(This
is the edited version of the University of Massachusetts
Extension team's Landscape Pest Message.
Click here for the full version. I took out what I
considered to be less relevant to central Massachusetts. It may
still be a little eye-glaze inducing, but is well worth skimming
through at the very least. Ed Bemis)
UMass Extension Landscape Message #12 May 18, 2007
SCOUTING INFORMATION BY REGION
REGIONAL NOTES
-
Central Region (Boylston) - General Conditions:
No report available this week. See Amherst area below.
Pioneer Valley Region (
Amherst) - General Conditions: Heavy rains coupled with
warmer weather knocked the petals off several of the trees and
shrubs in full bloom last week. In gardens, phlox and tulips
continue their colorful contribution to the landscape while some
irises and Vinca minor have begun to add another splash
of color. Lawns continue to grow lush and green.
Pests/Problems: Small, water soaked lesions of possible
apple scab infections were visible on a few crabapple leaves.
Sporulation of Rhizosphaera needle cast is evident on infected,
browning 1-year old Colorado spruce needles. See the
Woody Ornamental Disease section below for
management information. In addition, the eye-catching but seldom
health-threatening disease, spruce needle rust (Chrysomyxa
weirii), is displaying orange fruiting structures on
yellow-banded spruce needles.
ENVIRONMENTAL DATA
-
Growing degree days are sort of like
heating degree days for plants. It is measures from 50 degrees.
One day with an average temperature of 60 degrees would count as
10 growing degree days.
The following growing-degree-day (GDD) and
precipitation data was collected for a one-week period, May 10,
2007 through May 16, 2007. Soil temperature and phenological
indicators were observed on or about May 16, 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
(1-Week Gain)
|
|
1-Week Gain
|
Total accumulation for 2007
|
|
Cape Cod
|
82
|
201
|
65°
|
0.00"
|
|
Southeast
|
31
|
180
|
71°
|
0.01"
|
|
East |
98
|
270
|
55°
|
1.00"
|
|
Metro West
|
~110
|
224
|
60°
|
0.70"
|
|
Central
|
84
|
189
|
52°
|
0.67"
|
|
Pioneer Valley
|
101
|
262
|
62°
|
1.86"
|
|
Berkshires
|
84
|
153
|
63°
|
0.63"
|
|
AVERAGE
|
80
|
211
|
61°
|
0.70"
|
|
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. |
|
|
|
|
Spirea x vanhouttei (Van Houtte
Spirea)
|
begin
|
*
|
begin
|
*
|
*
|
*
|
*
|
|
R. carolinianum (Carolina Rhododendron)
|
begin
|
full
|
begin
|
begin
|
*
|
full
|
*
|
|
Lonicera tatarica (Tatarian Honeysuckle)
|
*
|
full
|
begin
|
full
|
full
|
full
|
begin
|
|
Cytissus scoparius (Scotch Broom)
|
begin
|
*
|
begin
|
*
|
full
|
*
|
*
|
|
Elaeagnus umbellata (Autumn Olive)
|
*
|
full
|
*
|
*
|
*
|
*
|
*
|
|
Aesculus hippocastanum (Horsechestnut)
|
*
|
full
|
full
|
full
|
begin
|
full
|
begin
|
|
Syringa vulgaris (Common Lilac)
|
begin
|
full
|
full
|
full
|
full
|
full
|
b/full
|
|
Rhododendron spp. (early Azaleas)
|
begin
|
full
|
end
|
end
|
f/end
|
full
|
full
|
|
Cornus florida (Flowering Dogwood)–bracts
|
begin
|
full
|
full
|
full
|
full
|
full
|
full
|
|
Cercis canadensis (Redbud)
|
begin
|
full
|
f/end
|
full
|
full
|
full
|
full
|
|
Halesia spp. (Silverbell)
|
*
|
full
|
f/end
|
full
|
full
|
*
|
b/full
|
|
Malus spp. (early Crabapple)
|
b/full
|
full
|
f/end
|
full
|
full
|
full
|
full
|
|
Chaenomeles speciosa (Floweringquince)
|
full
|
full
|
*
|
*
|
full
|
full
|
full
|
|
Amelanchier spp. (Shadbush, Serviceberry)
|
full
|
end
|
end
|
*
|
end
|
f/end
|
f/end
|
|
Spiraea prunifolia (Bridalwreath Spirea)
|
f/end
|
full
|
*
|
full
|
*
|
*
|
*
|
|
Prunus x cistena (Purpleleaf Sand
Cherry)
|
f/end
|
full
|
*
|
end
|
*
|
f/end
|
full
|
|
P. calleryana ‘Bradford’ (Bradford Callery
Pear)
|
f/end
|
end
|
end
|
*
|
end
|
end
|
end
|
|
Rhododendron ‘PJM’ (PJM Rhododendron)
|
end
|
end
|
end
|
*
|
end
|
f/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 -
The spring of 2007 in Massachusetts has been one
of starts and stops, overall, with unpredictable mixtures of
temperatures and precipitation in between. It has been a very
difficult season for predictions of insect activity. Some pests
that we expected to be in large population numbers by now are
not there, yet, while other species are displaying a staggered
emergence from one geographic region to another within the
state. Recent rain in the western part of the state has been
beneficial for plants by relieving some of the near-drought
conditions that have prevailed for the past two to three weeks.
Windy conditions have also contributed to the frustrations of
being able to properly apply foliar sprays.
Defoliators:
Lepidoptera (moths/ butterflies, but
their caterpillar stage):
 |
Forest Tent Caterpillar (FTC) is once
again in big numbers and very active. The warmer
regions are already experiencing defoliation,
especially on oaks. The Connecticut River Valley
region in MA (e.g., Greenfield) already has
experienced complete defoliation of trees that are
typically late to have bud break, such as pin oaks.
However, fully leafed and blossoming crabapples have
also been defoliated. In Greenfield, FTC is now
around 1.5 inches in length while just 10 miles from
there, in the slightly higher elevations, FTC larvae
are only about 0.75 inches in length. Last year, an
Entomophaga fungus, similar to the one that
attacks gypsy moth, was observed having an effect on
FTC, and it is not yet known to what extend it
reduced population numbers, if at all. This pest,
when occurring in large numbers, can quickly
defoliate trees. If necessary, treat the
caterpillars with a product that contains spinosad
or with one of the labeled pyrethroid insecticides.
Oaks, maples, birches, crabapples, and many others
are common host plants.
|
|
Gypsy Moth is not expected to be in
large numbers across the state, but it is not
uncommon for small, localized areas to
experience gypsy moth in outbreak proportions.
This pest has hatched in most of the state and
is settled and feeding, but no reports of large
populations have yet been received. Monitor for
their activity and treat in a similar fashion,
if necessary, as for winter moth or FTC.
|
|
Eastern Tent Caterpillar has been
active for a few weeks and is rapidly gaining in
size. Webs on cherries and apples are numerous and
quite large in the areas of heavy infestation. Some
areas that have experienced outbreaks of this pest
in recent years are reporting much lower numbers
this year. If this pest is active in your area, it
should be obvious by now. Treat the same as the
above-mentioned pests, if necessary.
|
|
Fall Cankerworm should just be
beginning its activity now. Large numbers of FCW
similar in appearance to winter moth but has two and
a half pairs of prolegs on the abdomen where winter
moth only has two pairs. They are sometimes found in
mixed populations with winter moth on the same host
plant. Treat, if necessary. |
Hymenoptera:
|
European pine sawfly has the
potential to completely defoliate branches and
entire plants. Monitor mugo pine, in particular,
for clusters of this green caterpillar, which
are almost the same color of the needles. The
very young caterpillars can be successfully
treated with an insecticidal soap spray while
caterpillars of all ages can be treated with a
product that contains spinosad or with one of
the labeled pyrethroid insecticides. This pest
has mostly been reported in the eastern regions
of the state, including Cape Cod, in past years.
Monitor oaks, in particular, for this
(currently) tiny looper (inchworm) caterpillar.
|
| Azalea sawfly caterpillar is
now active in much of the state. This pale green
caterpillar is almost the exact color of the host
plant foliage and often hugs the leaf margin while
it feeds. Therefore, it is very cryptic, and much
damage can be created before it is noticed. Treat
established populations with a product that contains
spinosad or with one of the registered pyrethroid
products that is labeled for this pest. |
Coleoptera:
|
Lily leaf beetle
has been active in the adult stage for several
weeks now. Feeding injury, showing up as notches
to leaf margins and holes in the foliage, is
becoming noticeable. Eggs, on the undersides of
leaves, in the form of an irregular tan-colored
line about one inch in length have not yet been
seen or reported, but they will be appearing
within the next couple of weeks. Treat the
adults with a registered and labeled pyrethroid.
Later on, treat the larvae with a product that
contains spinosad. NEEM products do work to
deter feeding activity, but they need to be
reapplied every 10-14 days for as long as the
pest is active, which is much of the growing
season. NEEM, therefore, is a good choice in
smaller plantings of true lilies.
|
| European chafer adults should
start to appear within the next few weeks,
especially in the warmer regions. This large scarab
often goes unnoticed due to its nocturnal habits,
BUT it sometimes clusters by the hundreds or even
thousands on individual plants for mating purposes.
While there, they can often create plant injury in
the form of ragged notches on the leaf margins.
Rhododendrons are common host plants along with many
others. If suspected, inspect at night with a
flashlight for their presence. Treat with a
pyrethroid, if necessary. |
Piercing-Sucking Pests :
| Many spider mite species are now
active. Inspect foliage with a hand lens for their
presence; also, make note of the ratio of predatory
mites to spider mites. Spider mites are often present on
plant foliage, and predatory mites usually keep their
numbers in check. Treatments for spider mites are
usually only necessary if populations of them are high
and when numbers of predators are low.
|
| Many aphid species are now very
active, such as snowball aphid on many different species
of viburnum, aphids on various species of maples
(including Japanese maple), and balsam twig aphid.
Inspect for clusters of aphids, honeydew, sooty mold,
and distorted foliage. Unlike most of the other
piercing-sucking pests, aphid feeding usually does not
result in yellow stippling injury. Treat large
populations, if necessary, with a spray of insecticidal
soap, or with a systemic application of a product that
contains imidacloprid.
|
|
Hemlock Woolly Adelgid
- is active, and the white cottony masses are
quite obvious right now. Once foliage has fully
expanded, treat with a horticultural oil spray at the
summer rate. Small populations can be treated with a
systemic application of imidacloprid. This pest is
actively feeding and will produce one more generation
within the next several weeks.
|
Leafminers:
|
Birch Leafminer is active, and in the
warmer regions it may be too late to treat for the
adults in those areas. Monitor for emergence with yellow
sticky cards and treat with a pyrethroid to break the
cycle of reinfestation. If larvae are already active
within the foliage, consider using an insecticide that
has translaminar activity for the larvae within the
mines. For the past several years and for unknown
reasons, this pest has been at very low levels
statewide.
|
Reported by Robert Childs, Entomologist, UMass Extension
Landscape, Nursery and Urban Forestry Program, Amherst.
DISEASES -
Flowering dogwoods (Cornus florida, not Cornus kousa)
susceptible to
dogwood anthracnose
are vulnerable to infection during wet seasons. Apply
fungicide to protect developing leaves on high value
trees, as the buds break open, again when bracts have
fallen, and ~4 weeks later. If this is a persistent
problem, consider planting one of the many resistant
cultivars of flowering dogwood and Kousa dogwood now
available.
Apply fungicides to protect emerging apple and
crabapple leaves from
apple scab
as the buds turn pink, again around petal fall, followed
by 1-2 additional times at 7-10 day intervals (assuming
wet conditions linger). In addition, prune densely
branched trees to increase air circulation and sunlight
penetration that speeds drying of foliage. There are
numerous resistant varieties of apple, crabapple, and
mountainash to grow and simplify disease management.
It is difficult to determine based on field symptoms
alone whether or not junipers with browning foliage have
the disease juniper blight or suffered
damage from another agent. Environmental stresses such
as soil compaction, snow and ice damage, deicing salt
exposure, and physical bruises often result in browning
of foliage that looks like a juniper blight disease.
During dry weather remove and destroy dead foliage to
improve the plant’s appearance as well as reduce juniper
blight inoculum if that should be present. If it clear
there is juniper blight caused by Phomopsis
juniperovora, begin fungicide control as new growth
emerges, and repeat applications if wetness persists. If
the problem persists, gradually replace problem junipers
with disease-resistant shrubs better adapted to the
site.
Maximize the effectiveness fungicide treatments in
the management of
black spot on rose
by initiating them now as buds swell and repeat
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.
Gymnosporangium rust fruiting
structures are noticeable on eastern red cedar (really a
juniper) and Rocky mountain juniper, as well as the
occasional Chinese, common, creeping, and savin juniper.
Specifically,
cedar-apple rust
galls are visible on eastern red cedar as eruptions of
orange, gelatinous masses protruding from pea- to golf
ball-sized galls. These fruiting structures release
spores that infect the leaves of alternate hosts such as
apple and crabapple at this time of the year during
cool, rainy periods. Likewise, fruiting structures of
quince rust
are visible as red-orange “cracks” in the bark of
infected branches on several of these junipers. Leaves
and fruit of amelanchier, crabapple, and hawthorn are
common alternate host of quince rust. Because the damage
to tree health is so minor, chemical interventions are
seldom worthwhile except with specimen or nursery
plants. Now is the time to begin fungicide applications
to protect leaves, green shoots, and fruit of the
susceptible, high value alternate rosaceous hosts from
Gymnosporangium rust infections. Treat susceptible
rosaceous host plants 2-3 times at labeled intervals.
Status of Phytophthora ramorum in
2007:
Forest Detection Survey - There was
no report this week.
Federal Regulation, State Inspection, Nursery
Survey, and Other Finds - There was no report
this week.
Reported by Dan Gillman,
Plant Pathologist, UMass Extension Plant Diagnostic Lab,
Amherst
WEEDS -
The warm weather of the last couple of days
has moved winter annuals along. Continue the treatment of
winter annuals and perennials in ornamental
beds with glyphosate or glufosinate. Monitor beds for annual
weed germination. If they are still weed free, apply a
preemergence herbicide.
Garlic mustard - (See last
week’s message.)
There are a large number of weeds of the mustard
family in ornamental beds this spring. Attempt
to control them before they seed. Species include
bittercress, whitlowwort, shepard’s-purse, pennycress,
and Virginia pepperweed.
Visit the UMass Weed Herbarium, click on Sort
list by Family Name. Then, select Brassicaceae (Cruciferae)
- Mustard Family to see images.
Reported by Randall Prostak,
Weed Specialist, UMass Extension Landscape, Nursery and Urban
Forestry Program, Amherst
LANDSCAPE TURF
WEEDS -
Forsythia has completed its flowering period.
Therefore, preemergence herbicide applications
should be finished by now. Any remaining preemergence
applications should be made with dithiopyr products and,
preferably, those that are a sprayable formulation. See
last week's message for explanation.
Still more calls and emails on
star-of-Bethlehem infestations. First, let me
state that paraquat is not a viable control strategy for
us in the north who are managing cool-season turfs
despite what information many are finding on the
Internet’s web. Some control strategies include: 1)
ignore them and wait until they go away as we get warmer
days, 2) diligently dig up clumps and reseed, or 3)
apply an herbicide product that contains the active
ingredient carfentrazone.
Wild garlic is noticeable now.
Ignore it and it will go away, or treat it with a
broadleaf turf herbicide. Control is increased if weed
is stepped on or rolled before application. Granular
broadleaf herbicide formulations should not be used.
Dandelion and violet can now be
treated with postemergence broadleaf herbicide products.
Reported by Randall Prostak,
Weed Specialist, UMass Extension Landscape, Nursery and
Urban Forestry Program, Amherst.
DIAGNOSTIC SERVICES
UMass 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 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 May 25, 2007
|
PLEASE
LET US
KNOW
HOW WE'RE
DOING!
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our continuing effort to serve you better, we would
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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.
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