Thrips as vectors of tospoviruses

This chapter reviews the thrips–tospovirus pathosystem and the cellular and molecular determinants of thrips acquisition of tospoviruses. Viruses in the genus Tospovirus (family Bunyaviridae) are transmitted by thrips and have become an ever increasing problem for the producers of agricultural and horticultural crops worldwide. The genus Tospovirus is the genus within the Bunyaviridae containing plant-infecting viruses. Tomato spotted wilt virus (TSWV) is the type species of this genus. Thrips cause significant direct damage to plants, but it is their transmission of tospoviruses that is most difficult to control and frequently causes the most severe damage to crops. At least ten species of thrips transmit tospoviruses, all of which are in the Thysanopteran family Thripidae. Most thrips vector species deposit their eggs into plant tissue and the eggs hatch after 2–3 days, depending on temperature and plant host. For tospoviruses to be transmitted by thrips, they must be acquired by the larvae. Thus, only immature thrips that acquire tospoviruses or adults arising from such immatures are important to the transmission of the virus. This concept is extremely important in managing tospoviruses, because only the plants that serve as hosts for both the insect and the virus are important in epidemics.