Rice yellow mottle virus
Rice yellow mottle virus (RYMV) is a plant virus disease. The most important symptom on a rice plant is that leaves turn yellow, with alternate yellow and green stripes that give its typical mottled appearance to the plant (see photo above). The other symptoms are: stunting, reduced tillering, leaf mottle with yellow stripes, incomplete panicle exsertion, the panicle sometimes being badly formed, and spikelet sterility.
In natural conditions, RYMV is transmitted from an infested plant to a healthy plant by insect vectors of the beetle group (most important Sesselia pussilla and other vectors such as Chaetocnema spp., Aulacophora africana, Trichispa sericea and Dicladispa viridicynea), or by lesions caused by tillage practices (transplanting, weeding, etc.). The disease can be transmitted mechanically; touching an infested plant and later a healthy plant can transmit the disease. In an infested field, yellow patches indicate the infestation (see photo below).
Extract from PLAR-IRM Curriculum: Technical Manual (Wopereis et al., 2009)