Chrysanthemum stem necrosis tospovirus is transmitted by Frankliniella schultzei and F. occidentalis
In Brazil, Chrysanthemum stem necrosis tospovirus (EPPO Alert List) has been found in São Paulo and Minais Gerais states on chrysanthemum and tomato crops. Despite its importance on these crops, its vector was so far unknown. The ability of 3 thrips species (Frankliniella schultzei, F. occidentalis, Thrips tabaci) to transmit Chrysanthemum stem necrosis tospovirus was studied. New-born thrips larvae were placed for 16 h (acquisition period) on Datura stramonium plants infected by Chrysanthemum stem necrosis tospovirus (isolated from tomato fields in Minais Gerais). Larvae were then transferred to cages with non-infected D. stramonium until they became adults. Transmission by individual adults was evaluated using a leaf disk assay (inoculation access period of 48 h at 25°C). The presence of the virus on leaf disks and in individual thrips was then tested by DAS-ELISA. Results showed that Chrysanthemum stem necrosis tospovirus was efficiently transmitted by Frankliniella schultzei (78.1 %) and F. occidentalis (65.1%), but not at all by T. tabaci. In individual adult thrips, the presence of the virus was found in all three species: F. schultzei (75.9%), F. occidentalis (97.4%) and T. tabaci (75%). The fact that T. tabaci carries the virus but does not transmit it might be explained by the low concentration of the virus and eventually by the absence of the virus in salivary glands (which remains to be demonstrated). The authors concluded that F. schultzei and F. occidentalis are probably the major vectors of the disease in Brazil.
Sources
Nagata, T.; de Avila, C. (2000) Transmission of chrysanthemum stem necrosis virus, a recently discovered tospovirus, by two thrips species. Journal of Phytopathology, 148(2), 65-128.