Seasonal and lifecycle changes in behavior affect the trapping efficiency of an insect vector, Circulifer tenellus (Hemiptera: Cicadellidae)

Authors: Foutz, Jillian; Cooper, William - Rodney; Swisher Grimm, Kylie; CROWDER, DAVID - Washington State University

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2024
Publication Date: 3/15/2024
Citation: Foutz, J.J., Cooper, W.R., Swisher Grimm, K.D., Crowder, D. 2024. Seasonal and lifecycle changes in behavior affect the trapping efficiency of an insect vector, Circulifer tenellus (Hemiptera: Cicadellidae). Annals of the Entomological Society of America. 117(3):199-205. https://doi.org/10.1093/aesa/saae011.
DOI: https://doi.org/10.1093/aesa/saae011

Interpretive Summary: Beet leafhopper is an important vector of at least three pathogens of vegetable crops. Crop consultants often use glue-based traps to monitor pests, but low quality of insects removed from these traps makes pathogen detection in insect vectors difficult. 3D printed traps that capture insects in a preservative provide specimens more suitable for pathogen detection, but it was not known whether these traps capture beet leafhopper. Researchers at the USDA-ARS in Wapato WA and Washington State University compared capture of beet leafhopper on glue-based traps and 3D printed traps at two heights. They found that both traps captured more beet leafhoppers at ground level than at waist height. During summer months, glue traps captured more leafhopper adults than 3D printed traps. However, the 3D printed traps captured more beet leafhoppers in fall suggesting a seasonal shift in leafhopper behavior that altered trap efficiency. These results highlight the importance for understanding seasonal insect behaviors when choosing traps and will help crop consultants monitor beet leafhopper and associated plant pathogens.

Technical Abstract: Accurate sampling of pests is the foundation of pest management. Choosing the best trap for pest monitoring can be complex, however, because trap performance is affected by pest preferences and behaviors. Moreover, preservation of DNA in traps is a consideration when insect specimens are used in molecular assays such as detection of insect-borne pathogens. We assessed efficiency of two trap designs and two trap placements on capture of beet leafhopper, Circulifer tenellus (Baker) (Hemiptera: Cicadellidae), vector of “Candidatus Phytoplasma trifolii” and beet curly top virus. Trap designs included standard yellow sticky cards and 3D-printed traps that capture insects directly in a DNA preservative. We found that yellow sticky cards captured more adults than did 3D-printed traps during summer months, but captured fewer adults during autumn when leafhoppers move to overwintering sites. 3D-printed traps captured more nymphs than sticky cards, regardless of season, and traps hung at ground level captured more nymphs and adults compared to traps at 1-m height. Contrary to predictions, we did not find differences between trap types in molecular detection of Ca. P. trifolii or beet curly top virus, perhaps because 3D-printed traps captured few leafhoppers during summer when the pathogen rates were highest. Our results suggest behavioral differences in C. tenellus trap preference based on seasonality and life stage, and underscore the importance of understanding insect behaviors when choosing trap designs for pest monitoring as well as for properly interpreting trap capture data.