EFFECTS OF AERIALLY APPLIED GYPCHEK ON GYPSY-MOTH (LEPIDOPTERA, LYMANTRIIDAE) POPULATIONS IN MARYLAND WOODLOTS

Moderate to high density gypsy moth, Lymantria dispar L., populations in eastern and northern Maryland were aerially treated with the nucleopolyhedrosis virus product, Gypchek. A tank mix containing Orzan LS (6% wt/vol) as a sunlight protectant, Pro Mo liquid supplement (12.5% by vol) as a feeding stimulant and humectant, and Rhoplex B60A (2% by vol) as a sticker was applied twice to nine woodlots at the rate of 18.7 liters and 1.25 x 10(12) polyhedral inclusion bodies per ba per application. Compared with numbers in control woodlots, this rate reduced numbers of egg masses by 98% in eastern Maryland, and by 80% in northern Maryland. Differences in defoliation between sprayed and control woodlots in either area were not significant.