Development of a combined sex pheromone-based monitoring system to detect population density changes and monitor moth condition of Malacosoma disstria and Choristoneura conflictana

A combined sex pheromone-based monitoring tool was developed for the aspen defoliators Malacosoma disstria and Choristoneura conflictana in Alberta, Canada. A system employing a single synthetic pheromone blend formulated in one lure to monitor two forest pests simultaneously represents a novel approach. The combined lure attracted both M. disstria and C. conflictana males throughout their flight period but lure age had a negative effect on attraction of M. disstria. Male moth captures were related to abundance of immature stages both within and between generations for each species but were not predictive of immature counts in the subsequent generation for either species. The combined lure does not attract M. disstria males in direct proportion to population density. Captured males of each species were measured for wing area and pathogen load as indicators of moth condition. The application of pheromone trapping for ecological studies is discussed.