UMass
Extension Landscape Message #25
October 5, 2007
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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 or about November 9, 2007.
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SCOUTING
INFORMATION BY REGION
REGIONAL
NOTES
-
Cape
Cod Region (Barnstable) - General Conditions: We are back
into a serious dry spell, with no measurable rainfall since the
last report, with the exception of a brief downpour that occurred
only from Dennis to Chatham on Saturday, September 29. The rest
of the Cape remained bone dry, with no foreseeable rain in the
extended forecast. Temperatures are more seasonable, with mild
days in the 60s F and cool nights in the lower 50s. It dipped to
40° F overnight on September 30-October 1. Many trees are dropping
leaves early, with little color change to date. Dahlias look spectacular
in the fall garden. Pests/Problems: Skunks are
digging up drought stressed lawns in search of grubs. Powdery mildew
continues to be on anything that is susceptible. Wasps and yellowjackets
are everywhere, and they are aggressive. Many reports of accidental
digging into underground colonies with subsequent multiple stings
are coming into the office.
Southeast
Region (Hanson) - General Conditions: Hanson received
0.20 inches of rain over the past two weeks. Soils remain dry,
and unirrigated plants continue to appear drought stressed. Remind clients to
water any newly planted plants. Several towns in Plymouth County now
have water bans on outside watering. It was reported that in the Boston
area, August was the second warmest and third driest on record. Landscape roses, Hydrangea
paniculata, butterflybush, Aster divaricatus, and other fall asters, Lamium, Sedum sp.,
Japanese anemones, many ornamental grasses, Nepeta, Cimicifuga (now Actea)
simplex, and Liriope are in full bloom. The fruits of autumn
olive, staghorn sumac, kousa dogwood, crabapple, hollies, hawthorne, and Viburnum are
providing landscape color. Pests/Problems: Premature fall
color of many deciduous plants, due to drought stress, continues. The leaves
on many maples (red, sugar and Japanese) along with many other deciduous trees
are dropping leaves. Red-headed pine sawfly was reported on mugo pine;
and like many other sawflies, they can defoliate a plant very quickly if
left unnoticed and untreated. Boxelder beetles, earwigs, slugs, mites, snails,
lacebugs, ticks, and mosquitoes are all active. Giant tar spot
is evident on Norway maple, and 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: Drought.
Metro
West (Waltham) – General Conditions: Still
very dry, but cool.
Central
Region (Boylston) - General Conditions: Dry.
Pioneer
Valley Region ( Amherst) - General Conditions:
The weather was warm for late September and continues to be dry. Fall color is
slowly developing and is most notable on honeylocust, ash, sugar maple, red maple,
sumac, and Virginia creeper to name a few. Aster, mums, and marigolds are blooming
profusely in gardens while lawns remain green but dry.
Berkshire
Region (Great Barrington) - General Conditions: Soil moisture levels are very low. Rainfall deficit for the year is about 9 inches.
Premature leaf drop is common with trees and shrubs on drought prone sites.
ENVIRONMENTAL DATA -
The following growing-degree-day (GDD) and precipitation data
was collected for a two-week period, September 20, 2007 through
October 3, 2007. Soil temperature and phenological indicators were
observed on or about October 3, 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.
| Region/Location |
2007 GROWING DEGREE DAYS
|
Soil
Temp
(°F
at 4" depth) |
Precipitation
(2-Week
Gain) |
2-Week
Gain |
Total
accumulation for 2007 |
| Cape Cod |
214 |
2722 |
70° |
0.00" |
| Southeast |
221 |
2757 |
68° |
0.20" |
| East |
232 |
2789 |
60° |
0.10" |
Metro West |
219 |
2805 |
66° |
0.07" |
| Central |
165 |
2453 |
62° |
0.00" |
| Pioneer Valley |
199 |
2620 |
64° |
0.05" |
| Berkshires |
310 |
2764 |
62° |
0.41" |
AVERAGE |
223 |
2701 |
65° |
0.12" |
n/a = information
not available |
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
E. |
EAST |
METRO
W. |
CENT. |
P.V. |
BERK. |
|
|
Heptacodium miconoides (Seven-Sun
Flower) |
end |
f/end |
f/end |
* |
f/end |
* |
* |
Clematis paniculata (Sweet
Autumn Clematis) |
f/end |
full |
end |
* |
f/end |
* |
f/end |
Polygonum cuspidatum (Japanese
Knotweed) |
end |
end |
end |
* |
end |
end |
f/end |
Hydrangea paniculata (Panicle
Hydrangea) |
end |
f/end |
end |
* |
end |
f/end |
f/end |
Campsis
radicans (Trumpetvine) |
end |
end |
end |
* |
* |
f/end |
* |
Lythrum salicaria (Loosestrife) |
end |
end |
end |
* |
end |
end |
end |
Hibiscus syriacus (Rose-of-Sharon) |
end |
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.
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
-
Defoliators:
Lepidoptera:
- Fall
webworm tents are obvious. Feeding by this
pest is now finished for the year, but the silken webs
will remain for months. Overall, population levels of
this native caterpillar were quite low this year statewide.
- 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.
Hymenoptera:
Piercing-Sucking Pests:
- Cool-season spider mites remain active. Inspect spruces
for the presence of spruce spider mite. This pest can
feed well into October and possibly November if the weather remains somewhat
mild.
- Hemlock
Woolly Adelgid
 is
still dormant as it remains on stems at the base of needles
in the nymphal stage. It can still be treated with horticultural
oil at the summer rate but watch the weather closely.
Avoid freezing temperatures. This pest will emerge from
dormancy around mid October and resume feeding and development.
Scale Insects:
- Elongate hemlock scale (aka fiorinia
scale)
is a tiny and elongate-shaped scale found
attached to the undersides of hemlock needles. It is a very
serious pest and should be treated when found. It can often
be mixed in with hemlock woolly adelgid on the same plant.
Miscellaneous:
- Western conifer seedbug - This common house
invader in the fall 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.
- Multi-colored ladybird beetle will be seeking
over-wintering sites very soon. While being an important predator
of aphids during the growing season, it becomes a very obnoxious
home invader starting around mid October. Inspect windows and
doors for holes in the screens and failed caulking; repair
if needed.
- Boxelder bug feeds primarily on the seeds
of boxelder all summer. However, it becomes a nuisance home
invader in the autumn.
Reported
by Robert Childs, Entomologist, UMass Extension Landscape,
Nursery and Urban Forestry Program, Amherst.
DISEASES
-
Powdery mildew is
quite apparent on rose, flowering dogwood, sycamore, phlox,
and horsechestnut, to name a few . The fungus is visible as
dusty, gray to white areas on foliage and rose buds. In addition,
the tiny, black, spherical fruiting structures are also visible
with a hand lens on many host plants. Remove severely infected
buds and shoots, as well as collect fallen leaves to reduce
overwintering inoculum.
Horsechestnut
(Guignardia) leaf blotch is
visible as scattered, irregular-shaped orange-brown blotches
with yellow margins on some leaves while others are entirely
brown. The impact of the disease on the appearance of landscape
trees is very dramatic, but horsechestnuts infected year after
year continue to grow vigorously in spite of their blighted
appearance in late summer.
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 -
LANDSCAPE
TURF
DISEASES
-
No report this week.
INSECTS
-
It appears to be a banner year for white grubs!
We have seen damage at levels I had not observed in several years
- large areas torn apart by skunks or raccoons scavenging for
the grubs. Damage has been significant throughout the state,
and all three major species (European chafers, Japanese beetles,
and oriental beetles) have been very active.
As the saying goes, "hindsight is 20 - 20", so here is what I think happened:
The dry weather of August forced some beetles to delay laying eggs because
they could sense that the soil moisture was very low at that time and the eggs
would not survive in the dry soil. So we saw lots of very small grubs in late
August and early September, more so than usual. We did not see much damage
at that point because many of the grubs were still pretty little.
Then as the "late" grubs matured and joined their brothers and sisters who
had developed "on schedule", the numbers of large grubs exceeded threshold
levels pretty quickly. And meanwhile of course, most areas have not received
much rain in September, so there has been little moisture available to mask
the damage.
For many of you, the main problem now is dealing with the secondary damage
- the critters (skunks, raccoons, crows, starlings) that are dining on the
grubs. As I have said so many times, they provide excellent biological control
because there are very few grubs left in the areas where they forage, but we
have never been able to teach them to "put the grass back".
My counterpart in Ohio, Dr. Dave Shetlar, suggests that Milorganite™ applied
to the surface in areas where skunk activity is greatest can convince the grubs
to move on to other locations. That may or may not be a good thing, depending
on where they go! I do not have personal experience with this approach but
am passing it along to offer an alternative to those of you who are really
struggling with grubs right now.
Ordinarily early October would be too late to apply a curative product such
as trichlorfon (Dylox™). But with air and soil temperatures so unseasonably
mild this year, you might get some relief. This is not a recommendation because
the date is so much later than usual.
If you do decide to apply trichlorfon, do it before the weather turns colder
and remember:
- Trichlorfon cannot be used on school grounds in Massachusetts
(and is subject to similar restrictions in some other states
as well.)
- Trichlorfon must be watered in - with at least 0.25 inch
of water this late in the season, especially because the soils
are so dry. (Even more irrigation would be even better).
- Trichlorfon is sensitive to rapid breakdown in water with
high pH, so if your water supply has a pH above 7.0 to 7.2,
plan to use a buffering agent to reduce that sensitivity.
Reported by Pat Vittum, Professor & Extension
Entomologist, UMass Department of Plant, Soil, and Insect Sciences,
Amherst, MA
WEEDS
-
No report this week.
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
NEXT UPDATE: The next issue will be available
on November 9, 2007
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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