Tomato spotted wilt virus (TSWV) is from the tospoviruses genus and is common worldwide due to the spread of its main vector, the western flower thrips. The infection results in spotting and wilting of the infected crop, reduced yield, and in a later stage, it will lead to the death of the plant. Early symptoms show on the stems and leaves, while symptoms upon fruits appear at a later stage. Foliage and stems: the appearance of circular stains of about 5.0 cm in diameter and quickly become necrosis. Fruits: round halo-like and sometimes spiral spots. When the plant is fully infected then the leaves have all over chlorosis with formations of necrotic spots and delayed development.
The virus is transmitted by thrips (mainly the western flowers thrips), and it is not seed-borne. There are a large number of hosts, such as weeds, that allow the virus to remain present even after the contaminated crop was harvested. This can cause the weeds to contaminate crops the following season and makes disease control difficult.