Location: Application Technology Research Unit
Title: Electrophysiological and Behavioral Responses of the Ambrosia Beetle, Xylosandrus germanus, to Repellent Formulations Authors
Submitted to: National Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 23, 2009
Publication Date: December 13, 2009
Citation: Ranger, C.M., Reding, M.E., Oliver, J., Schultz, P. 2009.Electrophysiological and Behavioral Responses of the Ambrosia Beetle, Xylosandrus germanus, to Repellent Formulations. National Entomological Society of America Annual Meeting, December 13-16, 2009, Indianapolis, Indiana. Technical Abstract: Exotic ambrosia beetles are increasingly being recognized as key pests of ornamental nursery stock, and Xylosandrus germanus is one of the most problematic species. Conventional insecticides are used almost exclusively by growers in an attempt to prevent attacks by X. germanus. Due to the importance of host-derived volatile compounds in the host-selection behavior of X. germanus, repellent formulations may instead be used to repel host-seeking ambrosia beetles away from valuable nursery stock. Electrophysiological, behavioral, and field efficacy experiments were subsequently conducted in an attempt to identify botanical formulations with repellence to X. germanus and other ambrosia beetles. Six commercially-available botanical formulations were evaluated against adult female X. germanus, namely, Armorex, Azatin, Cinnacure, Eco-Trol, Triact, and Veggie Pharm. The electroantennographic (EAG) response of X. germanus varied depending on the botanical formulation, but Eco-Trol and Cinnacure elicited significantly higher EAG responses than the remaining formulations. Eco-Trol and Cinnacure also elicited repellence to X. germanus in olfactometer experiments at 0.1% dilution, while the remaining commercially-available formulations were not considered repellent. Efficacy trials of the botanical formulations were conducted following the electrophysiological and behavioral experiments. Prior to the application of the botanical formulations, multistem Magnolia virginiana trees were injected with 75 ml of 50% ethanol in order to ensure ambrosia beetle pressure. Tunnel entrances were then counted on the M. virginiana trees associated with each treatment. The selected commercially-available botanical formulations varied in their ability to disrupt colonization by X. germanus and other ambrosia beetles. Two weeks after application, the fewest ambrosia beetle tunnel entrances were created in M. virginiana trees treated with Veggie Pharm and Armorex. The mean number of attacks did not differ among Cinnacure, Eco-Trol, and the untreated control. EAG and olfactometer studies involving these botanical formulations therefore did not accurately predict their efficacy under field conditions. However, results from these experiments determined Veggie Pharm and Armorex are promising commercially-available botanical formulations against X. germanus. The overall goal is to incorporate repellents and odor-based trap trees into a push-pull management strategy, whereby repellents push host-seeking beetles away from valuable nursery stock and attractants pull beetles into specific trap trees prior to their disposal.