Prospects for genetic control of the gypsy moth

Abstract

Male gypsy moths, Lymantria dispar L., that have been irradiated as pupae with a substerilizing dose of gamma radiation (10 krads) and mated with normal females, yield sterile F 1 progeny. This inherited sterility enhances classical sterile-insect release methods, since control is exerted on the target population for two generations with a release in the first generation. However, difficulties associated with large-scale deployment of partially sterile males renders genetic control impractical on a large scale. Diapausing F 1 eggs (progeny of 10-krad male x normal female) can be stockpiled in the laboratory and released into target populations, greatly simplifying deployment of sterile insects. With the release of F 1 eggs, the overflooding of fertile males by F 1 sterile males will reduce reproduction in the year of release, provided that F 1 egg and larval hatch, establishment, development and survival are comparable to that in wild populations. Releasing F 1 egg-masses is a significant step forward in making sterile-insect technology operational for the gypsy moth. Field trials in isolated infestations have been conducted, and the technique has been successfully used in eradicating an isolated population in Bellingham, Washington, U.S.A. Prospects for its continued use in gypsy-moth management programs are discussed.