Tomato Spotted Wilt Virus (TSWV)

Tospovirus TSWV

This virus is unusual in that it can infect a very wide range of plants, including not just tomatoes, but also eggplant, peppers, potato, celery, lettuce, onion, peanut and many legumes. It also affects many common weeds (including a who’s who of most common garden weeds) and ornamentals, which can complicate controlling it.

Tomato Spotted Wilt Virus (or TSWV) is also unusual in that is one of few viruses that is mostly spread by thrips. The larvae acquire the disease by feeding on infected plants (often weeds) and spread it to other plants when they mature into flying adults.

This virus is mainly a problem for areas with lots of thrips and warm weather. Symptoms of infection include wilting, dieback of growing tips, bronzing of leaves (which eventually develop necrotic spots), stunting, deformed fruit and reduced yields. In extreme cases so many leaves die that the plant is killed.

TSWV is not easy to control as there are so many potential hosts to provide a source of infection and controlling the vector (thrips) is difficult (kill the ones on your plants and others will come in from elsewhere). If you can recognize the symptoms you can remove infected plants promptly and reduce sources of infection. Row covers can help prevent thrips reaching your plants. You can also rotate crops, remove weeds and avoid planting infected plants. Some cultivars are resistant.

Image: David B. Langston, University of Georgia, Bugwood.org