Incidence and distribution of Raspberry bushy dwarf virus in commercial red raspberry (Rubus idaeus) crops in Scotland

A survey was done in 1998 to determine whether Raspberry bushy dwarf virus (RBDV) was established in raspberry fruiting plantations in Scotland. Raspb erry-producing holdings were selected according to geographical area and si ze. Samples (201), each comprising 60 shoots per stock, were obtained from 77 holdings and tested by enzyme-linked immunosorbent assay (ELISA). ELISA- positive shoots from each infected stock were grafted onto cultivar Glen Cl ova, which is resistant to the Scottish-type isolate of RBDV (RBDV-S), to e stablish whether the virus is a resistance-breaking (RB) isolate. RBDV was detected in 22% of the stocks sampled, with 2 to 80% incidence of infection . No RBDV was in any of the 40 plantations containing cultivars resistant t o RBDV-S or in Glen Clova plants, which were grafted successfully with samp les from 15 infected plantations, indicating that no RB isolates were detec ted. The percentage of infected plantations increased with time from the pl anting date. In order to investigate possible sources of infection, ELISA f or RBDV was made in 1999 on samples of stocks of raspberry cultivars entere d for the lowest certified grade (Standard Grade) in Scotland and, in 1994 to 1997, on certified stocks planted with material originating from outside Scotland. No RBDV was detected in any of the samples. RBDV was found only rarely in samples of wild raspberry in Angus and Perthshire.