Abstract

Hoy, M.A. 1982. The gypsy moth — here again. California Agriculture 36(7): 4-6.

During 1981, 41 male gypsy moths were trapped in Santa Barbara County. Lesser numbers were trapped in other southern and northern California counties — Los Angeles (3 months), Marlin (7), San Diego (3), Santa Cruz (2), and Ventura (2). Capture of male moths in traps does not prove that the gypsy moth has become established; those found may have developed from eggs or pupae brought into the state on vehicles and camping equipment from infested areas in the eastern United States. However, intensive surveys in Santa Barbara during the fall and winter revealed four egg masses, indicating that a breeding population of the gypsy moth exists there. Surveys for egg masses at the other locations have been negative to date, so it is unclear if those trap catches indicate establishment. The gypsy moth, Lymantria dispar, is not new to California. Over 400 egg masses were found in Santa Clara County in 1976, and the California Department of Food and Agriculture mounted an apparently successful eradication program against that infestation using two aerial applìcatons of the insect growth regulator difluben-zuron (Dimilin). The impact the gypsy moth might have had upon California’s forest and shade trees, if not eradicated from Santa Barbara or elsewhere in the state, can’t be predicted precisely, because our climate and vegetation are different from those in the northeastern United States, where this pest has occurred for over a century. However, the gypsy moth is likely to be a serious pest in California.