DISEASES OF IRRIGATED SPRING WHEAT AND SPRING BARLEY IN SASKATCHEWAN FROM 1986 TO 1989

In irrigated commercial fields of spring wheat and spring barley in the South Saskatchewan River irrigation area, the level of foliar diseases increased during each growing season, 1986-89. Disease levels were highest in 1986 and 1987, when lesions covered 5-10% of the surface of upper leaves and 50% of the surface of middle and lower leaves by the end of the season. There was less disease in 1989, and very little foliar disease in 1988. The causes of foliar disease in wheat varied but Septoria spp., particularly S. nodorum, were the most important. The exception was in 1986 when leaf rust [Puccinia recondita] was the most important foliar disease. In barley, powdery mildew [Erysiphe graminis], spot blotch [Cochliobolus sativus], the septoria complex, and the spot form of net blotch [Pyrenophora teres) were present. Common root rot, caused mainly by Cochliobolus sativus, was the most important underground disease but low levels of take-all [Gaeumannomyces graminis] were also present. Glume blotch [S. nodorum] on the heads and kemel discolorations were of minor importance.