Dependence of Gypsy Moth (Lepidoptera: Lymantriidae) Capture on Pheromone Release Rate from Laminate and Other Dispensers

Emission rates from cotton wicks baited with 1-400 μg of (+)-disparlure ranged from 7 to 2,000 ng/h at 35°C in a laboratory oven. A 100-μgdose, which is a reference in field tests, produced a rate of 470 ng/h. Release rates, residual lure contents, and captures of male gypsy moths, Lymantria dispar (L.), were correlated with duration of greenhouse aging. High male captures were obtained in tests with controlled-release, plastic laminate dispensers when the pheromone release rate was at least 30 ng/h and the residual content was at least 100 μg. These thresholds were provided by laminates aged in a greenhouse (mean low, 24.4-27.5°C; mean high, 36.7-39.1°C) for as long as 8-11 wk. Release rates from the laminates increased 3.5-fold for each 10°C increase in temperature. Several commercial dispensers with (+)-disparlure were evaluated, but the laminate design generally performed better than other designs with respect to the number of males captured.