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UMass Extension Landscape Message #22
September 3, 2010
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. This issue has been updated to provide timely pest management information and the latest regional news and environmental data throughout Massachusetts.
The message will be updated bi-weekly throughout the months of August and September. The next update will be available on or about September 17, 2010.
SCOUTING INFORMATION BY REGION
REGIONAL NOTES -
Cape
Cod Region (Barnstable) – General
Conditions: The Cape continues on a hot and dry path in spite of approximately 2.5” of rain that fell over the two week period. Some part of the outer Cape reported higher amounts - up to 5” in Orleans. All eyes are on Hurricane Earl, which should approach the Cape and Islands late Friday night of the Labor Day weekend. Pests/Problems: Typical late season problems are here. Lots of powdery mildew on anything that is susceptible. Many trees, shrubs, and perennials are exhibiting signs of drought stress. Most of the insect pests in the landscape have come and gone and it is time to start the fall clean up.
Southeast Region (Hanson) – General Conditions: Hanson received 6.6 inches of much needed rain over the past two weeks. More rain is expected this Friday from Hurricane Earl which is reportedly coming close to SE Mass. Despite the rain, many plants continue to exhibit signs of drought stress as evidenced by premature leaf drop and early fall color. More rain is needed. Many unirrigated lawns look to be in bad shape. Temperatures continue in the high 80’s and low 90’s. Rose-of Sharon, landscape roses, Hibiscus ‘Copper King’ and other perennial hibiscus, Clerodendron trichotomum, Hydrangea paniculata, butterflybush, Caryopteris sp., Sedum sp., many ornamental grasses, Rudbeckia trilobum, Perovskia atriplicifolia (Russian Sage), Corydalis lutea, Rudbeckia fulgida ‘Goldsturm,’ Physostegia, Chelone, Coreopsis ‘Harvest Moon’, goldenrod, Hosta plantaginea and other late blooming Hosta , Joe-pye-weed, and Lobelia syphilitica are in full bloom. The fruit of autumn olive (invasive), crabapple, Staghorn sumac, Kousa dogwood, and Viburnum are also providing landscape color. Pests/Problems: Dogwood sawfly, earwigs, slugs, aphids, mites, snails, lacebugs, ticks, deer flies and mosquitoes are all active. Be on the lookout for ground-nesting wasps as well as wasps nesting in bushes and trees. Deer are browsing and reports have come in of increased vole, chipmunk, field mice and squirrel activity. It appears to be a good year for rodents. Powdery mildew continues to be found on a wide range of plant material. Giant tar spot is showing up on Norway maple. Leaf blotch of horse chestnut, caused by the fungus Guignardia aesculi, is rampant . This is a common disease which causes the leaves to turn brown. Poison ivy is having a great year along with crabgrass and other weeds. Goldenrod and ragweed are in bloom. Pollen from ragweed may cause allergies in some people, but goldenrod is often mistakenly blamed. Remind clients, that if they prune spring flowering shrubs now (lilac, rhododendron, forsythia, azalea, etc.) that they will most likely reduce the number of flowers next spring. Also, remind clients to continue to water landscape plants that were planted this season or plants that were damaged by winter moth caterpillars.
East Region (Boston) – General Conditions: We received 6.03 inches of rain between the 22nd and 25th of August while the Blue Hills Observatory (BHO) recorded 7.3 inches of rain during this same period. For the BHO, this was the second greatest single rainfall event for the month of August since 1955 when they received 12.77 inches of rain. Despite this event last week, the soil has dried considerably due to the 5 day heat wave with temperatures reaching over 90 °F. Vines in bloom include: Bignonia capreolata, Campsis [C. radicans (Trumpet creeper), C. grandiflora (Chinese Trumpet Vine), C. x tagliabuana], Clematis [C. maximowicziana (Sweet Autumn Clematis), C. vitalba (Pilgrim's Clematis)], Cocculus trilobus (Japanese Snailseed), Lonicera [L. x heckrotti (Everblooming Honeysuckle), L. periclymenum (Woodbine Honeysuckle), L. sempervirens (Trumpet Honeysuckle)] and Wisteria macrostachya ‘Blue Moon’ (Wisteria). Shrubs in bloom include: Callicarpa kwangtungensis (Chinese Beautyberry), Calluna vulgaris (Scotch Heather), Calycanthus sp. (Sweetshrub), Caryopteris x clandonensis (Bluebeard), Ceanothus x pallidus, Clematis heracleifolia var. davidiana (Hyacinth-flower Clematis), Clerodendrum trichotomum (Harlequin Glorybower), Daphne x transatlantica (Daphne), Elsholtzia stauntonii (Mint Shrub), Erica vagans (Cornish Heath), Hydrangea [H. arborescens (Smooth Hydrangea), H. quercifolia (Oakleaf Hydrangea)], Indigofera [I. kirilowii (Kirilow Indigo), I. pseudotinctoria (Indigo)], Kerria japonica (Japanese Kerria), Lavandula angustifolia (English Lavender), Lespedeza bicolor (Shrub Bushclover), X Phylliopsis ‘Sugar Plum’ , Rhus [R. chinensis (Chinese Sumac), Rhus copallina (Shining Sumac)], Viburnum [V. plicatum f. tomentosum (Doublefile Viburnum), V. sargentii ‘Onondaga’ (Sargent Cranberry Bush)], and Wikstroemia trichotoma (Wikstroemia). Aconitum sinomontanum (Monkshood) is blooming as the late flowering Koelreuteria paniculata (Golden Rain Tree) continues to hold its blossoms. Pests/Problems: Weeds continue to flourish thanks to the 4 days of rain followed by 5 days of heat. Weeds in bloom include: Aster pilosus, now Symphyotrichum pilosum (Wood Aster), Cyperus esculentus (Yellow Nutsedge), Oxalis stricta (Yellow Wood Sorrel), Taraxacum officinale (Common Dandelion). A white glaucous caterpillar has been spotted defoliating various dogwoods including Cornus alba. New plantings continue to show signs of water stress.
Metro West (Waltham) – General Conditions: Total rainfall for the month of August was 3.79”, which exceeded the historical rainfall average of 3.54” for the month. A good amount of that rain, 3.54” fell within a four day period falling beginning on August 22nd and ending on the 25th. Eight days were recorded for the month of August with temperatures into the 90’s. The highest temperature of 95° was recorded on the last day of the month. The coolest temperature for the month was recorded on the 28th with a low of 49°. Foliage has begun to turn on some trees such as Acers (Maples) and Nyssas (Tupelos). Pests/Problems: Continue to monitor soil moisture and continue to scout for the Asian Longhorned Beetle because it is still active!
Central
Region (Boylston) – General
Conditions: Three days of cooler temperatures and gentle rains last week provided short relief from the hot dry conditions - which have now returned. Soils are dry once again, and lawns are beginning to show drought stress again. Many trees and shrubs are taking on fall foliage hues prematurely and/or dropping leaves.
Pests/Problems: Fall Webworm is abundant.
Pioneer Valley Region (Amherst) - General Conditions: During the last two weeks, the Pioneer Valley had variable weather from cool and cloudy with occasional drizzle to hot, dry and another heat wave. Now Hurricane Earl on its way to cool things down again and possibly bring rainfall by the end of the week. Soil conditions are very dry. Soaking irrigations of recently transplanted woody plants can be critical to their survival. In addition, a cooling 2-3 inch layer of composted mulch over their root zone is helpful to retain soil moisture.
Berkshire Region (Great Barrington) - General Conditions: Hot, humid, and dry weather continue to characterize this year’s growing season. Despite occasional downpours, soils remain very dry since showers tend to be brief and with so much volume that most precipitation runs off soil surfaces rather than infiltrating the soil. Even where soils do absorb some moisture it quickly evaporates with the persistent hot weather and wind. However, conditions may change soon in the wake of hurricane Earl and a cold front moving in from the northwest. Pests/Problems: Premature fall color and leaf drop is still an issue for many trees and shrubs. Wasps are at their peak population and most aggressive state at this time of year. Caution is advised when working outdoors. Leaf tiers continue to be active on many plants, woody and herbaceous. Powdery mildew is the prominent disease in the landscape though leaf spot infections are very apparent. Though direct pest and disease control is not warranted in most cases this late in the season, landscape managers should still take note of these in order to plan control measures next spring. Examine landscape plants now and identify damage from specific diseases and pests. Many should be obvious, e.g. white pine weevil damage to leaders on pines and spruce, spruce gall caused by adelgids, stippling on needled evergreens and other plants caused by spider mites, leaf spots, botrytis, and powdery mildew. Where diseases have occurred, management begins now with good sanitation.
ENVIRONMENTAL DATA -
The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, August 19 through September 1, 2010. Soil temperature and phenological indicators were observed on or about September 1, 2010. 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.
Region/Location |
2010 GROWING DEGREE DAYS
|
Soil
Temp (°F at 4" depth) |
Precipitation 1-Week Gain) |
|
1-Week
Gain |
Total
accumulation for 2010 |
|||
Cape Cod |
274 |
2495 |
82° |
2.50” |
Southeast |
242 |
2469 |
84° |
6.60” |
East |
303 |
2707 |
86° |
6.03” |
Metro West
|
276 |
2521 |
72° |
3.54” |
Central |
n/a |
2448 |
75° |
2.96” |
Pioneer Valley |
241 |
2450 |
76° |
0.10” |
Berkshires |
241 |
2285 |
70° |
1.51” |
AVERAGE |
263 |
2482 |
78° |
3.32” |
n/a = information not available |
||||
ENVIRONMENTAL DATA -
Indicator Plants - Stages of Flowering (begin, b/full, full, f/end, end) |
|||||||
PLANT NAME (Botanic/Common) |
CAPE |
SOUTH EAST |
EAST |
METRO W. |
CENT. |
P.V. |
BERK. |
|
 |
||||||
Heptacodium micinioides (Seven-Son Flower) |
begin |
begin |
begin |
begin |
begin |
* |
* |
Clematis paniculata (Sweet Autumn Clematis) |
begin |
begin |
begin |
b/full |
end |
* |
begin |
Polygonum cuspidatum (Japanese Knotweed) |
f/end |
full |
b/full |
begin |
b/full |
full |
full |
Sophora japonica (Japanese Pagodatree) |
end |
* |
end |
b/full |
end |
end |
* |
* = no
activity to report/information not available |
|||||||
METRO WEST REGION – Julie Coop, Horticulturist, reporting from the UMass Extension Center, Waltham.
WOODY ORNAMENTALS
INSECTS -
Asian Longhorned Beetle - With approximately 25,000 trees having been surveyed within the epicenter of the initial find of ALB in Jamaica Plain and no new finds of ALB being detected, survey work there is now being scaled back. Thus far, only 6 red maples at Faulkner Hospital, which were quickly removed and destroyed on July 6th, 2010 have been the only positive finds in that Regulated Area. In the Worcester Regulated Area, survey work and removal of infested trees continues.
"It is extremely important that we get the word out ASAP to everyone in the Boston, Brookline and Newton area to be on the lookout for:
Asian longhorned beetle adults are now in the peak of their activity cycle. Be consciously looking for this insect, new exit holes, sawdust, and egg-laying sites. Report ASAP if found. August is ALB Awareness Month! |
Viburnum leaf beetle - The adult beetles remain very active. Adult beetles are capable of defoliating host plants. Treat adult beetles with a labeled pyrethroid or organophosphate insecticide when they appear.
Japanese beetle adults remain active but their numbers are waning.
Fall Webworm caterpillars have finished their feeding activity.
Mimosa Webworm remains active and tying together the foliage of honeylocust, primarily. This caterpillar will feed into the fall by using silk to make loose ‘pouches of leaflets’, which it then skeletonizes. If population size is large, entire trees can appear ‘bronzed’ by late August into September from the dead foliage. If necessary, treat with a product that contains Spinosad. However, most damage from this pest has already occurred.
Rose of Sharon Moth (aka: Hibiscus caterpillar) (Anomis commoda) remains actively feeding, especially on Rose of Sharon. This caterpillar is cryptically colored and often rests with its body pressed against and parallel to the stems. If foliage displays large notches of feeding damage (don’t confuse with the skeletonizing of Japanese beetle) then inspect very carefully for this caterpillar, which is hard to find. If touched or handled, this caterpillar will thrash wildly but is harmless. Large populations are capable of completely defoliating plants. If necessary, treat with a product that contains Spinosad or with one of the registered pyrethoid insecticides.
Red-headed Pine Sawfly larvae are active. These yellow larvae have black spots
and a rust-colored head capsule. They feed in clusters, typical of most of the pine sawfly species. If temperatures remain mild, this pest can feed well into October and cause much defoliation damage. Treat larvae with a product that contains Spinosad.
Dogwood Sawfly is very active. This larva is yellow with black spots but it is usually covered with a white pubescence that makes it resemble a bird-dropping on the foliage and stems of host plants. This pest feeds through September and can create much damage. Treat with a product that contains Spinosad.
Pearslug Sawfly remains active on such hosts as cotoneaster and ornamental plum, among others. The larvae are a shiny, black color and resemble slugs. This pest sits on top of the foliage and scrapes away leaf tissue. Large populations are capable of causing most of the foliage of the host plant to appear bronzed as if killed by fire. This insect will feed well into September. Treat with a product that contains Spinosad.
Hemlock Woolly Adelgid remains dormant as nymphs settled on the small stems. Horticultural oil sprays can still be applied but manufacturers warn to avoid treatments on days where the temperatures are above 85-90 degrees. Applications of systemic imidacloprid is effective, as well, but soil applications may take 2-3 months before they are fully systemic within a large tree. Also, avoid applications while the weather is hot and dry. Feeding will resume in mid-October.
Tuliptree Scale females are feeding and maturing on the stems and branches of tuliptree and magnolia. Currently, they are about ½” long, oval, covered with a light white pubescence with the body beneath being a light pink color. Heavily infested trees will have problems with sooty molds and will be attractive to large numbers of hymenoptera (ants, bees, wasps) interested in feeding on the honeydew exuded by the scale insects. Systemic applications of an Imidacloprid product may be warranted for large populations. This scale has one ladybug predator that resembles a mealybug in its larval stage. It is not uncommon to find these mixed in with the scale populations on magnolia and tuliptree. Do not confuse these beneficial insects with that of a mealybug pest.
Two-spotted Spider Mite remains active on a variety of host plants. This warm-season spider mite species will only become more prevalent as warm to hot weather continues. Inspect for chlorotic foliage that is finely stippled. Mites can be found primarily on the leaf undersides. Under current weather conditions, populations of this mite can suddenly become extremely large and destructive.
Lacebugs on Shrubs are actively feeding. Plants growing in sunny locations are at a higher risk for attack. Soil applications of a systemic imidacloprid product may still be applicable at this time as long as irrigation is available to keep soil moist during the uptake period. Inspect such plants as: Japanese andromeda, azalea, rhododendron, hawthorn, and others. Hot and dry weather drives lacebug populations to large numbers quickly.
Reported by Robert Childs, Extension Entomologist, Plant, Soil and Insect Sciences Department, UMass, Amherst.
DISEASES -
Gymnosporangium rust infections are visible as red to yellow spots on susceptible hawthorn, apple, and crab apple leaves. Often there are tiny yellow-white tube-like fruiting structures extending from the underside of leaf spots. From mid-summer to autumn, spores are wind-carried from the broadleaf host’s leaves and, when conditions are wet, they infect green shoots and needles of junipers. Pea-sized to 2” 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 Gymnosporangium rust resistant hawthorn, apple, and crab apple as well as juniper varieties. In addition to gall formation on junipers, Gymnosporangium rust infections may cause twig and branch dieback. If desired, apply fungicides to protect high value eastern red cedar and other susceptible junipers from now through mid-September.
Continue to apply fungicide treatments to manage black spot on high value roses and repeat the applications per label directions into the fall. 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 to reduce buildup of inoculum and the need for fungicide treatment.
Powdery mildew fungi are visible as a dusty, gray to white spots on a number of host plants including red horsechestnut, dogwood, sycamore, phlox, and rose. 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. Now spherical, black fruiting structures are visible with a hand lens on the underside of many leaves in the dusty, gray mycelia. 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 there are a number of unconventional applied materials labeled to protect susceptible plants.
Reported by Dan Gillman, Plant Pathologist, UMass Extension Plant Diagnostic Lab, Amherst.
LANDSCAPE TURF
INSECTS -
Webworms, crane flies, and grubs, Oh My!
As we enter September, we can hope the hot weather will finally break for good - and that Hurricane Earl will stay well east of Cape Cod. But late summer is the time when we can expect to see several turf insects in a variety of settings.
Invasive crane flies
A year ago invasive crane flies (the "marsh crane fly", Tipula oleracea) were confirmed on Martha's Vineyard and in Falmouth. You may still be seeing some adults flying in those areas. The adults look like giant mosquitoes. (Remember that there are also many native species of crane flies that fly at this time of year, so just because you see crane flies is not necessarily cause for panic.) The adults will be laying eggs soon. The eggs survive better in areas where the soil is moist - so if the hurricane drops a lot of rain in southeastern Massachusetts, that might increase the likelihood of those eggs surviving. The immatures (kind of leathery looking, often an olive green or gray color), will feed into November most years, and can feed through the winter months if temperatures are mild. They will complete their development next spring (sometimes as early as April), adults will emerge, and produce eggs for another generation.
There have been very few field trials conducted on this species of crane fly, but there appear to be many options. One approach is to treat affected areas just as larvae are hatching out of the eggs (likely to be mid to late September this year).
Webworms
Right on schedule, sod webworm adults are flying in large numbers in my own back lawn. I always see the moths flitting about in late afternoon or evening at this time of year, when I am mowing, and I am always impressed at the large numbers of moths. But to date I have never seen any damage caused by the webworm larvae that would have been feeding in the previous two to three weeks. While some turf managers do experience damage from webworms during the summer, most areas do not experience populations that warrant treatments. Furthermore, as we are approaching late summer and early autumn, surely we will get a break from the beastly hot temperatures, and our cool season turfgrass should be able to begin to recover from this record-breaking summer.
White grubs
This is an excellent time to monitor for white grub activity. Because the summer was so hot and dry in most locations, you might find that grubs are more active in areas that retain moisture better (heavier soils, low lying areas, areas near leaky sprinkler heads). Remember that ordinarily European chafers do better in dry conditions than our other main species (Japanese beetles and oriental beetles). Also keep in mind that some Japanese and oriental beetle females may have delayed egg laying because soils were so dry in so much of the region. So you may see some fairly small grubs, along with the more typical second instars, in many locations.
Reported by Pat Vittum, Professor and Extension Entomologist, UMass Department of Plant, Soil and Insect Sciences, Amherst.
AGRONOMY -
The dry conditions and high heat of this summer season have taken a visible toll on many lawn areas. Although some dormant turf is beginning to recover, lasting damage from drought and heat, insects, and disease is common. At this time and in the coming weeks, the timing is optimum for repair and re-planting of such affected areas.
NEXT UPDATE: The next issue will be available on or about September 17, 2010.
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.
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