North American Eradications of Asian and European Gypsy Moth

Abstract

Although European gypsy moth (Lymantria dispar dispar) is established in the northeastern and northern midwestern parts of North America, members of the three subspecies of gypsy moth are constantly being introduced into new locations. Between 1980 and 2007, multiple eradication efforts targeting gypsy moth populations were conducted in 24 states in the US. In more recent years, eradication efforts have also slowed the westward and southern spread of gypsy moth. Of particular concern are introductions of the Asian and Japanese gypsy moths. The former has a broader host range than L. dispar dispar, and in both strains females are capable of flight. Consequently, the threshold for initiating an eradication effort against Asian and Japanese gypsy moth populations is much lower than it is for European gypsy moth. In some cases, the detection of as few as one Asian gypsy moth could trigger an eradication effort. A critical component that enables eradication projects against gypsy moth to be successful is the availability of a sensitive monitoring tool that can detect very low density, newly-establishing gypsy moth populations. The primary method for eradication of gypsy moth today is use of the HD-1 strain of Bacillus thuringiensis kurstaki (Btk). For eradication programs, aerial applications of Btk are generally applied 2–3 times when early instars are present.