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Effects of Temperature on the Simultaneous Production of Zearalenone and Deoxynivalenol by Fusarium Graminearum on Maize Siame, B.A & Lovelace, C.E.A Abstract Fusarium graminearum (Schwabe), a fungus commonly encountered on maize ( Zea mays L) in Zambia, was analyzed for toxin production under temperature conditions prevalent during periods of high infestations. Ground maize samples were adjusted to a moisture content of 40% and inoculated with an isolate of F. graminearum. The samples were incubated at 26°C or 16°C for 10 weeks. Samples were analyzed for the toxins, zearalenone, deoxynivalenol, and nivalenol every two weeks. Nivalenol was not detected in any of the samples. Approximately five times more zearalenone than deoxynivalenol was produced at all temperatures tested. More zearalenone was produced at 16°C (5-1300mg kg-1) than at 26°C (5-750mg kg-1). When the fungus was grown at 16°C for five weeks and transferred to 26°C, production of zearalenone was stimulated. Although more deoxynivalenol was produced by the fungus at 26°C (1-62mg kg-1) than at 16°C (1-50 mg kg-1), most deoxynivalenol was produced by the fungus at 26°C (1-62 mg kg-1) than at 16°C (1-50mg kg-1), most deoxynivalenol was produced by the fungus grown at 16°C for five weeks and then transferred to 26°C for the next five weeks (1-137 mg kg-1). Growth of the fungus at 26°C for 5 weeks before transfer to 16oC did not result in any significant rise in either zearalenone or deoxynivalenol production. Keywords Toxins, Zambia, Zea mays

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