NEW DISPENSER FOR THE PHEROMONE OF THE GYPSY-MOTH (LEPIDOPTERA, LYMANTRIIDAE)

A new dispenser for (+)-disparlure was designed for use in gypsy moth, Lymantria dispar (L.), detection traps; this new dispenser is an alte rnative to the currently used plastic laminate. The dispenser consists of twisted nylon twine coated with polyvinyl chloride containing 500 mug of the pheromone. Comparison tests showed that this twine dispense r prolonged the release of (+)-disparlure at a rate greater-than-or-eq ual-to 30 ng/h for longer (240 versus 80 h) than did the 1989 batch of the standard laminate dispensers in an accelerated oven aging test at 59-degrees-C. Field tests showed that male moth captures with twine d ispensers, pre-aged 16 wk in a greenhouse, were as high as or higher t han those with unaged, laminate dispensers (from either 1988 or 1989 b atches). Pheromone contents and release rates as a function of duratio n of aging showed extended and more effective delivery of the active i ngredient by the twine dispenser in comparison with the laminate dispe nser. The twine dispenser is simple and inexpensive to make and is at least as effective as the presently used laminate dispenser.