A technique for the differential isolation of hop mosaic virus and hop latent virus.

Two rod-shaped viruses of similar length occurring in hops were isolated from a mixed infection. One (hop mosaic virus) infected Nicotiana clevelandii, produced mosaic symptoms in mosaic-sensitive hop cultivars, and did not infect Chenopodium murale. The other (hop latent virus) infected C. murale but not N. clevelandii and did not produce mosaic symptoms in hops. Neither N. clevelandii nor C. murale developed distinct symptoms after infection with the respective virus. Both viruses produced a systemic chlorotic flecking in Cluster hop seedling clones.