Occurrence and distribution of Fusarium graminearum and deoxynivalenol in sweet corn ears

Abstract

Unusual wet and cool weather conditions during the 1994 growing season in Maryland and Delaware resulted in a severe outbreak of Fusarium graminearum on sweet corn ears (‘Moore’ variety) prior to harvesting and canning. The number of ears visibly infected with Fusarium spp. ranged from less than 5% to 25% in some fields. Infection typically occurred at the tassel end of the ears. Fusarium graminearum was isolated from surface disinfected kernels, both those which were visibly infected and those kernels which appeared disease-free in an area up to 5cm from the edge of the visibly moulded areas. Infected ears were cut into four sections and the kernels only were analysed for deoxynivalenol (DON) using liquid chromatography (LC)and mass spectrometry/gas chromatography (GC/MS). Kernels from the visibly mouldy area of the ears contained DON at levels of approximately 446mg/g DON on average; whereas in the nonvisibly infected portion of the ears adjacent to the mouldy tips, DON levels averaged approximately 10mg/g. Sections of ears closest to the base contained no detectable DON or less than 1 μg/g. This is the first reported natural occurrence of the mycotoxin DON in sweet corn prior to harvest and canning.

Keywords:

• Deoxynivalenol Fusarium Graminearum Mycotoxin Sweet Corn