Population dynamics of three aphid species (Hemiptera: Aphididae) on four Ipomoea spp. infected or noninfected with sweetpotato potyviruses.

Three aphid species, Aphis gossypii Glover and Myzus persicae (Sulzer) (efficient sweetpotato potyvirus vectors) and Rhopalosiphum padi (L.) (an inefficient vector), are commonly found in sweet potato, Ipomoea batatas (L.), in Louisiana. Field-grown sweet potatoes are naturally infected with several potyviruses: Sweet potato feathery mottle virus, Sweet potato virus G, and Sweet potato virus 2. Thus, these aphids commonly encounter virus-infected hosts. What is not known is how each of these aphids responds to sweet potato, either infected or virus-free. The objectives of this study were to 1) determine if these aphid species can colonize mixed virus-infected sweet potato 'Beauregard', and if so, 2) determine the effects of virus infection on the population dynamics of each aphid. A. gossypii failed to larviposit and R. padi deposited a single nymph that died within a day on mixed virus-infected Beauregard. M. persicae larviposited and colonized Beauregard and further life-table analyses were warranted. M. persicae had a significantly greater reproduction on sweet potato cultivars Beauregard and 'Evangeline' with mixed virus infection compared with noninfected plants. On morning glory species, Ipomoea cordatotriloba (Dennestedt) and Ipomoea hederacea (Jacquin), M. persicae had a significantly lower reproduction on Sweet potato feathery mottle virus-infected compared with noninfected plants.