Identification of new aphid vector species of Blueberry scorch virus

Abstract

Transmission of Blueberry scorch virus (BlScV) by the aphid species Ericaphis fimbriata (Richards), Aphis spiraecola (Patch), Aphis pomi DeGeer, Acyrthosiphon pisum (Harris), Myzus ornatus Laing, Aphis helianthi Monell, Myzus persicae (Sulzer), and Rhopalosiphum padi (L.), was studied in the laboratory using timed aphid acquisition feeding periods and known numbers of aphid vectors. Successful infection of Nicotiana occidentalis Wheeler (Solanaceae), a newly identified herbaceous host, and highbush blueberry, Vaccinium corymbosum L. (Ericaceae), following brief virus-acquisition feeds lasting less than 5 min, demonstrated that BlScV was transmitted in a nonpersistent, non-circulative manner. Based on transfer of 10 aphids per plant, the most efficient vector of BlScV from infected to healthy N. occidentalis was M. ornatus. Compared with this herbaceous host, infection rates for blueberry were much lower even though higher numbers of aphids (25/plant) were used. The highest rate of infection for blueberry (20%) was achieved when the green colour form of E. fimbriata was used to transmit the virus. The relatively low rate of transmission from infected to healthy blueberry suggests that BlScV would spread slowly in the field. Planting of certified virus-free nursery material and aggressive removal of infected plants should help control this economically important disease of highbush blueberries.