Potential for Modifying the Behavior of the Multicolored Asian Lady Beetle (Coleoptera: Coccinellidae) with Plant-Derived Natural Products

Bioassays were conducted to study the effectiveness of selected chemicals to prevent the multicolored Asian lady beetle, Harmonia axyridis (Pallas), from overwintering in buildings. We discovered that certain monoterpenoids elicited avoidance in adults toward treated filter paper within a petri dish bioassay at 1.0 mg/cm2. Camphor and menthol were the most effective of the monoterpenoids tested. Y-tube olfactometer bioassays revealed that beetles spent significantly more time (within 10-min observation periods) in the untreated control arm than in the arm containing camphor or menthol (both at 100 and 1,000 μg). Another olfactometer bioassay revealed that significantly more beetles remained in the untreated control arm than in the arm containing camphor or menthol (142 μg), within 45-min observation periods. When camphor (9.4% emulsified concentrate) was sprayed onto crevices on the exterior of a building through which beetles were entering, 100% of approaching beetles were repelled for the duration of the tests (0.5 h, two replicates). In another field experiment, significantly fewer H. axyridis were captured in traps containing camphor versus un-baited control traps. Research is continuing to develop a protocol for repelling nuisance beetle aggregations and conserving the beetles for biological control applications.