Isolation of Fusarium graminearum from cereal, grass and corn residues from Alberta, 2001-2003

Fusarium species, which are typically associated with fusarium head blight of cereals, were isolated, identified and enumerated from residues collected in 239 cereal, 71 corn and 201 grass fields/sites in Alberta from 2001 to 2004. Cereal and grass residues were collected in the Peace River, central and southern regions of Alberta, while corn samples were collected from central and southern Alberta. The most frequently recovered species were F. avenaceum and F. culmorum followed by F. pseudograminearum and F. graminearum. Outside of southern Alberta, the most important causal agent of fusarium head blight, F. graminearum, was isolated at low levels in only one of 163 cereal fields, and was not isolated from the 39 corn fields or 105 grass sites surveyed. In contrast, in southern Alberta, F. graminearum was isolated from cereal residues in 10 of 76 cereal fields. Relatively high levels (46-50%) of node and crown infection occurred in one southern Alberta field in 2003. Fusarium graminearum was most common in corn residues from southern Alberta, being isolated from 24 of 32 fields, with average incidences of node infection ranging from 10 to 60% within these fields. In contrast, only three of 96 grass sites in southern Alberta had detectable, albeit low, levels of F. graminearum. The infrequent occurrence of F. graminearum, especially in central Alberta, and the Peace River region, suggests that Alberta's agricultural industry should continue to monitor its presence in grain and crop residues, while attempting to limit further build up and spread of this pathogen.