Colletotrichum tabacum

Böning (1932)

Anthracnose of tobacco

- Frequency and severity of disease incidence

Colletotrichum tabacum is responsible for a widespread disease (described in Asia, Africa, the United States, Brazil and Germany), which mainly affects tobacco seedlings in nurseries. It is usually not severe and seems in decline in some countries because of the susceptibility of the fungus to fungicides and their more frequent use. It is not observed in France.

- Symptoms

This fungus causes circular lesions that are initially dark and oily then become greyish, parchmentlike, and surrounded by a brown border. Some lateral veins may turn brown. Small elongated cankers are observed on petioles and stems, and sometimes these are covered by pink clusters of acervuli containing conidia (figure 1).

- Biology

Colletotrichum tabacum survives in plant debris, soil and seeds. It affects a large number of cultivated plants and weeds that serve as source of inoculum. The combination of high humidity, cool temperature and low light enhances the development and spread of the disease.

- Protection Methods

No product is approved for this use in France.