Electrophysiological and behavioral responses of the kudzu bug, Megacopta cribrari (Hemiptera: Plataspidae)to volatile compounds identified from, kudzu and soybean plants

Authors: YANG, LIU - Auburn University; HU, XING - Auburn University; Allan, Sandra - Sandy; Alborn, Hans; Bernier, Ulrich

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2019
Publication Date: 3/28/2019
Citation: Yang, L., Hu, X.P., Allan, S.A., Alborn, H.T., Bernier, U.R. 2019. Electrophysiological and behavioral responses of the kudzu bug, Megacopta cribrari (Hemiptera: Plataspidae)to volatile compounds identified from, kudzu and soybean plants. Journal of Agricultural and Food Chemistry. 67(15):4177-4183. https://doi.org/10.1021/acs.jafc.8b06765.
DOI: https://doi.org/10.1021/acs.jafc.8b06765

Interpretive Summary: While a primary host of the invasive kudzu bug is the invasive weed, kudzu, the kudzu bug has an affinity for feeding on soybean causing profound crop damage. The geographic range of this insect continues to expand in the US and measures for improved surveillance and control are needed to combat increased damage to soybean crops. In this study, scientists from Auburn University in collaboration with scientists from USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL, identified volatile chemicals from the kudzu plant and tested their activity to attract the kudzu bug. Several of the volatile chemicals were found to be highly attractive to the bug. These chemicals have promise for development of improved surveillance lures and potentially implementation of host plant-based attractants for semiochemical-based management as a component of an integrated pest management program for the kudzu bug.

Technical Abstract: The kudzu bug, Megacopta cribraria, is a key pest of soybean (Glycine max (L.) Merrill.) in the U.S., and its primary developmental hosts are currently known as kudzu (Pueratia montana (Lour.) Merr. var. lobata (Willd.) Maesen and S. Almeida) and soybean. Electrophysiological and behavioral responses of adult M. cribraria to plant volatile compounds from kudzu and soybean were examined to identify plant semiochemicals used for host location and attraction by M. cribraria. Headspace volatiles collected from undamaged potted soybean and kudzu plants were analyzed by coupled gas chromatography-electroantennographic detection (GC-EAD). Electroantennograms using adult female antennae indicated 11 active compounds. Subsequently, six compounds were identified in gas chromatography-mass spectrometry (GC-MS). These six compounds, along with some previously reported insect attractive chemicals were selected for electroantennogram (EAG) assays. The four chemicals that elicited the strongest EAG responses, 1-octen-3-ol, nonanal, benzaldehyde, and ocimene, were then selected to further confirm dose-dependent responses in EAG and olfactometer bioassays. Significant positive linear responses between antennal activity and chemical concentration were observed for all chemicals tested. Both benzaldehyde and 1-octen-3-ol resulted in dose-dependent responses at higher concentration. Nonanal at 1 µg/µL had a repellent effect, while ocimene had no significant effect on adult M. cribraria behavior in olfactometer bioassays. Our results provide an insight into the probable host location volatiles compounds used by adult M. cribraria. Moreover, these volatile compounds may be useful in developing a semiochemical-based monitoring technique and IPM program for M. cribraria.