Impact of Raspberry bushy dwarf virus on 'Marion' Blackberry

Raspberry bushy dwarf virus (RBDV), genus Idaeovirus, was first observed in 1997 in a planting of 'Marion' blackberry (a complex hybrid with Rubus idaeus, R. procerus, and R. ursinus in its background) established at the North Willamette Research and Extension Center (Aurora, OR) from tissue-cultured plants in 1993. RBDV was detected in 128 of the 280 plants. The incidence of RBDV in this planting did not increase from 1997 through 2001. In 1999 and 2000, we evaluated the impact of RBDV on yield, fruit quality, and plant growth of 'Marion' blackberry. RBDV had no effect on cane growth or fruit number, but it reduced yield (40 to 50%), fruit weight (23 to 40%), and drupelet number per fruit (36 to 39%) compared with uninfected plants. In 2000, we surveyed 32 commercial 'Marion' fields for RBDV using enzyme-linked immunosorbent assay. The locations of sampled fields were selected to reflect the acreage distribution of 'Marion' blackberry production in Oregon. RBDV-infected plants were detected in three fields.