Multi-cultivar grafting: Evaluating a novel low-cost, grower-friendly approach to monitor key apple pests

Among several early-season insect pests threatening apple production in Northeast USA, plum curculio (PC), Conotrachelus nenuphar (Coleoptera:  Curculionidae) is the most important fruit-damaging pest. Two additional early-season pests are the Tarnished plant bug (TPB), Lygus lineolaris (Hemiptera: Miridae) and European apple sawfly (EAS), Hoplocampa testudinea (Hymenoptera: Tenthredinidae). In this study, we quantified the attractiveness of perimeter-row trees grafted with multiple cultivars to PC, TPB, and EAS in comparison to  non-grafted trees, in 9 Massachusetts apple orchards. We monitored PC activity using unbaited black pyramid traps deployed near grafted and non-grafted trees. White sticky cards deployed on grafted and non-grafted trees were used to monitor TPB and EAS. Overall, the trapping devices captured more TPB and PC in grafted trees than in non-grafted trees. Furthermore, in 2020 more PC and TPB injury was observed on Ginger Gold, one of the cultivars that was selected for grafting. Because branches were grafted in 2018 and little fruit was produced in 2020, then further research is needed over multiple years to determine whether trees grafted with multiple cultivars can be used as “trap crop” to bring multiple pests to those trees