UMass Extension Landscape Message #19
July 24, 2008

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Quick Info Menu ------------------------------- SCOUTING INFORMATION REGIONAL NOTES - Cape Cod - Southeast - East - Metro West Waltham - Metro West Hopkinton - Central - Pioneer Valley - Berkshire ENVIRONMENTAL DATA PHENOLOGY WOODY ORNAMENTALS - Insects - Diseases - Weeds LANDSCAPE TURF INFO RESOURCES DIAGNOSTIC SERVICES Use this menu to instantly jump to any portion of the message!

The LANDSCAPE MESSAGE is an educational newsletter intended to guide landscape, nursery and urban forestry professionals in identifying pests in the landscape, monitoring their development, planning management strategies and creating site-specific records for future management reference. UMass Extension has updated this issue to provide timely pest management information and the latest regional news and environmental data throughout Massachusetts. During the months of July, August, and September this newsletter will be updated bi-weekly. The next update will be available on August 7, 2008. Missed a previous message? Visit the Landscape Message Archive. Interested in additional turf-oriented content? UMass Extension Turf Program Management Updates

SCOUTING INFORMATION BY REGION

REGIONAL NOTES -

Cape Cod Region (Barnstable) – General Conditions: Hot and humid conditions have been the norm for the Cape.  Pop-up thunderstorms have been widely scattered and have not produced very much precipitation, perhaps a quarter of an inch at best.  Soils are dry, and plants wilt quickly if not irrigated. Several Cape towns now have water restrictions.  Have your clients check to see what the restrictions in their towns are and irrigate accordingly.  Summer perennials are all in full bloom, and hydrangeas are still providing excellent color in the landscape.  Pests/Problems:  Foliar disorders are the top problem in the landscape.  Anything that is susceptible to a species of powdery mildew has it.  It is easy to pick out resistant phlox, beebalm, and crabapple as they have less powdery mildew than susceptible ones. Resistant does not mean immune!  Other foliar diseases such as black spot of rose and apple scab of crabapple are also very noticeable.  Cicada damage is quite visible on the Upper Cape, with the outer 12-15 to 15 inches in oak branches flagged and brown.  Fresh pitch tubes on pitch pine are a sure sign of the second generation of black turpentine beetle.  Oriental, Japanese, and Asiatic garden beetle adults are all feeding at this time.  It is a good year for Japanese beetle, with more apparently around than in recent years.  Damage from spruce mites is visible on evergreens.

Southeast Region (Hanson) – General Conditions: Hot, humid weather was the norm for the past two weeks. Unirrigated plants have been stressed due to high temperatures and lack of rainfall.  Rainfall for the past two weeks has been varied for many Plymouth County towns.  Some Plymouth County towns north and west of Hanson have received rain, but many towns did not.  Hanson received 1.3 inches of rain from a fast moving thunderstorm Friday night (7-18-08) while Halifax received only 0.5 inches from the same storm.  Remind clients that warm weather dries the soil out quickly and remind them to water newly planted trees and shrubs.  Koelreuteria paniculata, Campsis radicans, landscape roses, Hydrangea quercifolia (Oakleaf Hydrangea), Hydrangea macrophylla, Rose of Sharon, Albizia julibrissin (Mimosa), hollyhocks, daylilies, Hosta, Corydalis lutea, Liatris, shasta daisy, Nepeta, Heliopsis 'Summer Sun', Echinacea, Monarda didyma, Filipendula venusta, Campanula sp., Lysimachia clethroides, Phlox paniculata, and lilies are in full bloom.  Early cultivars of Hydrangea paniculata ('Praecox', etc.) are in full bloom.  Rudbeckia fulgida 'Goldsturm' is beginning to bloom.  Pests/Problems:  Oriental, Asiatic, and Japanese beetles are active.  Oriental beetles appear to be more numerous this year.  Oriental beetles are about the same size as Japanese beetles except their coloring is mottled, metallic brown with dark gray markings.  Oriental beetle adults feed on plants like echinacea, roses, phlox, and others usually at night. Earwigs, lily leaf beetle, slugs, snails, ticks, biting flies, and mosquitoes are all active.  Monitor dogwoods for signs of wilting or dead branches probably due to the dogwood twig borer.  Look for a small hole on the dying branch and follow it down to living tissue.  Prune, remove, and destroy the borer within.  Some white pine and spruce are sporting dead, brown terminals due to white pine weevil.  Too late for treatment.  Wasp nests are becoming larger.  Be careful when pruning and, also, be careful where you step.  Be on the lookout for ground-nesting wasps.  Powdery mildew is present on Phlox paniculata, Pulmonaria, crabapple, and dogwood.  Black spot is common on susceptible roses.  Slime molds are showing.  

East Region (Boston) – General Conditions: No conditions report available. See Environmental Data and Phenology below.

Metro West (Waltham) – General Conditions: Mostly very hot and dry.  Good rain over the weekend.  Lawns have greened back up.  Pests/Problems:  Starting to see bronze birch borer damage.

Metro West (Hopkinton) – General Conditions:Daily GDD totals have taken quite a jump during the past two weeks, and soil temperatures have followed.  Goldenrod is starting to flower at the edges of fields and woods.

Central Region (Boylston) – General Conditions: No conditions report available. See Environmental Data and Phenology below.

Pioneer Valley Region (Amherst) - General Conditions: The past two weeks there were days of rainy, humid, and warm weather with episodes of sudden severe storms in several parts of the Pioneer Valley.  Damage from the storms ranged from standing water to downed trees.  Goldenrod is just beginning to bloom while Queen Anne’s lace is in full bloom.  Lawns continue to grow well as do trees, shrubs, and herbaceous garden plants.

Berkshire Region (Great Barrington) - General Conditions: Growing conditions continue to be very good.  Soils do tend to get quite dry between periods of rainfall on some sites, but overall there are no signs of drought stress.  Most lawns are green and showing little summer dormancy.  Pests/Problems:  Plants in several areas of the county have incurred damage from hail.  There have been several hail events this summer, and leaves of many plants are tattered.  The most recent hail events occurred on July 18 and again on July 22 in the south county area.

ENVIRONMENTAL DATA -

The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, July 9, 2008 through July 22, 2008.  Soil temperature and phenological indicators were observed on July 22, 2008.  Accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our instruments from the beginning of the current calendar year.  This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

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:

Indicator Plants - Stages of Flowering (begin, b/full, full, f/end, end)
PLANT NAME (Botanic/Common)	CAPE	SOUTH EAST	EAST	METRO W.		CENT.	P.V.	BERK.
				Waltham	Hopkinton
Vitex agnus-castus (Chaste Tree)	begin	*	begin	*	*	*	*	*
Clethra alnifolia (Sweet Pepperbush)	*	*	begin	begin	begin	*	*	*
Hydrangea paniculata (Panicle Hydrangea)	begin	full	begin	*	full	*	*	*
Hybiscus syriacus (Rose of Sharon)	begin	full	b/full	full	full	*	begin	*
Oxydendron arboreum (Sourwood)	begin	full	begin	f/end	full	*	*	*
Lythrum salicaria (Loosestrife)	full	full	begin	full	full	*	begin	*
Campsis radicans (Trumpetcreeper)	full	full	b/full	f/end	*	*	full	*
Hydrangea arborescens (Smooth Hydrangea)	full	full	end	*	full	*	f/end	full
Cotinus coggygria (Common Smokebush)	f/end	full	end	f/end	full	*	f/end	*
Koelreuteria paniculata (Goldenrain Tree)	f/end	full	*	*	*	*	*	*
* = no activity to report/information not available

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.

METRO WEST REGION – James Martin, Consulting Arborist, reporting from the UMass Extension Center, Waltham.

METRO WEST REGION – Mark Sawyer, Horticulturist, Weston Nurseries, Hopkinton.

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

PIONEER VALLEY - Dan Gillman, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass, Amherst.

BERKSHIRES - Ron Kujawski, Specialist, UMass Extension Landscape, Nursery & Urban Forestry Program, Amherst.

WOODY ORNAMENTALS

INSECTS -

Lepidopteran Caterpillars:

• Fall Webworm is becoming active.  This caterpillar feeds within large groups by tying foliage together and feeding from within the web.  Silken webs begin at the tips of branches and get extended downward toward the trunk as new foliage is needed.  This pest causes little harm to the health of the tree, but the presence of the webs can be very unsightly.  Management can be challenging given that the caterpillars are somewhat protected from contact sprays by the silken web. 
  
  
• Mimosa Webworm is beginning to feed and tie together the leaflets of honeylocust.  Eventually, they can tie and skeletonize much of a tree’s leaves, which remain intact but die and turn brown.  By mid to late August, affected honeylocusts can have all of their foliage killed by this pest.  Damage usually begins at the branch tips.  Inspect for tied and skeletonized leaves.  Sprays that contain spinosad are effective.
  
  
• Juniper Webworm − This caterpillar is more common in eastern MA than in other parts of the state.  Inspect for browning foliage on junipers and the presence of foliage tied with silk.  Treat young larvae with a Bacillus thuringiensis 'Kurstaki' (B.t.K.) product or with a product that contains spinosad.
  

Hymenoptera Sawfly (Caterpillar) Larvae:

• Imported Pine Sawfly - This sawfly is more commonly found in the eastern parts of MA than it is in the central and western parts.  It is now active and feeding voraciously.  It shares many of the same host plants as the European pine sawfly, including mugo pine.  Treat larvae with a product that contains spinosad.
  
  
• Red-Headed Pine Sawfly is becoming active as well.  This species has a rust-colored head capsule and a yellow body with black spots.  (See Imported Pine Sawfly above for monitoring and management techniques.)
  
  
• Birch Sawfly − The caterpillars of this pest are active and feed by wrapping their bodies around the margins of foliage of birches as they consume all but the main veins of the leaves.  Although not abundantly common in the state, it does appear somewhere here every year and is capable of causing serious defoliation if not treated.  Spinosad products or one of the registered pyrethroids work well.  Also, insecticidal soap works well when the larvae are still quite small. 
  

Beetles:

• Japanese Beetle adults are quite common now.  Favored host plants are starting to show significant feeding injury in the form of a “window-paning” effect where the foliage is heavily skeletonized.  Such foliage will turn completely brown.  Adult beetles will need to be treated with a chemical insecticide, such as a pyrethroid, in order to protect plants.  New beetles will be emerging every day from now until early September.  Continue to monitor for the buildup of unacceptable numbers of this serious defoliator.  
  
  
• Asiatic Garden Beetle remains active.  This small, robust and oval-shaped scarab beetle is only active at night.  It feeds on a wide variety of deciduous landscape plants as well as many different garden plants.  Monitor at night with a flashlight between the hours of 9 PM and midnight.  This pest can cause much ragged foliage to favored plants.
  
  
• Lily Leaf Beetle - The next generation of adult beetles is very active and mating.  Adult beetles can be treated with a pyrethroid insecticide while the larvae can be treated with a product that contains spinosad.
  
  
• Viburnum Leaf Beetle  - Adult beetles are nearing the end of their mating and egg-laying cycle, and this pest will soon disappear for the year. Report any new finds in MA to Bob Childs rchilds@psis.umass.edu or 413-545-1053.  Treat the same as for lily leaf beetle. For current information about this pest, visit the Cornell web site at http://www.hort.cornell.edu/vlb
  
  
• Imported Willow Leaf Beetle remains active.  The adult beetle is rather small, rounded, and metallic green/blue in color.  The adult beetles will chew holes into the foliage, but it is the small black-colored larvae that create most of the injury.  Larvae will line up together on the foliage and scrape the upper layers.  This action causes the still-intact leaf to eventually die and turn brown.  This pest has multiple generations per year, and its damage can become severe by August when virtually all of the foliage on a willow will appear bronze in color, as if fire-swept.  All willows are susceptible.  Treating the adult beetle requires a pyrethroid insecticide while a product that contains spinosad works well for the larvae. 
  
  
• Black Vine Weevil adults will be active soon.  They only forage and feed at night, so detection is difficult.  One can monitor at night with a flashlight or inspect now for the small hemispherical notches in host foliage from last year’s feeding and then monitor every few days for increased notching.  Placing loosely folded (accordian-style) burlap strips around the base of favored plants, on the ground, is a good monitoring tool for the adults.  After feeding on the plant, they will crawl into the folds to wait out the daylight hours.  During the day, inspect the burlap by carefully unrolling it and checking for weevils.  In small populations, these beetles can be collected and destroyed every day.  In larger populations, use the presence of the beetles to time controls.  This is a tough pest to manage in the landscape where Rhododendron and Taxus are the primary hosts.  In the nursery, however, this pest can present serious problems for dozens of different plant species when grown in containers.  In the landscape, products that contain lambda-cyhalothrin (restricted use) have shown good levels of control.  Containerized plants can be soil drenched with other products for the larvae, but it is the adult stage that is becoming active now. 

Piercing-Sucking Pests:

• The Red-Banded Leafhopper (a.k.a. Sharpshooter Leafhopper) has arrived in MA now from more southern states.  This pale green leafhopper with two chevron-shaped stripes on its back is attracted to rhododendrons that continue to produce new foliage through July and August.  The egg-laying in the new leaf tissue causes the leaves to become stunted and distorted.  It is purely an aesthetic pest, but it can be an important pest, especially in the nursery.  Visually monitor for this insect by gently shaking foliage to dislodge the leafhoppers, which will fly up and then land again nearby.  When found in large numbers this pest should be treated.
  
  
• Maple Leafhopper − This is another leafhopper that migrates into the state every year and is mostly attracted to maples in the landscape and nursery.  Their piercing sucking feeding can create such extensive injury that foliage will appear to have been damaged by bleach - very chlorotic yet finely stippled foliage.  Monitor visually by shaking branches.  Treat if found in large numbers. 
  
  
• Lacebugs remain very active.  These serious pests always feed from the underside of the foliage, but they create the fine, yellow stippling feeding injury on the upper surface of the leaves.  Look at the bottom leaf surface of such affected leaves for the telltale signs of the brown fecal spots and the lacebugs themselves.  Inspect common host plants for this pest for last year’s damage.  Common hosts are Japanese andromeda, evergreen azaleas, rhododendron, cotoneaster, and hawthorn.  Systemic imidacloprid appears to be quite effective for managing this pest.  Also, horticultural oil sprays or insecticidal soap sprays that are targeted to the foliage underside is also effective for the small nymphs.  Susceptible plants growing in sunny areas will experience more damage given that heat greatly encourages lacebug populations. 
  
  
• Miscellaneous Aphid species continue to increase in numbers.  Monitor for honeydew and sooty mold.  Treat if necessary.  Systemic imidacloprid, or insecticidal soap sprays, or Horticultural oil sprays are all effective treatments.  Maples, catalpa, tuliptree, lindens, and many others are common hosts.
  
  
• Taxus Mealybug remains active.  Move the foliage of taxus back and inspect the inner branches and smaller stems for white, cottony masses.  This insect produces honeydew, which leads to the unsightly buildup of sooty molds.  Also, large populations can cause stunting and chlorosis of the foliage.  Treat with a systemic imidacloprid product or spray the inner branches and stems with either a horticultural oil spray or one of the registered pyrethroid insecticides.
  
  
• Spider Mites - Inspect spruce, hemlock, fir, and others for the signs of feeding damage by these tiny but very prolific and potentially damaging pests.  Inspect very closely for the active mites, which will require a good hand lens or microscope.  Inspect many different deciduous host plants for the signs of Warm-Season Mites, such as the two-spotted mite.  This pest favors the hot and dry times of summer, and their numbers can increase exponentially and quickly during such times. If found, treat with an oil spray or with one of the new mite growth regulators.  Monitor for the actual mites by shaking a branch over a piece of white paper and then inspecting with a hand lens for the mobile mites.
  
  
• Hemlock Woolly Adelgid - This pest is now dormant, but it can still be managed even in this stage.  A horticultural oil spray (at the summer rate), systemic imidacloprid, or systemic dinotefuran (Safari™) are all effective against this very serious pest.  Note: Safari™ is a State Restricted Use pesticide in Massachusetts. (See Elongate Hemlock Scale, which appears next.)
  
  
• Elongate Hemlock Scale (aka Fiorinia Scale) − Inspect hemlocks closely for this pest.  If the plant appears weakened or sickly and has hemlock woolly adelgid, which is very obvious, take the extra time to closely inspect the undersides of the needles for this scale.  Fiorinia scale is very small, brown and mostly oval in shape.  Many of these may be present per needle (on the underside only).  In some case, it will be the primary reason that a hemlock looks to be in ill-health.  Imidicloprid, which works pretty well systemically for hemlock woolly adelgid does not have much of an impact on this scale.  Horticultural oil sprays, which also work well on hemlock woolly adelgid tends to provide minimal control for this scale.  Safari™ (dinotefuran), a relatively new neonicotinoid, does show good promise for fiorinia scale and works well when utilized as a systemic.  However, in Massachusetts, it has a “State Restricted Use” labeling due to groundwater concerns.  Fiorinia scale is difficult to control.  Unlike most armored scales in the Northeast, it produces crawlers throughout much of the growing season.  If found, treat it aggressively.  Fiorinia scale is a very serious pest of hemlock and can occur on conifers other than hemlock.
  
  
• Tuliptree Scale - Inspect the small branches of tuliptree and magnolia for the presence of this pest.  The adult females may still be on the foliage feeding and will be rather flattened and translucent; but once they move to the stems to produce eggs, the covering over the female body rises up into a “gumdrop” shape and darkens.  This is one of the soft scales that can be a challenge to manage.  In large numbers it produces much honeydew and can weaken branches to the point of severely stunting growth.  It usually attacks tuliptree from the bottom branches, moving upward over the years, often killing those branches.  In MA it can also be found on magnolia.  There is a remarkably similar scale known as magnolia scale, but it will not be found on landscape magnolia in MA due to the severity of our winters.  Crawlers can be treated with horticultural oil sprays.  Systemic imidacloprid or systemic dinotefuran can be effective. 
  

Wood Attackers:

• Bronze Birch Borer − The adults of this pest are still emerging and will continue to emerge and be active into September.  This pest kills trees, but it can only survive in previously weakened trees.  Keep trees healthy to avoid attack.  Drought stressed trees are candidates for attack as are old trees or those growing in compacted soils.  Treatments become a challenge once infestation occurs.  Some arborists do not like to prune birches from June into September to avoid releasing plant volatiles that may attract beetles.  However, if the tree is healthy, then there should be little concern for colonization by this insect. 

• Dogwood Borer − This clear-winged moth is active and is seeking wounded dogwood trees from now until late August.  The females deposit eggs near bark crevices, such as branch collars, and around wounds.  The wood-boring caterpillar of this species tunnels into the cambium and later into the older wood.  Signs of an infestation now will be sap exudation on the trunk and scaffold branches.  Avoid wounding dogwood trunks with mowers and line trimmers.  Pheromone traps are available to monitor for the adult moths.  This caterpillar pushes out the sawdust as it tunnels thus leaving its tunnels open, unlike most wood borers.  Nematode products sprayed on the trunk are extremely effective for new infestations.

• Rhododendron Borer − This is another clear-winged moth species like that of the dogwood borer.  It attacks rhododendrons randomly, and infestations are often not noticed until a shoot wilts and dies.  Inspect the base of rhododendron shoots for entrance/exit holes and the presence of sawdust piled on the ground.  Prune out and destroy affected shoots or apply a coarse spray of beneficial nematodes to the base of the affected shoots. 

• Dogwood Twig Borer (a.k.a. Elm Twig Girdler) − This cerambycid beetle (longhorned beetle) attacks flowering dogwood primarily but can also be found attacking elm, viburnum, and various fruit trees.  The larvae tunnel in the smaller branches and ultimately kill them.  Usually it is not found congregated in large numbers, and individual branches can be pruned out and destroyed.

• Leopard Moth adults have been active for several weeks.  This robust, white moth with black spots lays eggs on dozens of different deciduous host plants.  Where each female moth can produce upwards to 1000 eggs, this pest fortunately is rarely successful in attacking any single tree in large numbers.  However, individual wood-boring larvae can kill smaller branches.  Occasionally, it is found attacking the trunk.  Their tunneling activity can attract woodpeckers.  When numerous larvae attack a single tree in the trunk, much internal injury may occur and the strength of the wood can be compromised.  In most cases, infestation is not noticeable until the caterpillar makes an exit hole for pupation, which often resembles that of the Asian longhorned beetle by being almost perfectly round and 3/8 of an inch in diameter.  Control measures, other than pruning out infested wood, is nearly impossible.

Other Stuff:

• Periodical Cicada − The cicada emergence is over now for another 17 years on Cape Cod.  The next opportunity to witness this amazing entomological event will be June of 2025.  However, this year’s emergence was very large in Mashpee, Falmouth, Sandwich, Bourne and other surrounding towns.  Right now, many of the deciduous trees in those areas, especially the oaks, are displaying countless dead and browned shoots from the cicada egg-laying activity.  In reality, the only dead parts of the trees are the distal two feet of most branches, which gives them an overall dead appearance.  However, the branches and foliage back from the dead tissue to the trunk is still healthy.  Trees may look terrible, but this is a form of natural pruning that these trees receive every 17 years.  Previously healthy trees should survive.  Smaller trees that lost most of their foliage will be rather stressed from this egg-laying injury.  Affected trees may require regular watering if drought conditions prevail.

• Tabanid Flies are now active.  Common members of this group are deer flies, horse flies, and the notorious greenhead fly found in coastal/marsh areas.  This particular family of blood-feeding flies is most obnoxious due to the nature of their bite.  Where mosquitoes and black flies steal blood by puncturing the skin with fine hypodermic-like mouthparts, the Tabanids literally snip away a piece of skin with scissor-like mouthparts and then sponge up the exuded blood.  These do not attack plants but are a bane to field workers at this time of the year.  Insect repellents are reported to have minimal effects against these flies.  Instead, it is often suggested that one apply a product to the skin that is oily thus making the skin too slippery for the fly to get a foothold for biting.  One such product that gets mentioned is Skin-So-Soft™, but its true effectiveness is not fully known.

• White-Spotted Pine Sawyer (WSPS) remains active as an adult.  This adult beetle is commonly confused with Asian Longhorned Beetle (ALHB), which has never been found in MA.  WSPS is native and is only attracted to very weak or freshly dead pines.  It is not considered to be a pest. 

A Few Comparisons/Differences Between ALHB and WSPS:

• ALHB has a very shiny black body, like that of patent leather; the pine sawyer is more of a dark mottled grey.
• ALHB has crisp white spots; pine sawyer has more diffuse white spots.
• ALHB has a blue-ish cast to the color of its tarsi (feet); pine sawyer does not.
• Both have antennal segments that alternate between white and black.

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

WEEDS -

Summer annual weeds have made great progress since the last message.  Many weeds have become very large.  Just spraying them will result in unsightly dead vegetation, so hand weeding may be necessary.  However, spot spraying with a non-selective herbicide is usually a better strategy than weeding by hand because it does not break the mulch barrier.  A determination on a site-by-site basis will need to be made.

Scout for weeds that may be creeping into beds from adjacent turf areas.  Use a non-selective herbicide to edge the bed.

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

LANDSCAPE TURF

INSECTS -

Entomopathogenic nematodes (EPNs) are tiny roundworms that can deliver pathogenic bacteria to certain kinds of insects. The nematodes either actively seek out the insect or lie in "ambush", waiting for an insect to pass nearby, depending on the nematode species. There are several species of nematodes currently available commercially, but they tend to be fairly specific as to the kinds of insects they attack.

Several people have asked recently about nematodes. The two most frequently asked questions are: 1) Which species is most effective against white grubs? and 2) When should I apply the nematodes?

1. Which nematode is most effective against white grubs?

Based on information from colleagues of mine in other states, the most effective species of nematodes against white grubs that is readily available is Heterorhabditis bacteriophora (HB). We have conducted trials in previous years that achieved acceptable levels of control with HB nematodes against Japanese beetles, oriental beetles, and European chafers. However, we were able to do everything "just right" - time the application when grubs were present and most susceptible, and water in very thoroughly.

Dr. Albrecht Koppenhofer, a turf entomologist at Rutgers University, knows more about nematodes and their interactions with white grubs than anyone else in the United States. He tells me that he has a very different experience - that HB works quite well against Japanese beetle grubs but not the other species. He has also tested other species of nematodes and some show promise, but most are limited in their availability. He also discovered a new species of nematode, Steinernema scarabaei, which shows tremendous potential against many species of white grubs, including all the ones that are problematic in New England. But that nematode has proven difficult to produce in large volumes. Dr. Koppenhofer's field and laboratory trials with S. scarabaei have been very well designed and have demonstrated the effectiveness of that nematode. (In fact, it appears that a single application may last for more than one season in some parts of New Jersey.) But because of the production issues, it will be a while before we see that nematode available on the market.

So for now, the best bet regarding nematodes on white grubs appears to be HB. Keep in mind, though, that the New Jersey research indicates HB may be marginal in its effectiveness against grubs other than Japanese beetles. If you are able to optimize the timing of application and follow with adequate water, you certainly increase the likelihood of success.

2.  What is the best time to apply nematodes to control white grubs?

The challenge in using nematodes to control white grubs is that the nematodes need to be able to penetrate through the grub, so the grub needs to be large enough for the nematode to get in. White grubs have "sieve plates" on their spiracles, which provide a level of protection. And grubs often can sense nematodes and spend some time "grooming", trying to prevent nematodes from entering through the mouth. And if you delay application until grubs are already in the third, and largest, developmental stage, nematodes may not be effective.

So ordinarily you want to make the application when most of the larvae have hatched out of the eggs and are first instars or very early second instars. For some of you in southeastern Massachusetts, that may be the first or second week of August. For those of you further north, you may need to give the grubs a chance to finish hatching, and your timing may be a week or two later.

Don't forget that you must follow the application with plenty of water - immediately after the application. Aim for at least a quarter inch, but a half inch is even better. The EPNs need the water to help move through the thatch to the soil. Also nematodes are very sensitive to high temperatures and sunlight, so do not apply between 9:30 AM and 3:00 PM.

Reported by Pat Vittum, Extension Entomologist, UMass Department of Plant, Soil and Insect Sciences, Amherst.

WEEDS

Crabgrass continues to mature at a fast rate.  Most crabgrass is past the growth stage were fenoxaprop will be effective.  Quinclorac may or may not be effective at this time and growth stage of crabgrass will need to be determined before application.  Do not attempt to control crabgrass when cool-season turfgrasses are dormant.

The weather has been very warm, and broadleaf herbicide applications should not be occurring except on irrigated sites where summer annual broadleaf weeds are the target weeds.  Beware of hot weather applications as injury may occur.

Yellow nutsedge is becoming apparent.  Postemergence applications for yellow nutsedge should be occurring now.

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

DIAGNOSTIC SERVICES

UMass Laboratory Diagnoses 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 Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Send specimens and payment (payable to the University of Massachusetts) to UMass Extension Plant Diagnostic Lab, Holdsworth Natural Resources Center, 160 Holdsworth Way, UMass, Amherst, MA 01003. The fee for a woody plant disease analysis is $50; the fee for turf disease analysis or nematode assay is $75. All insect, weed and turfgrass identification samples are $25 each. For more detailed submission instructions see http://www.umass.edu/agland/diagnostics

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

NEXT UPDATE: The next issue will be available on August 7, 2008.

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.

DISCLAIMER. This message is intended for commercial use. UMass Extension assumes no liability for recommendations. It is the responsibility of the applicator to verify the registration status of any pesticide BEFORE applying it. Different states have different regulations as well. The use of trade names (™) does not imply endorsement. Similarly, there may be other products you prefer to use.

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