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Developing attractants and deterrents for a push-pull striped cucumber beetle management system
In insect pest management, the plant volatiles and pheromones associated with host-plant location can be used to manipulate insect pest behavior by attracting or “pulling” insects from a valuable resource. Conversely, deterrents can be used to prevent behaviors or “push” insects away from a resource. If combined, attractants and deterrents can have powerful synergistic effects that promote greater response than the individual components. This dissertation explores the use of attractants and deterrents of the specialist herbivore and challenging agricultural pest, the striped cucumber beetle, Acalymma vittatum, to ultimately develop a push-pull management system.
In first chapter, we examine the combination of two striped cucumber beetle attractants in attract-and-kill mass trapping: live striped cucumber beetles as a proxy for aggregation pheromone, and cucurbit floral volatiles. In the second chapter, we examine natural products—essential oils, pawpaw extract, squash bugs, and kaolin clay—as a means for repelling or deterring beetles from cucurbit crops. Lastly, we combine the findings of previous chapters as way of using both attractive and deterrents to further modify striped cucumber beetle behavior and to observe potential synergies in removing these pests from cucurbit crops. In this, we use the aggregation pheromone and floral lures in attract-and-kill trapping with the deterrent kaolin.
We found that while aggregation pheromones and floral lures were useful in trapping striped cucumber beetles, floral lures may potentially distract pollinators. Striped cucumber beetle response to floral lures varied across the season and were most attractive in the late growing season, when plants were in bloom. The tested natural products did not successfully prevent beetles from colonizing plants, but instead deterred the specialist herbivore from feeding. While the attractant and deterrent did not have a synergistic effect, they remained complementary in that aggregation pheromones were useful in reducing pest populations, while kaolin clay deterred feeding. Thus, pest management systems should be flexible in timing and type of management used, and should look toward other metrics, such as feeding damage, rather than population density thresholds to measure management success.