Brassicas, Stocks and Wallflowers affected. Leaves become discoloured and wilt in sunny weather. Roots are swollen and distorted and plants grow slowly or die. Affected roots have an unpleasant smell. Cultural measures: Ensure land is adequately drained and well limed. Plant resistant varieties. Practice crop rotation. Lift and burn diseased plants. Try not to plant Brassicas or related plants on the same site for several years. There are currently no chemicals for the control of this problem.