UMass Extension Landscape Message #11
May 11, 2007

Quick Info Menu ------------------------------- SCOUTING INFORMATION REGIONAL NOTES - Cape Cod - Southeast - East - Metro West - Central - Pioneer Valley - Berkshire ENVIRONMENTAL DATA PHENOLOGY WOODY ORNAMENTALS - Insects - Diseases - Weeds LANDSCAPE TURF - Insects - Diseases - Weeds 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 period April through June, this newsletter will be updated weekly. The next update will be available on May 18, 2007. 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: The weather fluctuates between cool but sunny and cold and windy. With little actual precipitation, soils are drying out and Red Flag conditions are posted for brush fires. The Cape had a good freeze early Monday morning, when temperatures reached 30° F around 6:00 AM. Weather predictions for the immediate future are for temperatures to gradually warm. Planting is somewhat delayed in many landscapes as it has been too chilly for anything but pansies! Lawns are green and lush, and the mowing season is off to a good start. Tulips are replacing daffodils for early color, along with early perennials such as creeping phlox (Phlox divaricata) and lungwort (Pulmonaria sp.). Pests/Problems: Winter moth caterpillars are actively feeding. Eastern tent caterpillar webs are enlarging and are visible on wild black cherry. Gypsy moth eggs should begin hatching, as we are slightly over 100 GDD. In many areas of the Cape, gypsy moth and forest tent caterpillar populations collapsed last July due to disease. We are not expecting them to be in such high numbers this year. Termites are beginning to swarm, which is about two weeks later than we normally see them. We have seen samples of fresh bark mulch infested with both worker and reproductive termites. Lily leaf beetles adults are feeding on emerging shoots of Asiatic lilies. Polistes wasps are quite active.

Southeast Region (Hanson) - General Conditions: Hanson received no rain this past week, and soils are dry.  Some areas of the county experienced frosts this past week. Warmer weather mid-week is pushing plant development. Magnolia 'Elizabeth', Pieris floribunda (Mountain Pieris), Pieris japonica, Pyrus calleryana 'Bradford' (Bradford Pear), Kerria, Arabis , Arisaema, Corydalis lutea,  Sassafras , Pieris 'Brouwer's Beauty', Mayflower viburnum, Helleborus orientalis, Helleborus foetidus, Vinca, daffodils, Pulmonaria, Epimedium, blueberries, Chaenomeles speciosa (Common Floweringquince), Dutchman's breeches, tulips, Trillium, anemones, royal azalea, Phlox subulata, and violets are in full bloom. Pearlbush, Tiarella, bleeding heart, and Phlox divaricata are beginning bloom. Norway maple, Magnolia stellata (Star Magnolia), Magnolia x loebneri 'Leonard Messel' (Leonard Messel Magnolia), and Corydalis solida are past bloom. Pests/Problems: Gypsy moth caterpillars have hatched. Last year, the small ballooning caterpillars caused skin irritation after landing on the arms and necks of people working outside in the landscape. Winter moth caterpillar is in second and third instar, depending on location and plant development. Winter moths can be found on apples, crabapples, oaks, red and Japanese maples, and other hosts. They often web the leaves together making it difficult to see them.  Right now, we don't know what impact winter moth will have on the landscape this season. It is still early.  However, on some Norway maples there is very little sign of feeding by winter moth. We should know more next week. Tents of eastern tent caterpillar are visible and expanding; they can be easily removed and destroyed at dusk when the caterpillars retreat to the tent. Hemlock woolly adelgid, larch casebearer, lily leaf beetles, carpenter bees, mosquitoes, mayflies, and ticks are all active. Chickweed, violets, and dandelions are in full bloom. Beneficial insects are active.

East Region ( Boston) – Pests/Problems: Crabgrass seed has begun to germinate indicating it may be too late for preemergent weed control. Corn gluten meal has been applied to turf in the Arnold Arboretum with success in previous years. It has been applied again over the past week.

Central Region (Boylston) - General Conditions: Dry, sunny, and finally warmer. Early perennials are adding to the spring color—Bleeding Heart (Dicentra spectabile), Brunnera, Moss Phlox (P. subulata), trilliums, Virginia bluebells (Mertensia virginica) are all in full bloom. Shrubs like Viburnum x burkwoodii, Fothergilla gardenia, Pieris floribunda, and Viburnum carlesii, in addition to those listed below, are in full bloom.

Pioneer Valley Region ( Amherst) - General Conditions: Chilly mornings with mild, sunny days describe the weather pattern of the last week in the Pioneer Valley. Soils are drying out. Deciduous trees are filling out their crowns, and flowering trees and shrubs fill the landscape with color. Lawns continue to be green and lush, phlox and bleeding heart are beginning to bloom, and there was a piece of a robin’s eggshell lying on the ground under a grove of mature oaks this morning. Pests/Problems: There is evidence of eastern tent caterpillar in black cherry, apple, and crabapples in the Valley and nearby hills. Bob Childs expects them to cause significant defoliation again this year. Symptoms of leaf spots, shoot blight, and anthracnose are absent so far this spring.

ENVIRONMENTAL DATA -

The following growing-degree-day (GDD) and precipitation data was collected for a one-week period, May 3, 2007 through May 9, 2007. Soil temperature and phenological indicators were observed on or about May 9, 2007. 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:

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.

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 -

Some parts of the state have remained a bit cool and have received small amounts of rain in the form of drizzle while other parts have been warmer and dry. Foliage is expanding slowly and insect activity, sot the most part is slow to get started. Gypsy moth eggs are hatching now with the exception of the cooler regions, such as Berkshire County, which will not have egg hatch for another week or more. Winter moth, in the eastern part of the state, has hatched and is feeding voraciously. As of last week, small holes were already appearing in host foliage.

Adelgids: 

• Eastern Spruce Gall Adelgid - Norway and white spruces are hosts to this pest. Examine the base of healthy buds carefully with a hand lens for the presence of white cottony fibers and actual adelgids. These tiny aphid-like insects overwinter exposed at the base of buds. Prior to budbreak, they begin to feed and cause galls to form at the base of the expanding shoot. When in large numbers, countless new shoots will be killed. It is now too late for the use of dormant oil sprays.

• Cooley Spruce Gall Adelgid - This pest is very similar to the eastern spruce gall adelgid, but this one makes galls on blue spruce here in the eastern USA. If Douglasfir is within close proximity to a blue spruce, the problem can be severe. Oil sprays, of course, will cause blue spruce to become a dull green color for 2-3 months. In most cases, the blue color will eventually return to the needles, but clients should be informed ahead of time. Insecticidal soaps along with many of the registered chemical insecticides should also be effective against these soft-bodied and exposed insects during the early part of the season.

• Hemlock Woolly Adelgid - This pest has been active all winter by feeding and developing at the base of needles on the twigs of our native and Carolina hemlocks. They have already produced eggs for the new generation in the spring and are actively feeding and growing. Monitor with a hand lens for the presence of these tiny insects. Especially inspect twigs from the undersides for fine cottony masses, plump adelgids, and reddish-colored eggs. Treat with an oil spray when the weather allows for their use. This pest appears to have survived the atypical weather of this past winter and is now feeding and reproducing in large numbers.

Caterpillars:

• Winter Moth - The eggs of this pest have now all hatched, and the larvae are actively feeding on expanding foliage. It appears that this pest is occurring, once again, in large numbers in much of eastern Massachusetts including North Shore, the Greater Boston area, South Shore, and Cape Cod. Host plants include maples, oaks, birches, crabapples, and many other deciduous hosts. Once the foliage has expanded fully, treat with a spinosad product or Bacillus thuringiensis Kurstaki (B.t.K.), if necessary.

• Fall Cankerworm - This pest, a native caterpillar, is similar to winter moth and remains active in many of the same areas as winter moth. Eggs are in barrel-shaped clusters wrapped around small stems. Treat the larvae the same as winter moth, once they appear. Oaks, among other deciduous hosts, are commonly attacked. This pest will be appearing within the next 1-2 weeks.

• Forest Tent Caterpillar - This caterpillar has been on the increase in MA and other surrounding states for several years now. In areas of higher population densities, some mortality of this pest due to natural causes (such as disease) was seen in 2006. However, all areas where this pest occurred last year should be prepared to deal with it, again, in 2007. Oaks in eastern MA seem to be the favored host while maples are the preferred host in western MA. However, this pest does have a rather wide deciduous host range overall.

• Gypsy Moth - Some areas witnessed natural decline of building populations last year due to the fungus, Entomophaga maimaiga. Monitor now for the tawny-colored egg masses to get a rough idea of population sizes. Once the eggs have hatched and the larvae have settled to feed, treat with a spinosad product or Bacillus thuringiensis Kurstaki (B.t.K.), if necessary. Eggs usually begin hatching when the shadbush (Amelanchier spp.) is in bloom. Gypsy moth eggs will be hatching any day now, if they haven’t already.
  
• Eastern Tent Caterpillar - Common to Malus and Prunus species, this pest overwinters as an egg that appears in a tight cluster wrapped around small stems of the host plant. Inspect for the presence of these eggs. The larvae are now actively feeding, and their silken webs are quite obvious. Once again, this pest is occurring in high numbers. Treat the caterpillars with a spinosad product or Bacillus thuringiensis Kurstaki (B.t.K.).
  
• Bagworm caterpillar - This caterpillar did manage to survive the Massachusetts’ winter and is now in the egg stage. Mostly, this pest comes into New England on plant material from southern states, primarily on arborvitae and juniper, and usually cannot survive our winters. This last autumn was mild well into November thus allowing these intruders to pupate, emerge as adults, and then produce upwards of 1000 per female. Inspect plants for the characteristic “bags”, which contain the eggs. When occurring in small numbers, remove by hand and destroy. If they occur in large numbers, wait until approximately mid –late June and treat with a Bacillus thuringiensis Kurstaki (B.t.K.) or a spinosad product for the caterpillars. Eggs hatch from late May into June.
  
• European pine sawfly - The caterpillar of this pest will be active soon. Look for the sites where the female wasps layed their eggs—within the needles of such host plants as Mugo pine. Eggs appear as a row of blocky-shaped patches along the needles. They are often found in clusters on the plant. Small infestations can be pruned away and destroyed. The larvae feed in packed groups and can also be pruned away and destroyed. Larger populations can be treated with insecticidal soap (young larvae) or with a spinosad product.
  
• Larch Casebearer - Deborah Swanson reports that this caterpillar is now active and feeding on emerging foliage of the host plants. Treat with a product that contains Bacillus thuringiensis Kurstaki (B.t.K.) or a spinosad product for the caterpillars.

Beetles:

• Rhododendron Borer - Most affected rhododendron shoots now display signs of wilt and dying foliage. Don’t confuse this with winterkill, which is also prevalent in much of the state. Inspect the base of injured shoots for entrance/exit holes and for piles of sawdust on the ground just below these holes. Prune out and destroy affected shoots. The larvae within the shoots are very mature and have plugged the holes with sawdust, so treatments in the spring are difficult. Specific pheromone traps can be hung in rhododendron plantings to monitor for the adult moths, which appear wasp-like, in mid-late May and through June. Use a knockdown spray for the adults when they appear. In July, if infestations are suspected, apply a coarse spray of beneficial (entomopathogenic) nematodes to the lower trunk and base of the scaffold branches.

Leaf Miners:

• Inkberry Leafminer - This pest overwinters within the mine in the leaf. Inspect for tip browning on foliage. This browning usually does not appear until late November or December and often goes unnoticed. If it is seen, it is usually attributed to winter injury. However, the browned part of the leaf should be rolled gently between the thumb and forefinger to feel the small lump within the mine that indicates a pupa of the inkberry leafminer. Leaf tips will also be hollow when torn open, if there is a miner present. Make a note to hang yellow sticky cards in early May to determine when the adult flies are emerging. That will be the time to apply a cover spray to prevent re-infestation.
  
• Birch Leafminer - As the old-time entomologists used to say, “When the birch leaves are about the size of a dime, it’s time to start thinking about the birch leafminer.” This adage turns out to be a good phenological indicator for the emergence of adult birch leafminers. The females require tender new foliage for oviposition (egg-laying). Make note of the white-barked birches that may have been attacked last year and hang yellow-sticky cards soon after budbreak, which will attract and catch the females. This strategy is not a control measure but rather an indicator for when to apply a cover spray to break the cycle of re-infestation.

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

The warm weather of the last couple of days has moved winter annuals along. Continue the treatment of winter annuals and perennials in ornamental beds with glyphosate or glufosinate.

Monitor beds for annual weed germination. If they are still weed free, apply a preemergence herbicides.

Garlic mustard is now beginning to flower and should be controlled now before seed is produced. Garlic mustard is a biennial, therefore control now will control both first-year seedlings and second-year plants before they go to seed. A non-selective translocation or contract herbicide can be used.

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

LANDSCAPE TURF

INSECTS -

It is that time of year again - the grubs are up in the root zone, munching happily.

A few frequently asked questions:

1.  Should we apply products that contain imidacloprid (Merit™, and now that it has gone off patent, several other products as well) now?

Several turf entomologists have tested spring applications of imidacloprid and found that it does not reduce populations of grubs that are present in the spring. So even though some of the products purport "season long control" with imidacloprid, we do not recommend that turf managers use that active ingredient in the spring in New England. (Keep in mind that imidacloprid normally takes a couple weeks to start having a visible impact on grubs.)

In some areas of the country, May applications of Merit™ are appropriate because they can reduce populations of other turf pests, such as billbugs. But in New England, our grub complex is just that, complex. Many turf managers are dealing with European chafers and/or oriental beetles, and imidacloprid applications targeting these species have to be done more "precisely". Aiming to treat when the adults are laying eggs (usually late June or later for European chafers, early July or later for oriental beetles) would be a good plan.

2.  What about the other new products that are related to imidacloprid?

There are two "new" products that are in the same chemical group as imidacloprid. Chlothianidin, sold as Arena™ (through Arysta Life Science), was registered last year, and many people have been using it in New England. I am not aware of any trials that have determined whether spring applications of Arena™ will work on spring grubs. But we did conduct a trial last fall that indicated that chlothianidin can work more quickly than imidacloprid.

The other new product is thiamethoxam, sold as Meridian™ (through Syngenta). It received federal registration in early 2007, and several of the New England states have also registered it. Again I am not aware of any field trials that have been conducted to determine whether spring applications of Meridian™ will reduce spring grub populations.

Both companies claim that their product (chlothianidin or thiamethoxam) is active against a wider range of turf insects than is imidacloprid.

3.  So what should I do if I have major grub problems right now?

There are only two insecticides available that work quickly enough to reduce spring grub populations. Those are Dylox™ (trichlorfon) and Sevin™ (carbaryl), both quite fast acting and soluble. Neither of those products can be used on school grounds in Massachusetts (and Dylox™ cannot be used on any turf in Maine).

Grub feeding should begin to decline relatively soon (within the next three or four weeks) so in most cases, it might be best to just manage the damage for the next few weeks. Monitor where the grub activity is now, and figure that in many situations, those areas will be subject to attack again later in the summer when the new adults emerge. Because soil temperatures just began to warm up, the window for spring treatments was shorter than usual this year.

4.  What's new with May beetles?

May beetles are beginning to emerge. I encountered a couple specimens (may they rest in peace) last night in my own back yard. There are many species in the Phyllophaga genus, some of which have annual life cycles like our more common Japanese beetles and oriental beetles. But most Phyllophaga species in New England take two or three years to complete a life cycle. The adults lay eggs from late May through mid July, depending on the species and the location.

For now, watch with curiosity. In most situations the Phyllophaga populations are sporadic and not normally very dense. If a heavy population does develop, you can expect major disruption from skunks, raccoons, or other foragers. The fun will begin in August as the grubs grow larger.

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

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 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

NEXT UPDATE: The next issue will be available on May 18, 2007.

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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