Abstract

A range of plants was tested for their susceptibility to Drechslera avenacea (M.A. Curtis ex Cooke) Shoem., the possible active ingredient in a bioherbicide for use against the weed Avena fatua. Test plants were chosen on the basis of phylogenetic proximity to the weed, recorded susceptibility to closely related pathogens or physical proximity in agricultural systems to wheat, the crop in which the weed is to be controlled. The fungus caused mortality of A. fatua and Avena byzantina cv. Yarren. Sporulation occurred on A. fatua and, on one occasion (of three challenges), on Brassica napus cv. Oscar. Severe disease symptoms were recorded on 13 species of grass and mild infection on a further seven species. We observed a much broader host range than previously recorded. The reasons for, and implications of, this are discussed and the suitability of D. avenaceaas a bioherbicide assessed.