Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2011
Publication Date: 10/1/2011
Citation: Pinero, J.C., Agnello, A., Tuttle, A., Leskey, T.C., Faubert, H., Koehler, G., Morin, G., Leahy, K., Loss, L., Cooley, D., Prokopy, R.J. 2011. Effectiveness of odor-baited trap trees for plum curculio (Coleoptera: Curculionidae) monitoring in commercial apple orchards in the Northeast. Journal of Economic Entomology. 104:1613-1621. Interpretive Summary: The plum curculio is a serious pest of apples and peaches in eastern and central North America. In order to effectively manage plum curculio in commercial orchards, growers rely on insecticide applications. However, there has never been a reliable monitoring method available for growers to facilitate management decisions. In this study, we demonstrate the effectiveness of using odor-baited trap trees as a monitoring tool to determine need for and timing of insecticide applications against plum curculio. Plum curculios are attracted to baited trap trees, resulting in aggregated mating and oviposition activity. The presence of fresh egg-laying scars within trap trees can be used as a trigger for the need for insecticide applications. The appearance of fresh egg-laying scars was compared with existing management approaches based on three calendar-driven sprays or heat unit accumulation models that predict how long insecticide should be applied to orchard trees to prevent injury by plum curculio. Trap tree plots received a whole plot insecticide spray at petal fall; subsequent sprays were applied only to peripheral-row trees if a threshold of one fresh plum curculio egg-laying scar was detected in trap trees (out of 25 fruit sampled). In both years, level of plum curculio injury to fruit sampled from trees in trap tree plots managed conventionally, and plots managed using the heat unit accumulation approach did not differ significantly. However, the amount of insecticide used in trap tree plots was substantially less than that applied to plots managed with the conventional approach. This information is useful for plum growers to manage this pest.
Technical Abstract: The plum curculio, Conotrachelus nenuphar (Herbst.), is a key pest of pome and stone fruit in eastern and central North America. For effective management of this insect pest in commercial apple orchards in the northeast, one of the greatest challenges has been to determine the need and timing of insecticide applications that will protect fruit from injury by adults. In a 2004-2005 study conducted in commercial apple orchards in seven northeastern states, the effectiveness of a reduced-risk IPM approach involving an odor-baited trap tree approach to determine need and timing of insecticide use against plum curculio based on appearance of fresh egg-laying scars was compared with existing management approaches based on three calendar-driven sprays or heath unit accumulation models that predict how long insecticide should be applied to orchard trees to prevent injury by plum curculio late in the season. Trap tree plots received a whole-plot insecticide spray by the time of petal fall, and succeeding sprays (if needed) were applied to peripheral-row trees only depending on a threshold of one fresh plum curculio egg-laying scar to out of 25 fruit sampled from a single trap tree. In both years, the level of plum curculio injury to fruit sampled from perimeter or interior-row trees in trap tree plots did not differ significantly from that recorded in plots subject to conventional management or in plots managed using the heat unit accumulation approach. Amount of insecticide used in trap tree plots was substantially less than that applied to plots managed with the conventional approach. Advantages and potential pitfalls of the trap tree approach to plum curculio monitoring in apple orchards are discussed.