DISEASE-LOSS-RELATIONSHIPS OF POWDERY MILDEW IN WINTER-WHEAT DEPENDING ON GROWING YEAR AND PRODUCTION SYSTEM

During a 4-year-lasting field experiment, the influence of year and cropping system on disease-loss-relationships of powdery mildew in winter wheat was examined. The main components were two different cultivars, two seeding rates and the variation of N-fertilization. Results show that the yield and the disease-loss-relationships differ between and within the years. Depending on year and cropping system, different mildew severities can be tolerated before a treatment can be recommended. For that reason, threshold levels for mildew must be considered as variable and not as static values.