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A Toxin from Myrothecium roridum and its Possible Role in Myrothecium Leaf Spot of Red Clover. B. M. Cunfer, Pennsylvania Agricultural Experiment Station and United States Regional Pasture Research Laboratory, University Park 16802, Present address of senior author: Department of Plant Pathology, Washington State University, Pullman 99163; F. L. Lukezic, Pennsylvania Agricultural Experiment Station and United States Regional Pasture Research Laboratory, University Park 16802. Phytopathology 60:341-344. Accepted for publication 19 September 1969. DOI: 10.1094/Phyto-60-341.

A phytotoxic metabolite was purified and partially characterized from the fluid associated with sporodochia of Myrothecium roridum grown on autoclaved red clover leaves. The compound, which is stable for long periods of time, produces necrosis on red clover foliage and other species. It is neutral, aliphatic, nonproteinaceous, and contains a carbonyl bond. Isolates of M. verrucaria that were tested also produce the toxin. Based on its infrared spectrum and phytotoxic properties, the compound is similar to necrocitin, and antifungal, phytotoxic metabolite from M. roridum culture filtrates. Though not directly linked to pathogenicity, the toxin aids in symptom development by creating infection courts on which spores may germinate and penetrate the foliage.