How to Manage Pests

Parasites of western grapeleaf skeletonizer

Two insect parasites, Apanteles harrisinae and Ametadoria misella, attack western grapeleaf skeletonizer larvae.

A. harrisinae is a parasitic wasp that attacks early larval instars and usually deposits three to nine eggs in a host. Fully grown parasite larvae emerge from the fully grown host larva immediately after it has spun its cocoon. The cocoons are spun within the cocoon of the host, surrounding the dead caterpillar.

The parasitic fly, A. misella, prefers to attack fourth and fifth instars. Larviposition occurs during the middle of the day and larvae immediately penetrate the host. Little development occurs until the host larva turns into the pupal stage. The parasite larva then develops rapidly and soon kills the host pupa. Its puparium is always formed within the host cocoon.