EN
Modern decision support systems for disease control – important elements of integrated plant protection – should recommend optimal time of fungicide spray. The aim of this study was to compare the efficiency of autumn and spring treatments in relation to the concentration of Leptosphaeria maculans and L. biglobosa ascospores in air samples. The experiment was done over two seasons in two climatic regions of Poland. In three out of four field situations the fungicide treatment following maximum ascospore release was more efficient than the early spring spray. However, the latter treatment was more efficient in the case of very late ascospore release (end of November), observed in southern Poland in the autumn of 2006. The increase of the seed yield correlated with the time of fungicide application and was on average 16.1% in the case of autumn spray following maximum ascospore release and only 6.23% when treatment was done in the spring.