Outbreak of western cucumber mosaic on sugar beets

Abstract

Western cucumber mosaic occurs in the interior regions of California, and not in the coastal fog belt. The symptoms of western cucumber mosaic on naturally infected sugar beets are: large, pale-yellow chlorotic areas; white or green veinbanding or interveinal chlorosis; blisterlike elevations on younger leaves, often accompanied by distorted midribs and veins or by outward-rolled leaf margins; and deformed or twisted young leaves. The green peach aphid, Myzus persicae (Sulzer), is the most important vector of the virus to sugar beets. The bean or dock aphid, Aphis rumicis Linnaeus, rarely transmits the virus to beets. Systemic infection was obtained with 20 per cent of the beets inoculated by the green peach aphid and 26 per cent of those mechanically inoculated.