UMass Extension Landscape Message #22
September 4, 2008

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Quick Info Menu ------------------------------- SCOUTING INFORMATION REGIONAL NOTES - Cape Cod - Southeast - East - Metro West Waltham - Metro West Hopkinton - Central - Pioneer Valley - Berkshire ENVIRONMENTAL DATA PHENOLOGY WOODY ORNAMENTALS - Insects - Diseases - Weeds LANDSCAPE TURF 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 month of September this newsletter will be updated bi-weekly. The next update will be available on September 18, 2008. Missed a previous message? Visit the Landscape Message Archive. Interested in additional turf-oriented content? UMass Extension Turf Program Management Updates

SCOUTING INFORMATION BY REGION

REGIONAL NOTES -

Cape Cod Region (Barnstable) – General Conditions: Crisp, fall-like conditions made an appearance over the past two weeks. While we have had two inches of rain, most of it came down with one thunderstorm.  Sandy soils are a bit dry.  Late summer perennials are providing good color in the landscape.  Pests/Problems: Wasp colonies are reaching their peak numbers at this time of year.  Lacebugs are still active on azalea, sycamore, and pieris.  A pigeon tremex woodwasp was observed on a dying sycamore maple.  Fall webworm nests are getting large.  Many mushrooms are popping up in turf.

Southeast Region (Hanson) – General Conditions: No report this week.

East Region (Boston) – General Conditions: No conditions report this week. See Environmental Data and Phenology below.

Metro West (Waltham) – General Conditions: Sunny, dry, starting to get cooler.  Fall must be on the way.  Some red maples are beginning to show early color.  Pests/Problems:  Japanese bamboo is in full flower.  The nests of fall webworm are getting larger.  

Metro West (Hopkinton) – General Conditions: No report this week.

Central Region (Boylston) – General Conditions: No conditions report this week. See Environmental Data and Phenology below.

Pioneer Valley Region (Amherst) - General Conditions: The Pioneer Valley has been the driest it has been all summer during the last two weeks.  There is adequate soil moisture and for the most part lawns, gardens, and trees are thriving.  Pests/Problems:  Early fall color continues to be evident on a number of trees and shrubs including declining sugar maples, as well as apparently healthy katsuratree, staghorn sumac, and winged euonymus, to name a few.   Powdery mildew continues to be visible on herbaceous and woody ornamentals such as phlox, zinnia, flowering dogwood, sycamore, and lilac.  There also are a plethora of spotted leaves and blighted shoots caused by a variety of disease fungi and a few bacteria on many plants.

Berkshire Region (Great Barrington) - General Conditions: One of the drier two week periods of the summer.  Still, soil moisture levels are good and plant growth, especially turfgrass, is vigorous.  Despite very favorable weather for plant growth this year, premature color changes are visible on some trees and shrubs, an indication of stress.  Where this is occurring, an evaluation of causes of this stress should be done.  Pests/Problems:  Powdery mildew is rampant.  Slugs, snails, mosquitoes, ticks, wasps and hornets, and fall webworm are the most prominent pests in landscapes.  Overall, pest and disease pressures this growing season have been low to moderate.

ENVIRONMENTAL DATA -

The following growing-degree-day (GDD) and precipitation data was collected for a two-week period, August 20, 2008 through September 2, 2008.  Soil temperature and phenological indicators were observed on September 2, 2008.  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.

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:

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.
				Waltham	Hopkinton
Heptacodium miconoides (Seven-Sun Flower)	begin	*	begin	begin	*	begin	*	*
Polygonum cuspidatum (Japanese Knotweed)	begin	*	full	full	*	full	b/full	b/full
Clematis paniculata (Sweet Autumn Clematis)	b/full	*	full	*	*	begin	*	begin
Vitex agnus-castus (Chaste Tree)	f/end	*	full	*	*	full	*	*
Hydrangea paniculata (Panicle Hydrangea)	f/end	*	full	full	*	full	f/end	full
Hybiscus syriacus (Rose of Sharon)	f/end	*	full	f/end	*	f/end	f/end	f/end
Campsis radicans (Trumpetcreeper)	end	*	full	end	*	*	f/end	*
Lythrum salicaria (Loosestrife)	end	*	f/end	end	*	f/end	full	f/end
Sophora japonica (Japanese Pagodatree)	end	*	end	*	*	*	end	*
Clethra alnifolia (Sweet Pepperbush)	end	*	end	end	*	end	*	end
* = no activity to report/information not available

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.

METRO WEST REGION – Mark Sawyer, Horticulturist, Weston Nurseries, Hopkinton.

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 -

Lepidopteran Caterpillars:

• Hibiscus or Rose of Sharon Caterpillar (Anomis commoda) is active.  These cryptically-colored caterpillars usually rest on the stems of hibiscus (Rose-of-Sharon, in particular) and writhe wildly when disturbed or handled.  Their feeding usually results in nothing except the main veins being left, but often they consume those as well.  Inspect for defoliation and then inspect very closely for the dull-colored caterpillars lying on the stems; they are difficult to see.  When occurring in large numbers this pest is capable of creating complete defoliation.  Treat with a spinosad product. 
  
  
• Fall Webworm webs are extremely noticeable now.  This caterpillar feeds within large groups by tying foliage together and feeding from within the web.  Silken webs begin at the tips of branches and get extended downward toward the trunk.  This pest causes little harm to the health of the tree, but the presence of the webs can be very unsightly.  Potential host plants include a rather wide deciduous plant range.  Management can be challenging given that the caterpillars are somewhat protected from contact sprays by the silken web. 
  
  
• Mimosa Webworm damage is obvious now.  The tied and skeletonized foliage is turning brown.   Eventually, this caterpillar can tie and skeletonize much of a tree’s leaves, which remain intact but die and turn brown.  By mid to late August, affected honeylocusts can have all of their foliage killed by this pest.  Damage usually begins at the branch tips.  Inspect for tied and skeletonized leaves.  Sprays that contain spinosad are effective.
  
  
• Juniper Webworm − This caterpillar is more common in eastern MA than in other parts of the state.  Inspect for browning foliage on junipers and the presence of foliage tied with silk.  Treat young larvae with a Bacillus thuringiensis Kurstaki (B.t.K.) product or with a product that contains spinosad.
  
  
• Oak Skeletonizer − This tiny yellow caterpillar can often be seen hanging by nearly invisible threats from the host tree (primarily red and black oaks).  They feed by scraping away tiny patches of the epidermis on the leaves.  When occurring in large numbers, individual leaves will have dozens of tiny 'window-paning' injuries.  Even in high densities, this is rarely a problem.  Controls consist of pyrethroids or a spinosad product, if necessary. 
  

Hymenoptera Sawfly (Caterpillar) Larvae:

• Red-Headed Pine Sawfly remains active.  This species has a rust-colored head capsule and a yellow body with black spots.  The caterpillar can remain active well into October and is capable of causing much damage if not treated.  A product that contains spinosad or one of the registered pyrethroid products may be necessary to reduce or eliminate the numbers of this pest.  Mugo pine is a preferred host. 
  
  
• Dogwood Sawfly remains active and can be found feeding well into October if the weather remains mild.  Common host plants are the redosier dogwoods and grey dogwood.  This caterpillar is a pale yellow color and has black spots.  However, in many larval stages, it has a white pubescence covering the body.  This white color and the typical posture of the caterpillar to lie in a curled position on the foliage gives it the appearance of a bird dropping and not an insect.  Inspect for these white caterpillars and for feeding damage.  Treat with a product that contains spinosad if found in large numbers.  Smaller populations can be removed by hand and destroyed.
  

Beetles:

• Japanese Beetle remains active, but its numbers are waning significantly.  Favored host plants display significant feeding injury in the form of a  'window-paning' effect where the foliage is heavily skeletonized.  Such foliage will turn completely brown.  Adult beetles will need to be treated with a chemical insecticide, such as a pyrethroid, in order to protect plants.
  
  
• Viburnum Leaf Beetle adults remain active.  They can be found mating and laying eggs on favored host plants.  Treat with a registered pyrethroid insecticide, if necessary.  The adult beetle will remain active until the first frost.
  
  
• Imported Willow Leaf Beetle remains active.  The adult beetle is rather small, rounded, and metallic green/blue in color.  Treating the adult beetle requires a pyrethroid insecticide while a product that contains spinosad works well for the larvae. 
  

Piercing-Sucking Pests:

• The Red-Banded Leafhopper (a.k.a. Sharpshooter Leafhopper)continues to feed and reproduce.  This pale green leafhopper with two chevron-shaped stripes on its back is attracted to rhododendrons that continue to produce new foliage through July and August.  The egg-laying in the new leaf tissue causes the leaves to become stunted and distorted.  It is purely an aesthetic pest, but it can be an important pest, especially in the nursery.  Visually monitor for this insect by gently shaking foliage to dislodge the leafhoppers, which will fly up and then land again nearby.  When found in large numbers this pest should be treated.
  
  
• Lacebugs remain very active and, if the weather remains mild, it can feed through September.  These serious pests always feed from the underside of the foliage, but they create the fine, yellow stippling feeding injury on the upper surface of the leaves.  Look at the bottom leaf surface of such affected leaves for the telltale signs of the brown fecal spots and the lacebugs themselves.  Inspect common host plants for this pest for last year’s damage.  Common hosts are Japanese andromeda, evergreen azaleas, rhododendron, cotoneaster, and hawthorn.  Systemic imidacloprid appears to be quite effective for managing this pest.  Also, horticultural oil sprays or insecticidal soap sprays that are targeted to the foliage underside is also effective for the small nymphs.  Susceptible plants growing in sunny areas will experience more damage given that heat greatly encourages lacebug populations. 
  
  
• Spider Mites - Inspect spruce, hemlock, fir, and others for the signs of feeding damage by these tiny but very prolific and potentially damaging pests.  Inspect very closely for the active mites, which will require a good hand lens or microscope.  Inspect many different deciduous host plants for the signs of warm-season mites, such as the two-spotted mite.  This pest favors the hot and dry times of summer, and their numbers can increase exponentially and quickly during such times. Cool-season mites, such as the spruce spider mite are now reappearing and will be active for many more weeks on such hosts as spruce, fir, and hemlock.  If found, treat with an oil spray or with one of the new mite growth regulators.  Monitor for the actual mites by shaking a branch over a piece of white paper and then inspecting with a hand lens for the mobile mites.
  
  
• Hemlock Woolly Adelgid - This pest remains dormant, but it can still be managed even in this stage.  A horticultural oil spray (at the summer rate), systemic imidacloprid or systemic dinotefuran (Safari™), are all effective against this very serious pest.  Note: Safari™ is on the Massachusetts State Restricted Use Product List. (See Elongate Hemlock Scale, which appears next.)
  
  
• Elongate Hemlock Scale (aka Fiorinia Scale) − Inspect hemlocks closely for this pest.  If the plant appears weakened or sickly and has hemlock woolly adelgid, which is very obvious, take the extra time to closely inspect the undersides of the needles for this scale.  Fiorinia scale is very small, brown, and mostly oval in shape.  Many of these may be present per needle (on the underside only).  In some case, it will be the primary reason that a hemlock looks to be in ill-health.  Imidicloprid, which works pretty well systemically for hemlock woolly adelgid does not have much of an impact on this scale.  Horticultural oil sprays, which also work well on hemlock woolly adelgid tends to provide minimal control for this scale.  Safari™ (dinotefuran), a relatively new neonicotinoid, does show good promise for fiorinia scale and works well when utilized as a systemic.  However, in Massachusetts, it is labeled as a State Restricted Use Product due to groundwater concerns.  Fiorinia scale is difficult to control.  Unlike most armored scales in the Northeast, it produces crawlers throughout much of the growing season.  If found, treat it aggressively.  Fiorinia scale is a very serious pest of hemlock and can occur on conifers other than hemlock.  
  
  

Wood Attackers:

• Asian Longhorned Beetle has been positively found in the northeastern section of Worcester, MA in an established population.  The current 'Regulation Area' is approximately 16 square miles and extends towards the towns of Holden, West Boylston, and Shrewsbury.
  
  

  For complete details on this emerging issue please visit our recently established web information center, Asian Longhorned Beetle in Massachusetts.

  
  
• Rhododendron Borer − This is another clear-winged moth species like that of the dogwood borer.  It attacks rhododendrons randomly and infestations are often not noticed until a shoot wilts and dies.  Inspect the base of rhododendron shoots for entrance/exit holes and the presence of sawdust piled on the ground.  Prune out and destroy affected shoots or apply a coarse spray of beneficial nematodes to the base of the affected shoots. 
  
  
• Dogwood Twig Borer (a.k.a. Elm Twig Girdler) − This cerambycid beetle (longhorned beetle) attacks flowering dogwood primarily but can also be found attacking elm, viburnum, and various fruit trees.  The larvae tunnel in the smaller branches and ultimately kills them.  Usually it is not found congregated in large numbers, and individual branches can be pruned out and destroyed.

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

LANDSCAPE TURF

INSECTS -

Here come the grubs!  It is that time of year again.  White grubs are starting to show up in turf around the region.  So, if you have some areas that are looking a little parched, now would be a good time to take a closer look!  Soil moisture is likely to be the main driving force in determining where grub activity will be greatest.  Adult females look for sites that have just the right amount of soil moisture―if it is too wet, the eggs may not develop and if it is too dry, the tiny grubs may not be able to find healthy roots quickly enough after they emerge.

Areas that received steady rainfall throughout the summer may experience higher grub populations than usual, especially of Japanese beetles and oriental beetles.  In areas that received lots of rainfall this year and flooded on at least one occasion during July or August, you might find grub populations showing up in sites that are a little "higher and drier" than usual.  In other words, if there were some areas that were submerged more than a few days earlier in the summer, when eggs were just being laid or tiny larvae were just beginning to hatch, those areas may be less likely to experience heavy grub activity.

So get out there now and take a look.  If you find grubs that are already well established, you can make a curative application to clean up the populations.  Trichlorfon (Dylox™) is always a good quick option, but remember that it cannot be used on school grounds in Massachusetts.  There are many other turf areas that are restricted in other states as well.

Dr. Dave Shetlar reports that there are several field reports from trials conducted by turf entomologists around the country that suggest neonicotinoids can be used in late August and still provide curative control, so that may be an option for those who cannot use trichlorfon.  However, I am not sure whether any of those trials were conducted on European chafers or oriental beetles which, in general, are a little trickier to control than Japanese beetles or masked chafers.

Reported by Pat Vittum, Extension Entomologist, UMass Department of Plant, Soil and Insect Sciences, Amherst.

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

Soil and Plant Tissue Testing - The University of Massachusetts Soil and Plant Tissue Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Tissue Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant tissue Testing Laboratory web site at: http://www.umass.edu/plsoils/soiltest Alternatively, call the lab at (413) 545-2311.

NEXT UPDATE: The next issue will be available on September 18, 2008.

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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