Exploiting floral-based volatile blends for striped cucumber beetle (Acalymma vittatum and A. trivittatum) attraction that avoid non-target effects on pollinators

Alternative pest management practices that limit pesticide use are important to help stem pollinator declines. However, non-chemical approaches may result in non-target effects in pollinator-dependent crops; for example, when using floral volatiles that are attractive to both pests and pollinators. In this study, we investigated semiochemical lures to attract the focal pest – striped cucumber beetle (Acalymma vittatum) – without distracting pollinators. To do so, we tested the efficacy of floral volatiles as part of a commercial blend, TIC (1,2,4-trimethoxybenzene [500 mg], indole [500 mg], and (E)-cinnamaldehyde [500 mg]), paired with a beetle aggregation pheromone, vittatalactone. We simultaneously tested the interactive effects of indole, a component of TIC that is predicted to maintain beetle attraction without affecting pollinator behavior. We also predicted floral volatiles would synergize with pheromone to attract beetles compared to their individual effects. These permutations were tested on sticky cards in cucurbit crops in major hubs of cucurbit production in the Midwest (Indiana) and Mid-Atlantic (Maryland). Key cucurbit pests, the striped (A. vittatum) and spotted cucumber beetles (Diabrotica undecimpunctata howardi), were recorded. Pollinator attraction was measured separately in response to the same volatile-pheromone treatments using yellow-colored bee bowls secured on stakes. Overall, there was a significant increase in trap capture of striped cucumber beetles when floral volatiles were combined with vittatalactone, indicating the possibility to exploit these semiochemicals in an attract-and-kill management system. From these data, we found a synergistic combination of olfactory cues to manage pests while avoiding pollinator distraction.