Variations in aphid transmission of leaf roll virus to and from potato

摘要

As many potato seedlings became infected with leaf roll virus when infested with viruliferous aphids (Myzus persicaeSulz.) by a fast cut-leaf method, as when infested by a slower brush method. More plants, however, became infected when infested at emergence than at any of five other periods of growth including that of sprouts.In recovery tests, more infected plants were detected by testing sprouts and excised leaves of 7-week-old plants than by testing newly emerged plants. Any of the small leaves from the upper 6ensp;cm of infected plants were equally good sources of virus for aphids. Also, when tests were made for 18 successive weeks after inoculation on infected Netted Gem plants, it was only during the first 9 weeks and at the 13th week that all infected plants were detected.No differences resulted, in the number of infected plants produced, when eyes were grown from the bud or stem end or from the middle of infected tubers.