Tomato Spotted Wilt Virus - TSWV

Symptoms of spotted wilt vary according to the age of the plant at the moment of infection, environmental conditions and the part of the plant that is infected. Attacks can occur from seedling stage through to maturity. It may stunt the growth of infected plants, and normally the symptoms are more severe on one side of the plants and in the apical bud, which may be distorted and bend towards one side of the plant. Young leaves show yellowish spots, and they can turn into necrotic spots of reddish-brown color. Tissue necrosis along midribs is also a common characteristic of spotted wilt. When infections occur close to flowering time, ringspots may develop along the stem, with dark streaks on one side of the plant.

Spotted wilt is caused by the TSWV virus, which is transmitted by very small insects, called thrips.

Damages can be considerable, as this disease can cause the plant to die. The later the infection takes place, the smaller the damage. If infections occur close to, or at flowering, there will be small losses.

There are no cultivars resistant to this disease and, therefore, preventive measures should be taken, particularly in previously affected areas.

To prevent the disease, plants that host thrips should be eliminated from areas close to seedbeds and tobacco fields. Thrips can survive in several weeds, especially in broad leaf species. The application of preventive insecticides to control the insect from seedbed to field, is of fundamental importance.

Symptom disease pictures: