Submitted to: Acta Horticulture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2004
Publication Date: 9/1/2004
Citation: Damsteegt, V.D., Stone, A.L., Gildow, F.E., Schneider, W.L., Luster, D.G. 2004. Potential prunus host range of ppv-penn isolates by aphid transmission. Acta Horticulture 657:201-206
Interpretive Summary: Plum pox virus is a destructive disease of stone fruits including peach, apricot, plums, almonds, and cherries. Spread of the virus in nature is through aphids feeding on infected trees and then passing it to healthy trees. Since the virus was first discovered in Pennsylvania in 1999, the goal has been to eradicate the virus from the U.S. However, the virus has a broad host range among wild and ornamental Prunus species and we are attempting to determine what species are susceptible to the virus isolates in Pennsylvania. To date we have inoculated many of the common species associated with stone fruit orchards in Pennsylvania by aphids commonly found in the orchards and have found some species that are susceptible to infection. These species are observed for symptoms, assayed for the presence of the virus, subjected to a cold treatment to induce dormancy, and then reassayed for persistent virus infection. Sour (tart) cherries are not susceptible to infection with our plum pox isolate but sweet cherries and some flowering cherries are susceptible.
Technical Abstract: Natural spread of plum pox potyvirus (PPV) occurs by aphid transmission, grafting, or movement of infected nursery stock. Two proven aphid vectors of plum pox virus, Myzus persicae and/or Brachycaudus persicae, were used to transmit North American isolates of PPV to a range of commercial and ornamental Prunus species to test the ability of these species to function as PPV reservoirs. Inoculum sources were Lovell peach seedlings infected with the PPV-PENN-3 or PPV-PENN-4 isolates by previous aphid transmission. Aphids were starved for 30 min, placed onto either detached symptomatic PPV-infected peach leaves or intact peach seedlings, and then allowed a 3-day acquisition-inoculation feeding period from infected tissues to the healthy Prunus seedlings. Seedlings were sprayed with insecticide, placed onto greenhouse benches and observed for 6 to 8 weeks for development of symptoms. Test plants were analyzed by ELISA and PCR, and then back-assayed to Lovell peach peach seedlings by healthy Myzus persicae. Test plants then were vernalized at 4.1 C for 8-10 weeks. At four-weeks post-vernalization, plants were tested by ELISA and/or RT-PCR to verify systemic infection. Fourteen of the 15 Prunus species tested positive for PPV infection following the initial aphid transmission. Twelve of the 14 infected species were verified to function as potential PPV sources in subsequent aphid transmissions to peach. To date, at least 10 of the 14 Prunus species maintained systemic PPV infection following vernalization. Only P. cerasus (sour cherry) tested negative to PPV infection. Other cherry species, including P. avium, P. cistena, and P. serrulata maintained systemic infection through vernalization. Results suggest that all species tested except P. cerasus could function as PPV hosts associated with unintentional movement of infected nursery stock and as reservoirs for aphid transmission.