Assessment of Hand-Applied Pheromone Dispenser Densities and Efficacy of Mating Disruption Plots on Management of Plutella xylostella (L.) (Lepidoptera: Plutellidae)

The diamondback moth, Plutella xylostella (L.), is a significant threat to brassica producers around the globe. Insecticide-resistant P. xylostella populations are increasing across the United States as frequent insecticide applications remain common. Alternative control tactics, such as mating disruption, have been developed for P. xylostella and can be useful for managing populations in brassica systems. To measure the efficacy of mating disruption for reducing P. xylostella trap captures in the field, two experimental studies were designed to: (1) evaluate the dispenser density needed to reduce P. xylostella trap captures and (2) test hand-applied dispensers under commercial field conditions. Results from the dispenser density study showed P. xylostella trap captures were significantly reduced in plots treated with 32 dispensers per 0.4 ha. In plots treated with zero dispensers, a total of 78.1% of plants scouted were damaged by larval feeding. In Experiment 2, P. xylostella trap captures were significantly reduced in treated plots. Larval abundance and plant damage ratings did not differ between plots. These studies indicate that hand-applied pheromone dispensers at 32 dispensers per 0.4 ha can reduce adult P. xylostella trap captures in commercial broccoli fields.