Tomato spotted wilt virus

Tomato spotted wilt virus (TSWV) is a devastating plant pathogen that belongs to the genus Orthotospovirus. It is a persistent, propagative virus that significantly impacts both protected and open-field horticulture, causing severe economic damage globally.

The host range of TSWV is extremely extensive, encompassing over 800 plant species. It is a major threat to crops such as tomatoes, peppers, potatoes, and tobacco. Furthermore, it frequently infects leafy greens like lettuce, as well as various ornamental flowers, making it a difficult pathogen to isolate in agricultural environments.

Symptoms of the infection vary widely depending on the plant species and growth stage. Common signs include chlorotic ringspots, necrotic spotting, leaf distortion, and stunted growth. Infected fruits often develop irregular shapes and unsightly spots, rendering them unmarketable. The foliage may exhibit a characteristic bronzing effect before the plant eventually withers.

Transmission occurs exclusively through thrips, with the western flower thrips being the primary vector. The virus is acquired by larvae feeding on infected tissue, and once acquired, the thrips remain infective for their entire lifespan. The transmission process is efficient and can occur even with low population densities of the insect vector.

Management of TSWV is difficult once a plant is infected, as there is no cure for viral diseases. Therefore, prevention is critical. Growers should focus on using virus-resistant cultivars, maintaining weed-free fields, and implementing aggressive thrips management programs using both chemical and biological control methods. Monitoring populations with sticky traps is essential for early intervention.