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ENVIRONMENTAL
DATA
The statewide GDD averages for this period are as follows: Total = 568; GDD/week = 76; GDD/day = 10.9 REGIONAL
NOTES Southeast Region (Hanson) - General Conditions: Summer is officially here. Hanson received 0.5 inches of rain and unirrigated soils are very dry. Many oaks throughout Plymouth County show signs of defoliation by the winter moth and forest tent caterpillars. Continue to encourage customers to water newly planted trees, shrubs and perennials. Tuliptree, viburnums, beautybush, Kousa dogwood, climbing hydrangea, Rosa rugosa, privet, Spirea, Styrax japonica, Corydalis lutea, Dicentra eximia, Peonies, Campanula, Baptisia sp., Columbine, Geranium sp., foxgloves, Dianthus, Dictamnus, Siberian Iris and early daylilies are in full bloom. Rutgers hybrid dogwoods, Physocarpus, Miss Kim lilac, Chionanthus virginicus, Pulmonaria, Phlox subulata, Trillium and Vinca minor are past bloom. Pests/Problems. The Plymouth County Extension office continues to receive phone calls regarding forest tent, eastern tent and gypsy moth caterpillars many of which are still feeding but many have begun to pupate. Adult moths of the larch casebearer, pieris or andromeda lacebug, arborvitae leafminer adults (small silver-colored moths), aphids, cottony camellia scale on Taxus, fruitworms, carpenter bees, lily leaf beetle (eggs, larvae, adults), mosquitoes, ticks, Asiatic garden beetles, columbine leaf miner, European chafer beetles, June beetles and ladybugs are all active. Sod webworm adult moths are active on turf. Clover is in full bloom. Deer have started to graze hosta. Plymouth County Extension does not spray for mosquitoes. The number to call for Plymouth County residents is 781-585-5450. East Region (Boston) - General Conditions: No report. Central Region (Boylston) - General Conditions: No report. Pioneer Valley Region (Amherst) - General Conditions: The week was cooler with occasional downpours; but when the sun comes out, it is definitely summer! Gardens, turf and woody ornamentals continue to look vigorous and healthy. Soil moisture continues to be adequate where there was rainfall. Berkshire Region (Great Barrington) - General Conditions: Though some turfgrass remains stressed, the rain during the past week has helped the landscape in general to remain lush. Pests/Problems. Large clusters of aphids were seen on the undersides of birch leaves and these aphids were tended to by numerous ants. Warm season spider mites are also abundant. Roseslug sawfly larvae are still active and the usual assortment of leaf eaters on trees and shrubs are present but the damage is minimal. Slugs are abundant in perennial borders. Rust diseases can be found on their alternate hosts but foliar diseases in general are not as prevalent as expected. 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 onslaught of caterpillars is beginning to subside but more and more people are just now beginning to notice the levels of defoliation and have become belatedly concerned. This has drawn the attention of the media and Massachusetts is currently receiving local, regional and nation-wide coverage about our caterpillar situation. The bottom line is that winter moth has finished feeding for the year and is now in the soil under the host plants and beginning pupation. Other caterpillars, such as gypsy moth, forest tent caterpillar, and fall cankerworm continue to feed but the staggered process of pupation is beginning for these pests as well and all will cease feeding within the next two weeks. However, as some of these achieve mature size, they can be voracious feeders and consume large amounts of foliage per day per caterpillar. Caterpillar management now needs to be taken on a case-by-case basis to determine if applied controls are still necessary; in some cases, the answer will still be “yes.” Lepidopteran caterpillars:
Mushrooms in lawns often develop from thatch, buried logs, dead roots, stumps or even construction debris. They have many different sizes, colors, shapes and habits of growth and invade lawns after prolonged wet weather. The fungi that produce these mushrooms are beneficial because they decompose organic matter in the soil, making nutrients available to other plants. These mushrooms usually are harmless to grasses, but some people consider them unsightly or want to get rid of them because young children play in the area. Neither spray applications nor drenches of fungicides are effective in controlling these mushrooms. Remove mushrooms growing from buried wood or roots by picking them as they appear or by digging out the wood. Elimination of excess thatch and aerating the soil to improve water penetration also helps in some cases. In addition, if the mushrooms are left to themselves, they just disappear when the weather becomes dry. Botrytis blight is noticeable as a gray moldy blight of flowers, leaves and shoots in herbaceous perennial gardens, as well as on some young woody plants with dense foliage. Cool temperatures and shaded conditions enhance the damage by this fungus. To manage Botrytis blight, remove dead plant material that the fungus uses as a beachhead for the development of more inoculum. Irrigate before mid-afternoon so needles dry off before nightfall. Consider fungicide applications to protect succulent growth on high value plants from becoming infected. Fungicides labeled include: chlorothalonil, chlorothalonil plus fenarimol, copper sulfate pentahydrate, ferbam, fosetyl-Al, iprodione, mancozeb, thiophanate methyl, triflumizole, thiophanate methyl plus chlorothalonil, thiophanate methyl plus flutolanil and PCNB. Repeat applications at labeled intervals until warm, drier weather prevails and Botrytis blight is less able to infect plants. Cedar-apple rust is visible as orange-yellow spots on susceptible hawthorn, apple and crab apple leaves. By mid-summer tiny yellow-white tube-like fruiting structures will extend from the underside of infected leaves. From mid-summer to autumn, spores are wind-carried from the apple leaves and, when conditions are wet, they infect green shoots and needles of junipers. Pea-sized to two inches diameter round, brown galls develop on susceptible juniper needles and twigs between 12 and 20 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. Fungicide protection of eastern red cedar and Rocky mountain junipers is seldom performed; but if it were desired, it would be from mid-August through September. The minute red-purple spots of hawthorn (Entomosporium) leaf spot are visible on leaves of susceptible hawthorn. Now that the fungus is established, it regularly produces spores; and with recurring wet periods the disease spreads via these secondary infection cycles. A long-term management strategy to consider is replacement of susceptible hawthorns with resistant trees. Otherwise, preventative fungicides must be applied as buds open or when the first rains begin after the leaves start to develop in the spring; these should be repeated at labeled intervals several times until early summer. There is little benefit from chemical controls of this disease when they are started this late in the season. Horsechestnut (Guignardia) leaf blotch is evident as scattered, irregularly-shaped orange-brown blotches on infected leaves. They are primarily affecting lower, inside leaves, and less than 10% of the total leaf area. However, as the summer progresses the impact of the disease may be more noticeable, but chemical intervention at this time for this season is of little benefit. Likewise, it has been noted that horsechestnut that suffer repeated severe infections continue to grow vigorously in spite of Guignardia leaf blotch. Powdery mildew fungi are now visible as a dusty, gray to white spots/blotches on horsechestnut, phlox, dogwood, sycamore and rose leaves in the Amherst area. Once established on plants, powdery mildews grow superficially on both upper and lower leaf surfaces as well as green shoots and flower buds. They are obligate parasites and derive sustenance only from living host plants. They do this using minute, tube-like structures (haustoria) that penetrate the epidermal cells and draw out material they need to survive. Later this summer spherical, black fruiting structures (cleistothecia) will be visible with a hand lens on the underside of leaves in the dusty, gray mycelia. Generally, the damage caused by powdery mildew is of minor consequence to healthy plants and does not warrant chemical control if unsightliness is not a critical concern. If chemical control is desired, there are a number of unconventional applied materials that are labeled to protect susceptible plants. They include summer horticultural oil, commercial baking soda preparations (sodium bicarbonate and potassium bicarbonate), anti-transpirants, as well as a number of conventional fungicides. Chemical spray programs are most effective when begun just as symptoms of powdery mildew begin to show. 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. Oak leaf blister is showing up on red and pin oak leaves as yellow-green to brown blister-like spots. Puckering is minimal but noticeable, if you look closely. This is a not a serious fungal disease problem in Massachusetts. If a severe outbreak is occurring on specimen trees, note that for future reference. Chemical control activities should be started just as buds open next spring. Apple scab is more visible on susceptible crab apple leaves after the warm, humid weather. The heavy, prolonged rainy periods and cool temperatures earlier in the spring suppressed early scab infections. Some leaves are curling or cupping where lesions developed before the leaves were mature, and the dead leaf tissue constricted leaf expansion. Within weeks after infection the olive green fruiting bodies produce new spores. New infections can occur essentially the entire growing season during wet and mild conditions. Now is a favorable time to maintain scab_susceptible crabapples in the landscape in which infection has just begun with fungicides. These fungicides act primarily to prevent new infections, especially those infections that would develop on newly emerging leaves. Systemic fungicides can reduce the incidence of apple scab as the season goes on if they are applied soon, before the extent of infection is too severe, and protection is maintained at labeled intervals. Alternate every second or third systemic fungicide spray with a broad-spectrum fungicide to reduce problems with the development of fungicide resistance by the apple scab fungus. Prune to increase sunlight penetration and air circulation to promote rapid drying of wet foliage. If apple scab is a chronic problem, consider planting resistant varieties of crabapple if replacement is an option. This fall remove and destroy fallen leaves in the vicinity of the tree to reduce primary inoculum available for initial infections next spring. 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 affect an otherwise healthy tree. New flushes of growth are evident on sycamore, sugar maple and white oak that will help fill out the crowns. 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. Dogwood anthracnose is visible as tan spots/blotches with purple margins as well as some shoot blighting. Remove and dispose of dead leaves, twigs and branches to reduce anthracnose inoculum in infected trees. 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. It is too late this spring to protect new shoots and leaves with fungicide applications. Next spring begin as buds break open, when bracts have fallen, and four weeks later. Later this summer after flower buds form, if there is wet weather, a fungicide application may protect the flower buds from infection. If dogwood anthracnose is a persistent problem consider planting one of the many resistant cultivars of Cornus florida and C. kousa now commercially available. 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. The 2005 National Nursery Survey is underway. As of June 10, 30 states have reported survey results; 1,530 nurseries have been visited, 25,288 samples collected and four national survey positives have been confirmed. Georgia reports two positive nurseries and Louisiana reports two. California has found 19 positive nurseries during their Federal Order compliance surveys and annual cleanliness surveys. Oregon has identified three positive nurseries during their Federal Order compliance surveys. Of the 19 nurseries in California found positive through Federal Order compliance surveys and annual cleanliness surveys and the two California nurseries found positive as trace back nurseries, seven were positive in 2004. These seven nurseries went through the Confirmed Nursery Protocol (CNP) and were found to be free of evidence of P. ramorum. The positives found at these nurseries suggest that the CNP could be improved. We asked our Center for Plant Health Science and Technology to review the protocol and to make suggestions to improve it. We have received their suggestions and will incorporate many if not all into a future release of the CNP. The US Forest Service and states are conducting nursery perimeter and general forest detection surveys in 38 states during 2005. As of June 15, USFS reports 74 nursery perimeter surveys in eight states. Two hundred-three samples have been collected; results have not been reported. USFA reports 43 general forest surveys have been conducted in four states; 74 samples have been collected. There are no confirmed positives. 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 June 20 through June 24, 2005:
Reported by Dan Gillman, Plant Pathologist, based in the Urban Forestry Diagnostic Lab at UMass, Amherst, Mass Cultural Practices:
J. Scott Ebdon, Assoc. Professor and Turf Agronomist, Department of Plant, Soil, and Insect Sciences, UMass Amherst 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. 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, July 8, 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 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. 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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Controls are no longer warranted. This pest is no longer in the caterpillar (feeding)
stage.
Note: A new fact
sheet entitled '
,
for current information on this pest. Report any new findings
in MA to Robert Childs, 