Optimizing the use of curative late blight fungicides
Fungicides that can act curatively (within the incubation period of pathogen development) are an increasingly important component of late blight (Phytophthora infestans) control strategies. This study aims to produce a simple decision aid for the use of products with curative activity by growers and agronomists. Interim results, which form the basis of the decision aid, are presented here. Data from glasshouse bioassays with a representative curative fungicide (fluopicolide + propamocarb), a susceptible variety (King Edward), and an isolate belonging to an aggressive genotype suggest that curative control declines 24 hours after infection, with little benefit gained from curative treatments applied 40 hours or more post infection. However, results from field trials suggest that varietal resistance is a significant modifying factor: curative treatments sprayed 43 hours after infection significantly reduced lesion number for the varieties Cara and Sarpo Mira but not the more susceptible King Edward.
Other Titles/Title of Conference
Sixteenth EuroBlight Workshop, Aarhus, Denmark
Stichting Wageningen Research
PAGV - Special Report no.18