Natural Biotic Control Factors of the Eye-Spotted Bud Moth, Spilonota ocellana on Apple in Wisconsin1

Abstract

A 4-year study of the naturally occurring biotic control factors affecting the eye-spotted bud moth, Spilonota ocellana (Denis and Schiffermüller), on apple in Wisconsin revealed the existence of parasitic, predatory, and microorganismal agents. Nine hymenopterous parasites, three predators, and four pathogens were involved. Principal parasitic species were Itoplectis conquisitor (Say) and Habrocytus phycidis Ashmead. Aspergillus flavus Link and a polyhedral virus were the most prevalent causes of disease. A high mortality occurring in the pupal stage could not be attributed to known causes. It is postulated that the comparatively low numbers of primary species and their small part in the regulation of the eye-spotted bud moth population may have been due mainly to the extensive use of pesticides in the area. The need for the use of selective pesticides in an integrated control program is emphasized.