UMass Extension Landscape Message #3 March 6, 2008
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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. |
SCOUTING INFORMATION BY REGION
REGIONAL NOTES
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Central Region (Waltham) – General Conditions: Deer
continue to ravage unprotected plants.
ENVIRONMENTAL DATA
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The following growing-degree-day (GDD) and
precipitation data was collected for an approximate one- month
period, February 6, 2008 through March 4, 2008. Soil
temperature and phenological indicators were observed on or
about March 4, 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.
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Region/Location
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2008 GROWING DEGREE DAYS
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Soil Temp
(°F at 4" depth)
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Precipitation
(4-Week Gain)
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|
~4-Week Gain
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Total accumulation for 2008
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Central
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0
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0
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Frozen
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5.45” rain/13.7” snow
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AVERAGE
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1.3
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3.6
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-
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-
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n/a = information not available
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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. |
|
Hopkinton
|
Waltham
|
|
 |
|
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Hamamelis x intermidia (Witchhazel
hybrids)
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b/full
|
full
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*
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begin
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*
|
full
|
*
|
*
|
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Hamamelis x mollis (Chinese
Witchhazel hybrids)
|
*
|
full
|
*
|
*
|
*
|
full
|
*
|
*
|
|
* = no activity
to report/information not available
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CENTRAL REGION - Joann Vieira, Superintendent of
Horticulture, Tower Hill Botanic Garden, Boylston.
WOODY ORNAMENTALS
INSECTS -
Piercing-Sucking Pests:
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Hemlock Woolly Adelgid
- Populations of this pest are resurging in the
state after several years of being reduced in
numbers. Sudden cold in January of 2000, after a
mild entry into winter, reduced HWA populations in
MA significantly. Then, the extended and deep cold
during the winter of 2005, again, reduced their
numbers by as much as 90% in some areas. However,
early indications are that HWA is once again
rebounding in high numbers. Monitor for building
populations and treat in the spring when the weather
is conducive for the application of dormant oil
sprays or the application of a
systemic imidacloprid product. Dr. Joseph Elkinton
at UMass Amherst is currently working on a new
predatory beetle which, initially, shows great
promise as being a natural control for hemlock
woolly adelgid in MA. For more information on the
Laricobius nigrinus beetle, visit the
following web site:
http://www.invasive.org/hwa/laricobius.cfm
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Fiorinia Scale (aka Elongate Hemlock
Scale) - This very serious pest of hemlock
is often found attacking the same trees, at the same
time, as hemlock woolly adelgid. Monitor for the
presence of this pest as well and treat when
appropriate. If left unchecked, Fiorinia scale can
be a devastating pest for hemlock.
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Defoliators:
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Winter Moth - Flight of the adult
moths in late 2007 was, initially, quite noticeable;
but the incidence of earlier than normal snowfall
may have reduced the numbers emerging from the
soil. If so, this event may result in lower numbers
of caterpillars in some areas this coming spring.
However, the eggs of winter moth are difficult to
detect. Starting around early to mid April,
carefully inspect the interior of buds on
susceptible host plants for the activity of this
pest. Dr. Elkinton and his research lab continue to
rear the parasitic fly, Cyzenis albicans,
for release this coming spring in MA. Last year,
they were able to recover some winter moth larvae on
Cape Cod that had been parasitized by flies from
their earlier releases.
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Reported by Robert Childs, Entomologist,
UMass Extension Landscape, Nursery and Urban Forestry Program,
Amherst
Trees and shrubs - The spring of
2007 was wet in many parts of New
England and resulted in a lot of leaf spot and shoot
blight diseases. These diseases, as well as branch
cankers, may disfigure woody plants, but they seldom
kill otherwise healthy plants. However, if leaf spots
and blights were serious problems last year, infected
plant material from last years may produce fungal
fruiting structures this spring that release an
abundance of inoculum. During wet springs, these spores
infect young leaves and shoots. For high value plants
where appearance is important, consider several
applications of fungicides beginning as buds open, if
conditions are wet this spring. Alternatively, consider
replacing plants with recurring leaf spots and blights
with resistant varieties or other plant materials better
adapted to the site.
In addition, scout rosaceous plants watching for
brown-black branches infected with the
fire blight
bacterium, such as crabapple, apple, pear, firethorn,
hawthorn, cotoneaster, and related plants. Remove dead
branches and dispose of them away from the plants to
reduce inoculum. Lilacs with dead shoots from
bacterial blight also benefit from their
removal. Disinfect pruning tools between each cut with
70% ethyl alcohol, a 10% bleach solution, or a
comparable bacterial disinfectant.
Look for swollen branches (twice or more the normal
diameter) on plum and cherry trees infected with
black knot
canker. Prune to remove infected branches, but also to
improve the branch structure within the tree crown.
Removal of inoculum before the fruiting structures erupt
through the bark helps reduce inoculum that could cause
new infections in the spring and is a key factor in
managing this disease.
Reported by Dan Gillman,
Plant Pathologist, UMass Extension Plant Diagnostic Lab,
Amherst
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