Thrips probe or insert their tubular stylets into cells to suck out the contents. It is during this process that Western flower thrips transmit TSWV.  Without feeding, there is no passage of the virus.

TSWV damages a wide range of plant hosts, including ornamentals, field crops, and fruits and vegetables. The virus wilts and stunts the plants, adversely affecting the quality and the yield. Tomato spotted wilt virus symptoms are diverse, depending on the host, but one of the most striking and common of these symptoms is the development of concentric rings of chlorosis.

TSWV is transmitted in a persistent manner by just 10 thrips species, including the western flower thrips; the onion thrips, Thrips tabaci, and the chili thrips, Scirtothrips dorsalis. It is found worldwide primarily due to the global movement of virus-infected plant material and infected thrips. Early and accurate detection of infected plants combined with thrips control strategies can reduce virus spread.

Thrips, which belong to the order Thysanoptera, are up to a millimeter long or less. Worldwide, there are more than 5,000 known species of thrips. The pest species annually cause billions of dollars in damage to U.S. agricultural crops. Thrips can also be beneficial by feeding on mite and insect eggs.

The research was supported by the UC Davis College of Agricultural and Environmental Sciences and the graduate program of the UC Davis Department of Plant Pathology.