Host plant-virus interactions on green peach aphid population dynamics

Sweetpotato feathery mottle virus (SPFMV), and Sweetpotato virus G (SPVG) are two important viruses affecting sweetpotato, Ipomoea batatas L., production. The U.S. sweetpotato virus complex, which includes these potyviruses, can cause up to 40% yield loss in mixed infections. Both SPFMV and SPVG are non-persistent stylet-borne viruses and green peach aphid, Myzus persicae (Sulzer), is one of the important vectors. Virus infected plants often have improved host plant nutritional quality which, in turn, increases aphid development and fecundity. Our objective was to determine the effect host plant; sweetpotato cultivars Beauregard and Evangeline and two morning glory species Ipomoea hederecea Jacq. and I. cordatotriloba Dennst., with or without virus infection, have on green peach aphid population dynamics. Single green peach aphid adult apterae were clip-caged onto individual host plants. Adults were allowed to larviposit and then were removed. Days to adult and number of progeny per day were recorded for each nymph. Highest intrinsic rate of increase (r_m) among host plants was on Beauregard with mixed infections (0.369 ± 0.014), while the lowest was on I. cordatotriloba with SPFMV (-0.097 ± 0.08). There were no significant differences in r_m between any virus infected and virus free host plants. M. persicae is capable of colonizing and utilizing sweetpotato and wild morning glory species as hosts. Plants infected with SPFMV and mixed natural infections did not affect M. persicae population dynamics. Further work is in progress studying feeding behavior of M. persicae on Ipomoea spp using electrical penetration graph technique.