The codling moth (Cydia Pomonella [L.]) is the number one worldwide pest of apples, pears and other pome fruits. Conservation of natural enemies is one way to reduce the costs of managing this pest by reducing the need for insecticide sprays. Successful conservation of the codling moth's natural enemies in Michigan requires 1) identifying them and 2) determining major factors that affect their abundance and effectiveness in the apple agroecosystem. The first chapter of my dissertation presents a literature review of the major natural enemies of codling moth by life stage. The second chapter presents a field study using real time video observation of sentinel prey to identify codling moth's key natural enemies in Michigan apple orchards. The third chapter provides experimental data and analysis aimed at identifying major factors that may impact the efficacy of natural enemies in Michigan orchards. In chapter 4 I present the results of two laboratory investigations exploring behavioral factors affecting codling moth infection by entomopathogenic nematodes. I identified, ants, lacewings, spiders, and predatory beetles as major natural enemies of codling moth in my experimental apple orchards. Relative abundances of these organisms were very site-specific. Organically certified orchards had higher natural enemy abundance and attack rate of sentinel fifth instar codling moth compared to non-organic orchards. This was not found for codling moth egg natural enemy abundance or activity. Further investigations revealed that orchard sanitation and orchard floor vegetation management affect natural enemy abundance and effectiveness against fifth instar codling moth larvae and codling moth pupae on the orchard floor. The implications of these findings for organic pest management and for future avenues of research are also discussed in the concluding chapter.
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