Landscape Message - Landscape Nursey and Urban Forestry

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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 months of October through February this newsletter will be updated monthly. The next update will be available on October 5, 2007.

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Interested in additional turf-oriented content? UMass Extension Turf Program Management Updates

REGIONAL NOTES -

Cape Cod Region (Barnstable) - General Conditions: The two rain events that occurred on September 11 and September 15 relieved the extreme dry conditions. Rainfall totals differed greatly from the upper Cape to the lower Cape, with Falmouth receiving 2.4 inches from the two events while Chatham only received 1/8 of an inch. Crisp, cool fall-like weather has moved in, with early morning temperatures in the low 40s F. and afternoon highs in the mid 60s F. Fall maintenance is underway in the landscape. Dahlias, asters, and early mums are providing color. Pests/Problems: Even with the recent rainfall, soils remain dry at a depth of 5 inches. Some unirrigated turf may not recover well from this dry period. A species of armored scale was observed on trumpet vine. Wasps and hornets remain very active and aggressive. Western conifer seed bugs are appearing around screens and windows. Adult deer ticks are becoming active again.

Southeast Region (Hanson) - General Conditions: Hanson received 1.51 inches of much needed rain over the past two weeks, and we could use more. Soils remain dry, and unirrigated plants continue to appear drought stressed. Landscape roses, Hydrangea paniculata, rose-of-sharon, butterflybush, Aster divaricatus, and other fall asters, Sedum sp., Japanese anemones, many ornamental grasses, Corydalis lutea, Nepeta, Heliopsis 'Summer Sun,' Physostegia, Chelone, Rudbeckia 'Herbstonne,' Coreopsis 'Moonbeam,' and Lobelia syphilitica are in full bloom. In some areas Hydrangea macrophylla is still producing blooms. Phlox paniculata and Rudbeckia 'Goldsturm' are ending bloom. The fruit of autumn olive, staghorn sumac, and Viburnum are providing landscape color. Pests/Problems: Premature fall color of many deciduous plants, due to drought stress, is evident. The leaves on some trees are turning brown, and some trees are dropping leaves. Barberry looper was observed on barberry. Earwigs, slugs, mites, snails, lacebugs, ticks, and mosquitoes are all active. Powdery mildew is prevalent on a wide range of plant material. Continue to be on the lookout for ground-nesting wasps as well as wasps nesting in bushes and trees.

East Region (Boston) – Pests/Problems: Rainfall deficit is still apparent.

Metro West (Waltham) – General Conditions: There was a bit of rain, but the soil is still dry. Temperatures are starting to cool off.

Pioneer Valley Region ( Amherst) - General Conditions: The asters, roses, and mums are coming on as the goldenrods fade. Fall colors are becoming more visible on some woody plants such as dogwood, ash, katsuratree, sumac, and poison ivy. There were episode of rain and generally cool conditions during the last two weeks. Pests/Problems: The diseases that stand out now are powdery mildew on sycamore, flowering dogwood, lilac, phlox, and others, as well as giant tar spot on Norway maple

Berkshire Region (Great Barrington) - General Conditions: The drought-like conditions of August and early September came to an end with some ample rainfall. Lawns that had been browning quickly recovered. It is beginning to shape up as a banner year for fall foliage. A light frost was reported in a few areas of the county on the morning of September 17. Three mornings of temperatures in the 30s were recorded this week. Pests/Problems: Pest and disease pressures remain low. Powdery mildew is prominent. Aphids are still visible on certain perennials, particularly milkweed. Wasps and hornets continue in abundance.

The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, September 6, 2007 through September 19, 2007. Soil temperature and phenological indicators were observed on or about September 19, 2007. Accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our instruments from the beginning of the current calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

The phenological indicators are a visual tool for correlating plant development with pest development. The following are the indicator plants and the stages of bloom observed for this period:

CAPE COD REGION - Roberta Clark, Horticulturist for Barnstable County, Barnstable.

SOUTHEAST REGION - Deborah Swanson, Horticulturist for UMass Extension in Plymouth County, Hanson.

EAST REGION - James R. Allen, Horticulturist and Greenhouse Manager for UMass Biology Department, Boston.

METRO WEST REGION – James Martin, Consulting Arborist, reporting from the UMass Extension Center, Waltham.

CENTRAL REGION - Joann Vieira, Superintendent of Horticulture, Tower Hill Botanic Garden, Boylston.

PIONEER VALLEY - Dan Gillman, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass, Amherst.

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

Much needed rain occurred between Saturday night, September 8, through Tuesday, September 11, with most of the state receiving around 1.5 inches on average. However, parts of western Massachusetts received more than 4.0 inches during this time. Up to 0.75 inch of rain fell on Massachusetts during the night of Friday, September 14, into the morning of Saturday, September15. Overall, this is very good news for our drought-stricken trees and shrubs. However, it is not a sudden cure-all. Trees in the eastern region of the state suffered almost three months without rain while western Massachusetts trees went the month of August and into September with little or no rain. Also, trees in eastern Massachusetts experienced defoliation by winter moth, gypsy moth, forest tent caterpillar, eastern tent caterpillar, and/or fall cankerworm earlier in the year. Some of these trees were also defoliated in previous years. This sequential defoliation followed by drought has left many trees dead and dying in those areas. Many of those, especially in Plymouth County, are becoming potential hazard trees.

Lepidoptera:

Mimosa webworm webs are obvious on honeylocust, but it is now too late for treatments.

Fall webworm tents are quite obvious. Feeding by this pest is virtually finished for the year, but the silken webs will remain for months.

Rose-of-Sharon caterpillar (aka hibiscus caterpillar, Anomis commoda) remains active on rose-of-sharon hibiscus. This introduced pest has the potential to completely defoliate this host plant when it occurs in large numbers. Where Japanese beetle tends to create a skeletonizing type of defoliation on this host plant, the rose-of-sharon moth caterpillar consumes leaves in their entirety. Initially, this introduced pest was prevalent on Nantucket and then the coastal areas of mainland Massachusetts. Deborah Swanson of Plymouth County has been reporting its presence there for several years now. In 2006, it was noted for the first time in parts of western Massachusetts (Amherst area). This gray caterpillar will hug the stems of the host plant closely when at rest, which is very cryptic posturing and renders it almost impossible to see when scouting. Inspect for defoliation that is not indicative of Japanese beetle. Then, inspect very slowly and meticulously for the presence of the caterpillars on the stems. Once one is found, it becomes apparent just how difficult they are to find. When this caterpillar is handled, it will thrash wildly in an attempt to escape. Treat infestations with a product that contains spinosad or with one of the registered pyrethroid insecticides. For more information about this pest, refer to the book, Caterpillars of Eastern Forests by Dr. David Wagner, page 371.

Maple webworm is active, mostly on sugar maple. This caterpillar ties several leaves with silk, and its feeding activity shreds the foliage leaving the appearance of a fall webworm tent that was started but abandoned. Many webs may be found per tree. This insect appears sporadically and rarely, if ever, requires treatments of any kind.

Hymenoptera:

Red-headed pine sawfly is active. In Massachusetts it prefers mugo pines but can be found on other pines as well. Inspect for the very visible clusters of yellow caterpillars with black spots and rust-colored head capsules. Treat with a product that contains spinosad or with one of the registered pyrethroid insecticides. Insecticidal soap sprays are also effective but mostly when the caterpillars are still quite small. This pest can feed well into October if warm conditions prevail.

Dogwood sawfly is active. This yellow hymenopteran caterpillar with black spots often has its body covered with a thick white pubescence. As the caterpillar rests on the foliage in a curled position, its presence resembles that of a bird dropping. It consumes most of the foliage down to the mid vein of each leaf. It is mostly common on Cornus sericea (Redosier Dogwood) and C. sericea 'Flaviramea' (Yellow Twig Dogwood) and gray dogwood but can be found feeding on others. If necessary, treat with a pyrethroid insecticide or with a product that contains spinosad.

Coleoptera:

Viburnum leaf beetle adults have ceased their activity for this year. Adult female beetles laid eggs back in July, and the pest will not resume activity until next spring. Several reports of this pest being active in very western Massachusetts ( Berkshire County) were received this year. It finally looks like viburnum leaf beetle has become established in Massachusetts. Inspect for damaged foliage and especially for bare twigs that feel rough, like that of sandpaper; these are egg-laying sites. Report any finds of this pest to Bob Childs at UMass Amherst (413-545-1053 or rchilds@psis.umass.edu). For more information about this pest and to view high-quality photographs, visit the following Cornell University web site at http://www.hort.cornell.edu/vlb

Piercing-Sucking Pests:

Tuliptree scale is very active on tuliptree. This large scale is easily seen clustered together along smaller stems. It also produces copious amounts of honeydew, which, of course, encourages much sooty mold. This is a tough pest to manage.

Borers:

Shoot-killing bark beetles on white pine - (there is no common name for this bark beetle). This year in much of Massachusetts and also in many areas throughout New England, especially Maine, we have been seeing white pines with randomly scattered dead tips. These “brown flags” are obvious and give the initial impression of a severe problem. This shoot-inhabiting bark beetle was first noticed about fifteen years ago in Massachusetts. It was quite prevalent for a few years, but then it almost vanished until this year when we are seeing it statewide. Maine is also reporting more incidences of it this year, as well. Massachusetts Department of Conservation and Recreation (MDCR) has keyed it out to being in the genus, Pityophthorus. However, the exact species is not known; it could possibly be LeConte. The United States Forest Service (USFS) publication, “Insects of Eastern Forests” (Publication #1426, pg. 363, December 1985) describes the genus as having more than 100 species in North America. Drought may play a role when we see larger numbers of them. Thus far, no one has had to treat for this insect. It is viewed as being an occasional curiosity.

Miscellaneous:

Western conifer seedbug is a common house invader in the fall and is very active right now on various conifers. Although causing no injury to our conifers, it has the potential to become a serious nuisance pest in October as it invades homes.

DISEASES -

Continue to apply fungicide treatments to manage black spot on high value roses and repeat the applications per label directions into the fall. It is also beneficial to remove severely infected canes and foliage. Provide good air circulation and irrigate early in the day to minimize the period of plant wetness to further suppress the disease. If the problem persists, gradually replace susceptible varieties of roses with those resistant to black spot and powdery mildew to reduce the maintenance needs.

Ramorum blight , also known as sudden oak death (SOD) and ramorum dieback. Since 1995, oaks and tanoaks have been dying in the coastal counties of California. Since then, surveys found other plants infected or associated with this disease caused by the water mold Phytophthora ramorum . Researchers in the U. S. first isolated the pathogen in Mill Valley ( Marin County) on tanoak, but since that time additional surveys confirmed the pathogen on various native hosts in fourteen coastal California counties and in Curry County, Oregon. Through ongoing surveys of nurseries, USDA-APHIS-PPQ continues to define the extent of the pathogen’s distribution in the U. S. and limit its artificial spread beyond infected areas through quarantine and a public education program.

Status of Phytophthora ramorum in 2007:

Forest Detection Survey - As of August 24, the United States Forest Service (USFS) reported 151 streams baited in 28 states with 772 samples collected. Thirty-five streams tested positive for Phytophthora ramorum during the water baiting survey, one in Washington, one in Mississippi; and 33 in California.

Federal Regulation, State Inspection, Nursery Survey, and Other Finds - As of August 29, there have been 19 positive nursery finds of Phytophthora ramorum so far. The states with these detections include California, Oregon, Washington, Florida, Georgia, Mississippi, and Pennsylvania.

Reported by Dan Gillman, Plant Pathologist, UMass Extension Plant Diagnostic Lab, Amherst

WEEDS -

DIAGNOSTIC SERVICES

UMass Laboratory Diagnoses Turf and Landscape Problems - Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Send specimens and payment (payable to the University of Massachusetts) to UMass Extension Plant Diagnostic Lab, Holdsworth Natural Resources Center, 160 Holdsworth Way, UMass, Amherst, MA 01003. The fee for a woody plant disease analysis is $50; the fee for turf disease analysis or nematode assay is $75. All insect, weed and turfgrass identification samples are $25 each. For more detailed submission instructions see http://www.umass.edu/agland/diagnostics

This message is produced by the UMASS Extension, Landscape, Nursery and Urban Forestry Program. The copy is prepared by 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.

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 #24 September 21, 2007

DIAGNOSTIC SERVICES

UMass Extension Landscape Message #24
September 21, 2007