Image Number: 1402008

Descriptor:
Symptoms
Description:
This fungal disease is encountered in tobacco seed beds and occasionally in the field. Small gray-white, usually circular, spots develop on leaves. As lesions age and dry, they become papery and thin and are surrounded by a raised water-soaked border. Leaf tissues, especially veins and midribs, may appear "pitted" or sunken when viewed from the underside. The lesions become brown. Larger spots may have a dark brown center. Lateral veins on the lower leaf surface may turn dark. Affected leaves may become wrinkled and/or distorted. As the disease continues, the entire leaf may die. Small plants may be killed, resulting in large barren spots in plant beds. In the field, leaf lesions may be followed by cankers on midribs and stems. Anthracnose is favored by wet conditions and is sometimes confused with weather fleck. Symptoms of anthracnose are also similar to those of target spot. Target spot has more consistently circular, pin-head sized lesions which usually do not affect the major leaf veins until the whole leaf begins to die, whereas anthracnose often attacks leaf veins and petioles early in the disease development.
Image type:
Field

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Image location:
United States

Subject

Kingdom: Fungi
Phylum: Ascomycota
Subphylum: Pezizomycotina
Class: Sordariomycetes
Subclass: incertae sedis
Order: Phyllachorales
Family: Phyllachoraceae
Genus: Colletotrichum
Subject: Colletotrichum nicotianae Av.-Saccá

Host

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Asteridae
Order: Solanales
Family: Solanaceae
Genus: Nicotiana
Subject: Nicotiana tabacum (flue-cured type) L.
Node Affiliation:
Image uploaded:
Sunday, March 10, 2002
Image last updated:
Friday, May 6, 2011