The Effects of Succinate Dehydrogenase Inhibitor Fungicide Dose and Mixture on Development of Resistance in Venturia inaequalis

Of much debate is the effect of fungicide application dose on resistance development, as fungicide resistance is a critical barrier to effective disease management in agricultural systems. Our field study in apples investigated the effect of fungicide application dose and mixture on the selection of succinate dehydrogenase inhibitor resistance in Venturia inaequalis, a fungal pathogen that causes the economically important disease apple scab. Understanding how to best delay the development of resistance can result in increased efficacy, fewer applications, and sustainable fungicide use. Results from this study may have relevance to other perennial crops that require multiple fungicide applications and that are impacted by the development of resistance.