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ENVIRONMENTAL
DATA
The statewide GDD averages for this period are as follows: total = 172.5; GDD/week = 17; GDD/day = 2.4 REGIONAL
NOTES Southeast Region (Hanson) - General Conditions: Cool weather continues to continue! Cool, wet weather has been the norm for the past week with temperatures below normal. According to Bob Skilling of the Blue Hill Observatory in Milton, "this has been the only May in 120 years in which temperatures rose above 70 degrees on just one day, May 11." Then a frost occurred the next night! Hanson received 2.75 inches of rain this past week and it is still raining as this report is being written. Lawns are growing like weeds and all this wet weather makes mowing difficult! A few saucer magnolia flowers remain. Crabapples, flowering dogwoods, Exochorda racemosa (pearlbush), Fothergilla,Kerria, Wisteria, Arabis, Arisaema, Corydalis lutea, Dicentra eximia, Dicentra spectabilis, Epimedium, Helleborus foetidus, Lunaria, Pulmonaria, Polemonium, Phlox divaricata, Phlox subulata, Primula, Tiarella, Trillium, Vinca minor, ajuga and violets are in full bloom. Viburnum 'Mohawk', Amelanchier, Fothergilla, tulips, and daffodils are past bloom. Doublefile viburnum and Phlox stolonifera are starting to bloom. Pests/Problems: Winter moth caterpillars continue to feed on a wide range of plant material. The cool weather appears to have slowed caterpillar development. Usually they have started to pupate at this time. Silver maples and Norway maples leafed out but have sustained damage. Oak and ash have very little foliage to date and oaks sampled had mixed populations of gypsy moth, forest tent and winter moth caterpillars, with winter moth being the dominant caterpillar. Winter moth caterpillars are also feeding on Japanese and other Asian maples, crabapples, Katsura, weeping cherry, American fringetree and lilac buds and flowers. Some oak and ash trees look nearly bare, like it is winter instead of May. European pine sawfly, lily leaf beetle, hemlock woolly adelgid, carpenter bees and bumble bees, mosquitoes, black flies, ticks, are also active. Chickweed, buttercups, ground ivy, and veronica are all in full bloom. The bright orange gelatinous fruiting structures are still visible eastern red cedar. Barberry and burning bush, two Massachusetts invasive plants, are in bloom. If potential seed dispersal is of concern to clients, prune or shear plants now to remove flowers. Seed production will be interrupted and plants will grow and fill in nicely while producing fewer seeds. East Region (Boston) - General Conditions: Wind and rain have curtailed most landscape activities and have delayed seasonal flowering. Pests/Problems. Storm damage is apparent in the form of broken branches and trees. Central Region (Boylston) - General Conditions: No report. Pioneer Valley Region (Amherst) - General Conditions:The woody plants are thriving in the raw, wet and occasionally windy weather. They are rich green and/or flowering well and the flowers are slow to fade. Lawns are thriving and verdant. Gardens are bursting with green and color, too. Pests/Problems: Frost damage from the first week in May as well as May 12 and 13, has browned tender foliage on oaks, London plane (sycamore), Japanese maple, and magnolia to name a few, in the Valley and the Berkshire Hills. They should recover but the youngest leaves look brown now. The bright orange fruiting structures of cedar-apple rust are beginning to show up on the upper surface of crabapple leaves, whilst the gelatinous fruiting structures are still visible on and releasing spores from galls on the eastern red cedar. Speaking of rust diseases, the golden-orange bands with bright orange fruiting structures of spruce needle rust (Chrysomyxa species) are becoming noticeable on Colorado and other susceptible spruce. Berkshire Region (Great Barrington) - General Conditions: Raw (cold, windy, and damp) conditions dominated much of the past week. The rain was sorely needed as the ground had been dry. Turfgrass has benefitted the most from these conditions and most lawns are lush and growing at a steady pace. Pests/Problems: Observations this past week included: skunk damage to turf areas, snowball aphid on Burkwood viburnum, extensive infestations of eastern tent caterpillar, European pine sawfly, carpenter bees, deer ticks and frost injury to some plants. PHENOLOGYThe 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. WESTERN REGION - Dan Gillman, Plant Pathologist, Urban Forestry Diagnostic Lab, UMass, Amherst. BERKSHIRE REGION - Ronald Kujawski, Nursery Specialist, UMass Extension Agroecology Program, Great Barrington. The cold and wet weather continues to slow the pace of leaf expansion. Trees that typically have late budbreak, such as oaks, have suffered from much winter moth injury in the east and some frost injury in the western part of the state. Pollination of fruit crops, such as apples, has been greatly reduced this year. Insect activity remains slow and the cold weather has thus far kept mosquito and blackfly activity to a minimum. Lepidopteran caterpillars:
Reported by Robert Childs, Entomologist, UMass Extension Landscape, Nursery and Urban Forestry Program, Amherst Leaf Spot and Shoot Blight - The rainfall has given plants a good watering. But, with leaves developing they are vulnerable to leaf spot and shoot blight infections, especially when accompanied by temperatures of 50-70 degrees F. This is the time to apply protective fungicides to nursery and specimen woody landscape plants that are known to be susceptible to these types of diseases. Sycamore, Maple, Oak and Ash Anthracnose. Sycamore, maple, and oak anthracnose are evident now as dark-green to dark-brown curling leaves and shoots, while ash anthracnose is apparent as young green leaves with tiny brown spots falling from the trees. Anthracnose is widespread on early leaves and shoots this year due to the abundance of inoculum on over-wintering twigs and fallen leaves, as well as the consistently wet weather. These diseases cause some premature leaf loss, but that is not going to seriously an otherwise healthy tree. In the fall fine prune infected twigs and collect and dispose of fallen leaves. Promote drying of foliage by pruning and spacing plants to increase the penetration of sunlight and air circulation in and around plants. Phomopsis Tip Blight - The current wet conditions, along with the development of immature scale-leaves/needles are favorable for infection of juniper by Phomopsis tip blight. Juniper shoots that are tan-gray with pinhead-sized, black fruiting bodies are producing spores at this time. New growth that becomes infected this spring with Phomopsis tip blight will turn green-yellow, then brown and die within a few weeks of infection. Management begins with the removal and disposal of infected shoot tips to reduce inoculum. Cut an inch or so below the boundary between dead and healthy tissue. Now is the time to initiate fungicide control of juniper tip blight to improve plant appearance. Grow junipers in an open, sunny location to promote drying of foliage. Also, grow those that are adapted to the site and that have resistant to tip blight. Slime Mold - The bright-colored, but unusual looking stuff that goes by such common names as dog vomit, scrambled eggs, the yellow blob and regurgitated cat breakfast is actually a slime mold; that is, a fungus. Slime molds are primitive organisms that feed on bacteria, other fungi and dead organic material of many sorts. This is the reason why they’re more common in lawns and mulch. Slime mold is now visible on lawns, woodchip mulch and patios. On lawns, it can be gray, white or purple and range from several inches to a foot-wide diameter lump. Slime mold may use living plant material as a physical support, but it does not “infect” the turf. In fact, slime molds harm lawns only if their structures become so thick that they cover entire leaf blades and thus block the plants’ sunlight. If it looks unsightly, simply use a shovel to discard the offensive organism and then stir up the remaining mulch to aerate it. Or, if the structures don’t look too bad, just leave them alone. They’ll dry out, become ash-gray, and break up easily when raked. Slime molds become noticeable when damp weather triggers their colorful reproductive stage any time from spring through fall. Bacterial blight,caused by Pseudomonas syringae, blackens flowers, new leaves and shoots on lilacs, and stone fruits, as well as frost-damaged Japanese, Norway, and red maples. The host range is actually wider, but these are the most common hosts in our area. In severe cases shoots are girdled and killed and flower clusters become limp and brown. Infection begins during mild (60-70 degrees F), rainy periods. The bacteria typically enter tender plant leaves and flowers through natural openings (stomata, lenticels, nectarathodes, etc.) and frost wounds. As leaves mature, they are less susceptible and leaf infections late in the season are rare. Remove infected shoots during dry periods at least 8-12 inches below the edge of the lesion or where the infected branch attaches to another branch. Disinfect pruning tools with 10% bleach or 70% ethyl alcohol between cuts. Chemical control is not usually necessary, as the blight does not usually kill plants. However, when appearance is important, this is the time to initiate chemical controls to protect flowers and new growth on nursery and specimen plants from infection. Many copper-containing fungicides are labeled to control this disease. One or two follow-up sprays at 10-14 day intervals are needed if wet weather continues this spring. If this is a persistent problem on lilac, consider replacing susceptible ones (Chinese [Syringa x chinensis], Japanese [Syringareticulata], Persian [Syringa x persica] and white-flowered common lilac) with some of the many cultivars of resistant varieties that are available. Dogwood anthracnose fruiting structures are apparent on trees where there are buds that did not open and twigs and branches that died back. Water shortage, heat stress, compacted soils and winter damage weaken trees and increase the severity of the disease. Dogwoods receiving good cultural care are better able to limit the extent of dogwood anthracnose damage. Water during dry periods and maintain 2-4 inches of composted bark mulch over as much of the root area as possible. Prune off and dispose of diseased twigs and branches to reduce anthracnose inoculum that is in the tree and is readily splashed to nearby leaves and shoots. Four fungicide applications are usually needed to control dogwood anthracnose on susceptible trees during wet seasons. Begin now (as buds break open), when bracts have fallen, and four weeks later as well as in late summer if there is wet weather after flower buds form. If this is a persistent problem consider planting one of the many resistant cultivars of C. florida and C. kousa now commercially available. Rhabdocline Needle Cast - The fruiting bodies of Rhabdocline needle cast are visible on infected Douglasfir needles. Symptoms of Rhabdocline infection appear as elongated, red-brown spots and bands on infected needles. Spots often coalesce and most of the needle turns color except for the base, which often remains green. Infection tends to occur on the bottom of the tree first; but with wet springs during the last several, more of the tree is affected. Infected needles drop prematurely from winter into the summer. Spores are released from fruiting structures during cool, wet episodes from now to early summer and infect new needles as they develop. Avoid overhead irrigation of Douglasfir at this time of the year. Provide adequate spacing and limit weed growth around young trees. If this spring continues to be wet, apply fungicides such as chlorothalonil, copper hydroxide, mancozeb, or chlorothalonil plus fenarimol on susceptible, high-value trees. Maintain protection during the vulnerable period when the needles are first emerging from buds until they expand to full size. Sphaeropsis (Diplodia) Shoot Blight - This disease can cause significant damage to weakened red, pitch, Japanese black and, especially, Austrian pine in our area. If wet weather continues, new shoots developing on these trees are vulnerable to infection. Consider applying fungicides such as propiconazole, copper salts of fatty acids, thiophanate methyl and mancozeb to susceptible trees as soon as buds swell significantly. Sprays should be reapplied at labeled intervals until the new growth is fully expanded, if wet conditions persist. A significant amount of inoculum is produced on the outer scales of second-year cones, as well as infected shoots and needles. Pruning affected shoots can be done when foliage is dry to improve appearance, but this will make little difference in reducing inoculum for new infections unless these cones are removed, too. If replacement of severely affected pines is an option, plant trees resistant to Sphaeropsis as well as plants better adapted to grow on the site. Cedar-Apple Rust - The galls on eastern red cedar (Juniperus virginiana) and Rocky Mountain juniper (J. scopulorum) continue to erupt with the orange, gelatinous telial horns (fruiting structures) throughout Massachusetts. The orange, gelatinous horns release spores that infect wet apple and crab apple leaves at this time of the year during cool, rainy periods. 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, ramorum leaf blight or ramorum dieback, or by regulation as Phytophthora ramorum. SOD was first seen in 1995 in Mill Valley (Marin County) on tanoak. Since that time, the disease has been confirmed on various native hosts in fourteen coastal California counties (Marin, Santa Cruz, Sonoma, Napa, San Mateo, Monterey, Santa Clara, Mendocino, Solano, Alameda, Contra Costa, Humboldt, Lake and San Francisco), and in Curry County, Oregon. Research being conducted by the Agriculture Research Service, US Forest Service, universities and others is under way to better identify hosts, methods of detection and effective treatments. Currently, 64 plants are regulated, two of which at the genus level (Camellia and Rhododendron). There are no chemical treatments currently available to eliminate the disease in nursery stock. Status of Phytophthora ramorum Monitoring Surveys. Officially there were 36,137 samples that states submitted for laboratory testing in 2004. A total of 458 (1.3 %) of the samples submitted were found positive for P. ramorum. These positive reports came from eight states, CA (301), OR (54), GA (51), WA (45), LA (3), MD, (1) VA (1), OK (1) and NJ (1). Note that samples from New York and Connecticut that were previously listed are no longer considered to be positive for ramorum blight. That is, the oak tree in Nassau County, NY, and the three Connecticut nurseries that received plants from an Oregon nursery are no longer considered positive finds of the disease. The 2005 National Nursery Survey is underway. Ten states have reported on their progress. As of May 5, 2005, 221 sites have been surveyed and 1744 samples have been collected; none have been confirmed as positive for P. ramorum. UMass Extension’s Landscape, Nursery & Urban Forestry Diagnostic Lab Report. The following are some of the interesting disease/abiotic disorder samples received at the diagnostic lab in Amherst during the period May 13 through May 20, 2005:
Reported by Dan Gillman, Plant Pathologist, based in the Urban Forestry Diagnostic Lab at UMass, Amherst, Mass LANDSCAPE WEEDS Garlic mustard is beginning to flower and should be controlled now before seed is produced. Garlic mustard is a biennial; therefore, control now will also control seedlings and small first year plants. A non-selective translocation or contract herbicide can be used. Randall Prostak, Weed Specialist, UMass Extension Landscape, Nursery, and Urban Forestry Program, Amherst. Diseases: No report: Visit the Landscape Message Archive for previous messages. Insects: No report: Visit the Landscape Message Archive for previous messages.
Randall Prostak, Weed Specialist, UMass Extension, Plant, Insect & Soil Sciences Dept., Amherst. IMPORTANT INFORMATIONAL RESOURCES Two UMass Extension Web Sites are specially designed
to provide Green Industry professionals with resources, upcoming
educational programs and events, and other relevant information.
The Internet address for the Landscape, Nursery, and Urban Forestry
Program is http://www.umassgreeninfo.org.
The Turf Program address is http://www.umassturf.org
New England Guide to Weed Control in Turfgrass -
The updated 2005 New England Guide to Weed Control in Turfgrass
is now available. It
contains extensive information about currently registered turf
herbicide products, including specifics on application, timing
and environmentally responsible use. The guide is available as
a free, downloadable PDF file in the Online Publications section
of http://www.umassturf.org 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 DIAGNOSTIC SERVICESUMass 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 Urban Forestry Diagnostic Laboratory is available to serve commercial landscape contractors, turf managers, arborists, nurseries, and other green industry professionals. It provides woody plant disease analysis, woody plant and turf insect identification, turfgrass identification, landscape and turf 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 made payable to the University of Massachusetts to Urban Forestry Diagnostic Lab, 160 Holdsworth Way, Holdsworth Natural Resources Center, UMass, Amherst, MA 01003. The fee for a woody plant disease analysis is $50.00. All insect, weed, and turfgrass identification samples are $25.00 each. For complete information and instructions on how to send specimens, visit the Urban Forestry Diagnostic Lab page. Turfgrass disease samples should be directed to
the UMass
Turf Disease Diagnostic Lab NEXT UPDATE: The next issue will be available in Friday, June 3, 2005. 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 Turfgrass 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. DISCLAIMER. This message is intended for commercial use. UMASS Extension assumes no liability for recommendations. The use of trade names does not imply endorsement. Similarly, there may be other products you prefer to use. Comments or suggestions in regard to the Landscape Message? Please e-mail the webmaster. Missed a previous message? Visit the Landscape Message Archive.
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Most coastal towns as well as some inland towns in Massachusetts are now experiencing
large numbers of this introduced pest. Although, some areas of Plymouth County
which experienced large populations last year now appear to have lower numbers
of this pest this year. The reason(s) for this are not yet understood. However,
reports of serious infestations continue to be reported from other areas. Much
damage is already noticeable in Plymouth and Barnstable counties. Common hosts
include the following: oaks, maples, fruit trees, blueberry plants and many other
deciduous hosts. The larvae are now free-feeders on the foliage and exposed to
sprays. This year, the oaks are experiencing heavy damage as are the silver maples
on Cape Cod.
Bacillus
thuringiensis kurstaki or a spinosad product (e.g., Conserve
SC™) or a
tebufenozide product (e.g., Confirm™) or one of the registered
pyrethroid insecticides should be very effective if applied now. Note: A new fact
sheet entitled '
,
for current information on this pest. Report any new findings
in MA to Robert Childs, 