Temperature Effects on Aphid Transmission of Nonpersistent Viruses with Notes on Morphological Variation Within Clones of Aphids with Differing Vector Efficiencies1234

Abstract

Additional studies have been made on transmission efliciency of 3 strains of potato virus Y (DPVY, MPVY, and RPVY) and 1 strain of cucumber mosaic virus (CMV) using the green peach aphid, Myzus persicae (Sulzer), and a green form of the potato aphid, Macrosiphum euphorbiac (Thomas). Acquisition temperatures of 10, 21-23, and 32°C were compared factorially with inoculation temperatures of 10, 21-23, and 32°C for most of the virus-vector combinations. Aphids always acquired virus at 10°C but sometimes failed to inoculate at this temperature. In contrast to earlier results, all virusvector combinations showed positive correlations between transmission efficiency and increasing temperature. Effects were more pronounced with increase in inoculation than with acquisition temperature. The potato aphid transmitted all 3 strains of potato virus Y with equal efficiency. Varying the transmission temperature and/or length of acquisition (access) feeding period resulted in similar changes in vector efficiency among alI 3 strains. However, the green peach aphid transmitted each strain of potato virus Y with a different efficiency. DPVY was not temperature labile as was RPVY, even though it also was transmitted inefficiently by green peach aphids. Apparently more than 1 mechanism is involved in the inefficient transmission by the green peach aphid of these 2 strains of potato virus Y. Morphological differences among clones of green peach, potato, and cotton aphids, Aphis gossypii Glover, were found in several instances. However, these differences were not associated consistently with virus-transmitting ability.