Landscape Message - Landscape Nursey and Urban Forestry

The following growing-degree-day (GDD) and precipitation data was collected for a one-week period, May 4, 2006 through May 10, 2006. Soil temperature and phenological indicators were observed on May 10, 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: Typical Cape spring weather is the norm, with alternating periods of chilly, wet conditions and sunny and mild days. Plant development is progressing nicely, with many trees and shrubs providing color in the landscape. Tree pollen is extremely high, as allergy sufferers well know. Pests/Problems: Winter moth caterpillars are free-feeding on foliage; eastern tent caterpillar webs are quite visible on black cherry; gypsy moth caterpillars are beginning to hatch; feeding damage from adult lily leaf beetles is now visible. White grubs are actively feeding in turf root zones. Deer ticks and dog ticks are active. Cedar-apple rust galls are visible on eastern red cedar. The prolonged wet, misty weather sets up good conditions for foliar diseases such as dogwood anthracnose and apple scab on susceptible crabapples.

Southeast Region (Hanson) - General Conditions: Continued cooler weather continues to extend bloom time. Hanson received approximately 1.50 inches of much needed rain this past week. Prior to receiving rain, soils were very dry despite the rain received last week. Halesia , Magnolia 'Elizabeth', flowering dogwood, eastern redbud, pearlbush, Pieris floribunda (Mountain Pieris), Pieris 'Brouwer's Beauty, Mayflower viburnum, Helleborus orientalis, Helleborus foetidus, Vinca, daffodils, Pulmonaria, Epimedium, tulips, Trillium, anemones, royal azalea, bleeding heart, Phlox subulata, Phlox divaricata, and violets are in full bloom. Norway maple, sugar maple, Pieris japonica, Pyrus calleryana ‘‘Bradford’’ (Bradford Pear), Forsythia x intermedia (Border Forsythia), Lindera benzoin, Chaenomeles speciosa (Common Floweringquince), Dutchman's breeches, and Omphalodes are ending bloom. Pests/Problems: The Hanson office has received reports of small gypsy moth caterpillars causing skin irritation after being found on arms and necks of people working outside in the landscape. Gypsy moth, eastern tent caterpillar, forest tent caterpillar, winter moth caterpillar, hemlock woolly adelgid, larch casebearer, lily leaf beetles, carpenter bees, mosquitoes, mayflies, and ticks are all active. Chickweed, violets and dandelions are in full bloom. The orange jelly-like galls of cedar-apple rust are present on eastern cedar. Beneficial insects are active.

Pioneer Valley Region (Amherst) - General Conditions: The lawns continue to grow green and lush with many of them in the Valley ready for their second mowing of the year. In addition, flowering trees, shrubs, and tulips provide vibrant color to the landscape. Pests/Problems: Loss of green leaves at this time of the year from green ash is often a symptom of ash anthracnose. Dandelions are not only blooming, but some are going to seed already. Lastly, forest tent caterpillar is extremely abundant on several oak trees on the UMass campus.

Berkshire Region (Great Barrington) - General Conditions: Cool, often cloudy, weather has prevailed of late. There has been little rainfall, but the prospect for some significant rainfall lies ahead. The cool conditions have extended the life of many flowers on trees and shrubs resulting in a spectacular spring show of bloom. Soil moisture is good to poor, but rain being predicted, this is an ideal time for planting. Pests/Problems: Carpenter bees and wasps remain very active. Deer ticks are also common. Other pests observed include eastern tent caterpillars, spittlebug on pines, european pine sawfly. Spruce spider mite is active, but predatory mites were found in numbers on the same plant where the observation was made.

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, UMass Extension Plant Diagnostic Lab, UMass, Amherst.

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

Hymenopteran Caterpillars (Sawflies):

European pine sawfly has become active. Eggs, in the form of blocky yellow patches, started to appear within the last two weeks, and caterpillars began to hatch in the warmer regions more than a week ago. Feeding injury is beginning to appear. These caterpillars become voracious feeders as they grow and are capable of consuming large amounts of foliage daily. Monitor for their presence now, and treat the very young caterpillars with an insecticidal soap or a product that contains Spinosad or use one of the registered chemical insecticides. Mugo pine is one of the more common hosts for this pest.
Azalea sawfly is not, yet, active (too early), but it will appear soon enough. Its coloration and posture on the plant (usually 'Exbury' and 'Mollis' azaleas = deciduous) are so cryptic that much damage can be created before it is noticed. Monitor for the appearance of feeding damage that leaves nothing but the main veins. Then inspect much more closely for the green caterpillars that hug the margins of the foliage and that are almost the same color as the foliage. Treat with a product that contains Spinosad.

Beetles:

Lily leaf beetle is active. Inspect for the bright red adult beetles, which are foraging and beginning to feed. Within a few weeks, start to inspect the undersides of foliage for short (about one inch long) irregular-shaped tan-colored lines that are actually a row of eggs. Once found, they can be removed and destroyed. Just before these eggs hatch, they will turn orange and then a deep red color. Nymphs, which won’t appear for several more weeks, can be treated with a product that contains Spinosad.

Piercing-Sucking Insects and Mites:

Spruce spider mite is active. Damage in the form of fine yellow stippling that contributes to an overall appearance of chlorosis has now become obvious from last fall’s feeding. Monitor for these two-toned (tan color) mites with a hand lensm and treat if numbers appear to be high. Oil sprays (at the summer rate) work well on all life stages, but take caution with tender new foliage that is now emerging from the buds. In such cases, it may be prudent to wait until it has fully expanded to apply oil. Some of the newer Mite Growth Regulator products can be quite effective on the egg stage (ovicidal) and immatures of many spider mite species (Tetranychidae) while not being harmful to predatory mite species. Adult spider mites are often not killed by exposure to these products, but exposed female mites may produce eggs that are not viable.
Hemlock eriophyid mite will be active very soon. These tiny, peg-shaped and pale yellow mites are just visible to the naked eye and can be seen feeding actively on the needle surface. Large populations will lead to much chlorosis and plant stress. Manage when found in large numbers.
Balsam twig aphid is active. The “Stem Mothers” have been feeding but have now produced many offspring that are capable of creating much feeding injury in the form of needle distortion and much sticky honeydew. True firs, such as Balsam and Frasier, are most susceptible. High numbers of this pest can render Christmas trees unfit for sale.
Snowball aphid is active. Its’ preferred hosts are certain viburnum species, such as Korean spicebush, cranberry viburnum, mapleleaf viburnum as well as others. When the aphids hatch they begin to feed with their piercing-sucking mouths on newly expanding foliage, which causes severe leaf curling and distortion. The aphids continue to feed through the rest of April until about the end of May within the confines of the curled leaves. Their feeding does not kill the foliage nor does it create yellow-stippling injury that is so typical to other piercing-sucking insects. However, it can create so much leaf distortion that it de-values the aesthetics of affected plant material. Imidacloprid that is already systemic within the plant from last summer works very well. Treating with a contact insecticide offers little management given that these aphids are so well hidden within the curled foliage. In the Amherst area, new leaves have already been affected and in most cases, it is too late for treatments.
Larch adelgid is active and can be seen as white cottony masses scattered throughout the needles of its host. When in large and very noticeable numbers, it should probably be managed.
Pine bark adelgid is active again, and large populations can appear like wind-driven snow on trunks and the undersides of scaffold branches of white pine. Although very showy, it rarely requires treatment.
Hemlock woolly adelgid (HWA) is producing the crawler stage right now. This is a very dangerous time for this pest to be moved from plant to plant or to different locations (by wind, birds, humans or wildlife). They will settle and begin to feed and then not be mobile again until the next generation of crawlers in June. Oil sprays (summer rate) work very well, but care should be taken to avoid applying oils when tender new foliage is appearing. Systemically applied Imidacloprid is also effective, but translocation can take from weeks to months to get to where this pest is feeding.
Honeylocust plantbug is active. The over-wintering eggs have been imbedded in the tender shoots, and they hatched at bud break. The tiny, pale green nymphs are now feeding with their piercing-sucking mouths on expanding foliage. When this pest occurs in large numbers and the weather becomes cool for an extended period of time (many days to more than a week), the injury can become great to tiny foliage to the point where it never fully expands. During certain years, honeylocust can be defoliated by this piercing-sucking pest. Monitor by shaking branches over a sheet of paper and inspecting for the nymphs. When numbers are high, it may be prudent to treat.

Leaf Miners:

Inkberry leafminer mines are 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-mid May to monitor for the emergence of the adult flies, which will indicate the time to apply controls to break the cycle of reinfestation.
Native holly leafminer mines are very obvious right now on American holly, but there is nothing to be done for management. Wait until June to place out yellow sticky cards to monitor for the next generation of adult flies, and treat at that time with a knockdown type spray such as a pyrethroid.
Birch leafminer - Yellow sticky cards should now be placed out in susceptible birches where leaf expansion has begun. Adult sawflies should appear around the time that the leaves are half-emerged from the buds. Treat when the adults appear.

Gall Formers:

Eastern spruce gall adelgid is actively feeding and about to stimulate new gall formation. In cooler areas where bud break has not yet begun, oil sprays at the summer rate can be very effective. Once galls are formed, managing this pest is extremely difficult. Norway and white spruce are two common hosts for this pest in MA.
Cooley spruce gall adelgid is also active on blue spruce. Its biology, damage, and management are very similar to that of eastern spruce gall adelgid. However, bear in mind that oil sprays do remove the blue color from blue spruce needles for at least a few months.

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

DISEASES

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. This is especially omportant for those known to be susceptible to diseases such as apple scab on flowering crabapple, dogwood anthracnose on flowering dogwood, fire blight on mountain ash, crabapple and Callery pear, Entomosporium leaf spot on English hawthorn, Phomopsis tip blight on juniper, Rhabdocline needle cast on Douglasfir, and black spot on rose.

In addition, scout rosaceous plants commonly infected with the fire blight bacterium, such as crabapple, apple, pear, firethorn, hawthorn, and cotoneaster. Remove dead branches and dispose of them away from the plants to reduce sources 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.

Rhabdocline needle cast fruiting structures will soon be 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 remains green. Infection tends to occur on the bottom of the tree first. Infected needles drop prematurely from now into the summer. Spores released from these fruiting bodies during cool, wet weather infect new needles that will soon start developing. Avoid overhead watering of Douglasfir at this time of the year. Provide adequate spacing, and limit weed growth around young trees. Consider fungicide applications to susceptible, high-value trees if this spring is wet. Maintain protection during the vulnerable period when the needles are first emerging from buds until they expand to full size.

Sphaeropsis (Diplodia) shoot blight on pine can cause significant damage to stressed 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 to protect susceptible trees as soon as buds swell significantly. Reapply sprays at labeled intervals until the new growth fully expands, if wet conditions persist. The Sphaeropsis fungus produces significant amount of inoculum on the outer scales of second-year cones, as well as infected shoots and needles. Prune affected shoots when plants are dry to improve appearance, but this will make little difference in reducing inoculum for new infections without cone removal, too. If replacement of severely affected pines is an option, plant trees resistant to Sphaeropsis shoot blight as well as better adapted to grow on the site.

Gymnosporangium rust fruiting structures are visible on eastern red cedar (really a juniper) and Rocky mountain juniper, as well as the occasional Chinese, common, creeping and savin juniper hosts. Specifically, cedar-apple rust galls are visible on eastern red cedar (really a juniper) as eruptions of orange, gelatinous masses protruding from pea- to golf ball-sized galls. These fruiting structures release spores that infect apple and crab apple leaves at this time of the year during cool, rainy periods. Likewise, fruiting structures of hawthorn rust and quince rust are on many of these junipers, but the fruiting structures are less conspicuous. Hawthorn rust develops pea-size or smaller galls while the quince rust fruiting structures emerge as red-orange “cracks” in the bark of infected branches. Leaves, green shoots, and fruit of serviceberry, hawthorn, mountain ash, quince, flowering quince, and pear, as well as apple and crabapple are susceptible broadleaf alternate hosts.

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. USDA APHIS currently regulates 84 plants, two of which are 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 2006 National Nursery Survey is likely just getting underway. In past years the survey visited nurseries and collected samples from host plants exhibiting leaf spot, blight, and canker symptoms associated with Phytophthora ramorum infections.

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

TURFGRASS

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

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

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

UPCOMING EVENTS

For a complete listing of upcoming events, see our Conferences and Workshops page.

2006 UMass Green School to Start October 31 in Milford, MA
Green School is a comprehensive certificate training program for Green Industry professionals taught by UMass Extension Educators and Faculty. This course is designed for landscape, turf, and other horticultural practitioners wishing to gain an understanding of horticulture fundamentals and strategies and their relation to environmental quality. Green School attendees learn about sustainable approaches to turf and landscape management in managed environments. Green School's curriculum is based on research and information emphasizing environmental stewardship and integrated pest management (IPM). Participants develop an understanding of how proper management practices impact natural resources such as soil and water. Participants learn to make environmentally appropriate decisions related to turf and plant selection, plant maintenance, pest and nutrient management.

The 2006 schedule and application form will be posted on www.umassgreenfino.org in June.

Scouting for Pests and Problems of Turf and Woody Ornamentals, 5:00-7:00 p.m.
May 30, 2006 - Springfield, MA
June 1, 2006 - Wellesley, MA
June 15, 2006 - Bridgewater, MA
Learn how to put IPM practices to work efficiently. Join us in a walk through the landscape for demonstrations of IPM tools and techniques, as well as a close look at some of the most common cultural problems and troublesome insect, mite, and disease problems. Workshop held rain or shine. Two Pesticide contact hours for categories 29, 36, 37, and Applicators License available.ISA, MCA, MCH, and MCLP credit requested. See our Conferences & Workshops page for registration information.

July 19, 2006 - Nursey & Landscape Summer Meeting & Trade Show - The day will offer horticulture education workshops presented by well known researchers and educators, a trade show and hands-on insect, disease, and weed laboratory. At press time, plans were underway to feature an actual outdoor set-up of garden center displays showing examples of today’s most successful marketing and plant branding strategies. Plans to organize class reunions for Stockbridge School of Agriculture and UMass alumni the day before and have University Admission officials on hand to answer questions about student applications are also in discussion.

This special event will also showcase Dr. Michael A Dirr, respected author, lecturer and retired Professor of Ornamental Horticulture from the University of Georgia, Athens as keynote speaker. Dr. Dirr will give a presentation on Breeding, Evaluating, Introducing and Marketing New Woody Plants. Professor Dirr has had a long and varied career since he received his Ph.D. in Plant Physiology from the University of Massachusetts, Amherst, in 1972. Before moving to Georgia he held appointments at the University of Massachusetts, the University of Illinois, Urbana, and the Arnold Arboretum of Harvard University.

You will want to mark your calendars now. For more information, go to http://www.mnla.com , http://www.umassgreeninfo.org, or contact UMass Extension’s Landscape, Nursery and Urban Forestry Program at (413) 545-0895, eweeks@umext.umass.edu. Time: 9 AM to 3:00 p.m. Location: UMass Amherst Student Union and Metawampe Park.

IMPORTANT INFORMATIONAL RESOURCES

2006 UMass Extension Green Directory: Now Available! The 2006 UMass Extension Green Directory is a comprehensive guide to educational resources for Massachusetts Agriculture industry professionals. This 25 page guide is used as a reference document all year long! To receive a copy, send mailing address: email greeninfo@umext.umass.edu; fax requests to 413-577-1620. The complete directory is also available online in PDF format. Visit http://www.umass.edu/agland and click 'The Green Directory' link in the right hand menu.

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 .

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

The freshly revised 2006-2007 Professional Guide for IPM in Turf for Massachusetts features the latest techniques critical to environmentally sensitive, integrated management of lawns, athletic fields, and golf courses. The guide, intended for use by professionals, presents research-based material regarding turfgrass selection and water conservation, as well as current approaches for managing disease, insect, weed, and nematode problems. Municipal and school officials charged with establishing IPM programs in their communities and gardeners and homeowners serious about sensibly caring for their properties will find unique and critical information in the guide as well.

The 2006-2007 Professional Guide can be used effectively in a wide range of management schemes: from organic, to low-maintenance, to high-intensity care of high-use turf. Alternative and cultural pest control options are highlighted, and pesticide selection advice is based on least environmental impact. While certain portions of the guide are specific to Massachusetts, much of the information is applicable throughout New England. Initially developed in 1991, this revision for 2006-2007 marks the 8th edition of this popular publication.

To obtain a copy, order online from the Outreach Bookstore (http://umassoutreachbookstore.com); or call the UMass Outreach Bookstore. The phone number is (413) 545-2717. In either case, payment may be made by credit card. Alternatively, you may visit the UMass Outreach Bookstore during normal business hours; Monday through Thursday from 9AM-3PM, closed Friday. The bookstore is located in Draper Hall on the UMass campus.

UMass Extension’s Turf Management Guide and IPM Facts: For more information about the turf pests mentioned in this message, you will need to refer to the following publications: the freshly revised Professional Guide for IPM in Turf for Massachusetts, 2006-2007 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 Monday, May 22, 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.

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 #11 May 12, 2006

DIAGNOSTIC SERVICES

UMass Extension Landscape Message #11
May 12, 2006