Fungi isolated from Sclerotia ofSclerotium cepivorum and from soil and their effects upon the pathogen

Summary Data are presented on the antagonistic effects of the fungi isolated from sclerotia ofSclerotium cepivorum and from nonrhizosphere soil taken from around the roots of infected onions upon mycelial growth and sclerotial germination ofS. cepivorum. Most of the isolated fungi especiallyPenicillium species were antagonistic to mycelial growth. Sclerotial germination was slightly inhibited by diffusates of these fungal isolates. Testing the antifungal effect of someAllium extracts against the fungal isolates by the inhibition zone method showed that garlic extract has the greatest antifungal effects and onion extract is the least potent. However, spore germination tests indicated that onion extract completely inhibits the spore germination of all test fungi. The role of host-plant extracts in stimulating sclerotial germination is discussed.