WHAT IS IT?
Verticillium Wilt (VW) is a soil-borne disease caused by a fungus in the Verticillium genus. Verticillium dahliae is the most common species of fungus that causes wilt.
VW affects a wide range of different plant species. Various species of vegetables, fruit trees, flowers, field crops, and shade and forest trees are all susceptible to VW. There are over 350 different species of plants that are affected by VW.
The most common sign of the disease is the actual wilting from which the disease gets its name. This manifests in small or yellow foliage, leaf scorch, slow growth, or the sudden death of the branches. Often times leaf curling or drying will occur. In its most lethal form, VW will cause a sudden and total collapse of the plant. Due to the vast range of species that can be affected by VW, the specific symptoms vary from plant to plant.
Because VW is caused by multiple different fungi, the specific life cycle of the disease can vary. There are still several steps in the life cycles however that are consistent between the various species of fungi.
The fungi will attempt to enter the vascular system of their host plant, and the easiest way to do this is by entering through an existing wound in the plants root system. Once the disease enters the part of the plant's vascular system that carries water (xylem), the fungi can spread throughout the plant. Because the fungi can spread as either hyphae or as spores, it is able to spread throughout the plant very quickly. When the host plant dies the fungi are able to survive on their own until they enter into a neighboring plant and the cycle begins again.
IF LEFT UNTREATED:
VW can have a devastating effect on the infected plant. In crops the disease can significantly decrease the crop yield either by discoloration, stunting growth, or death. Once an individual plant is infected in can not be cured. The only option is to prevent the disease from spreading and causing widespread damage. The full extent of the potential damage depends on environmental factors as well as the susceptibility of the host plants.
Verticillium Wilt is treated with a fungicidal soil treatment.