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How to Manage Pests

UC Pest Management Guidelines

Girdling of fig limbs caused by carpenterworm feeding.



Scientific Name: Prionoxystus robiniae

(Reviewed 7/06, updated 7/06)

In this Guideline:


Carpenterworm larvae are woodboring insects and attack many species of deciduous fruit trees. Eggs are laid in crevices in the bark; the larvae hatch out by boring through the bottom of the egg directly into the wood. Larvae are cream colored with a brown head capsule and have conspicuous spots surrounding the scattered hairs on the body. They grow to about 2 inches long. The adult carpenterworm is a large, gray and brown, mottled moth with a wing span of about 2.25 inches. Females are heavy bodied and cannot fly more than a few yards. They have one generation per year with the adults emerging from pupation in late April through June.

Carpenterworm larvae burrow in the cambium layer of the tree and eventually girdle the limb, causing it to die. Active galleries can be recognized by copious amounts of sap and sawdust that result from the larvae cleaning out their burrows.


Carpenterworms infest several species of native hosts in river bottom areas. Therefore, orchards planted near riparian habitats are more prone to attack. Because adults cannot fly very far, the infestation is slow to spread through the orchard. Prune infested wood judiciously to slow down the spread of the insect. Maintain trees in vigorous growth to help them tolerate damage longer.

Commercial preparations of the entomophagous nematode Steinernema feltiae (Neoaplectana carpocapsae), such as Scanmask, have been found to give good control of the carpenterworm. Follow supplier's directions for application of their particular preparation.



[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Fig
UC ANR Publication 3447
Insects and Mites
R. L. Coviello, UC UC Cooperative Extension, Fresno County
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier

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