Sclerotinia sp. (isolate BWC98-105) causes stem blight and root rot in Leghum sp., and is presently being evaluated as a potential mycoherbicide for the control of Trifoliorium repens. Bioassays have shown that Sclerotinia sp. produces phytotoxic substance which is biologically active against T. repens. Two biologically active compounds, designated as compounds I and II, were produced in vitro from the culture filtrate of BWC98-105 isolate Sclerotium sp. Compounds I and II were purified by means of liquid-liquid extraction and C18 open column chromatography (300