Transmission of pangola stunt virus by Sogatella kolophon

A fijivirus causing minor enations, stunting, leaf notching, seed head deformity and excess tillering of Digitaria spp. was transmitted from naturally infected Digitaria ciliaris to D. ciliaris, D. decumbens and Urochloa panicoides by the planthopper Sogatella kolophon; 40–70% of insects transmitted after an incubation period of 15–21 days, and continued to transmit for up to 30 more days until death. Symptoms developed in test plants 30–50 days after inoculation. Sogatella longifurcifera failed to transmit the virus under similar conditions. Virus particles were present in roots, stems and leaves of infected plants, and particles were found in regular arrays and random aggregates in fat body cells of transmitting insects. Viroplasm and tubular structures were associated with these particles. Extracts from infective insects contained 10-segment dsRNA when analysed by polyacrylamide gel electrophoresis. Virus survives over winter in planthoppers and D. ciliaris seedlings in frost-free areas of coastal Queensland, but infected plants have debilitated root systems and compete poorly with healthy plants.