Verticillium dahliae

A soil-borne fungal pathogen affecting a wide range of plants

Verticillium dahliae is a fungus in the division Ascomycota, known for causing Verticillium wilt in a wide range of host plants. This soil-borne pathogen is notorious for its ability to persist in the soil for many years, making it a significant challenge for agriculture.

Description

Verticillium dahliae is characterized by its production of microsclerotia, which are small, dark, and resistant structures that allow the fungus to survive in the soil under adverse conditions. The fungus infects plants through the roots and colonizes the vascular system, leading to wilting and often plant death.

Host Range

Verticillium dahliae has a broad host range, affecting over 300 species of dicotyledonous plants. Some of the most economically important hosts include cotton, tomato, potato, and olive. The pathogen can cause significant yield losses in these crops, making it a major concern for farmers.

Symptoms

Infected plants typically exhibit symptoms such as wilting, chlorosis, and necrosis of leaves. The vascular tissues of affected plants often show discoloration, which is a diagnostic feature of Verticillium wilt. Symptoms can vary depending on the host species and environmental conditions.

Disease Cycle

The disease cycle of Verticillium dahliae begins with the germination of microsclerotia in the soil. The fungus penetrates the plant roots and spreads through the xylem vessels, disrupting water transport. As the plant dies, the fungus produces more microsclerotia, which are released back into the soil, completing the cycle.

Management

Managing Verticillium dahliae is challenging due to its persistence in the soil. Strategies include crop rotation with non-host plants, use of resistant plant varieties, and soil fumigation. Biological control methods and cultural practices, such as improving soil health, can also help reduce the impact of the disease.

Related pages

• Verticillium wilt
• Plant pathology
• Fungal plant pathogens

References

• Pegg, G. F., & Brady, B. L. (2002). Verticillium Wilts. CABI Publishing.
• Fradin, E. F., & Thomma, B. P. (2006). Physiological and molecular aspects of Verticillium wilt diseases caused by V. dahliae and V. albo-atrum. Molecular Plant Pathology, 7(2), 71-86.