Methyl salicylate improves the effectiveness of the odor-baited trap tree approach for adult plum curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae) monitoring and attract-and-kill

Authors: REGMI, PRABINA - University Of Massachusetts; Leskey, Tracy; PINERO, JAIME - University Of Massachusetts

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/25/2023
Publication Date: 6/15/2023
Citation: Regmi, P., Leskey, T.C., Pinero, J. 2023. Methyl salicylate improves the effectiveness of the odor-baited trap tree approach for adult plum curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae) monitoring and attract-and-kill. Journal of Economic Entomology. https://doi.org/10.1093/jee/toad110.
DOI: https://doi.org/10.1093/jee/toad110

Interpretive Summary: The plum curculio (PC) is a serious pest of tree fruit in Eastern North America. Monitoring this pest using traps and alternative management tactics like attract-and-kill are dependent on baiting with lures. Lures for PC are expensive and include a pheromone called grandisoic acid and a plant volatile, benzaldehyde. Here, we evaluated methyl salicylate lures as a replacement for benzaldehyde in both traps and in attract-and-kill studies, and found that it worked equally well, but cost ~50% less. This reduction in cost should improve adoption of these sustainable monitoring and management tools for PC by the grower community.

Technical Abstract: The plum curculio (PC), Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae), is one of most important insect pests of pome and stone fruit in eastern North America. In commercial apple orchards, the odor-baited trap tree approach serves as an effective monitoring tool as well as an attract-and-kill strategy for PC management. The standard synergistic lure used to bait the canopies of trap trees consists of benzaldehyde (BEN) and the PC aggregation pheromone grandisoic acid (GA). However, the relatively high cost of the lure and the degradation of commercial BEN lures by UV light and heat discourage its adoption by growers. To identify a potential replacement for BEN, we sought to compare, over a three-year period, the attractiveness of methyl salicylate (MES), either alone or in combination with GA, to PC with that of the binary combination of BEN + GA. Treatment performance was quantified using two approaches: 1) black pyramid traps to capture PC adults and 2) PC oviposition injury on apple fruitlets of trap trees and of neighboring trees to assess potential spillover effects. Traps baited with MES captured significantly more PCs than unbaited traps. Trap trees baited with a single MES lure and one GA dispenser attracted a similar number of PCs, as trap trees baited with the standard lure composed of four BEN lures and one GA dispenser based on PC injury. Trap trees baited with MES + GA received significantly more PC fruit injury than neighboring trees suggesting no or limited spill-over effects. Our findings collectively suggest that MES can be used as a replacement for BEN, thereby, cutting costs of lures by 50% while maintaining trap tree effectiveness.