Key unknowns about Asian citrus psyllid biology in Florida: Overwintering sites and alternative hosts

Dormant sprays are currently an effective tactic for managing the Asian citrus psyllid (ACP), Diaphorina citri.  Although effective for reducing ACP populations, dormant sprays for managing ACP may not always prevent resurgence of their populations in the spring. Furthermore, inadequate knowledge of ACP overwintering habits limits our ability to improve upon existing winter management techniques.  We propose to identify ACP overwintering habits within citrus trees and to identify alternative hosts in major Florida citrus growing regions (specific to the dormant winter season) by: 1) sampling natural ACP populations in trees, 2) fogging individual trees as a method of insect sampling, and 3) conducting mark-recapture experiments in controlled field experiments during the winter, spring, summer, and fall seasons within both commercial groves and their surrounding habitats. In addition, forced oviposition (egg-laying) and feeding studies will be conducted in controlled settings with alternative hosts to determine their capacity to serve as overwintering sites for ACP. We will also determine the effect of heat (spring, summer conditions) and cold (winter conditions) acclimation on the susceptibility of ACP to insecticides.  It is expected that the results from this work will provide vital information for enhancing winter management practices for ACP control. This should further improve current management tactics, such as dormant insecticide spray application, in order to optimally reduce ACP populations during the weakest point of their annual lifecycle—the dormant winter season, when little to no reproduction is occurring.