have been collected; none have been confirmed as positive for P. ramorum.

UMass Extension’s Landscape, Nursery & Urban Forestry Diagnostic Lab Report. The following are some of the interesting disease/abiotic disorder samples received at the diagnostic lab in Amherst during the period May 31 through June 3, 2005:

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

Insects:

Turfgrass ants
I have received several phone calls in the last couple days from people asking about ant activity in lawn-type settings. In many cases the "turfgrass ant" (Lasius neoniger) is the guilty party. The main problem is that the worker ants build large mounds around the colony entrances. The mounds are large and unsightly, and can damage mowing equipment.

There are few control options. The "heart" of the activity is in the center of the colony, where a queen is busy laying eggs. There are a few ant baits on the market around the country, but not all are labeled for use in different turf settings.

The only "non-chemical" alternative I have heard mentioned is pouring boiling water down the entrance holes of the colony. Obviously this can be labor-intensive and carries its own risk of injury. Meanwhile mechanically breaking up the mounds can provide some "relief" for the short term, but the ants will rebuild the mounds eventually. Ant activity will persist through the summer months.

June beetles on the wing
Some of the native June beetles (Phyllophaga spp.) are emerging now and some are occurring in rather impressive numbers! I witnessed such an emergence at my own house (just north of Amherst) two nights ago. Very shortly after I turned on the lights outside the garage, many large beetles were flying to the lights. I collected more than 20 beetles in less than two minutes, in spite of the fact that the beetles should have been able to evade my efforts!

In any case watch for these flights, often heaviest in the first couple hours after sunset when temperatures remain high. Remember that the most common Phyllophaga species in New England usually takes three years to complete its development. Often the insects are "synchronized", meaning that most of them are in the same year of development. The adults flying now will be laying eggs in about a month. In areas where you have had a history of damage from June beetles, the most effective control can be achieved in July of the year the adults fly (just as young larvae are hatching from eggs). So you may need to scout your properties in mid July to look for young larvae, and determine whether treatment will be necessary. In the meantime, watch for the emergence flights - they really are quite impressive!

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

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

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 .

New England Guide to Weed Control in Turfgrass - The updated 2005 New England Guide to Weed Control in Turfgrass is now available. It contains extensive information about currently registered turf herbicide products, including specifics on application, timing and environmentally responsible use. The guide is available as a free, downloadable PDF file in the Online Publications section of http://www.umassturf.org

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 in Friday, June 17, 2005.

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 Turf Program as well as cooperating horticulturists and Green Industry professionals. 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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