ABSTRACT
This chapter provides information on diseases of linseed, their symptoms, pathogen characters, epidemiology, and management. The diseases covered are rust, wilt, pasmo disease, powdery mildew, stem break and browning, seedling blight and root rot, sclerotinia stem rot, aster yellows, and crinkle. Rust is potentially the most destructive disease affecting flax. The last major rust epidemic occurred in the 1970’s. Although it is effectively controlled by genetic resistance, it remains a potential threat to flax production as it can survive locally and complete its life cycle on flax, thus having the ability to produce new races that attack hitherto resistant varieties. The fungus invades plants through the roots at any growth stage during the growing season and continues infection inside the water-conducting tissue of the root. The causal organism of this disease is Septoria linicola, a fungus that attacks above-ground parts of flax and overwinters in the soil on infected flax stubble.
