The Role of the Helper Virus in Aphid Transmission of Potato Aucuba Mosaic Virus and Potato Virus C

Abstract

Potato aucuba mosaic virus and potato virus C were transmitted by the aphid Myzus persicae, not only from plants also infected with a helper virus, but also from plants infected with them alone, provided the aphids fed first on plants infected with the helper virus. Several different viruses acted as helpers but all are in the potato virus Y group. Helper viruses differed in the efficiency with which they aided potato aucuba mosaic virus and potato virus C, and some potato aucuba mosaic virus isolates were transmitted more frequently than others. With potato virus Y as helper, up to 30% of the aphids transmitted potato aucuba mosaic virus. Aphids were usually fed for brief periods on plants infected with the helper virus but aphids fed for 2 days also transmitted potato aucuba mosaic virus readily. Starving the aphids for 1 to 2 hr between their acquisition feeds on plants infected with helper and aided virus decreased but did not eliminate transmission.