Timing of fungicide application against Cercospora leaf spot disease based on aerial spore dispersal of Cercospora beticola in sugar beet

Abstract Cercospora leaf spot is an important foliar disease in sugar beet caused by beticola . Tolerant cultivars are available, but application of fungicides still mandatory for control. The timing the fungicide crucial as it determines outcome epidemiology. A incidence (DI) 5% widely used a threshold application. Recently method was developed that allows quantification aerial spore dispersal C measuring flight intensity. It aimed this study to prove if based on might improve control compared DI. In field trial with artificial inoculation, single at onset slowed down development indicated reduced severity and dispersal. However, did not provide sufficient terms yield. Only second detection achieved efficacy similar two applications contrast, either or DI on-farm trials under natural infection moderate pressure. This highlights necessity early timed first followed high pressure induced inoculation. Although success trials, seems usage threshold.