Apple scab: role of environment in pathogen and epidemic development

Abstract

Scab continues to be a serious disease in virtually all apple-producing regions worldwide despite the steady flow of research reports on its biology, epidemiology and management throughout this century (for a review see MacHardy, 1996). Largely due to these efforts, the disease has been satisfactorily managed but lasting solutions do not exist. Periodic outbreaks of problems with fungicide resistance (Köller, 1994) and the breakdown of resistance in scab-resistant cultivars (Parisi and Lespinasse, 1996) are constant reminders that scientists are only temporarily ahead of the pathogen.