Ambrosia Beetle Diversity, Vector Potential and Response to Solarization Treatments Associated with Sassafras Trees Killed by Laurel Wilt

Riney Woodbridge

Environmental Studies

Albert Mayfield and Irene Rossell

Laurel wilt is a plant disease caused by the fungus Harringtonia lauricola and vectored by the invasive red bay ambrosia beetle (Xyleborus glabaratus),. Laurel wilt affects trees in the Lauraceae family and has caused extensive mortality of redbay (Persea borbonia), forests in the southeastern US. The disease is currently spreading north on sassafras (Sassafras albidum),, which is also in the Lauraceae family. Other species of ambrosia beetles colonize dead host trees and are able to carry the H. lauricola fungus. My study investigated the presence of ambrosia beetles and H. lauricola in sassafras trees in an area recently infected with laurel wilt. I also evaluated the use of solarization (covering infested material with plastic sheeting to kill insects and pathogens with heat),, as a potential method for sanitizing infested sassafras. Emerging ambrosia beetles were collected from felled sassafras trees killed by laurel wilt. The diversity of beetle communities found within sassafras trees was compared to that captured in funnel traps, and live beetles that emerged from sassafras logs were tested for H. lauricola. To evaluate solarization, infested material was wrapped in plastic sheeting and left in the sun. After one month, beetle emergence from solarized logs was compared to emergence from controls. We did not recover any redbay ambrosia beetles in funnel traps or within felled trees. The overall ambrosia beetle community in sassafras logs was more diverse than in funnel traps, but seasonality is likely a key factor in this finding. The pathogen H. lauricola was recovered from several ambrosia beetle species, including species not previously documented as carrying the fungus. Solarization reduced beetle emergence, but not significantly. Improvements on methodology are discussed as a way to further evaluate solarization as a viable method for sanitization.

Jan-9-2024