Testing repellents on the striped cucumber beetle Acalymma vittatum

The striped cucumber beetle Acalymma vittatum (Coleoptera: Chrysomelidae) is a major pest of cucurbits. Adult beetles feed on foliage, while larvae consume roots, greatly reducing crop productivity. Additionally, A. vittatum vectors bacterial wilt (Erwinia tracheiphila), a severe disease that can decimate cucurbit yields. Current management relies heavily on pesticide applications, yet effective organic pest management strategies remain limited. Since A. vittatum is attracted to cucurbit volatiles, disrupting host plant location through repellents presents a promising ecologically friendly alternative.

In this study, we tested essential oils as potential repellents against A. vittatum. We assessed repellency in two ways: (1) using an olfactometer, where beetles were exposed to airflow containing repellent and host plant volatiles; and (2) through cage choice assays, where beetles were allowed to choose between plants with or without a repellent, and settlement patterns were recorded. In preliminary assays, we tested lavender oil, eucalyptus oil, Ferula asafoetida oil, and methyl anthranilate. Initial results suggest that beetles exhibit strong avoidance behavior in response to lavender oil, eucalyptus oil and methyl anthranilate but not to F. asafoetida oil.

Our results identify promising repellent components that disrupt host location cues in A. vittatum. Ongoing research will test different concentrations and isolate specific active compounds responsible for repellency, supporting the development of ecologically based pest management strategies for organic cucurbit production.