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, bio logical control effects obtained in a former screening programme again st Fusarium culmorum. The most successful antagonists against seedborn e Fusarium culmorum um and Bipolaris sorokiniana were isolates of Chae tomium sp., Idriella bolleyi and Gliocladium roseum. These results wer e also obtained when the antagonists were applied to B. sorokiniana-in fected barley sown in field soil in pots. In held experiments, G. rose um gave the best control of F. culmorum in winter wheat. One month aft er sowing, germination increased by 170%, the disease index decreased by 73% and plant dry weight increased by 25%, compared to untreated pl ots. At harvest, the number of tillers per row was found to have incre ased by 53%, yield had increased by 160% and the 1000-grain weight had increased by 4%. For all evaluated parameters the effect was signific antly different from the untreated plots and not significantly differe nt from the plots treated with the fungicide, Sibutol LS 280. I. bolle yi gave a lower but still significantly effective control, when evalua ted for disease index and numbers of tillers per row, while Chaetomium sp. did not show any reduction in the disease. Furthermore, in held e xperiments using barley infected with B. sorokiniana, a significant ef fect of G. roseum was demonstrated as increased plant dry weight after 1 month and increased 1000-grain weight at harvest. The disease-contr olling effect of G. roseum on F. culmorum was shown in a field experim ent with spring barley.