UPDATES ON FLAX DISEASES IN WESTERN CANADA

K. Y. Rashid¹ and S. Duguid

Flax (Linum usitatissimum L.) is the second major oilseed crop in Canada with a total production ranging from 600,000 to 1 million hectares.  Flax in western Canada is affected by several diseases that are spread widely in all flax growing regions.  Fusarium wilt caused by Fusarium oxysporum Schlechtend.:Fr. f.sp. lini (Bolley) Snyder and Hansen is a soil-borne pathogen that infects the roots at any stage of the plant growth and causes wilt and death of the plant.  Pasmo caused by Septoria linicola (Speg.) Garassini (sexual state Mycosphaerella linorum Naumov)  is a stubble-borne pathogen that infects the leaves and stems causing defoliation and stem break under severe epidemics.  Powdery mildew caused by Oidium lini Skoric infects leaves and stems causing severe defoliation and weakening the stems.  Alternaria blight caused by Alternaria Spp. infecting the leaves and causing defoliation.  All these diseases are major factors in reducing the flax yield and the quality of the harvested seed including reduced oil content, protein content, seed weathering and discoloration, and seed contamination with fungi (1-5).   Rust caused by Melampsora lini (Ehrenb.) Desmaz. has been under complete control in Western Canada through the use of resistant cultivars with genes conferring immunity to local races of flax rust.  The objectives of this study were to assess the incidence, severity and distribution of the major flax diseases in western Canada.