Prevalence of Fusarium species of the Liseola section on Zimbabwean corn and their ability to produce the mycotoxins zearalenone, moniliformin and fumonisin B-1

Maize samples were collected from nine Grain Marketing Board (G.M.B) center s in Zimbabwe during the 1991 harvest season. A further 47 samples collecte d directly from farmers and from the G.M.B., centers in Chinhoyi and Kwekwe during the 1992 harvest season. These samples were analyzed mycologically and the predominant flora was Fusarium although Penicillium, Nigrospora, As pergillus and Chaetomium could be isolated from some samples. From the firs t nine samples studied, F. verticillioides and F. subglutinans were isolate d in almost equal proportions on samples from the central and the south of the country whereas only F. verticillioides was isolated on the samples fro m the north. The subsequent study demonstrated that there was a greater fun gal diversity in samples from North (Mashonaland West) than samples from th e South (Midlands area) with species of Nigrospora, Chaetomium, Acremonium and Diplodia occurring in significant numbers. From a total of 2821 fungal isolates obtained from all the maize samples analyzed, 1485 (53%) were foun d to belong to the liseola section of Fusarium. The ability of these isolat es to produce the mycotoxins zearalenone, moniliformin and fumonisin B-1 wa s tested using a simplified TLC Agar plate method. Out of the 886 isolates tested, only one produced all the three mycotoxins simultaneously whilst mo st produced fumonisin B-1 and/or moniliformin. Only nine isolates produced zearalenone.