Further Studies on the Transmission and Retention of Inoculativity of Potato Leaf-Roll Virus in its Vector, Myzus persicae

Abstract

This paper reports the results of further investigations of the transmission and retention of inoculativity of potato leaf-roll virus (PLRV) in the green peach aphid, Myzus persicae (Sulz.).The frequency of virus transmission, the length of the latent period, and the retention period of inoculativity of the virus in the injected aphids were dependen ton the virus concentration of inocula. Virus recovery from viruliferous aphid extracts was influenced by the length of the acquisition feeding period of the aphids used as sources of inoculum. However, irrespective of the length of the acquisition feeding period, the virus concentration in the aphids tended gradually to decrease after leaving the source plant. The virus was recovered from the guts and blood, but not from the salivary glands of aphids given a 4-day acquisition feeding period on infected plants. Virus recovery from the aphid blood was also dependent on the length of the acquisition feeding period of aphids used as sources of inoculum. PLRV was detected in the blood of aphids up to 2 days after injection with a massive dose of the virus solution using aphid extracts as the inoculum. The results of virus recovery with the blood of the injected aphids were the same as for those following an acquisition feeding period. Attempts to maintain the virus inoculativity in serial passage using extracts or blood of viruliferous aphids were unsuccessful.