Epidemiology and strain identification of Blueberry scorch virus on highbush blueberry in British Columbia

The epidemiology of Blueberry scorch virus (BlScV) in highbush blueberry (Vaccinium corymbosum) was studied over four consecutive years (2001 to 2004) in British Columbia. BlScV was first identified in British Columbia in 2000 and was identified in 40 commercial blueberry fields in 2001, and by 2004, it had spread to 122 fields. BlScV was also detected in cranberry (V. macrocarpon) and black huckleberry (V. membranaceum). The rate of BlScV spread in three commercial blueberry fields was determined by mapping diseased plants over three years. The perc ent increase in diseased plants ranged from 4.4% to 5.2% from 2001 to 2002, and from 4.2% to 9.6% from 2002 to 2004. Partial coat protein gene sequences of 12 BlScV isolates from BC shared 88-100% amino acid sequence identity with each other, and were more closely related to previously described strains BC-2 and NJ-2, than to strains BC-1, NJ-1 and WA-2.