Robust manipulations of pest insect behavior using repellents and practical application for integrated pest management

Authors: WALLINFORD, ANNA - Cornell University; Cha, Dong; LINN, CHARLES - Cornell University; WOLFIN, MICHAEL - Cornell University; LOEB, GREGORY - Cornell University

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2017
Publication Date: 7/24/2018
Citation: Wallinford, A.K., Cha, D.H., Linn, C.E., Wolfin, M.S., Loeb, G.M. 2018. Robust manipulations of pest insect behavior using repellents and practical application for integrated pest management. Environmental Entomology. 46(5):1041-1050. https://doi.org/10.1093/ee/nvx125.
DOI: https://doi.org/10.1093/ee/nvx125

Interpretive Summary: Repellent chemicals have huge potential as part of integrated pest management (IPM) programs. However, the lack of a mechanistic understanding on how repellents actually affect insect behavior has limited their application for specific behavioral manipulation necessary for successful IPM. As a part of efforts to develop an effective push-pull management strategy for spotted wing drosophila (SWD), a serious invasive pest of berries and cherries in U.S. and Europe, researchers at the USDA-ARS laboratory in Hilo, HI and Cornell University in Geneva, NY are exploring differences in mode of action of two suggested oviposition deterrents. One compound (1-octen-3-ol) inhibited oviposition prior to SWD’s contact with fruit, while the other compound (geosmin) caused inhibition after the contact, demonstrating potentially different modes of action by 1-octen-3-ol and geosmin. In addition to reporting on lab and field experiments quantifying the affect of these two candidate repellents on behavior and oviposition, this forum paper further discusses more generally how deterrents of different modes of action might be useful to develop more efficient IPM strategies.

Technical Abstract: In agricultural settings, examples of effective control strategies using repellent chemicals in integrated pest management (IPM) are relatively scarce compared to those using attractants. This may be partly due to a poor understanding of how repellents affect insect behavior once they are deployed. Here we attempt to identify potential hallmarks of repellent stimuli that are robust enough for practical use in the field. We explore the literature for success stories using repellents in IPM and we investigate the mechanisms of repellency for two chemical oviposition deterrents for controlling Drosophila suzukii Matsumura, a serious pest of small fruit crops. Drosophila suzukii causes injury by laying her eggs in ripening fruit and resulting larvae make fruit unmarketable. In caged choice tests, reduced oviposition was observed in red raspberry fruit treated with volatile 1-octen-3-ol and geosmin at two initial concentrations (10% & 1%) compared to untreated controls. We used video monitoring to observe fly behavior in these caged choice tests and investigated the mode of action for deterrence through the entire behavioral repertoire leading to oviposition. We observed fewer visitors and more time elapsed before flies first landed on 1-octen-3-ol treated fruit than control fruit and concluded that this odor primarily inhibits behaviors that occur before D.suzukii comes in contact with a potential oviposition substrate (pre-contact). We observed some qualitative differences in pre-contact behavior of flies around geosmin treated fruit, however, we concluded that this odor primarily inhibits behaviors that occur after D.suzukii comes in contact with treated fruit (post-contact). Field trials found reduced oviposition in red raspberry treated with 1-octen-3-ol and a combination of 1-octen-3-ol and geosmin, but no effect of geosmin alone. Recommendations for further study of repellents for practical use in the field are discussed.