After reaching the water-conducting xylem tissues, it then progresses up the root and into stem, effectively blocking water transport. Because the pathogen may survive in mid-western soils, long rotations are not always effective in preventing Fusarium yellows in future crops. The best way to control the disease involves using yellows-resistant varieties and avoiding fields with a history of the disease. White Rust White rust, caused by Albugo candidans , is a disease of crucifers that causes yield loss through defoliation, root injury, and reduction of market quality. Spinach, horseradish, and mustard are affected more seriously than other crucifers.
White rust produces small white pustules on the undersides of affected leaves.
The pustules may enlarge and grow together to form larger, irregularly shaped lesions filled with the white spores. The upper surface of affected leaves shows a distinct mosaic pattern. Sometimes the disease results in clublike swellings on roots. Disease Cycle . The overwintering spores germinate in the spring and infect young seedlings.