Raspberry Viruses in the Czech Republic, with Identification of a Novel Virus: Raspberry Virus A

Although global raspberries production has grown in the past decade, it remains threatened by plant viruses. This study surveyed raspberry viruses and associated arthropods in the Czech Republic between 2021 and 2022 across five regions. A total of 257 plant and 151 arthropod samples were tested using RT-(q)PCR for 12 viruses listed in the EPPO Certification scheme, plus raspberry leaf blotch virus (RLBV) and a novel virus, tentatively named raspberry-associated virus A (RaVA). Raspberry bushy dwarf virus (RBDV) was most prevalent (51.8%), followed by black raspberry necrosis virus (BRNV, 42.0%) and raspberry leaf mottle virus (RLMV, 28.4%). Four viruses-arabis mosaic virus, apple mosaic virus, strawberry latent ringspot virus, raspberry ringspot virus-were not detected. RBDV was also identified in <i>Sambucus nigra</i>, a new host, while mixed RLBV and RaVA infection was found in wild <i>Rubus occidentalis</i>. RLBV was experimentally transmitted to <i>Nicotiana occidentalis</i> 37B in the presence of <i>Phyllocoptes gracilis</i>. Seven of 39 arthropod species carried viruses, but only two-<i>Amphorophora rubi idaei</i> and <i>Aphis idaei</i>-are known vectors. PCR amplicons from 92 isolates were sequenced, revealing high variability in several viruses. These findings offer new insights but highlight the need for continued monitoring and research.