A method for scoring the risk of fungicide resistance in vineyards

摘要

Because the risk of resistance towards single-site fungicides in populations of Plasmopara viticola and Erysiphe necator, the causal agents of downy mildew (DM) and powdery mildew (PM), respectively, is substantial, fungicide resistance management is important in vineyards. Available methods for assessing resistance risk mainly focus on single fungicides and do not consider the risk of resistance of a complete fungicide schedule, which typically includes multiple fungicides, used solo or in mixture and at different doses, and other actions (behaviors) of the farmer. A simple scoring method (fungicide resistance risk score, FRRS) was developed to account for both (i) the intrinsic risk due to the fungicides used, the target pathogens, and agronomic factors, and (ii) the behavioral risk, which includes how the fungicides are used during the season. FRRSs were then calculated for 10 representative vineyards (10 cases) and ranked from 1 (highest score) to 10 (lowest score). For comparison, 20 assessors (four winegrowers and 16 experts including public advisors, field technicians, and consultants) ranked the same cases based on their individual "perception of risk" from 1 (highest risk) to 10 (lowest risk).