The fungus Verticillium dahliae causes Verticillium wilt, a soil-borne disease. It has the potential to harm a wide range of plant species, including deciduous trees, flowers, berries, and vegetables. Fungicides will not cure the condition. Thus, prevention is essential. The disease’s diagnosis can be difficult since the symptoms change between plant species and might be confused with other causes such as drought, fusarium wilt, root rot, or excessive soil moisture. Verticillium disease affects many plant species, including hops, Cotton, and alfalfa.
Verticillium Wilt Management in Cotton
The Causal Organism of Verticillium Wilt Disease
Verticillium wilt disease is caused by the fungus Verticillium dahliae. It produces hyaline mycelium and two types of spores: conidia (single-celled, hyaline, and spherical to oval) and microsclerotia (globose to oblong, measuring 48-120 X 26-45um). These fragments play a crucial role in the spread of the disease.
Disease Cycle of Verticillium Wilt Disease
The Verticillium wilt disease cycle in Cotton involves the fungus living as microsclerotia in diseased plant waste and soil for up to 14 years. The fungus can infect crops, including brinjal, bhendi, chili, and tobacco. The disease spreads in two ways: primary spread via soil microsclerotia or conidia and secondary spread by interacting infected roots with healthy ones, as well as dispersion of infected plant parts via irrigation water and agricultural instruments. Furthermore, the illness can spread through seeds that have microsclerotia and conidia on their fuzz.
Favorable Conditions for the Spread of Verticillium Wilt Disease
Specific circumstances, such as low temperatures of 15-20°C, low-lying and poorly drained soils, heavy soils with an alkaline response, and high nitrogenous fertilizer application, promote the spread of Verticillium wilt disease. These factors generate an environment that promotes the growth and spread of the pathogenic fungus Verticillium dahliae. Growers and agricultural practitioners can reduce the danger of disease formation and spread in their crops by recognizing the favorable circumstances for the spread of Verticillium wilt.
Symptoms of Verticillium Wilt Disease in Cotton
- Stunted growth: Early-stage infected plants show severe stunting.
- Bronzing of veins: The first visible symptom is the bronzing of the veins on the leaves.
- Interveinal chlorosis: This is followed by the yellowing of the leaves, especially between the veins.
- Scorched appearance: The leav