Specificity of accumulation and transmission of tomato spotted wilt virus (TSWV) in two genera, Frankliniella and Thrips (Thysanoptera: Thripidae)

The accumulation and transmission of tomato spotted wilt virus (TSWV) was examined in second instar larvae and adults of two thrips genera, Frankliniella and Thrips. The species tested were F. occidentalis (Pergande), F. intonsa (Trybom), T. tabaciLindeman, T. setosus Moulton, T. palmi Karny and T. hawaiiensis (Morgan). In a standard petunia leaf disc assay, the efficiencies of TSWV transmission by two species of Frankliniella were higher than those of any Thrips species in the adult stage. A triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) showed that large amounts of the TSWV-nucleocapsid (N) protein were present in the ELISA-positive larvae of each species, with the exception of T. palmi. The ELISA titre of and the proportion of virus-infected individuals of the two Frankliniella species increased or did not significantly change from the larval to the adult stages, whereas those of the four Thrips species decreased significantly. These results show that the specificity of virus transmission by adult thrips is probably affected by the amount of viral N protein accumulation in the adults and that the accumulation pattern from the larval to the adult stages is in between the two genera tested in the present study.