Symptoms
Large round exit holes in trunk. Coarse sawdust-like frass piled around holes. Girdling of trunk or major branches. Weakened trees susceptible to wind breakage at tunneled points. Sap exudation from entry points.
Prevention
Maintain tree health through proper nutrition and irrigation. Protect bark from mechanical wounds. Apply white wash to lower trunk. Remove and destroy dead wood. High-value trees can be wrapped with wire mesh to exclude adults.
Treatment
Organic
Insert entomopathogenic nematodes into bore holes using a syringe and seal with mud or wax. Apply Beauveria bassiana paste to entry holes. Prune and destroy heavily infested limbs.
Chemical (last resort)
Inject chlorpyrifos solution into bore holes and seal. Apply contact insecticides to bark surface to kill newly hatched larvae before they bore in. Systemic insecticides have limited efficacy for established borers.
Affects 1 crop
Sources
MARDI Durian Production Guide; DOA Extension Bulletin