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

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.

Outcomes of co-infection by two potyviruses: implications for the evolution of manipulative strategies

“…drastic changes in host size or longevity [49]), and comparisons of their impact on plant-aphid relationships are quite rare. In one example, mixed infections of potato leafroll virus (PLRV; a persistently transmitted virus) with the potyvirus potato virus Y exhibited an increase in virulence symptoms compared with single infections, along with an increase in aphid attraction and performance [50]. On the other hand, in another well described synergy between CMV and potyviruses [30], aphid transmission of either virus was less efficient in double infections compared with single infections [51].…”

Divergent effects of PVY-infected potato plant on aphids

“…After landing, aphid feeding behaviour (particularly superficial tissue probing and sustained phloem sap ingestion) can be enhanced on plants infected by PLRV ). Finally, PLRV infection was also reported to enhance host plant preference and acceptance, thus improving aphid fitness (Castle and Berger 1993;Srinivasan and Alvarez 2007). In contrast to the effect of persistent viruses, mechanically transmitted infection of potato plants by the vector-independent virus Potato virus X, induced no effect on aphids Castle et al 1998;Eigenbrode et al 2002;Srinivasan and Alvarez 2007).…”

“…Finally, PLRV infection was also reported to enhance host plant preference and acceptance, thus improving aphid fitness (Castle and Berger 1993;Srinivasan and Alvarez 2007). In contrast to the effect of persistent viruses, mechanically transmitted infection of potato plants by the vector-independent virus Potato virus X, induced no effect on aphids Castle et al 1998;Eigenbrode et al 2002;Srinivasan and Alvarez 2007). Potato virus Y (PVY), a less vector-dependent virus, transmitted in a non-persistent manner by a broad range of aphid species, induces various modifications of aphid behaviour and physiology depending on the species (Srinivasan and Alvarez 2007).…”

Pest Management Strategies for Potato Insect Pests in the Pacific Northwest of the United States

“…PLRV causes necrosis while strains of PVY can cause internal brown lesions in the tubers. Srinivasan & Alvarez (2007) reported that mixed viral infections of heterologous viruses occur regularly in potatoes.…”

“…Early aphid infestations commonly occur on a number of weeds including species of mustards and nightshade; therefore, those weeds should be kept under control. Research in Idaho indicates that hairy nightshade is an excellent aphid and virus host (Srinivasan & Alvarez, 2007), thus, control of this weed is highly recommended. In some instances, the number of insects available to infest crops in the spring depends upon winter survival .…”