Efficacy of pheromone-baited traps for detection and quantitative sampling of longtailed mealybug (Pseudococcidae: Psuedococcus longispinus) in production nurseries

Pseudococcus longispinus (Targioni-Tozzetti) is one of several key mealybug pest species in California nurseries that produce ornamental plants. Our recent research has shown that the number of male longtailed mealybugs caught in pheromone-baited traps correlated well with the density of mealybugs on plant material. Thus, on three sampling dates, multiple replicates of pheromone-baited traps were deployed in a commercial nursery growing Ruscus hypoglossum (Ruscaceae), an ornamental, cut-foliage crop. Stems of the crop were removed and destructively sampled for mealybugs at a distance of 1 meter from each trap, in the 4 cardinal directions. There was a highly significant correlation between trap catches and mealybug densities, on all three sampling dates. These results demonstrate that pheromone-baited traps can be used to assess not only the presence of mealybugs, but also their density in a crop. In additional studies, pheromone-baited traps deployed continuously for two years were used to assess seasonal trends in mealybug populations. In both years, populations were highest during the late fall and winter months. Optimal pheromone dose and effective field lifetimes of lures also were determined. Continuously deployed lures containing 25 micrograms of pheromone attracted male P. longispinus for at least 12 weeks under field conditions. Overall, our results demonstrate that pheromone-baited traps may be valuable tools for both detection of incipient pest problems, and for improved timing of pest management measures.