Transmission of Nepoviruses by Xiphinema americanum-group Nematodes.

The transmission of North American nepoviruses by putative species belonging to the Xiphinema americanum-group is reviewed. Xiphinema americanum sensu stricto, X. californicum, and X. rivesi each transmit cherry rasp leaf (CRLV), tobacco ringspot (TobRSV), and tomato ringspot nepovirus (TomRSV), and X. bricolensis is a vector of TomRSV. The apparent lack of specificity in the transmission of North American nepoviruses by X. americanum-group species markedly contrasts with the specific associations between European nepoviruses and their vector nematode species. Two complementary projects are described examining the taxonomic identity of putative species in the X. americanum-group, their morphological and genetic relationships, their ontogeny, and their ability to transmit viruses.