Tubers are often small, and in case of spindle tuber, elongated. Several viruses can infect potato without causing noticeable symptoms. However, yields can be reduced drastically. Use of seed certified to be true to variety and free of disease agents is the best way to control tuber-borne viruses. This virus is vectored by thrips insects.
Early symptoms are dead spots on upper leaves and death of the upper plant parts.
Early leaf symptoms may somewhat resemble early blight, but spotted wilt symptoms will usually be in the top of the plant rather than on lower leaves. Plant seed certified to be free of disease agents. Control broadleaf weeds in and around fields 4 to 5 weeks before planting. These are discussed in separate sections in order to provide more information. White, raised spore masses appear on the underside of leaves.