UMass Extension Landscape Message #25
October 6, 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. During the period November to February, this newsletter will be updated monthly. The next update will be available in early November. 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, September 23, 2006 through October 4, 2006. Soil temperature and phenological indicators were observed on October 4, 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: Lovely fall weather continues to predominate, with scattered rain events giving landscape plants sufficient moisture. Red maple (Acer rubrum) and Tupelo are beginning to show fall color, and chrysanthemums brighten up the landscape. Nippon daisies are in bloom. Pests/Problems: The usual fall invaders are beginning to show up. Western conifer seed bug is moving indoors, and wasp colonies are a bit aggressive. Mushrooms are popping up in lawns, and adult deer ticks are active.

Southeast Region (Hanson) - General Conditions: Hanson received one inch of rain. Aster divaricatus and other fall asters, Sedum sp., Japanese anemones, landscape roses, many ornamental grasses, Corydalis lutea, Phlox paniculata, and goldenrod are in full bloom. Heptacodium miconoides, Hydrangea paniculata, rose-of-Sharon, butterflybush, Lobelia syphilitica, Lobelia hybrids, and hosta are ending bloom. The red fruits of many plants are adding color to the landscape including Kousa dogwood, cotoneaster, Viburnum trilobum, staghorn sumac, and hollies. Fall color has started to show up on red maples. Pests/Problems: Wasps, earwigs, slugs, snails, and ticks are all active. Powdery mildew continues to be prevalent on a wide range of plant material. Tar spot is showing up on Norway maple. Many oaks throughout the county are in decline or dead. Many of these trees started to show brown leaves after the extreme heat and dry soils this past August. Inspection of many of these trees in SE Massachusetts shows evidence of flat-headed borers which often appear when trees are in severe stress or decline. Driving through the county, many of these dead trees can be observed along roadways and may pose a threat to passing motorists and pedestrians. Some Plymouth County towns have a hazard tree removal program and are busy marking trees for take down before they pose a possible problem this winter due to winter storms.

East Region (Boston) - General Conditions: No report.

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

Pioneer Valley Region (Amherst) - General Conditions: It is a colorful time in the Valley! Fall color on the ash, maples, hickory, and oak arrives a little more each morning. There is plenty of annual leaf and needle color on many broadleaved and needled evergreens, too. Then, there are the asters, mums, marigolds, roses, and even a few blossoms on the rose-of Sharon. Pests/Problems: Maple anthracnose is browning a few of the leaves, too. There is still plenty of color, but the brown blotches on the sugar and Norway (tar spot here, too) maples are even more conspicuous as the leaves change color.

Berkshire Region (Great Barrington) - General Conditions: Frost has eluded much of the County though a few locations at higher elevations and in the northern parts of Berkshire County have been touched by frost. With occasional rains, soil moisture levels have remained high, and plants should be in good shape going into winter. Mushrooms in lawns and gardens and the natural landscape are a common sight. Pests/Problems: Premature leaf drop caused by a variety of foliar diseases has left many trees already defoliated. Fall foliage color on other trees is good for the most part. On warm days, wasps and a few mosquitoes are still a nuisance.

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, UMass Extension Plant Diagnostic Lab, UMass, Amherst.

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

WOODY ORNAMENTALS

INSECTS

The warm and sunny days continues to drive lacebugs and warm-season spider mite populations. Infested plants in sunnier locations are experiencing greater injury, overall. A few late season caterpillars remain active on fairly specific host plants while the handful of nuisance household invaders are about to become obvious.

Lepidopteran Caterpillars (moths) :

• Fall webworm - the webs are now fully formed, and only a few stragglers remain in the webs. Chances are that these are parasitized individuals and will linger in the webs but no longer feed on foliage. Unsightly webs may be pruned out, but treatments are no longer feasible.

Hymenopteran Caterpillars (Sawflies):

• Red-headed pine sawfly - this yellow caterpillar with black spots and a rust-colored head capsule is now active. Treat young larvae with an insecticidal soap spray or treat caterpillars of all ages with a product that contains spinosad. This pest can be active into October and is capable of creating much late-season defoliation on pines, especially mugo.
  
• Dogwood Sawfly - This yellow caterpillar with black spots is usually covered with a dense white pubescence that gives it the appearance of a bird dropping. Larger populations that go untreated can cause much defoliation. When found in considerable numbers, treat with a spinosad product.
  
• Hibiscus sawfly remains very active and is causing much skeletonizing of host plant foliage. Inspect for ‘lacy’ foliage, and then look more closely for the rather small and pale green caterpillars. Treat with a product that contains spinosad.

Beetles:

• Viburnum Leaf Beetle - Adult beetles are no longer active. Look for eggs along the bare twigs that result in a ‘sandpaper’ texture. Visit the Cornell web site at http://www.hort.cornell.edu/vlb/index.html for current information on this pest.
  
• Japanese Beetle - Adult activity is virtually over for this year.

Piercing-Sucking Pests:

• Hemlock Woolly Adelgid (HWA) - This pest remains in its summer dormancy, and the tiny nymphs are settled along the stems at the base of the needles. Feeding will cease until mid-October. Horticultural oils can still be applied at the summer rate when the correct weather conditions prevail; avoid very hot and humid days for oil applications.
  
• Andromeda lacebug remains extremely active. Inspect leaf undersides of Japanese andromeda for the activity of this pest. Treat the plant with a soil-applied systemic treatment of imidacloprid, or spray the leaf undersides with an insecticidal soap. Pyrethroid insecticides are also labeled for this pest.
  
• Azalea lacebug remains extremely active. Plants that are in sunnier locations can be severely damaged by this pest. (See Andromeda Lacebug above for recommendations.) Untreated plants in sunny locations can have foliage with a bleached appearance by mid to late August.

Spider Mites:

• Inspect the needles and stems of conifers now for injury from spruce spider mite. Now that the hot and humid weather has been here for a while, this pest remains in its summer dormancy but will return by the end of August and can be active well into the fall. Horticultural oil sprays (at the summer rate) can be effective once they return to feed on the plant.
  
• Two-spotted spider mite (one of the warm-season mites) is now very active on a wide range of host plants. Warm season mites prefer, and thrive, during hot weather. Their rate of development is greatly accelerated by the heat; and at the same time, predatory mites often leave the host plant and go into summer dormancy in the leaf litter or mulch. This gives spider mite populations the potential to explode in numbers and to create much plant injury in a short amount of time. Continue to monitor on a regular basis, and treat increasing populations before they become too large. Horticultural oil sprays used at the summer rate can be quite effective, as are the new mite growth regulator products. Avoid the overuse of chemical pesticides; spider mites are quite adept at developing pesticide resistance.

Scale Insects:

Armored Scales:

• A group of scale insects characterized by a hard, convex covering over their bodies, such as pine needle scale, euonymus scale, juniper scale, and white prunicola scale can be monitored now using a piece of black electrical tape that has been repeatedly daubed on the stems; the tiny euonymus scale crawlers will appear as orange spots on the tape. Treat with a horticultural oil spray (summer rate) when plant phenology and correct weather conditions prevail.

Soft Scales:

• Cottony camellia scale (aka. cottony taxus scale) remains active. Inspect leaf undersides for the nymphs. Females, when present, are tan-colored and round with an elongate and white egg sac attached to their covering. When they are present in large numbers, this pest can greatly diminish plant growth and also be responsible for much unwanted sooty mold.

Leaf Miners:

• Locust leafminer remains extremely active. Black locusts in most locations now appear as if swept by fire from this pest’s feeding. Nothing can be done now.

Wood Borers:

• Dogwood Borer - The adult moths remain active. Pheromone traps are available for this pest. Keep flowering dogwood free of wounds from mowers and line trimmers, which encourage invasion by this insect. Treat infested trees in August and early September with a trunk/branch spray of entomopathogenic (beneficial) nematodes.

• Rhododendron borer - This is another clear-winged moth caterpillar that is a wood borer and a close relative to the dogwood borer (Sesiidae Family). Inspect around the base of rhododendrons, on the ground, for coarse sawdust that has been expelled by the caterpillar boring in the shoot. Physically prune out and destroy infested shoots or use a coarse spray of entomopathogenic nematodes.

Nuisance Pests:

• Boxelder bug will soon be leaving its preferred host, female boxelder, where it feeds primarily on the seeds, and will seek shelter in protected areas, such as your house. When infested trees grow within close proximity to homes, thousands of these black bugs with red markings will cluster on the sides of homes.
  
• Birch catkin bug is still active and feeding on seeds of birch. These very small and tan-colored bugs also can be a nuisance when infested plants are close to homes or other often utilized buildings.
  
• Western conifer seed bug , which has been feeding mostly on seeds of conifers all summer, will soon seek shelter, often in homes. These bugs are rather large (approximately 3/4"), dark in color and rather slow movers. They emit a foul-smelling odor when handled.
  
• Asian ladybird beetle (ladybugs) will seek winter shelter within the next month, depending on the weather. These dull-orange-colored beetles have between zero and nineteen black spots and can invade by the thousands. Although very beneficial through much of the growing season by feeding on scale insects and aphids, they become a horrific nuisance when they invade houses. When handled, this insect exudes an orange colored liquid that is not only noxious, it can stain fabrics and other surfaces.
  
• Management of House Invaders- the following are guidelines for management of insects that seek shelter indoors for the winter:

  • inspect and fix all caulking around windows, doors, and attic vents.
  • repair all screening.
  • repair loose siding that may act as entry points.
  • once they are inside, vacuum up the invaders; then remove the bag from the cleaner and place outside. Otherwise, they will crawl out of the vacuum and re-invade the house.
  • bug bomb type treatments can be utilized; but if the above precautions are utilized, these pests will be prevented from invading in the first place.

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

Cedar-apple rust is visible as orange-yellow-brown spots on susceptible hawthorn, apple, and crab apple leaves. Tiny needle-like fruiting structures extend from the spotted areas on the underside of leaves. From mid-summer to autumn, spores are wind-carried from the infected leaves and twigs of rosaceous hosts, to infect wet green shoots and needles of junipers. Pea-sized to 2” diameter round, brown galls develop on susceptible juniper needles and twigs between twelve and twenty months after infection. The best long-term approach to manage this disease is to grow cedar-apple rust resistant apple and juniper varieties. Also, prune dormant galls on juniper during the summer, fall, winter, and early spring (before jelly-like horns form). Avoid growing susceptible junipers close to apples. The time to apply fungicides to protect high value apples from cedar-apple rust has passed for this spring. If desired, apply fungicides to protect high value eastern red cedar and Rocky Mountain junipers from August through September.

Horsechestnut (Guignardia) leaf blotch is visible as irregular-shaped orange-brown blotches and causes early loss of infected leaves. As the summer progressed, the impact of the disease became more noticeable. Collect and dispose of fallen leaves to reduce the amount of Guignardia inoculum that provide spores for new infections next spring. Keep in mind that horsechestnut infected year after year continue to grow vigorously in spite of Guignardia leaf blotch.

Powdery mildew fungi are evident as dusty, gray to white spots on a number of plants including horsechestnut, dogwood, Norway maple, sycamore, phlox, lilac, and rose leaves. Once established on plants, powdery mildews grow superficially on both upper and lower leaf surfaces as well as green shoots and flower buds. Later this summer spherical, black fruiting structures are visible with a hand lens on the underside of leaves in the dusty, gray mycelial masses. Generally, the damage caused by powdery mildew is of minor consequence to healthy woody plants and does not warrant chemical control if unsightliness is not a critical concern. If considering chemical control next season they are most effective when begun just as symptoms of powdery mildew begin to show in late May or June. Once powdery mildew is extensive on the plant, there is little benefit from chemical control that season. Applications need to coat both surfaces of all susceptible plant parts to prevent infection. Spray on a regular schedule, and repeat more often during warm, humid weather.

Black spot on rose can be ugly and destructive to highly susceptible plants. Black, rounded spots develop on infected leaves and rose hips. Infected first year canes have lesions that are reddish colored initially and then turn black. Black, pin_head sized fruiting structures develop in the center of the spots. Repeated black spot infection cycles will occur during wet periods throughout the remainder of the growing season. Eventually, spotted leaves turn yellow and drop off prematurely. Plants that sustain considerable leaf loss fail to thrive and are more prone to winter damage. Remove and dispose of infected leaves and canes. Avoid wetting foliage during irrigation because the longer the foliage and canes are wet the more time for black spot spores to germinate and infect the plant. Apply fungicide sprays at intervals specified on the label to reduce infection of healthy foliage and canes. If replacement is an option, many beautiful, resistant varieties are available.

Tar spot on maple is especially obvious on Norway maple leaves as black, tar-like fruiting structures grow in size within rounded, yellow-tan leaf spots. Spores from the fungus, Rhytisma, infected the developing leaves last spring when there were extended periods of mild, wet weather. This provided optimal conditions for the Rhytisma fungus to infect the leaves. Tar spot infections do not threaten the fitness of an otherwise healthy tree. Most of the leaf area remained green throughout the summer so the tree had plenty of leaf area to photosynthesize and produce what it needs to thrive. Reduce the potential for next year’s infections by collecting and disposing of diseased leaves as they fall. This reduces the amount of inoculum available when conditions are cool and moist next spring and the fungus spores can infect young maple leaves. Applications of protective fungicides are unnecessary except to preserve the appearance of high value trees.

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 2006 Monitoring Surveys:

New Hosts Added. APHIS will be regulating eight new species, effective October 1, 2006. This action is necessary as we have learned that Castanopsis orthacantha, Cornus kousa x Cornus capitata, Distylium myricoides, Eucalyptus haemastoma, Ilex purpurea, Loropetalum chinense, Manglietia insignis, and Parakmeria lotungensis can be infected by P. ramorum and need to be regulated in order to control the artificial spread of this disease. The list, “Plants Associated with Phytophthora ramorum” now includes these new plant taxa. With the completion of their Koch’s postulates assessment, the list, “Proven Hosts Regulated for Phytophthora ramorum” has four recent additions including: Acer pseudoplatanus, Aesculus hippocastanum, Laurus nobilis, and Michelia doltsopa.

Federal Order, State Inspection, National Survey, and Other Finds. The Federal Order, State Inspection, National Survey, and/or other detections identified 57 positive sites in 10 states.

National Nursery Survey. As of September 7, the forty-six participating states reported on their National Nursery Survey results. Inspectors visited 3,514 nurseries and collected 95,257 samples. Lab evaluation confirmed that 351 of the samples collected were positive for infection by P. ramorum.

Forest Detection Survey. The United States Forest Service (USFS) and States are conducting nursery perimeter and general forest detection surveys. As of August 28, USFS reports 567 nursery perimeter surveys in 29 states with 1498 samples collected. USFS also conducted 320 general forest surveys in 29 states, with 765 samples collected.

Maine State Officials Seek Homeowners' Help to Locate Possibly Diseased Lilac Plants August 11, 2006. Officials with the Maine Department of Agriculture and the Maine Department of Conservation, has discovered Phytophthora ramorum in Maine. They have been surveying nursery, garden centers, and urban forest sites for the past three years in an effort to assure that P. ramorum does not establish a foothold in Maine. In all, more than 70 horticultural businesses and 25 urban sites have been surveyed and hundreds of plant segments have been sent to laboratories for testing. To date, there is no indication that this disease has become established in Maine.

In June 2006, plant health officials in Maine were notified that plants at an Oregon nursery had tested positive for the disease and shipped plant material to locations in Maine. The shipments occurred in late April. The garden centers that received the plants were inspected, and one plant sample tested positive for the disease. The garden center staff has cooperated fully with state officials and all affected plant material remaining at the garden centers has been destroyed.

State plant health officials are currently trying to locate thirteen lilac plants purchased only from Agway Garden Centers in Winslow, Skowhegan, or Farmingdale earlier this year before the state was notified about the potential problem. The affected plants are one variety of common lilac, ‘Ludwig Spaethii’. In flower, the blossoms are a deep reddish-purple. Anyone who may know the location of these plants is urged to contact the Maine Department of Agriculture at (207) 287-3891. Sudden Oak Death is able to spread among a wide variety of plants and could have economic consequences for Maine’s horticulture and forestry industries.

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

WEEDS

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

TURFGRASS

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

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

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

Lyme Disease Diagnostics - UMass Extension, in cooperation with researchers at UMass Amherst, will assess deer ticks for the presence of Lyme Disease. There is a fee of $35 per sample. To submit a sample, follow the directions at the UMass Extension tick diagnostics website at http://www.umass.edu/agland/diagnostics/lyme_disease.htm (or Google: UMass Extension Tick). After submission, results will be reported within 10 business days. Be advised: If someone has been infected by a tick bite, symptoms may begin to occur even before the results of tick testing are available. People should not wait for tick testing results before seeking medical advice should any symptoms develop. For specific information, contact: Dr. Craig Hollingsworth, (413) 545-1055, chollingsworth@umext.umass.edu.

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NEXT UPDATE: The next issue will be available in early November.

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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