Effect of Aerial Application of Racemic Disparlure on Male Trap Catch and Female Mating Success of Gypsy Moth (Lepidoptera: Lymantriidae)1

Abstract

Studies were conducted in Cecil County, Md., during the summer of 1980 using racemic disparlure to disrupt mating communication of the gypsy moth, Lymantria dispar (L.). A laminated plastic flake formulation of racemic disparlure was applied aerially at rates of 0, 7.5, 30, or 75 g (AI)/ha to replicated 16-ha forest plots. Significant decreases in male trap catch and in mating success for three different female types (lab females [from a laboratory colony], wild females [pupae obtained from the field, adults emerged in the laboratory, then replaced in the field], and natural females [occurring naturally in the test plot]) were observed with increasing disruptant dose. Although degree of mating success was highly correlated for all three female types, differences among female types in slope, intercept, and linear and quadratic relationships were observed. Generally, plots having higher populations (as measured by larval counts) among replicate plots for each dose also had increased mating for all female types. The flake formulation was easily applied and provided season-long mating disruption.