Control of ambrosia beetles and laurel wilt with repellents in forest systems and avocado groves

Laurel wilt is a disease caused by the Phytopathogenic fungus Raffaela lauricola that affects Lauraceae trees in the Southeastern U.S. The fungus is predominately transmitted by the redbay ambrosia beetle Xyleborus glabratus in forest on redbay and swamp bay, whereas a group of different ambrosia beetle species vectors the fungus in avocado. This presentation will review the work we conducted to control laurel wilt with repellents in these two different systems. In forest, three 8-month field trials were conducted in central and north Florida. The trials demonstrated that verbenone repelled significantly the redbay ambrosia beetle and decreased mortality of laurel trees due to laurel wilt. The addition of attractive alpha-copaene lures did not improve the efficacy of the system. In avocado grove, we evaluated a push pull system using a mixture of verbenone and methyl salicylate as repellent, and ethanol lures as attractant. The push-pull system significantly reduced the number of different species of ambrosia beetles landing on avocado trees. We are investigating the addition of visual attractants to improve this push-pull system. In both systems, verbenone-based repellents showed potential to control ambrosia beetles and laurel wilt.