Phytophthora blight (Phytophthora nicotianae ) on burley tobacco (Nicotiana tabacum (burley type)) - 1440049

Phytophthora blight
Phytophthora nicotianae Breda de Haan

Host: burley tobacco (Nicotiana tabacum (burley type) L.)
Descriptor: Symptoms
Description: Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs.
Image type: Field
Image location: United States

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Specimen in collection: No
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Photographer Information

Name: R.J. Reynolds Tobacco Company Slide Set
Organization: R.J. Reynolds Tobacco Company
Country: United States

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Image Number: 1440049

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Image uploaded on Monday, January 01, 1990
Image Information last updated on Thursday, May 19, 2011