DESCRIPTION OF THE PEST
The dogwood borer
(Synanthedonscitula)is the larva (immature form) of a clearwing moth that resembles a
wasp. The borer is off-white in color with a reddish-brown head. It is about
5/8-inch long at maturity. The female moth lays eggs on the bark.
Symptoms and damage
The borers can become established
only if they locate a wound or opening in the bark. Inside the tree, they feed
on the cambium, which is where water and food-carrying structures of the tree
are produced. If the cambium is destroyed, branches or the entire tree will
die. Leaves of dogwoods infested with the dogwood borer will often turn red and
drop early. Bark sloughs off around holes on the trunk or branches. In late
summer, a brown sawdust-likeborerfrass (insect waste) may be seen near or below
the holes. Infested young trees can be killed in one to two seasons. Large,
established trees that are infested often lack vigor and have rough, knotty
areas on the trunk and large branches.
best prevention is to keep trees healthy by fertilizing and watering. In
addition, protect the trees from unnecessary wounding, such as from lawn mowers
and string trimmers, as this will reduce the chances of infestation. Permethrin
is labeled for use by the homeowner against dogwood borer .Since dogwood borer adults may
be present from late April through July, several applications may be needed for
good control. Begin treatment in early May and repeat four times at three-week
intervals. Thoroughly spray the trunk, major branches and any wounds on the
bark. Read and follow all label instructions and precautions.