Prevalence of fungi and fusariotoxins on hard red spring and amber durum wheat seed from western Canada, 2000 to 2002

Abstract

Producer samples of Canada western red spring (CWRS) wheat (Triticum aestivum) and Canada western amber durum (CWAD) wheat (Triticum turgidum var. durum) grown in Manitoba, Saskatchewan, and Alberta between 2000 and 2002 were composited by year and crop district, then analyzed for fungal infection and contamination by trichothecenes and moniliformin. One hundred and fourteen CWRS and 79 CWAD samples were composited from 1136 CWRS and 643 CWAD producer samples. Alternaria alternata was the most frequently isolated species from each province. Levels of Alternaria alternata, Bipolaris sorokiniana, and Fusarium graminearum were highest in Manitoba and eastern Saskatchewan, whereas Cladosporium spp., Pyrenophora tritici-repentis, and Stagonospora nodorum were highest in samples from further west. The frequency of the toxigenic species F. graminearum greatly exceeded that reported 20 or more years earlier. Samples from all 3 years were analyzed for the presence of eight trichothecenes, and from 2002, for moniliformin. Deoxynivalenol (DON) was found almost exclusively in wheat from the eastern Prairies, at levels up to 7.9 ppm, where it sometimes cooccurred with 15-acetyl deoxynivalenol. HT-2 was detected at low levels in 7 of 79 CWAD composites but not in the CWRS composites. Low levels of moniliformin were found in one CWRS and nine CWAD composite samples, the first time that this compound has been reported from naturally infected wheat in North America. Not detected were nivalenol, fusarenon X, trichothecin, 3-acetyl deoxynivalenol, neosolaniol, diacetoxyscirpenol, and T-2 toxin.