AMONG several viruses attacking cruciferous plants is one which affects turnips and, so far as we know, has not been previously described. The main symptom produced on the turnip is a bright yellow and green mosaic mottling, and the name we suggest for the virus is 'turnip yellow mosaic virus'. The host range is rather limited, but Chinese cabbage, Brassica chinensis, var. Chihli, is susceptible and reacts to infection with a brilliant white, yellow or green mottling which resembles a variegation rather than a mosaic (Fig. 1).