Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001719
11/12/99
Shoot, stem and trunk borers
Most borers are capable of successfully attacking only
trees that are dying or under considerable stress from
drought or some other source. Proper watering and tree
care are the first-line defense against borer injuries.
Good cultural practices can also help an infested tree to
better tolerate borer injuries.
Insecticidal control approaches require that the
insecticide be in place on the bark when the adult stages
of the insect are laying eggs and the eggs are hatching.
The timing of these life stages varies with different
borer species and often lasts a month or longer.
Consequently, repeat applications are often necessary for
control. After the eggs have hatched and the borers have
moved under the bark, insecticide treatments are
ineffective. Pheromone traps are available to aid in
timing treatments to control clear-wing moth borers (peach
tree, lilac and ash borers).
Flat-headed wood borers
The flat-headed wood borers include several destructive
pests of forest and shade trees. The adults are 5 to 15
mm long and somewhat flattened and have a beautiful
metallic shine. The larvae are all wood borers that
tunnel under the bark of trees. The first thoracic
segment is strongly flattened, giving the larvae the name
flat-headed wood borers. The larvae are white and
legless. The most familiar member of this group is the
bronze birch borer.
Round-headed wood borers
The adults of this family are called long-horned beetles
because of their extremely long antennae. Some species
have long legs as well. The common locust borer and
several related species are chestnut brown with bright
yellow stripes and mimic a wasp. The larvae are white,
segmented worms, with slightly enlarged, round heads.
They lack visible legs. Larvae bore under the bark of
trees into the wood. Some species are very destructive.
Clear-wing borers
Adults of this family are known as clear-wing moths
because the wings lack scales. Adult clear-wings mimic
wasps in color and hovering behavior. The larvae are
white, legless worms that resemble round-headed wood
borers. Clear-wing borers, however, do not have enlarged,
rounded heads. The larvae bore into roots, stalks,
branches and trunks of many species of trees and shrubs.
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This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
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