PHEROMONE DISRUPTION CONTROLS DOUGLAS-FIR TUSSOCK MOTH (LEPIDOPTERA: LYMANTRIIDAE) REPRODUCTION AT HIGH INSECT DENSITIES

Abstract
Hollow fibers containing synthetic pheromone (Z-6-heneicosen-11-one) were applied by helicopter to six plots of about 8 ha each. Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), had reached such high population levels on the plots that trees in some areas were completely defoliated. Reproduction of the moths was reduced 71 and 81%, respectively, at dosages of 8 and 25 g of pheromone/ha relative to untreated control plots.