Effects of Temperature and Length of Acquisition Feeding Time on Transmission of Nonpersistent Viruses by Aphids1

Abstract

Comparative transmission studies were made with 2 strains of potato virus Y (MPVY and RPVY) and of cucumber mosaic virus (CMV) using 7 clones of the green peach aphid, Myzus persicae (Sulzer), 11 clones of the cotton (melon) aphid, Aphis gossypii Glover, 4 clones of the green form of the potato aphid, Macrosiphum euphorbiae (Thomas), and 4 clones of the pink form of the potato aphid. Differences in transmission efficiency among clones of a given aphid species were almost as great as those found between aphid species. The effect on transmission efficiency of rearing the aphids on different host plant species was apparent only with the green peach aphid and PVY strains where aphids reared on kenaf, Hibiscus cannibinus L., were poorer vectors than those reared on pepper, Capsicum annum L., var. California Wonder. Single clones of green peach, cotton, and pink and green forms of the potato aphid were selected from the above and used in transmission trials with the 3 viruses under temperature regimes of 50, 70, and 90[degree]F. Using single acquisition feeding probes (9[long dash]60 seconds, depending on temperature) it was found that 4 vector-virus combinations transmitted optimally at 50[degree]F, 6 transmitted optimally at 70[degree]F, and 1 at 90[degree]F. One combination failed to transmit. When the trials were repeated using the 3 temperatures and also 3 lengths of acquisition feeding (1 probe, 5 minutes, ?nd 15 minutes) the effect on transmission of varying length of acquisition feeding was found to be independent of the temperature effect. The results with 1-probe acquisition feedings are interpreted as indicating that aphid behavior (probing?) was principally affected by changing temperature. It is believed that the general depression in transmission efficiency caused by increasing the length of acquisition feeding time at 70[degree] and 90[degree]F probably reflects the relative toxicities of the aphids'' mouthparts (saliva?) to the viruses.