Effects of tillage systems and crop rotations on root and foliar diseases of wheat, flax, and peas in Saskatchewan

Abstract

The dynamics of root and foliar diseases were studied in spring and winter wheat, peas, and flax and under zero, minimum, and conventional tillage at Indian Head, Saskatchewan, from 1987 to 1990. No disease was observed on flax during the 4 yr. Year-to-year variation was more important than tillage systems in explaining the incidence of bacterial leaf spot and foot rot of peas. Tan spot and septoria leaf blotch were the most important foliar diseases of wheat. Disease ratings (0–9) of the leaf spots were greater on winter wheat (average 2.2) than on spring wheat (average 1.9) and also greater on spring wheat following a cereal (average 2.0) than following peas or summer fallow (average 1.7). Hot and dry weather did not enhance development of foliar diseases, and no consistent effects of tillage on leaf disease ratings were observed. However, take-all and common root rot were affected by crop management. Incidence of take-all was greater on winter wheat (8%) than on spring wheat (1%) and also greater on winter wheat under conventional (11%) than minimum (8%) or zero tillage (6%). Severity of common root rot of spring wheat was greater following either spring (24%) or winter wheat (25%) than peas (22%) and summer fallow (15%). The severity of common root rot varied from year to year. In 3 of the 4 years, minimum-till and zero-till reduced the severity of the disease.Key words: Zero till, minimum till, conventional till, crop rotation, disease, spring wheat, winter wheat