UMass Extension Landscape Message #5
March 31, 2006

Quick Info Menu ------------------------------- ENVIRONMENTAL DATA REGIONAL NOTES - Cape Cod - Southeast - East - Central - Pioneer Valley - Berkshire PHENOLOGY WOODY ORNAMENTALS - Insects - Diseases - Lab Report - Weeds TURFGRASS - 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. The next update will be available on Friday, April 7, 2006. Missed a previous message? Visit the Landscape Message Archive. Interested in additional turf-oriented content? UMass Extension Turf Program Management Updates

ENVIRONMENTAL DATA

The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, March 16, 2006 through March 29, 2006 . Soil temperature and phenological indicators were observed on March 29, 2006. Accumulated GDDs represent the heating units above a 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.

REGIONAL NOTES

Cape Cod Region (Barnstable) - General Conditions: No report.

Southeast Region (Hanson) - General Conditions: Nice spring-like weather for most of the past two weeks. Soils are dry. Hanson received less than an inch of rain. According to reports, March 2006 was one of the driest on record. The peepers are peeping, the redwing blackbirds are back, and lawns are starting to turn green. Cornus mas flower buds and Pieris japonica sp. are just starting to bloom. Pussy willow, crocus, Helleborus niger, H. foetidus, H. x hybridus (orientalis), snowdrops, Taxus, and Hamamelis x intermedia 'Pallida' are in full bloom. Hamamelis 'Arnold Promise' is past bloom. Silver Maple is starting to go by. Helleborus x hybridus (Lenten Rose) is not as floriferous as in previous years and appears a bit winter damaged probably due to the cold as the new foliage and flowers were developing. Pests/Problems: Monitor for ticks. Plymouth County, like many other areas, are preparing for the onslaught of the winter moth caterpillar. Right now the eggs are pinkish-red and have not started to hatch. Judging by the number of forest tent and gypsy moth egg masses, it appears that Plymouth County will be preparing for another big caterpillar year.

East Region (Boston) - General Conditions: Cool and dry. Crocuses, snowdrops, and pussy willows are flowering! Pests/Problems:. None to report.

Central Region (Boylston) - General Conditions: Pretty dry for March, and beautifully warm today. The water in vernal pools is receding rapidly. Honeybees have been out flying off and on for the last few days. Early daffodils and minor bulbs such as scilla, chionodoxa, crocus, and Iris reticulata are blooming. Hellebores (H. nigra) are also in bloom. Pests/Problems: None to report.

Pioneer Valley Region (Amherst) - General Conditions: GDD reading was taken on morning of March 29, but with warming trend starting that day the GDD total will have added up quickly in following days. Generally dry conditions exist, so caution has to be taken with outdoor burning where it is permitted. Early blooming spring bulbs, i.e., snowdrops, crocus, winter aconite, dwarf iris, as well as hellebores are in bloom. Pests/Problems: This is the time of year when overwintering adult deer ticks are most active. Those that did not attach themselves to hosts last fall are now actively seeking a host in a last ditch effort to secure a blood meal. Apply appropriate repellents when working outdoors, and do a daily body check for ticks. The American Lyme Disease Foundation reports that sampling of deer ticks in the Northeast found 50% of the adult ticks carry the Lyme disease spirochete.

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.

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

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

WOODY ORNAMENTALS

INSECTS

Winter moth - Monitor now for the presence of winter moth eggs. Egg hatch is imminent and is projected to occur in about 4-5 more weeks. Currently, the eggs are small, oval, and orange. These can be found on the trunk and branches throughout a tree. Once the tiny caterpillars emerge from the eggs, they will seek buds that are just beginning to swell. Winter moth caterpillars wriggle into buds and feed on both foliage and flower parts within the buds. This exotic pest has been recently shown to be far more prevalent than previously understood. Most of eastern MA, all of RI, some spots in southeastern NH, southeastern CT, southern NH, and certain areas along the Maine coast have this pest. The highest population numbers, by far, are in MA and RI.

Gypsy moth is expected to be present in high numbers in MA, and other northeastern states. The fungus, Entomophaga maimaiga, that controls gypsy moth naturally has not performed well during the past two springs. This is primarily a function of spring weather conditions; rainy periods at critical times during the caterpillar stage are essential for the spread of this pathogen to gypsy moth caterpillars. There has been some anecdotal evidence provided recently that E. maimaiga may have been more active and successful in the westernmost part of MA last year (Berkshires) than it was in the rest of southern New England.

Eastern tent caterpillar is once again expected to be present in large numbers and attacking their favored host plants of apple and cherry. Egg hatch will occur once the leaves are half to fully emerged from the buds.

Forest tent caterpillar is also expected to occur in large population numbers once again in MA and other surrounding states. Last year, this pest caused more than 200,000 acres of defoliation in MA. Forest tent caterpillar has been a problem in eastern MA for several years, primarily on oaks, but it is now building in serious numbers statewide, as well as in VT, on sugar maple as well.

Fall cankerworm is expected in large numbers in eastern MA and on parts of Long Island, NY in 2006. Parts of RI may also experience some of this pest = s activity. The hatching of eggs will occur about early to mid May.

Hemlock woolly adelgid has been actively feeding since last October and has now produced the next generation. This will be the time when the cottony masses that surround the eggs will be most visible, especially from the undersides of the branches. Make note of those plants that will require treatment with oil sprays once the correct weather conditions prevail.

Spruce spider mite from last fall has not shown up, yet. It will suddenly become apparent on those affected plants, but no mites will be seen at that time. However, make note of those plants that were inured from last fall = s feeding, and expect to have more mites on those plants this spring. Once the correct weather conditions prevail, treat with an oil spray or, if eggs are present, they can be treated with one of the mite growth regulators that has ovicidal activity.

White pine weevil has been active. This species overwinters as an adult in sheltered places and will break its dormancy once we have achieved seven growing degree days, which has already occurred. Female weevils seek the base of terminal buds on white pine and spruce to chew small holes and lay their eggs. Larvae then tunnel downward through 2-3 years of growth and eventually cause the terminal to wilt and die. If treatments are deemed necessary, they should be applied while the adults are active to prevent (reduce) egg-laying.

Inkberry leafminer mines have now become obvious. Despite the larvae being in the mines since early last summer, the browning of these mines has only just occurred within the past month or two. Make note of plants with noticeable infestations, and prepare to place yellow sticky cards out around early May to monitor for the emergence of the adult flies, which will indicate the time to apply controls to break the cycle of re-infestation.

Birch leafminer - Purchase yellow sticky cards now to place out on susceptible birches at bud break. Adult sawflies should appear around the time that the leaves are half-emerged from the buds. Treat when the adults appear.

European pine sawfly will not become active for at least several more weeks. However, take inventory now of those plants that were attacked last year by this pest. Mugo pine is the most common host here, but other pines are also attacked. Treat the young larvae with insecticidal soap or a spinosad product.

Trees and shrubs - The spring of 2005 was wet in many parts of New England and resulted in a lot of leaf spot and shoot blight diseases. These diseases, as well as branch cankers, may disfigure woody plants, but they seldom kill otherwise healthy plants. However, if leaf spots and blights were serious problems last year, infected plant material from last year may produce fungal fruiting structures this spring that release an abundance of inoculum. During wet springs, these spores infect young leaves and shoots. For high value plants where appearance is important, consider several applications of fungicides beginning as buds open if conditions are wet this spring. Alternatively, consider replacing plants with recurring leaf spots and blights with resistant varieties or other plant materials better adapted to the site.

In addition, scout rosaceous plants commonly infected with the fire blight bacterium, such as crabapple, apple, pear, firethorn, hawthorn, cotoneaster, and related plants. Remove dead branches and dispose of them away from the plants to reduce inoculum. Lilacs with dead shoots from bacterial blight also benefit from their removal. Disinfect pruning tools between each cut with 70% ethyl alcohol, a 10% bleach solution, or a comparable bacterial disinfectant.

On plum and cherry trees that are infected with black knot canker look for swollen branches (~ twice the normal diameter). Prune not only to remove infected branches but, also, to improve the branch structure within the tree crown. Removal of inoculum before the fruiting structures erupt through the bark helps reduce inoculum that could cause new infections in the spring and is a key factor in managing this disease.

Finally, collect and dispose of fallen leaves around crab apple (apple scab) and horsechestnut (Guignardia leaf blotch), as well as leaves and twigs from around flowering dogwood (dogwood anthracnose) to reduce overwintering inoculum available to initiate new infections this spring.

Ramorum Blight, also known as Sudden Oak Death (SOD). Since the early 1990's, oaks and tanoaks were 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. The first positive identification of the disease was in 1995 on tanoak in Mill Valley (Marin County), California. Since that time, surveys confirmed Phytophthora ramorum on various native hosts and nursery plants in several locations in California, Oregon, Washington, and British Columbia. When nursery surveys find infected plants prompt quarantine and/or eradication activities ensue. Research conducted by the Agriculture Research Service, US Forest Service, universities, and others is under way to better identify hosts, improve methods of detection, and develop effective treatments. Currently, 84 plants are regulated, two of which at the genus level (Camellia and Rhododendron). There are no chemical treatments currently available to eliminate Phytophthora ramorum from infected plants.

Status of Phytophthora ramorum Monitoring Surveys. The 2005 National Nursery Survey involved 49 states and Puerto Rico. The survey visited 3,790 nurseries and collected 68,275 samples. Overall, the survey reported 99 positive sites in 2005. The breakdown by state was: CA (55), GA (4), LA (2), OR (20), TN (1), SC (1), and WA (16).

New Hosts Added. USDA APHIS issued a Federal Order on November 15 adding Abies concolor (white fir) and Viburnum opulus (= V. trilobum) (American cranberry viburnum) to the official list of host and associated host plants. In addition, USDA APHIS issued a Federal Domestic Quarantine Order on February 10 adding Frangula purshiana (formerly listed as Rhamnus purshiana), Adiantum aleuticum, and Adiantum jordanii to the official list of P. ramorum hosts. They also identified 13 new plants as associated hosts. One of the plants, found in an infested area of California and identified by Washington State, was Abies magnifica. The other 12 new species were reported from Canada, and include: Acer davidii, Ardisia japonica, Euonymus kiautschovicus, Gaultheria shallon, Hamamelis X intermedia (H. mollis & H. japonica), Leucothoe axillaris, Magnolia grandiflora, Michelia maudiae, Michelia wilsonii, Osmanthus decorus (=Phillyrea decora; =P. vilmoriniana), Prunus lusitanica, and Rosa rugosa. The Koch's postulate process for these plants (the process involves isolating the pathogen from the infected plant, reinfecting a healthy plant, and then reisolating the pathogen from the second plant to confirm infectivity) is not complete. Until USDA completes the Koch's postulate process, due to uncertainty about the pathogenicity of P ramorum on these plants, these 13 new species are on the associated host list.

Dan Gillman, Plant Pathologist, based in the UMass Extension Plant Diagnostic Lab at UMass, Amherst.

WEEDS

Many winter annuals are beginning to flower, and some perennials are starting to sprout by means of their vegetative propagules. Winter annuals in ornamental beds can be controlled with glyphosate or glufosinate as long as they are actively growing and flowering.

Beware of poison ivy when doing your early season pruning and cleanup. Look for stems with aerial roots and gray berries. Remember, even if the plant material is dead the oils in it can still cause a rash. For more information, check the following web page: http://www.umassgreeninfo.org/fact_sheets/weed_herbarium/pages/toxra.html

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

TURFGRASS

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

Weeds:

Applications of preemergence herbicides can begin now. The ideal timing for them is when the forsythia is in full bloom. Start early enough to allow enough time for all customers to be treated by the time the forsythia drops its blooms.

Randall Prostak, Weed Specialist, UMass Extension, Plant, Insect & Soil Sciences Department, Amherst.

Don't forget to visit the UMass Extension Online Weed Herbarium!

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 Outreach 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 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 Friday, April 7, 2006.

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.

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