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| Cankerworm |
| Cankerworms
are caterpillars when immature and later develop into moths as adults.
Both Spring and Fall cankerworm eggs hatch about the same time in the spring.
In Massachusetts, hatch occurs about mid-May. The larvae feed on the foliage
of many deciduous trees including: oaks, cherry, elm, apple, maples and
others. For the past 5 years many of the maple trees were severely injured
by these caterpillars. Their feeding initially causes the foliage to become
very tattered in appearance but later they may completely defoliate the
entire host plant if not treated. |
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| Eastern
Tent Caterpillar |
| Primarily found on species
of ornamental crabapples and cherries but sometimes feeds on other deciduous
trees. This tent maker initiates and gradually enlarges its web in the
crotches of the branches of its host. On warm, sunny days, the caterpillars
will emerge from the web and feed on the expanding foliage. Damage can
range from light to heavy defoliation depending on the size of the tree
attacked and the number of webs per tree. The caterpillars are dark, moderately
hairy, and have a distinctive white stripe going down the length of their
backs. During the winter and prior to budbreak, susceptible hosts can be
monitored for the presence of egg masses, which can be pruned out and destroyed. |
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| Birch
Leafminer |
| Gray
birch and the native paper birch are very susceptible host plants. The
tiny larvae of this leaf mining sawfly can incur complete defoliation on
the host plant. Repeated infestations, in consecutive years, can weaken
the host plant to the point where it is invaded by secondary pests such
as the bronze birch borer. The adults appear in May, in Massachusetts,
and their appearance is closely timed to the emergence of new foliage on
the host plant. Adult females require tender, newly expanding foliage within
which to lay their eggs. The eggs quickly hatch and mining begins. One
leaf may support a dozen or more larvae and be completely browned from
their feeding. |
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| Bronze
Birch Borer |
| The
most common hosts are paper birch, European white birch, and gray birch.
Tunneling by the larvae in the vascular portion of the wood leads to a
girdling of the tree and death. Larvae make a tortuous winding mine that
severely injures the vascular system. Initial symptoms may be chlorotic
foliage and a thinning canopy. Adults are active from approximately mid-June
until September. Females lay eggs in roughened area of bark on the main
trunk and the larvae soon hatch and tunnel through the bark and begin mining.
The most important factor in the management of this pest is to keep the
host plant healthy. This pest cannot physically survive in a healthy tree. |
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| Dogwood
Borer |
| Primarily
a pest of flowering dogwood but also may attack flowering cherry, apple
and various deciduous hosts. Flowering dogwoods that are older and especially
those that have been wounded by mowers or line trimmers are most susceptible.
Entrance holes with exuded sawdust are to be found on the main trunk and
on larger branches. Larvae feed in the inner bark area and damage the vascular
system. Classic symptoms of infestation are top dieback of the plant, adventitious
growth along the trunk, main branches and base of the trunk. Repeated infestations
can greatly diminish the health and aesthetic appearance of the host. The
clear winged moth adults of this pest appear around the time when the last
of the petals have fallen from flowering dogwood. |
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| Black
Vine Weevil |
| Primarily
a problem in the landscape on taxus and rhododendron. It can also be found
on several other broad-leaved evergreens including azalea, mountain laurel
and Euonymus. Adults feed along leaf/needle margins leaving distinctive
hemi-spherical notches. Larave feed on the fine, of the host plant, in
the fall and on larger roots in the spring. Leaves will yellow and plants
may be stunted or die. Larvae cause the greatest level of injury to the
host plant. The adult black vine weevil is black with subtle white flecking.
Larvae resume feeding on roots in the early spring, causing the heaviest
damage. Adults begin emerging in June and continue through July. Adults
feed at night and hide around the base of the plant during the day. Monitor
for adult damage to host plant in March through November by inspecting
foliage for notching. |
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| Hemlock
Woolly Adelgid |
It
attacks both the Carolina and Eastern hemlock and is capable of severely
weakening and killing its host plants. The Hemlock Woolly Adelgid is a
tiny insect that is closely related to the aphids. The HWA produces woolly
masses. This insect is atypical of most insect species in the Northeast
in that it is inactive for much of the growing season and very active throughout
the winter. From mid-July until mid-October, they are immatures and are
flat, black, oval and ringed with a fringe of white waxy strands. In mid-October,
they resume feeding by using their piercing-sucking mouthparets to remove
plant sap from the twigs of the host plant. While they feed, they develop
into adults with new egg masses appearing beginning in March. These are
the most noticeable stage of the pest and have the appearance of small,
white cotton balls lined up at the base of the needles.
All photos courtesy of R. Childs |
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