Male confusion of the nun moth with disparlure at high and low population densities

The feasibility of using the synthetic sex pheromone, disparlure, as a mating confusant of the nun moth (Lymantria monacha L.) was investigated on wild populations occurring in outbreak proportions in Poland and in low density in Czechoslovakia. The size of experimental plots ranged from 1 to 12 hectares. The amounts of pheromone applied were 10 or 20 g/hectare. Three types of slow-release formulations of a racemic mixture of disparlure were tested: (1) a spray formulation with latex as a carrier, (2) a tubing of natural rubber, and (3) sawdust of a porous material used for making tips of fiber-tip pens. All three pheromone formulations prevented significant numbers (98.6-100% in the low density situation, 90-96.2% during the outbreak) of the males from locating a discrete source of pheromone (a trap containing synthetic pheromone or a female) during the whole flight period, indicating long-lasting efficiency of the formulations.