Transmission features of Mal de Rio Cuarto virus in wheat by its planthopper vector Delphaeodes kuscheli

Mal de Rio Cuarto virus (MRCV, Fijivirus) infects maize (Zea mays) and other gramineae, producing significant losses in Argentina. Although MRCV mainly affects maize, other cereals, such as wheat, serve as potential virus reservoirs and hosts for the planthopper vector Delphacodes kuscheli. Aspects of the virus-vector relationships were elucidated by studying the minimum periods of acquisition access (AAP(min)), latency (LPmin) and inoculation access (IAP(min)) in wheat (Triticum aestivum L.). Trials were conducted under controlled conditions of temperature (24 +/- 1degreesC), photoperiod (12 h light) and humidity (50 +/- 5%). The results show that the AAP(min) was 5 h, LPmin was 10 days (even though, the median latent period was between 16 and 17 days) and IAP(min) was 30 min. Our experiments have demonstrated, for the first time, a persistent manner of virus transmission. No differences were detected in transmission ability between mates and females. The implication of these results on virus taxonomy and epidemiology are discussed.