These disorders are associated with an imbalance of nutrient elements in the plant. Such disorders are often found in soils high in lime and are most severe under high soil-moisture conditions. Leaf chlorosis may also occur in flax on water-logged soils. Since chlorotic plants are more sensitive to herbicides, care must be taken to apply herbicides under conditions that result in least injury.
Low spots are more conducive to frost canker.
Frost cankers are similar to heat cankers in appearance. The area below the constriction is usually thin and dry, while that above it consists of scar tissue which may appear swollen, rough and cracked. The scar tissue is brittle, and affected plants usually fall over. Less severely damaged plants may produce new shoots which grow to maturity, or they may topple over later in the season, turn yellow and die. The incidence of heat and frost canker is reduced by following recommended seeding practices to ensure good, vigorous stands.