Protect Potatoes From Black Scurf And Stem Canker

Black scurf and stem canker of potato are caused by the fungus Rhizoctonia solani Kuhn. R. solani is a cosmopolitan fungus and has a broad host range, but the strains that attack potato (mainly AG-3) generally do not attack other hosts. Symptoms can be observed on all plant parts. Black scurf is the most conspicuous. In this phase, the fungus forms dark brown to black hard sclerotia on the surface of the tuber. Although these structures adhere tightly to the tuber skin, they are superficial and do not penetrate or damage the tuber, even in storage. Management of the disease should not rely solely on chemical control but should combine several integrated management strategies. Avoid areas with history of potato production or history of the disease. Long rotations of three or more years will significantly reduce the amount of inoculum of R. solani in the soil. Use certified potato seed. Seed treatments and of fungicides in-furrow at planting provides significant control of this disease. More