Trap tree and interception trap techniques for management of ambrosia beetles (Coleoptera: Curculionidae) in nursery production

Authors: ADDESSO, KARLA - Tennessee State University; OLIVER, JASON - Tennessee State University; YOUSSEF, NADEER - Tennessee State University; O'NEAL, PAUL - Tennessee State University; Ranger, Christopher; Reding, Michael - Mike; Werle, Christopher

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2018
Publication Date: 1/10/2019
Citation: Addesso, K., Oliver, J., Youssef, N., O'Neal, P., Ranger, C.M., Reding, M.E., Werle, C.T. 2019. Trap tree and interception trap techniques for management of ambrosia beetles (Coleoptera: Curculionidae) in nursery production. Journal of Economic Entomology. 112(2):753-762. https://doi.org/10.1093/jee/toy413.
DOI: https://doi.org/10.1093/jee/toy413

Interpretive Summary: Wood-boring ambrosia beetles are attracted to ethanol, which could potentially be used for their management within ornamental nurseries. A series of experiments were conducted to determine if ethanol-based interception techniques could reduce ambrosia beetle pest pressure. In two experiments, trap trees injected with a high dose of ethanol were positioned in close and distant proximity to trees injected with a low dose of ethanol (simulating a mildly stressed tree) to determine if the high-dose trap trees reduced attacks on the low-dose trees. The high-dose trap trees sustained higher attacks than the low-dose trees and helped to minimize beetle pressure when in close proximity to the low-dose trees. However, the spacing effect was only significant in 2013, so the effectiveness of the trap tree to shield low stress trees from attack was inconsistent across years. In a third experiment, 60-m trap lines with increasing densities of ethanol-baited traps were deployed along a forest edge to determine if beetles could be intercepted before reaching sentinel trap trees or traps placed further in-field from the forest threshold. Trap densities of 2 or 4 traps per trap line were associated with fewer attacks on sentinel trees compared to trap densities of 0, 7, and 13 per line. Trap densities with 2 traps per line also resulted in fewer beetles reaching the sentinel traps compared to no interception traps. The ethanol-based interception techniques we evaluated were not 100% effective and need to be further optimized, but show promise for reducing ambrosia beetle pressure on vulnerable trees. The interception effect also might be enhanced by applying a repellent compound to the crop plants.

Technical Abstract: Wood-boring ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are strongly attracted to ethanol, which could potentially be exploited for management within ornamental nurseries. A series of experiments were conducted to determine if ethanol-based interception techniques could reduce ambrosia beetle pest pressure. In two experiments, trap trees injected with a high dose of ethanol were positioned in close and distant proximity to trees injected with a low dose of ethanol (simulating a mildly stressed tree) to determine if the high-dose trap trees reduced attacks on the low-dose trees. The high-dose trap trees sustained considerably higher attacks than the low-dose trees and helped to minimize beetle pressure when in close proximity to the low-dose trees. However, the spacing effect was only significant in 2013, so the effectiveness of the trap tree to shield low stress trees from attack was inconsistent across years. In a third experiment, 60-m trap lines with increasing densities of ethanol-baited traps were deployed along a forest edge to determine if beetles could be intercepted before reaching sentinel trap trees or traps placed further in-field from the forest threshold. Trap densities of 2 or 4 traps per trap line were associated with fewer attacks on sentinel trees compared to trap densities of 0, 7, and 13 per line. Trap densities with 2 traps per line also resulted in fewer beetles reaching the sentinel traps compared to no interception traps. The ethanol-based interception techniques we evaluated were not 100% effective and need to be further optimized, but show promise for reducing ambrosia beetle pressure on vulnerable trees. The interception effect also might be enhanced by applying a repellent compound to the crop plants.