An Overview of the Mode of Transmission, Host Plants and Methods of Detection of Rice Yellow Mottle Virus

Abstract

Investigations on the mode of transmission of rice yellow mottle virus (RYMV) revealed that it is located in the rice husks. It is therefore, not transmitted through rice seeds. The virus was transmitted through leaf debris, empty rice spikelets, intertwining roots, leaf contact, rice stubble, contaminated hands and from closely spaced plants. Chrysomelid beetles, Chnootriba similis Thurnberg (Coccinelidae) and some long homed grasshoppers transmitted RYMV. The virus is not transmitted by nematodes. Oryza sativa L., O. glaberrima, and O. barthii are systemic hosts while O. longistaminata and a few weed species are local lesion hosts. The virus was readily detected by visual assessment based on the standard evaluation system (SES) and a serological test utilising enzyme linked immunosorbent assay (ELISA) and agar gel diffusion.

Modes of transmission and stability of Rice yellow mottle virus

“…Consistent with the reports by Bakker (1974) and Abo et al (2000), short-horned grasshoppers might be vectors of RYMV in Uganda. …”

“…This mechanism of RYMV transmission is different from transmission by beetles, which have sucking mouth parts. Trichispa sericea can maintain the ability to transmit the virus for 1-2 days, and Chaetocnema similis can maintain it for up to 3 days (Bakker 1974;Abo et al 2000). Because the virus can be transmitted by C. pulla for up to 6 days, it is regarded as a persistent transmitter of virus (Abo et al 2000).…”

“…Trichispa sericea can maintain the ability to transmit the virus for 1-2 days, and Chaetocnema similis can maintain it for up to 3 days (Bakker 1974;Abo et al 2000). Because the virus can be transmitted by C. pulla for up to 6 days, it is regarded as a persistent transmitter of virus (Abo et al 2000). The mechanism of mechanical inoculation via the chewing action of short-and longhorned grasshoppers is similar to transmission of TMV by the bumblebee (Bumbus terrestris) (Okada et al 1999).…”

“…The virus is transmissible by animals, by wind-mediated leaf contact, and by abiotic factors (e.g. irrigation water) (Abo et al 2000;Sarra and Peters 2003;Sarra et al 2004;Traoré and Traoré 2008). Infection via farm equipment has also been confirmed (Sarra 2005).…”

“…Insect species in the families Chrysomelidae, Coccineliidae, and Tettigoniidae are important vectors of RYMV in Africa (Bakker 1971(Bakker , 1974Breniere 1983;Reckhaus and Adamou 1986;Nwilene 1999;Abo et al 2000). The major vector species may vary in each of the countries and localities, so insect transmission experiments performed in Uganda are important for effective vector insect management.…”