Increasing severity of late blight ebidemics in Switzerland?

Since 1990, late blight of potatoes is a major field of research at Agroscope FAL Reckenholz. The main focus is the development of the decision support system PhytoPRE to control late blight in IP- and organic potato production in Switzerland. Weather data and Swiss late blight epidemics of 16 years were analysed and characterised. The analysis showed the impact of late blight in Switzerland. In 12 out of 16 years more than 50 % of the untreated plots of our late blight monitoring net, established in the main potato cropping area of Switzerland, were attacked. With our analysis of the Swiss late blight epidemics, we did not get an indication for an increased severity. Most of the differences of late blight epidemics could be explained with the incidence of infection sources and weather conditions.