Occurrence of necrotrophic leaf pathogens in wheat and their relation to symptom development in Hungary (2000-2002)

1879-2720 leaf samples from 8-13 stations of Hungary were collected in March, April, May and June 2000-2002. Drechslera tritici-repentis, Septoria tritici, Stagonospora nodorum and Bipolaris sorokiniana were found in the leaf samples. The occurrence of necrotrophic pathogens was highest (10,79%) in 2001 and lowest (2,63%) in 2002. The occurrence and rate of the necrotrophic pathogens changed significantly among years and locations. The resistance of cultivars based on natural infection could not be properly evaluated, as the level of the epidemic was mostly low and contradictory among locations. Additionally forty four cultivars were tested in Szeged after winter wheat in protected and unprotected environment. Among the necrotrophic pathogens, the dominant pathogens were D. tritici-repentis (2001 and 2002) and S. nodorum (2001). The differences in variety resistance were significant. The biotrophic (leaf rust, yellow rust and powdery mildew) as well as the mentioned necrotrophic pathogens caused significant yield decrease in both years. According to values of correlation coefficients, the influence of biotrophic pathogens was greater on the yield