Observations on the occurrence of fusarium species and their toxins in corn in eastern ontario

Abstract

Fusaria were isolated from moldy corn (Zea A?7ov.s)harvested in late fall, or in early spring after overwintering in the field. Fusarium graminearum, F. moniliforme var. moniliforme. F. moniliforme var. suhglutinans, and F. sporotrichioides var. sporotrichioides accounted for 84% of the total isolates, with five other taxa accounting for the remaining 16%. Samples of moldy corn taken directly from the field were analyzed for a variety of mycotoxins but only deoxynivalenol (0.05-6.3 ppm) and zearalenone (< 0.002-0.11 ppm) were detected. F. graminearum isolates from the corn produced both these toxins in axenic rice cultures (201 -542 ppm deoxynivalenol; 91-1255 ppm zearalenone). These same isolates were used to inoculate ears of corn in the field. When harvested 53 days later, no zearalenone was detected in the ears, but deoxynivalenol was present at concentrations which varied from 0.8 to 3040 ppm based on fresh ear weight at harvest. These deoxynivalenol concentrations were inversely correlated with ear weight. Analysis of one ear showed 3-acetyldeoxynivalenol also to be present. © Taylor & Francis Group, LLC.