(above) Unseasonal shedding of leaves
while they still have green coloration is
a distinguishing symptom of oak wilt.
(left) An infected tree in Islip, NY
To prevent the spread of oak wilt,
NYSDEC has determined best manage-
ment practices to be followed. Plan
to prune oak trees only from October-
February. This avoids wounding oak
trees during the time nitidulid bee-
tles, which spread oak wilt, are active.
Pruning wounds from March-September
attract the beetles, which may have
spores from diseased trees on them.
These beetles initiate new infection
centers by carrying the disease for
miles and then feeding on new wounds
of healthy trees. Beetles can be attract-
ed to a tree wound within minutes. They
can carry this disease several miles—or
more if infected oak wood is moved by
humans.
Additional benefits of pruning during
October-February include increased
pruner efficiency due to better visibility
of branches and a healthier response to
wounding from the tree. If an oak tree is
wounded when beetles are active, such
as by storm damage, wound dressing is
recommended as a barrier to disease
transmission infestation by the beetles.
NYSDEC has resources available for
green professionals, upon whom we are
relying to help manage oak wilt. Please
visit NYSDEC's oak wilt page and fact-
sheet for more information.
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