UMass Extension Landscape Message #7
April 13, 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 April 20, 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: Winter still has the Cape in its grip, as cold temperatures predominate. Average daytime temperatures have ranged in the upper thirties to the mid forties, with night temperatures in the mid to upper twenties. Plant development is pretty much the same as in previous weeks. Even lawns still appear dormant. Daffodils are partially open, waiting the arrival of milder weather. P ests/Problems: Winter damage to rhododendrons and hollies are the primary problems being seen.

Southeast Region (Hanson) - General Conditions: Cool weather with temperatures below freezing most nights; be cautious using dormant oil in these conditions. (Please see the Insect section of this pest message regarding the use of dormant oil).  Only 0.05 of an inch of rain was recorded in Hanson. Cool weather continues to keep plant development in check. Some red maples and Pieris japonica are in full bloom, while others are just beginning, depending on location. Forsythia buds are plump and yellow but not open. Lawns have started to green up. Cornus mas, pussy willow, crocus, Helleborus niger, H. foetidus, H. x hybridus (formerly orientalis), Iris reticulata, Vinca minor, Hamamelis mollis 'Pallida' are in full bloom.  Hamamelis x intermedia 'Arnold Promise' and snowdrops are past bloom. Pests/Problems: Winter moth caterpillar eggs are pinkish-red and start to turn blue to blue-black just before hatch. They have not started to hatch here in Hanson. However, Gary Cusack at Hartney Greymont in Needham MA, found a small winter-moth-like caterpillar in the bud of a red maple, as did an arborist in Brookline. These caterpillars have not yet been confirmed as winter moth. Ticks are active; conduct tick checks frequently, especially after yard cleanups. Western conifer seed bugs and ladybugs are active indoors. Chickweed and ground ivy are staring to bloom. Winter damage to Ilex opaca (American holly), Ilex glabra (inkberry), Ilex crenata (Japanese holly), Buxus sp. (boxwood), Meserve hollies, Euonymous fortunei, Rhododendron, and Kalmia continue to show up in the landscape. Deer continue to browse. Skunks are digging up lawns. 

East Region ( Boston) - General Conditions: Cool and sunny for the most part. No accumulated GDD. Pests/Problems: Allergen reports - likely to be pollen and some mold.

Metro West ( Waltham) – General Conditions: Soil is warming.

Central Region (Boylston) - General Conditions: Cold conditions continue. Snowdrops (Galanthus), crocus, and winter aconite (Eranthus) continue to bloom. Early cultivars of daffodils, as well as squills (Scilla) and glory-of-the-snow (Chionodoxa) are beginning to bloom in protected locations. Pests/Problems: Extensive winter damage to evergreens is apparent.

Pioneer Valley Region ( Amherst) - General Conditions: Below normal temperatures appear to be suppressing plant growth and development. After last week’s rainfall the weather has been dry but with highs in the 40s and lows in the 20s F. Lawns are slow to green, crocuses and a few hyacinths are just beginning to bloom in open areas, and the buds on flowering trees and shrubs are swelling/slowly opening. Pests/Problems: Rhododendron, holly, mountain laurel, leucothoe, and hemlock growing in sites exposed to south and/or west sun, and drying winds sustained varying amounts of foliar damage. Some of the flower buds on Prunus serrulata cultivars and Forsythia species began to open in January on the UMass campus. As a result, these trees and shrubs may have a sparse bloom this spring. Many flower buds/flowers are dead, especially on the Japanese flowering cherries. Deer ticks are active

Berkshire Region (Great Barrington) - General Conditions: Cold and raw. Daytime highs for the past week have only reached the mid 30s, and lows have been in the upper teens and low 20s. And now a large snow storm is predicted with heavy wet snow. Typically, these spring snowstorms are the most damaging to branches of trees and shrubs because of the weight of the snow. Plant development virtually ceased due to the cold. Crocus and other blooming plants are in animated suspension. Pests/Problems: It’s beginning to sound like a broken record, but animal browsing of woody plants and ticks continue to be the only noticeable problems. It’s just too cold for insect development.

ENVIRONMENTAL DATA -

The following growing-degree-day (GDD) and precipitation data was collected for a one-week period, April 5, 2007 through April 11, 2007. Soil temperature and phenological indicators were observed on or about April 11, 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 -

Colder than expected temperatures prevail along with the chance of sleet and snow accumulation. This spring is proving to be challenging when it comes to predicting the emergence of early-season pests and for applying dormant oil sprays. Some springs are not conducive, overall, for oil sprays, and this is one of those years. As a known rule of thumb, we do not like to apply oils when freezing temperatures might occur within 24-48 hours after application. Such conditions can contribute greatly to the increased risk of phytotoxicity, especially on thin-barked trees and evergreens. We are beginning to see bud swell and budbreak on certain species, and that alone precludes the use of dormant oil sprays. Reports came in on April 11 that winter moth has begun hatching in Brookline, MA and that the tiny caterpillars have been found within buds of red maple. These reports have not yet been confirmed but are most likely accurate. The diagnostic lab is awaiting these samples for confirmation. Deborah Swanson reports that winter moth has not yet hatched in Plymouth County.

Adelgids: 

• Eastern Spruce Gall Adelgid on Norway and white spruces. 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. At budbreak, they begin to feed and cause galls to form. When in large numbers, countless new shoots will be killed. Treat before budbreak with a dormant oil spray, if necessary.

• Cooley Spruce Gall Adelgid on blue spruce. 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 are just now beginning to produce eggs. 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 a dormant oil spray when the weather allows for their use. It is not yet known what the effects of this winter’s weather pattern had on populations of this pest. There is some possibility that the warmer-than-normal December and January, followed by a sudden dip into very cold weather, has caused mortality of hemlock woolly adelgid in Massachusetts. We did witness this phenomenon a few years ago where up to 80% of this species was killed in certain areas. UPDATE: Now that egg-laying is well underway, we are seeing strong indications that HWA survived the winter weather and appears to be quite prolific, at least in western Massachusetts. Reports have not yet come in from other geographic areas.

Caterpillars:

• Winter Moth: We expect this introduced pest to be found in new areas this year as well in already established areas. Flight of the moths in December (mostly) was very spread out this year and it was difficult to establish population sizes. However, those places that had winter moth last year should be well prepared to deal with it this year. The eggs of this pest are on the trunks of trees now but are very difficult to see. Dormant oil sprays for the eggs may be effective for smaller plants, such as blueberries, which this pest also attacks. Once the foliage has expanded, treat with a spinosad product or Bacillus thuringiensis Kurstaki (B.t.K.), if necessary. If these warm days continue, we could see egg hatch within the next three weeks in Massachusetts. Note: Deborah Swanson reports from Plymouth County that winter moth eggs have NOT yet hatched as of April 11, 2007. However, two unconfirmed reports have been received from Brookline, MA indicating that winter moth has begun to hatch and is now invading the buds of red maples.

• Fall Cankerworm: A native caterpillar pest that is similar to winter moth, remains active in many of the same areas as winter moth. Eggs are in barrel-shaped clusters and wrapped around small stems. Treat the larvae the same as winter moth, once they appear.

• Forest Tent 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 forest tent caterpillar 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.
  
• Eastern Tent Caterpillar: Common to Malus and Prunus species, this pest overwinters as an egg that appears in a tight cluster and is wrapped around small stems of the host plant. Inspect for the presence of these eggs. If occurring in limited numbers, egg masses can be removed and destroyed (buried or burned). Once the larvae have begun to feed and form their silken webs, they can be treated with a spinosad product or Bacillus thuringiensis Kurstaki (B.t.K.).
  
• Bagworm 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 more 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 to 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.

Shoot Attackers:

• White Pine Weevil typically becomes active once we have accumulated 7 growing degree days (GDD) in Massachusetts. However, there are other circumstances that affect their appearance, such as snow cover and frozen soil. In many parts of Massachusetts, however, the snow is gone and the ground is no longer frozen. We are also well beyond the 7 GDD mark in those areas. It is assumed that this insect is now active and seeking new terminal growth for egg-laying. The time to treat is now for preventing damage from this pest.
  
• 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 to 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 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.

Nuisance Pests:

• Western Conifer Seedbug: This house invader may start to appear in the living areas of homes now that the sun is getting higher in the sky and warming roofs and siding. These insects may have been in homes all winter but dormant. Now that spring is arriving, they become active and seek a route to the outdoors. However, oftentimes they take a wrong turn and end up in the living room, sometimes in great numbers. Although relatively large insects (about 3/4”) they do not bite or sting. They can be vacuumed up and released outdoors, or the bag containing them can be destroyed.

• Ladybugs: See the above description of Western Conifer Seedbug. The reasons for ladybugs being in homes and how to best deal with them are the same.

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

No report this week.

LANDSCAPE TURF

INSECTS -

No report this week.

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 April 20, 2007.

This message is produced by the UMASS Extension, Landscape, Nursery and Urban Forestry Program. The copy is prepared by Dan Gillman 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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