Note to readers, attached is the complete final report for FNE94-040.
Two strains of Entomopathogenic nematodes were applied at two rates under apple trees in an attempt to reduce in-orchard reproduction of plum curculio (Conotrachelus nenuphar). Emerging plum curculio adults under treated trees were not reduced compared to controls. Trapping success suggested an alternative approach to reducing plum curculio numbers.
These results indicate that field application of nematodes was not effective in reducing in-orchard reproduction of plum curculio. In fact, application of nematodes at economically viable levels actually appeared to increase PC reproductive success.
However, this study suggests some promising approaches to non-pesticide control of PC. The traps used in this experiment could be modified and used in the Spring to trap PC adults in the orchard, thus reducing egg-laying damage. They could be placed by perimeter tree bases from green tip through the end of June, then throughout the orchard in August and September to reduce PC pressure in the following year. Such traps could be smaller, open-sided and baited in the same way as this trial. Also, some apple cultivators may be inhospitable to the reproduction of PC under their canopies. These cultivars, if any, need to be identified. They could then be used in perimeter rows to reduce in-orchard PC reproduction.