Transmission of Two Rice Tungro-Associated Viruses and Rice Waika Virus from Doubly or Singly Infected Source Plants by Leafhopper Vectors

Abstract

Transmission efficiencies of leafhopper vectoring rice tungro bacilliform virus (RTBV), rice tungro spherical virus (RTSV) and rice waika virus (RWV), a virus identical or related closely to RTSV, were tested under laboratory conditions. Nephotettix virescens efficiently transmitted these 3 viruses in certain combinations from rice plants infected with both RTBV and RTSV or RWV and also from plants with RTSV or RWV alone. N. cinctipceps also transmitted them, but less efficiently than did N. virescens. N. nigropictus transmitted the 3 viruses at very low efficiency from plants infected with both RTBV and RTSV or RWV; it transmitted RTSV and RWV rather efficiently from source plants with RTSV or RWV alone. The 3 leafhoppers were not able to transmit RTBV from plants infected with RTBV alone. Recilia dorsalis failed to transmit the 3 viruses. Possible implications from this study as to how RWV got established and caused an epidemic in Kyushu, Japan, are discussed.