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Evaluation of Semiochemicals for Improved Monitoring and Management of Plum Curculio (Conotrachelus nenuphar) (Coleopter: Curculionidae)

Among several early-season insect pests threatening apple production in eastern North America, plum curculio (PC), Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae), is one of the most devastating pests of pome and stone fruits. Historically, several methods have been used to monitor and control plum curculio in apple orchards. The odor-baited trap tree approach has proven to serve as an effective monitoring and attract-and-kill system for plum curculio. The synergistic lure consisting of benzaldehyde (a plant volatile) and grandisoic acid (the PC aggregation pheromone) is used in this approach. However, the high cost of the lure and the degradation of benzaldehyde by UV light and heat have resulted in limited grower adoption. The major goals of this study were (1) to evaluate under field conditions, the attractiveness of methyl salicylate (MES) to PC, and to determine if it can replace the benzaldehyde (BEN), and (2) to test whether we can manipulate insect pest behavior through host plant preference by grafting selected perimeter- row trees with multiple cultivars. My results indicated that (1) methyl salicylate in combination with grandisoic acid was as attractive to PC as the standard synergistic lure composed of benzaldehyde and grandisoic acid, therefore MES can be used as a replacement for BEN, (2) trees grafted with six cultivars were more attractive to PC and concentrated more PC fruit injuries, compared to non-grafted trees, and (3) ‘Wickson’ and ‘Red Astrachan’ received numerically more PC injuries while ‘Dabinett’ received the lowest level of injury compared with other cultivars. These results highlight that a semiochemical-based strategy is a low-cost and grower-friendly approach to monitoring and controlling the PC population.