Diagnostic and historical surveys of sweet cherry (Prunus avium) virus and virus-like diseases in Oregon.

Abstract

There are over 35 known virus and virus-like diseases of sweet cherry (Prunus avium), some with potential to cause severe economic impact by reducing vegetative growth, vigor, and/or fruit quality. Oregon is the second-ranked state for sweet cherry production in the United States. Statewide surveys were conducted in Oregon sweet cherry orchards for virus and virus-like diversity and distribution. Orchards in key production regions with suspected virus disease symptoms were sampled. Virus-specific ELISA, isothermal amplification, or qPCR were used to test for the presence of common and/or economically important sweet cherry pathogens, including: cherry leaf roll virus (CLRV), little cherry virus 2 (LChV2), prune dwarf virus (PDV), prunus necrotic ringspot virus (PNRSV), tomato ringspot virus (ToRSV), and Candidatus phytoplasma pruni (CaPP). Cherry leaf roll virus, a new virus of sweet cherry in Oregon, was found associated with enation and dieback symptoms in The Dalles. Some viruses were found in new regions, which included: Hood River (PDV, PNRSV, ToRSV) and the Umpqua Valley (PDV, PNRSV). A subsequent survey was conducted in the Mid-Columbia production region for the presence of little cherry symptoms associated with Little Cherry and X-Diseases. All symptomatic samples from The Dalles and Mosier, OR, or Dallesport, WA, tested positive for CaPP, but not LChV2. These findings provide a foundation for the current understanding and management of virus and virus-like diseases of sweet cherry in Oregon and context for further studies into these pathogens and their vectors.