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William Pound, Ohio Department of Agriculture; Amy K. Stone, Daniel A. Herms, David Shetlar, Kelly Harvey, |
Susceptibility of a forested area to gypsy moth damage will depend largely on the composition of species within the wooded area. Gypsy moths can feed on the leaves of more than 500 species of trees and shrubs. The intensity of the infestation will often influence which tree species are at risk. Generally, the trees most at risk include many of the oak species, particularly the white oak, aspen, grey and paper birch, larch, and apple. Tree species generally resistant to gypsy moth include yellow poplar, honey locust, red maple, silver maple, white ash, and dogwood.
There is no "silver bullet" for dealing with gypsy moth. Successful management requires an integrated approach based on a number of techniques. When population densities are high, the safest and most effective tool for preventing widespread defoliation is aerial applications of an insecticide derived from the naturally occurring bacterium, Bacillus thuringiensis, commonly known as Bt.
In regions where gypsy moth has been established for a number of years, natural controls help keep the populations in check during most years. Natural enemies include insect parasites that attack egg and caterpillar stages, predators such as birds, and disease organisms.
Gypsy moth is especially susceptible to a virus, NPV (nucleopolyhedrosis virus), that is often responsible for the crash of high populations. A fungal disease of gypsy moth caused by Entomophaga maimaiga has been introduced into Ohio and is a promising tool for gypsy moth management.