Wednesday, August 13, 2008

Landscape - Peachtree Borers in Ornamental Trees

The peachtree borer is native to North America. It is an importance pest around most peach-growing areas, and in the landscape will attack, cherry, plum, laurel, and other Prunus species of ornamental trees and shrubs. You will want to apply late summer controls in August. The following is more information.

Borer infestations can be detected by the presence of gum and frass around the base of a tree. The exudate around new feeding damage is soft, sticky, and light brown in color, while older damage is marked by hard sap and dark brown frass. Symptoms are often first noticed in the spring.


Adults are day-flying moths which resemble wasps in appearance and behavior. The female is bluish black with a bright orange band around the fourth or fifth abdominal segment. Her body may be up to 3/4" in length. The male moth is smaller with transparent areas in both front and hind wings. The hind edges of the second through sixth abdominal segments may be marked with yellow scales giving it several thin yellow bands.

Larvae are creamy in color with a brown head and three tiny pairs of legs on the thorax. Fully grown larvae may reach 1.5 inches in length.

Female moths lay eggs in crevices or under rough bark on the tree trunk around the lower portion of the trunk or near the crown. Larvae hatch in 8-9 days and attack the main trunk and larger roots near the soil surface. They feed on cambium tissue and may eventualy weaken or kill the tree. Borers overwinter as larvae in the tunnels and resume feeding the following spring. Most individuals complete development during the summer. Part of the population may require two years to complete the life cycle. Pupation occurs within a silken cocoon covered with chewed wood and frass.

About 99% of the cocoons are formed on the base of the trunk or in the soil within 3 or 4 inches of the tree. In Delaware, adults may emerge from early May to November, but the peak emergence usually occurs about September 1. Females mate about one hour after emerging from the cocoon and start laying eggs soon after mating is completed. They may lay over 1200 eggs with near 100% fertility.


In the landscape, literature sometimes suggests attempting to stab larvae in tunnels with a wire. This is laborious and difficult to accomplish. There are no effective chemicals for larvae already tunneling within the trunk or roots. Suggestions of paradichlorobenzene (PDB) or moth crystals in the soil are also not recommended. Management is aimed at chemical protective barriers to either discourage egg laying, or kill the tiny larvae upon hatching.

Suitable chemicals usually contain the ingredient permethrin. They need to be applied to the bark at the base and lower part of the trunk several times during the season, but especially before and after the peak moth emergence about the first of September. Commercial operations may use sex pheromone traps to monitor the population. The first few days of adult emergence are usually comprised of males. Chlorantraniliprole (Acelepryn) is a systemic labeled for clearwing borers.

Home owners may use multi-purpose landscape sprays labeled for borers containing active ingredients such as permethrin, esfenvalerate or cyfluthrin.

Information from "Peachtree Borer in the Landscape" by Stephen Bambara, Extension Entomologist, North Carolina State University.

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