“…Such ability ap peared at first to be associated only with viruses containing relatively large genomes [2], More recently, two viruses with small single-stranded RNA genomes, oat blue dwarf virus [3,4] and maize rayado fino virus (MRFV) [5][6][7], have been shown to multiply in their leafhopper vectors, and are consid ered to represent a new group of plant viruses [2,8,9], That MRFV multiplies in its leafhopper vector, Dalbulus maidis DeLong & Wolcott, was originally suggested by certain charac teristics of the virus-vector relationship, such as the existence of a long incubation period of the virus in the insect, the retention of inoculability by nymphs after moulting, the effect of temperature on transmission, the recovery of virus from viruliferous insects that had lost their ability to transmit, and the lack of effect of abdominal punctures [6,10], Direct evidence of multiplication was re cently provided by the demonstration, us ing enzyme-linked immunosorbent assay (ELISA), of increased virus titers in the bod ies of insects at different intervals after virus acquisition [6,7,11]. The hypothesis of multi plication is supported further by the visuali zation of MRFV particles in the internal or gans of viruliferous D. maidis [7,12], In this paper we examine in more detail the growth of MRFV in ieafhoppers, provid ing additional information on the propaga tive cycle of the virus in its vector. Part of this information was published in abstract form […”