Pollen-borne ilarviruses of peach: biology, ecology, and disease management

Abstract

Abstract Prunus necrotic ringspot virus (PNRSV) and prune dwarf virus (PDV) are pollen-transmitted ilarviruses that affect stone fruits. Both viruses are widespread in peach orchards in the southeastern United States. Although symptoms may not always be present, typical symptoms of PNRSV infection in peaches include stunting, chlorosis, and decline of the tree over time, while PDV infection is associated with stunted growth and shortened internodes. Co-infection with PNRSV and PDV can lead to peach stunt disease, causing yield losses of up to 55%. Here we provide information on the diagnostic methods currently available with considerations for selecting the best method based on plant tissue, sampling season, sample number, and cost. The ecology of PNRSV and PDV, including their movement within and between plants and the role of wild hosts as reservoirs, is also discussed. Both PNRSV and PDV are primarily transmitted through vegetative propagation and pollen; the latter could be horizontal between co-occurring blooming trees and/or vertical from parent to progeny. Certain insect groups play a role in spreading PNRSV and PDV in greenhouse and field settings. Management strategies to prevent virus spread, including clean plant programs which provide virus-negative propagation materials, and cultural management practices, such as removing infected trees, are emphasized to prevent secondary spread. While practical challenges persist in managing infection sources and wild hosts, proactive measures are essential to mitigate the spread of PNRSV and PDV and safeguard the peach industry.