Occurrence and distribution of Fusarium species in barley and oat seed from Manitoba in 1993 and 1994

A total of 136 seed samples of barley and 30 samples of oat grown in Manitoba in 1993 and 1994 were analyzed for the level and species of Fusarium infecting the kernels. Fusarium graminearum was the most commonly isolated of 11 Fusarium spp. In barley it ranged in mean frequency from 2% seed infection in samples from the northwestern (NW) region of Manitoba to 71% in samples from the central region of Manitoba. Oat had lower average levels of F. graminearum, ranging from nondetectable in the NW to 38% in central Manitoba. Definitive, reliable symptoms of fusarium head blight infection in harvested barley and oat were often absent. Due to the high frequency of F. graminearum in many samples, and this pathogen's known ability to produce deoxynivalenol, testing for this mycotoxin in these commodities appears warranted. This is especially true for barley grown in the central, eastern, or interlake regions of Manitoba in years when fusarium head blight is severe and the grain is destined for malting or pig feed.