Transmission of Three Strains of Tobacco Streak Ilarvirus by Different Thrips Species Using Virus-infected Pollen

When cucumber seedlings were dusted with tobacco streak ilarvirus (TSV)-infected pollen and infested with 5–10 thrips (adults and larvae mixed), Thrips tabaci transmitted all three Australian strains of TSV. In similar work, Microcephalothrips abdominalis transmitted both and Frankliniella schultzei one strain, respectively, of two TSV strains tested. Transmission of the Ageratum strain (TSV-Ag) infecting pollen of Ageratum houstonianum was very efficient (100%) by all three thrips species. However, transmission rates of only 0–28% were achieved using the Ajuga strain (TSV-A) and the strawberry strain (TSVS) in pollen of other hosts. A fourth thrips species, T. parvispinus , transmitted TSV-Ag from infected tomato pollen to Chenopodium amaranticolor seedlings. There was, therefore, little or no vector specificity in the thrips transmission of the three strains of TSV, but factors associated with the virus-infected pollen affected the efficiency of transmission. This is the first report of F. schultzei and T. parvispinus as vectors of TSV.