Prevalence and incidence of viruses in New Zealand hop (Humulus lupulus) gardens

Abstract

Viruses pose a significant constraint to hop (Humulus lupulus) production worldwide. The incidence of Hop latent carlavirus (HpLV), Hop mosaic carlavirus (HpMV), American hop latent carlavirus (AHLV), Arabis mosaic nepovirus‐hop strain (ArMV‐H), and Apple mosaic ilarvirus (hop ApMV‐H and intermediate ApMV‐I serotypes) was assessed in 60 gardens at 11 locations (farms) in the Motueka province of New Zealand. The survey included 10 New Zealand‐bred hop cultivars. Within each garden, one basal shoot was sampled from each of 50–75 plants and bulk‐tested in groups of five by enzyme linked immunosorbent assay (ELISA). Viruses were prevalent, with HpLV, ApMV (H+I), ArMV‐H, HpMV, and AHLV occurring in 55, 41, 37, 37, and 17 of the 60 gardens, respectively. ApMV and HpLV occurred at highest incidence, with 22 and 15 gardens, respectively, having >50% incidence. HpMV, ArMV‐H, and AHLV occurred at lower incidence with only four, two, and one gardens, respectively, having >50% incidence. Results suggested the prevalence and incidence of viruses was high and of concern to the continued production of high yields in New Zealand.