Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2008
Publication Date: 8/1/2008
Citation: Leskey, T.C., Pinero, J.C., Prokopy, R.J. 2008. Odor-Baited Trap Trees: A Novel Management Tool for the Plum Curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae). Journal of Economic Entomology. 101(4):1302-1309. Interpretive Summary: The plum curculio is one of the most serious pests of apple in eastern North America. Growers in the northeast generally apply three full insecticide applications to their entire orchard to control immigrating adults. After a full orchard application is made at petal fall (the period when fruit is most susceptible to plum curculio injury), the amount of insecticide applied to orchards can be reduced by treating only the perimeter rows of the orchard to control the immigrating population. A second approach that results in even more substantial reductions is to treat only odor-baited trap trees located in the border row. These particular apple trees are perceived as more attractive to foraging adult plum curculio because of a deployment of an attractive combination of synthetic fruit volatiles and aggregation pheromone within the canopies. Both of these approaches were evaluated in commercial apple orchards in New England and resulted in low levels of plum curculio injury within orchards. However, the trap tree approach resulted in a reduction of approximately 70 percent total trees being treated with insecticide compared with perimeter row sprays, and 93 percent compared with standard full block sprays. The odor-baited trap tree strategy appears to provide the means to reduce insecticide inputs against plum curculio in commercial apple orchards.
Technical Abstract: The plum curculio, Conotrachelus nenuphar (Herbst), one of the most important pests of apple in eastern and central North America, historically has been managed in New England apple orchards by three full block insecticide applications. Efforts to reduce insecticide inputs against plum curculio include perimeter row sprays, particularly after petal fall, to control immigrating adults. The odor-baited trap tree approach represents a new reduced input strategy for managing plum curculio based on the application of insecticides to a few perimeter-row trap trees rather than the entire perimeter row or full orchard block. Here we compared the efficacy of a trap tree approach with perimeter row treatments to manage populations after petal fall in commercial apple orchards in 2005 and 2006. Injury was significantly greater in trap trees compared with unbaited perimeter row treated trees in both years of the study. In 2005, heavy rains prevented growers from applying insecticide applications at regular intervals resulting in high injury in nearly all blocks regardless of type of management strategy. In 2006, both the trap-tree and perimeter-row treatments prevented penetration by immigrating populations and resulted in economically acceptable levels of injury. The trap tree management strategy resulted in a reduction of approximately 70 percent total trees being treated with insecticide compared with perimeter row sprays and 93 percent compared with standard full block sprays.