Causal Agent:
Verticillium albo-atrum 
Verticillium dahliae 
Two races (1 and 2) are reported.

Distribution:
Worldwide

Symptoms:
Wilting of older leaves begins at the leaflet margin and progresses into a yellow then brown V-shaped pattern. Older leaves eventually turn yellow and dry up. Diseased plants are stunted, do not respond to fertilizer or water and will show diurnal wilting on sunny days. When the base of the main stem is cut a light tan discoloration can be seen in the vascular system and across the pith at the crown. This discoloration usually does not extend far up the plant, however under severe disease pressure it can be found nearer the shoot tips.

Conditions for Disease Development:
The fungus has an extremely wide host range and can survive in the soil and plant debris as microsclerotia for several years. Disease development is favored by cooler temperatures (21-25°C, 70-77°F). The fungus can enter the plant through root wounds caused by cultivation, secondary root formation and nematode feeding.

Control:
The use of resistant varieties is the best way to reduce losses from this disease. Soil fumigation and solar sterilization have been shown to reduce disease incidence.

Typical V-shaped leaf lesions.           Foliar yellowing and necrosis.

Typical tan vascular discoloration.