Susceptibility of Hass avocado and native Mexican Lauraceae to attack by redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae)

Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring weevil first detected in 2002 near Savannah, Georgia, USA. The beetle’s dominant fungal symbiont causes laurel wilt, a lethal vascular disease of trees in the family Lauraceae. Laurel wilt and its beetle vector have since spread to 12 southeastern states, resulting in high mortality of native Persea species (redbay P. borbonia, swampbay P. palustris, and silkbay P. humilis) along the coastal plain, and sassafras (Sassafras albidum) at higher elevations inland. In addition, laurel wilt has had a devastating effect on avocado (Persea americana) production in Florida. With continued range expansion, X. glabratus is likely to enter Mexico, threatening native forest species as well as the Mexican avocado industry based predominantly on the Hass cultivar. In advance of such an event, this study was conducted to assess the potential risk posed by X. glabratus. We used freshly cut bolts from Hass avocado and 8 native laurels (collected from Veracruz) to determine boring preferences in lab bioassays and relative attraction in field tests (conducted in Florida). In addition, GS-MS was used to analyze terpenoid emissions from each species to relate behavioral responses with wood phytochemistry. Results indicated that three species (Hass avocado, Persea schiedeana, and Ocotea heribertoi) were highly attractive and likely to be attacked by female X. glabratus with incursion into Mexico. These findings emphasize the need for effective, early detection systems for this invasive pest.