Production and toxicity of 2,3-dihydro-5-hydroxy-2-methyl-4H-1-benzopyran-4-one by Phialophora gregata

2,3-Dihydro-5-hydroxy-2-methyl-4H-1-benzopyran-4-one, was isolated from 3 w eek old rice cultures of Phialophora gregata, a soybean pathogen, grown at 25 degrees C. This material in repeated bioassays prevented callus formatio n on soybean hypocotyl sections at 100 and 200 mu g/ml callus culture mediu m. This is the first report of the production of this metabolite by a membe r of the Phialphora genus and of its toxicity to soybeans. Published by Els evier Science Ltd.