Shoot, stem and trunk borers

By The Old House Web

Shoot, stem and trunk borers

List of files and visuals associated with this text.


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.

Visuals associated with this text.

Visual title - Visual size Visual title - Visual size
Two-lined chestnut borer - 82K Flat-headed apple tree borer larva - 11K
Lilac borer - 37K
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