BIOCONTROL OF SEEDLING DISEASES OF BARLEY AND WHEAT CAUSED BY FUSARIUM-CULMORUM AND BIPOLARIS-SOROKINIANA - EFFECTS OF SELECTED FUNGAL ANTAGONISTS ON GROWTH AND YIELD COMPONENTS

The purpose of this study was to verify, under natural conditions, biological control effects obtained in a former screening programme against Fusarium culmorum. The most successful antagonists against seedborne Fusarium culmorum um and Bipolaris sorokiniana were isolates of Chaetomium sp., Idriella bolleyi and Gliocladium roseum. These results were also obtained when the antagonists were applied to B. sorokiniana-infected barley sown in field soil in pots. In held experiments, G. roseum gave the best control of F. culmorum in winter wheat. One month after sowing, germination increased by 170%, the disease index decreased by 73% and plant dry weight increased by 25%, compared to untreated plots. At harvest, the number of tillers per row was found to have increased by 53%, yield had increased by 160% and the 1000-grain weight had increased by 4%. For all evaluated parameters the effect was significantly different from the untreated plots and not significantly different from the plots treated with the fungicide, Sibutol LS 280. I. bolleyi gave a lower but still significantly effective control, when evaluated for disease index and numbers of tillers per row, while Chaetomium sp. did not show any reduction in the disease. Furthermore, in held experiments using barley infected with B. sorokiniana, a significant effect of G. roseum was demonstrated as increased plant dry weight after 1 month and increased 1000-grain weight at harvest. The disease-controlling effect of G. roseum on F. culmorum was shown in a field experiment with spring barley.