In the past decade there has been an increase in the incidence of leaf spotting diseases of wheat in
western Canada. These are attributed mainly to Pyrenophora tritici-repentis (tan spot), Septoria
nodorum and S. tritici (septoria leaf blotch complex). All registered spring wheat cultivars are susceptible to this disease complex (Femandez and DePauw, 1998). Leaf spots have been reported to have a negative effect on yield and quality. P. tritici-repentis also causes red smudge/black point on wheat kernels (Femandez et al., 1994a and b). This kernel discoloration causes loss of grade, especially in durum wheat. However, the magnitude of the impact of leaf spots on grain yield and quality of wheat cultivars grown on dryland in southern Saskatchewan, and the minimum disease levels that would have a significant effect on these parameters, are not known.