Verticillium Wilt is a disease that affects more than 300 species of plants, including cotton, tomatoes, potatoes, eggplants and peppers. It is caused by two types of fungus; Verticillium Dahliae and Verticillium Albo-Atrum.
Verticillium Albo-Atrum is a plant pathogen most severe in temperate regions with cooler soils. Verticillium Dahliae can thrive in a wider range of soils and is therefore more common.
Signs and Symptoms
Verticillium Wilt is most often seen from spring to autumn. It infects plants through the roots and grows up through their water-conducting tissues. It eventually causes wilt due to stress. Furthermore, the Verticillium Dahliae and Verticillium Albo-Atrum fungi cause dieback.
Common symptoms of the fungal infection include yellowing and shriveling lower leaves and the wilting of part or all of the affected plants. The disease also creates brown or black streaks in tissue under bark. These symptoms are magnified during warm weather; plants may recover slightly in cooler, wetter conditions.
Trees with Verticillium Wilt may experience dieback in some limbs but not the entire tree; dead branches may indicate infection in previous years.
Verticillium Wilt can often kill the plants it affects.
Treatment and Prevention
It is imperative not to spread soil contaminated by Verticillium Wilt as the disease is distributed through earth. Outbreaks can be controlled in part by removing weeds and infected plants, including as much of the roots as possible. Heavy watering is also effective in the treatment of the affliction.
The spread of Verticillium Dahliae and Verticillium Albo-Atrum can be culled by applying Oxidate. While often used as a pre-plant dip or foliar treatment, it is also an effective soil drench. TerraClean can also be applied through drip irrigation to eliminate soil-born pathogens.
It is wise to avoid replanting with susceptible plants. Grassing for 15 years is a possibility, as is replanting with crops resistant to the fungi.