New seed should be used. Seed from previous years will show reduced vigor and germination. Harris Model is highly susceptible to the disease while Hollow Crown, All America and Andover are moderately resistant. The latter two cultivars are not widely grown in Ontario due to the extensive shoulder formation on the root which reduces acceptability to packers and consumers. One possible control measure could involve the early harvesting of these two cultivars before such shoulder development occurs.
Partial control is possible with registered fungicides.
Fungicide applications should be started in early August or sooner if the growing season has been wet. This information is provided as a public service, but we cannot guarantee that the information is current or accurate. Readers should verify the information before acting on it.