Disease Note.

First Report of Fumonisin B1, B2, and B3 Production by Fusarium oxysporum var. redolens. . Hamed K. Abbas, USDA-ARS, Southern Weed Science Lab, Stoneville, Miss. 38776 . Cynthia M. Ocamb, USDA Forest Service, North Central Forest Experiment Station, St. Paul, Minn. 55108 Weiping Xie, Chester J. Mirocha, and W. Thomas Shier, University of Minnesota, St. Paul 55108. Plant Dis. 79:968. Accepted for publication 26 July 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0968C.

Fumonisins were first isolated and identified in 1988 from Fusarium moniliforme J. Sheld six other species were later reported to produce fumonisins. Fusarium oxysporum Schlechtend.:Fr. has been characterized as pathogenic on a variety of plant species. Six isolates of this species and seven isolates of a subgroup, F. oxysporum var. redolens, were collected from root lesions of eastern white pine (Pinus strobus L ) seedlings and surrounding soil (1). When grown on rice, three isolates of F. oxysporum and all seven isolates of F. oxysporum var. redolens were found to produce fumonisin B1 ranging from traces (? l00) to 300,600 ppb as determined by microcapillary high-pressure liquid chromatography continuous flow/ fast atom bombardment/mass Spectrometry (CF/FAB/MS) and external standard curves. Three isolates of F. oxysporum var. redolens were found to also produce fumonisin B2 (2,380 to 5,900 ppb) and fumonisin B3 (787 to 866 ppb). Identity of fumonisins was confirmed by thin layer chromatography and FAB/MS. Culture filtrates of these fu-monisin-producing isolates exhibited phytotoxicity to 2-week-old jim-sonweed (Datura stramonium L.) and black nightshade (Solanum nigrum L.) symptoms ranged from mild to severe necrosis and mortality that correlated with levels of fumonisin produced in rice cultures. This is the first report of fumonisin production by F. oxysporum, thus expanding the range of Fusarium species known to produce fumonisins.