Prospects for novel approaches towards management of the diamondback moth

Primary reliance on synthetic insecticides for control of diamondback moth has usually failed because of insecticide resistance and/or reduction of natural enemies by insecticides. Insecticide resistance has also been more recently documented with biological insecticides such as Bacillus thuringiensis and some growth regulators. Insecticide resistance management programs must be implemented and new alternative management strategies must be developed. Our laboratory has documented high levels of resistance to the major insecticides, including Bacillus thuringiensis subsp. kurstaki, used against diamondback moth and proposed discriminating doses to assess potential field performance. Additionally, we have tested resistance management strategies for use of Bacillus thuringiensis when applied as a foliar spray and when incorporated into plants. Such strategies include both refuge size and placement. In laboratory, greenhouse and field studies we have promising results for managing diamondback moth using foliar sprays of a commercial formulation of Beauveria bassiana. However, we have had less promising results controlling diamondback moth through the presently available technology for mating disruption using pheromones.