Relationship of wheat streak mosaic and barley stripe mosaic viruses to vector and nonvector eriophyid mites.

Large amounts of wheat streak mosaic virus (WSMV) accumulate in the midgut of its mite vector Eriophyes tulipae reared on virus infected plants. Masses of flexuous rod shaped virus particles persisted in the midgut, without degradation, for at least 5 of the 6--9 day adult life of mites. WSMV particles also were found distributed in the body cavity and in salivary glands of mites suggesting that the virus is "circulative" in E. tulipae. Abacarus hystrix, a nonvector of WSMV, when reared on virus infected plants, occasionally contained a small number of virus particles in its gut only. Extracts of such mites were not infective. Barley stripe mosaic (BSMV)--a rod-shaped virus, was not transmitted by E. tulipae, although a large concentration of virus particles was found in the midgut of mites reared on virus infected plants. Extracts of such mites were infective and the virus particles were retained for several days in the gut of such mites held on virus-free plants. BSMV particles were also found in the body cavity of mites. Possible reasons for E. tulipae being a nonvector of BSMV are discussed.