The Structure and Biological Properties of Secondary Metabolites Produced by Peltaster fructicola, a Fungus Associated with Apple Sooty Blotch Disease. P. VENKATASUBBAIAH, Department of Botany, North Carolina State University, Raleigh 27695. T. B. SUTTON, Department of Plant Pathology, and W. S. CHILTON, Department of Botany, North Carolina State University, Raleigh 27695. PLANT DIS. 79:1157. Accepted for publication 18 October 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-1157.

Peltaster fructicola, one of the fungi that cause sooty blotch of apple (Malus X domestica) fruit, produced four metabolites in liquid culture that were isolated and structurally identified as trichothecolone, trichothecolone acetate, 6-methylsalicylic acid, and 2,5-dihydroxybenzoic acid. These toxins were nol detected in a culture of leptodontidium elatius, another fungus associated with apple sooty blotch. The four toxins were nonspecific; they caused necrosis when spotted on different cultivars or strains of apple and on eight weed species. In addition, trichothecolone acetate and 6-methylsalicylic acid showed strong antifungal properties against Botryosphaeria dothidea. B. obtusa, Colletotrichum gloeosporioides, and C. acutatum in vitro. Prior treatment of fruit with 6-methylsalicylic acid reduced infection of fruit inoculated with C. acutatum.