Rhizoctonia damping-off, blight and rot
Host: flue-cured tobacco (Nicotiana tabacum (flue-cured type)
Description: This soil-borne fungus infects the lower stem of the tobacco plant. Symptoms begin on seedlings and transplants as a dark brown lesion on the stem near or below ground level. Lesions vary in size and number depending on environmental conditions. In wet, cool weather, the lesions may enlarge upward and around the stem until the plant falls over. This may be confused with black shank or Pythium damping-off. On older plants, a dark brown lesion up to several inches long occurs at or near the soil line. It may girdle the stalk which becomes hard and brittle. The stalk may break at this lesion. The plant may be stunted with yellow to brown and/or wilted leaves. Roots usually show no evidence of decay.
Image type: Field
Image location: United States
Name: R.J. Reynolds Tobacco Company Slide Set
Organization: R.J. Reynolds Tobacco Company
Country: United States