Efficacy of Codling Moth Granulovirus: Effect of Adjuvants on Persistence of Activity and Comparison With Other Larvicides in a Pacific Northwest Apple Orchard

Abstract

Control of codling moth, Cydia pomonella (L), in conventional orchards has relied heavily on broad spectrum insecticides such as azinphos-methyl (Guthion®, Bayer CropScience, Research Triangle Park, NC). Alternative control options are needed for a variety of reasons, including environmental impact and worker and food safety concerns. Microbial control agents such as the codling moth granulovirus (CpGV) offer alternatives to conventional insecticides for the control of codling moth. Six weekly applications of the label rate (1 L/ha) of the Carpovirusine® formulation of CpGV in an experimental orchard naturally infested with codling moth provided control of first generation codling moth that was comparable to that of larvicidal oil and azinphos-methyl. Although the number of codling moth entries in fruit that were treated with virus alone was similar to that of control trees, the number of deep entries and the number of living codling moth larvae were significantly reduced on CpGV treated fruit. Despite blemishing, virus-treated fruit with minute entries were suitable for consumption or for processing. Studies on the residual activity of Carpovirusine revealed a steady decline in virus activity 1 to 3 d following application. The use of two adjuvants, Nu-Film-17® and Raynox®, did not protect virus from solar inactivation. Among the biological control options available for codling moth, CpGV provides effective and selective control of neonate larvae. Its use in lieu of broad spectrum insecticides will contribute significantly to the conservation of other natural enemies in the orchard agroecosystem.