Symptoms and Signs
Plants infected with Tomato spotted wilt virus exhibit bronzing of the upper sides of young leaves, which later develop distinct, necrotic spots. Leaves may be cupped downward. Some tip dieback may occur. On ripe fruit chlorotic spots and blotches appear, often with concentric rings. Immature eggplant fruit show slightly raised areas with faint, concentric zones.
Comments on the Disease
Tomato spotted wilt virus is transmitted by various species of thrips, including the western flower thrips, Frankliniella occidentalis, the onion thrips, Thrips tabaci, and the chili thrips, Scirtothrips dorsalis; however, western flower thrips is the most predominate of these three species. Tomato spotted wilt virus has the unique ability to also survive and multiply within the insect host. Nymphs that acquire the virus by feeding on infected plants will retain the ability to transmit it for the remainder of their lives. Tomato spotted wilt virus does not pass from infected females through the eggs. (For more information, see the section on THRIPS.)
This virus has an extremely wide host range, including many weeds and ornamentals as well as crop hosts. It is one of the few plant viruses with a host range that includes dicots and monocots (e.g., eggplants and onions). Recent outbreaks have occurred in isolated areas of the San Joaquin Valley where they are believed to be associated with nearby infested crops, weeds, or both.
Management
No management practices are used against tomato spotted wilt in California.