This pest overwinters in the burrows as a inch long mature larva. There is one generation per year. The boring activities of the larvae cause wilted, off-color foliage, reduced growth and dead branches. Monitoring Prune wilting branches and cut them open and try to locate the larvae. Pheromone traps can be used to determine if a rhododendron borer population is present and when it is active.
Pheromones are chemicals given off by the female to attract males in order to mate.
The traps only lure males, which do not lay eggs, and, thus, will not endanger the plants. Control Prune and destroy wilting branches in late summer or early spring. Spray branches with chlorpyrifos 10 to 14 days after the first males are caught in the pheromone trap, usually about mid-June. A second spray may be needed in four weeks if adults continue to be captured in traps. The body is pale yellow.