Evaluation of a nonconventional insecticide and appropriate application timing for destruction of gypsy moth (Lepidoptera: Lymantriidae) egg masses

Abstract

Two field studies were conducted in 2001-2002 and 2003 to evaluate the effectiveness and appropriate application timing of Golden Pest Spray Oil (GPSO) for destruction of gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), egg masses in Wisconsin. GPSO is a commercially available, registered pesticide that is predominantly comprised of a soybean-oil base (93%); its primary mode of action is by means of suffocation. Because gypsy moth spends the majority (>75%) of its life cycle in the egg stage (August-April), the potential utility of this product by arborists, city foresters, landscapers, and homeowners is high, especially because GPSO is a United States Environmental Protection Agency registered, nonconventional pesticide that is considered relatively nontoxic. When GPSO was applied at a 1:1 ratio with water, >96% control of gypsy moth egg masses was achieved, regardless of application timing (October, 3 d before egg hatch).