Dynamics of Myzus persicae arrestment by volatiles from Potato leafroll virus-infected potato plants during disease progression

Green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), an important pest of potato (Solanum tuberosum L.) (Solanaceae), preferentially settles on Potato leafroll virus (PLRV)-infected potato plants as compared with non-infected ones, primarily in response to volatile organic compounds (VOCs) released by the plants. In this study, we examined the dynamics of these effects, measuring arrestment of apterous M.persicae in response to VOC from upper, middle, and lower leaflets of PLRV-infected potato plants at the same stage in disease progression (4weeks after inoculation), but inoculated at 1, 3, or 5weeks after transplanting (WAT). Sham-inoculated plants were used as controls and VOC were collected and quantified. Aphid arrestment was greater on PLRV-infected plants inoculated at 1 and 3 WAT as compared with sham-inoculated plants, but this preference was reversed in plants inoculated at 5 WAT. Relative arrestment of M.persicae by infected plants and VOC release was greater for lower and middle leaflets than for upper leaflets at 1 and 3 WAT compared to sham-inoculated plants. The reverse was observed in plants inoculated at 5 WAT. Findings indicate that aphid preference is influenced by VOC release from PLRV- or sham-inoculated potato plants and that VOC emissions and aphid preference depend upon the age at inoculation and leaf position within the potato plants. The implications of these dynamics in vector behavior for spread of PLRV in the field in natural and managed systems are discussed.