The effect of species of Allium on soil bacteria in relation to germination of sclerotia of Sclerotium cepivorum Berk

SUMMARY Extracts made from Allium species were shown to exhibit marked antibiotic properties in a variety of tests. However, no evidence was obtained to suggest that intact Allium seedlings exude antibiotic compounds in sufficient quantity to cause inhibition of bacteria in the soil or in assay tests in the laboratory. Germination of sclerotia of Sclerotium cepivorum was induced by Allium extracts which were too dilute to cause antibiotic responses in laboratory tests using a number of bacteria. Synthetic methyl‐methanethiolsulphinate had little effect on germination of sclerotia. The specific reversal, by Allium species and their extracts, of the mycostatic effect of unsterile soil on sclerotia of S. cepivorum does not appear to be due to antibiotic effects.