Common name: Peachtree borer and lesser peachtree borer
Scientific name: Synanthedon exitiosa and Synanthedon pictipes
Hosts: Peachtree borer (Synanthedon exitiosa) attacks trees in the genus Prunus (peach, nectarine, apricot, plum, cherry, flowering almond, and purple-leaf sand cherry).
Older plants and those under stress are particularly susceptible, but healthy trees can be attacked.
The peachtree borer, which is native to much of North America, can do extensive damage to host trees.
There is a related species, the lesser peachtree borer (Synanthedon pictipes), which is found primarily in the eastern half of the United States.
Damage
Peachtree borer is damaging in the larval stage. The larvae bore into the trunks of the host plant near ground level. They feed in under the bark, forming tunnels. This damage can girdle the entire tree. Feeding can also occur in the roots, and this can reduce the vigor of the tree.
A thick amber colored gum often oozes from wounds made by the borer. Trees in the genus Prunus may produce gum for other reasons. When the cause of the gum is borers, the gum will be mixed with sawdust and excrement.
The lesser peachtree borer does similar damage, but the damage often occurs in major branches, or in existing wounds or cankers. Branch dieback can occur. Gum production will occur with this pest as well.
Life Cycle
The peachtree borer overwinters as half-grown larvae in tunnels under the bark. The larvae resume feeding in spring. They will then pupate and the adults will begin to emerge in very late spring. They can continue to emerge over most of the growing season.
The adult borer is a clear-winged moth that resembles a wasp. The male adult has a blue-black body with narrow yellow bands on the abdomen. The female is also blue-black, but with a bright orange band around her abdomen. The insect is about one inch long.
Each female can lay several hundred eggs over the course of six weeks. The eggs are laid in the crevices of the bark, on the lower six inches of the trunk. The eggs hatch into larvae with cream-colored bodies and light brown heads. The newly hatched larvae enter the bark near the areas where they hatched out of the eggs, and they make tunnels as they feed in the vascular tissues.
There is one generation per year.
The lesser peachtree borer has two generations per year. This pest also overwinters as larvae. The larvae pupate in mid-spring, with adult emergence beginning about a month later. Eggs laid by this generation will pupate and develop into the second generation of adults in late summer.
Management
Cultural Management
Trees and shrubs of low vigor, or in a weakened state of health, are especially susceptible to borer attack. Prevention is the key in controlling wood-boring insect pests. Grow only trees and shrubs that are adapted to the area and site. Keep plants healthy and vigorous through proper planting, mulching, watering, fertilizing, pruning, and winter protection practices. Protect trees from injuries. Remove dead limbs or trees promptly to avoid infestations. Remove bark from felled trees if stored for firewood.
Biological Management
Beneficial nematodes are available for management of peachtree borer.
Chemical Management
Systemic insecticides and trunk sprays are available to manage this pest.
The pesticide information presented in this publication is current with federal and state regulations. The user is responsible for determining that the intended use is consistent with the label of the product being used. The information given here is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement made by The Morton Arboretum.
For more information, contact The Morton Arboretum Plant Clinic at630-719-2424 or plantclinic@mortonarb.org.