Effect of Mixed Viral Infections (Potato Virus Y–Potato Leafroll Virus) on Biology and Preference of Vectors <I>Myzus persicae</I> and <I>Macrosiphum euphorbiae</I> (Hemiptera: Aphididae)

TLDR

Mixed infections of Potato virus Y and Potato leafroll virus are common in Idaho potato fields, yet their impact on vector biology and preference has not been studied. The study aimed to assess how mixed PVY–PLRV infection affects fecundity and host preference of the green peach aphid and potato aphid. Researchers clip‑caged adult aphids on PVY, PLRV, PVY‑PLRV, and noninfected plants, counted nymphs after 96 h, and used settling bioassays to evaluate preference. Mixed‑infected plants induced significantly higher fecundity and were preferentially settled upon by both alate and apterous aphids compared to singly infected or healthy plants.

Abstract

Mixed viral infections of heterologous viruses such as Potato virus Y (family Potyviridae, genus Potyvirus, PVY) and Potato leafroll virus (family Luteoviridae, genus Polerovirus, PLRV) are a regular occurrence in Idaho's potato, Solanum tuberosum (L.), cropping systems. An increased number of plant samples from Idaho's potato fields over the past 2 yr has serologically tested positive for both PVY and PLRV via double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and exhibited more severe symptoms than singly-infected plants (PVY or PLRV). Several studies have extensively examined the mixed infection phenomenon but to the best of our knowledge, none have examined the effect of such infections on vector biology and preference. Laboratory studies were conducted to examine the effect of mixed viral (PVY-PLRV) infection on the fecundity and preference of two of the most efficient PVY and PLRV vectors, the green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae). M. persicae and M. euphorbiae adults were clip-caged (one adult per cage) to leaflets of PVY, PLRV, PVY-PLRV-infected, and noninfected potato plants. The number of nymphs produced in all four treatments was recorded after 96 h. M. persicae and M. euphorbiae fecundity was significantly higher on mixed infected plants than on singly infected plants or noninfected plants. Preference of alatae and apterae of M. persicae and M. euphorbiae was determined with the use of settling bioassays. Both alatae and apterae of M. persicae and M. euphorbiae preferentially settled on PVY-PLRV-infected plants than on singly infected plants (PVY or PLRV) or noninfected plants.