Moniliformin production and toxicity of different Fusarium species from Southern Africa

Abstract

Four new moniliformin-producing species of Fusarium were found, viz., F. acuminatum, F. concolor, F. equiseti, and F. semitectum. Isolates of F. acuminatum and F. concolor produced large amounts of moniliformin (3.4 and 9.5 g/kg, respectively), whereas isolates of the other three species yielded less than 30 mg/kg. The production of moniliformin by isolates of F. oxysporum and F. avenaceum from southern Africa is described. All 14 toxic isolates of F. oxysporum produced moniliformin. Most isolates of F. fusarioides and all six isolates of Fusarium moniliforme va. subglutinans tested produced moniliformin, as did 28 of 36 toxic isolates of F. moniliforme. A number of F. moniliforme isolates produced greater than 10 g/kg, and one isolate yielded 33.7 g/kg in corn after incubation for 5 weeks at 25 degrees C. Moniliformin production in the field in corn ears was shown by inoculating plants with known moniliformin-producing isolates of three Fusarium species. Yields of up to 645 mg/kg were recorded. Isolates of F. acuminatum, F. equiseti, F. fusarioides, and F. moniliforme were found that were highly toxic to ducklings but which did not produce moniliformin.