Landscape Message - Landscape Nursey and Urban Forestry

REGIONAL NOTES -

Cape Cod Region (Barnstable) - General Conditions: Mild temperatures have been a welcome change from the deep freeze that has characterized the latter part of winter this year. Daytime temperatures in the 50s (degrees Fahrenheit) for several days in a row have made it feel like spring is here. Soils are still frozen at a depth of four inches, but the top one-quarter inch has melted, creating muddy conditions in thin turf. Pussy willow buds are fat and furry. Pests/Problems: With daytime highs in the 50° F range, expect that adult deer ticks will be active again. Western conifer seed bugs are emerging from their winter shelter indoors.

Southeast Region (Hanson) - General Conditions: Cold weather continued from the end of February into March. Temperatures for the past two weeks, were for the most part, below normal. Most of the week of March 5 saw night-time temperatures in the single digits. The lowest temperature in Hanson was 4° F. High winds and rain on Friday, March 2, produced approximately 0.21 inches of rain. The rain fell on frozen ground and created pools of standing water in some areas. Soils in some areas are still frozen. Winter damage to American holly (Ilex opaca), inkberry (Ilex glabra), Japanese holly (Ilex crenata), boxwood (Buxus sp.), Meserve hollies, Euonymous fortunei, Rhododendron, and Kalmia is showing up in the landscape. The damage is scattered and is not extensive at this time. Although on some of the observed American holly trees, the foliage on entire trees was brown. The flower blossoms on Helleborus foetidus and Helleborus x hybridus are dead from the cold. Hamamelis mollis 'Pallida' and Hamamelis x intermidia 'Arnold Promise' are in full bloom. Pests/Problems: Deer continue to browse. There were no other pest problems to report.

East Region (Boston) - General Conditions: Changeable. Pests/Problems: None, yet.

Metro West Region (Waltham) - General Conditions: Snow crocus (C. chrysanthus) are beginning to bloom; common snowdrops (Galanthus nivalis) are in full bloom.

Central Region (Boylston) - General Conditions: No report available this week.

Pioneer Valley Region (Amherst) - General Conditions: The snow is melting in earnest this week, and the rainfall expected later in the week will likely complete the process. The soil is still frozen at the four-inch depth, although thawed and saturated two inches down. The buds on the red and silver maples are red and swollen but are not breaking open yet. The warmth and intensity of the March sun is quite apparent when standing in it even when the air is cold in the morning. Pests/Problems: Deer were seen feeding on landscape shrubbery in the early morning during the previous very cold week.

Berkshire Region (Great Barrington) - General Conditions: Very mild two day period with significant snow melt. Ground is still 90-95 percent snow covered and frozen. Normal conditions expected after the very brief March thaw. Pests/Problems: Deer browsing is only significant problem. Be aware that excessive foot or vehicular traffic on turfgrass will lead to soil compaction over the next few weeks as ground thaws.

The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, March 3 through March 14, 2007. Soil temperature and phenological indicators were observed on or about March 14, 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.

December 2006 and much of January 2007 were atypically warmer than usual for southern New England. In some areas, such as coastal Massachusetts, a few growing degree days (GDD) were accumulated during that time period. Now that we are into mid-March, we are once again experiencing much warmer than anticipated temperatures with several consecutive days being in the 50s (daytime temps) and at least one day in the 60-degree range. The question has arisen, “What does this mean for insect activity?” Most likely, the GDD accumulation from early winter may have an effect on the hatching of over-wintering eggs. Now, coupled with the warm mid-March temperatures, we may see early-season insects like winter moth, cankerworms, gypsy moth, eastern tent caterpillar, and others appearing a few days to a week earlier than usual. If the warm late-winter temperatures persist, it will figure strongly into that possibility. Therefore, be prepared for an early start for certain insect activity.

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

DISEASES -

Trees and shrubs – The spring of 2006 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 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 2006 Monitoring Surveys

Federal Order, State Inspection, National Survey, and Other Finds. The Federal Order, State Inspection, National Survey, and/or other detections identified 62 positive sites in 11 states. Alabama, Connecticut, Georgia, Indiana, Maine, Mississippi, and Pennsylvania had one positive each; California had twenty-seven positives; Florida had three positives; Oregon had thirteen positives; and Washington had eight positives.

National Nursery Survey. As of October 16, the forty-six participating states reported on their National Nursery Survey results. Alaska , Iowa, Missouri, and Puerto Rico are not participating in the National Survey, and Wisconsin is looking for P. ramorum as part of their regular nursery inspection. In total, inspectors visited 4,843 nurseries and collected 147,347 samples. Lab evaluation confirmed that 362 of the samples collected were positive for infection by P. ramorum.

Massachusetts Nursery Survey. The 2006 Phytophthora ramorum survey conducted by the MA Department of Agricultural Resources in cooperation with the USDA, APHIS Cooperative Agricultural Pest Survey included 23 nurseries. The UMass Plant Disease Diagnostic Lab tested 100 samples from these sites by ELISA and culturing, and none were positive for P. ramorum.

Forest Detection Survey. The United States Forest Service (USFS) and states are conducting nursery perimeter and general forest detection surveys. As of October 16, USFS reports 637 nursery perimeter surveys in 29 states with 1842 samples collected. USFS also conducted 366 general forest surveys in 29 states, with 922 samples collected. In Massachusetts, the MA Department of Conservation and Recreation worked with the United States Forest Service (USFS) to conduct surveys near nurseries and within the forest environment.

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.

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 #4 March 16, 2007

DIAGNOSTIC SERVICES

UMass Extension Landscape Message #4
March 16, 2007