Hairy nightshade, Solanum sarrachoides (Sendtner), is one of the preferred host plants for the green peach aphid, Myzus persicae (Sulzer), the most efficient vector of potato leafroll virus. Recent studies have also shown the ability of S. sarrachoides to act as a reservoir of potato leafroll virus. Our previous field studies have revealed a greater number of winged and wingless green peach aphids on S. sarrachoides than on adjacent potato, Solanum tuberosum (Linnaeus), plants indicating a preference for S. sarrachoides. This apparent preference for S. sarrachoides was further studied in the laboratory through a series of settling and emigration bioassays. The settling bioassays were conducted under light and dark conditions to study the influence of visual cues on green peach aphid host-plant preference. Settling bioassays with both winged and wingless green peach aphid revealed a preference for S. sarrachoides over potato and for potato leafroll virus–infected plants over noninfected plants of both species. Settling patterns of green peach aphid remained the same under both light and dark conditions, indicating that visual cues were not required for the observed response, and other cues like gustatory, tactile, and olfactory could be involved. To explore the involvement of olfactory cues on the preference of green peach aphid, emigration bioassays with wingless green peach aphid were conducted in the absence of visual, tactile, and gustatory cues. Emigration rates of wingless green peach aphid were lower from the vicinity of leaflets of S. sarrachoides than those of potato and lower from the vicinity of leaflets of potato leafroll virus–infected plants than leaflets of noninfected plants of both species. The results suggest that olfactory cues attract and/or arrest green peach aphid, thereby influencing its preference for S. sarrachoides over potato and potato leafroll virus–infected over noninfected plants.