Image Number: 1402037

The black shank fungus can infect tobacco plants of any age. In young seedlings, stems may decay near the soil surface and the root system may become partly or completely black. A dark lesion may extend up the stem. Symptoms are sometimes confused with damping-off caused by other organisms. The photo above shows black shank damage as it appears in the field. Leaves may suddenly and uniformly wilt or droop, turn yellow, and hang down the stalk. Warm, moist weather conditions favor black shank development. Advanced stages of this disease may cause partial or complete decay of the root system. The black shank fungus is soil-borne and is readily translocated by equipment or water movement to noninfested areas. Since the spores of the fungus are so mobile, distribution of the disease within a field may not be uniform.
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United States


Kingdom: Chromista
Phylum: Oomycota
Class: Oomycetes
Order: Peronosporales
Family: Pythiaceae
Genus: Phytophthora
Subject: Phytophthora nicotianae Breda de Haan


Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Asteridae
Order: Solanales
Family: Solanaceae
Genus: Nicotiana
Subject: Nicotiana tabacum (flue-cured type) L.
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Image uploaded:
Sunday, March 10, 2002
Image last updated:
Tuesday, November 23, 2010