Landscape Message - Landscape Nursey and Urban Forestry

REGIONAL NOTES -

Cape Cod Region (Barnstable) - General Conditions: Spring-like conditions are the norm, with relatively mild days and cold nights prevailing. Soils are moist and unfrozen, with winter annual weeds growing nicely. Crocus flowers are turning lawns purple and white, and spring peepers have a nightly chorus. Pests/Problems: Deer tick adults are active; cluster flies and western conifer seed bugs are appearing indoors. Winter damage is readily apparent on some hollies, especially ‘Nellie Stevens,’ as well as on evergreen euonymus.

Southeast Region (Hanson) - General Conditions: Approximately 3.94 inches of precipitation were recorded for the Plymouth area. Some of the precipitation was in the form of snow which did not last very long. Soils are bare, and grass has not yet started to green up. The peepers are peeping, and the redwing blackbirds are back. Cornus mas flower buds are starting to open. Pussy willow, crocus, Helleborus niger, H. foetidus, H. x hybridus (former) orientalis, snowdrops, Silver maple, Hamamelis mollis 'Pallida' and Hamamelis x intermedia 'Arnold Promise' are in full bloom. Winter aconite is past bloom. Several Helleborus x hybridus (Lenten Rose) were damaged due to the cold in late January and February. Pests/Problems: Monitor for ticks. Winter moth caterpillar eggs are pinkish-red and have not started to hatch. Deer continue to browse. Western conifer seed bugs and lady bugs are active indoors. 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.

East Region (Boston) - General Conditions: More spring-like than last report, although still changeable. Pests/Problems: Winter damage to evergreens - Ilex opaca (American holly). Saturated soil conditions prevent many lawn repair needs.

Metro West Region (Waltham) - General Conditions: Soil cold & wet. Pests/Problems: Hemlock woolly adelgid egg sacks look plump and ready to hatch.

Central Region (Boylston) - General Conditions: Minor bulbs are coming into bloom, especially Iris reticulata cultivars (dwarf crested iris), Galanthus nivalis (snowdrops), and Crocus tommasinianus, C. ancyrensis (early crocus). The flowers and buds on some early perennials and shrubs were damaged by the dramatically variable temperatures earlier this year. Hellebores and Loniceras, in particular, have lost this year’s crop of flowers.

Pioneer Valley Region (Amherst) - General Conditions: Daffodils, tulips, and other early spring plants continue to poke ever higher out of the ground. The lawns lost most of the 10-12 inches of recent snow cover and are just beginning to turn green. Soil moisture is high with the snow and rain during the last couple of weeks. Pests/Problems: Besides some deer browsing there is little to report.

Berkshire Region (Great Barrington) - General Conditions: The past two weeks have been a very wet period. Most of the precipitation and melting snow has become runoff due to frozen or water-saturated soils. This has resulted in considerable soil erosion in areas where there is no vegetative groundcover. Most of the 20 inches of snow that fell in the early part of this reporting period has melted, except for densely shaded areas or where snow was piled. Saturated soils will delay most early season nursery, landscape and gardening activities, i.e., digging, transplanting, and planting. Snow drops and Iris danfordiae (dwarf yellow iris) are in bloom. Pests/Problems: Ticks, including deer ticks are active. Deer continue to browse heavily on landscape plants.

The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, March 15, 2007 through March 28, 2007. Soil temperature and phenological indicators were observed on or about March 28, 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.

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.

The warmer-than-normal temperatures in January and into February resulted in gained growing degree days in much of the state. During March, we also experienced warm days and now during this last week, we are seeing daytime temperatures in the upper 60s and perhaps 70s. All of this has had and will continue to have an acceleration effect on those insects that appear early in the year. It is difficult to predict exactly when these pests will first start to appear, but it is safe to assume that it will be earlier than the norm. Some are now becoming active. Pay special attention to such insects as white pine weevil, winter moth, hemlock woolly adelgid, eastern tent caterpillar, gypsy moth as well as others.

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

DISEASES -

Trees and shrubs – The spring of 2006was 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 watching for brown-black branches 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 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 leaves infected last year with leaf spot diseases. Especially around trees such as crabapple (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.

This is also a good time to begin management interventions that enhance the vitality of the woody plants help them make the most of inherent structural and biochemical resistance responses to disease infection. Suggestions include weekly soaking irrigations during dry periods, fertilization of poor soils, maintenance of a 2-3 inch layer of organic mulch over as much of the root zone as possible, as well as aeration of compacted soil, removal of dead branches, and pruning to improve branch structure and air movement throughout the crown.

Ramorum Blight, also known as Sudden Oak Death (SOD). Since 1995, oaks and tanoaks have been dying in the coastal counties of California. Since then, other types of plants have been found to be infected or associated with this disease, referred to as Sudden Oak Death (SOD), ramorum leaf blight or ramorum dieback. Phytophthora ramorum is the pathogen that causes these diseases. Sudden Oak Death was first seen in 1995 in Mill Valley ( Marin County) on tanoak. Since that time, the pathogen has been confirmed on various native hosts in fourteen coastal California counties and in Curry County, Oregon.

Through ongoing surveys of nurseries, USDA-APHIS-PPQ continues to define the extent of the pathogen’s distribution in the US and limit its artificial spread beyond infected areas through quarantine and a public education program.

Status of Phytophthora ramorum in 2007:

USDA-APHIS lifted the Phytophthora ramorum quarantine at Tiffany Creek Preserve, Nassau County, New York on January 25, 2007. After two years of prescribed survey, sampling, and testing for this disease in and around this area, APHIS determined that P. ramorum is known not to occur in the Tiffany Creek Preserve or any other parts of New York.

On June 29, 2004, a sample of red oak bark collected from the Tiffany Creek Preserve tested positive for P. ramorum. As a result, Tiffany Creek Preserve was placed under a Federal Emergency Action Notification and State Quarantine. The red oak tree in question was removed, and intensive monitoring for P. ramorum in and around the area was subsequently conducted. During May and September 2005 and 2006, the surveys collected vegetation, soil, and, water samples for testing. The last of these four P. ramorum surveys happened on September 19, 2006, more than two years after obtaining the initial positive-sample. These survey activities never detected additional P. ramorum-positive samples.

Forest Detection Survey. For 2007, the USFS will be conducting a watercourse pilot survey throughout the US to aid in detecting P. ramorum in the wild land environment. This new program will replace the nursery perimeter and general forest detection surveys, which were carried out from 2003 through 2006.

Phytophthora ramorum Interim Rule. On 27 February the Federal Registry published an interim rule regulating the movement of restricted and regulated plant materials. This rule took effect upon publication and replaces the rule of 2002 and the Federal Order.

To view and print out the rule visit:

http://www.aphis.usda.gov/plant_health/plant_pest_info/pram/regulations.shtml

If you have any comments on the new rule, these are due by 30 April 2007.

Reported by Dan Gillman, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass, Amherst.

WEEDS -

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

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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UMass Extension Landscape Message #5 March 30, 2007

DIAGNOSTIC SERVICES

UMass Extension Landscape Message #5
March 30, 2007