Blueberry Scorch Carlavirus Eliminated from Infected Blueberry (Vaccinium corymbosum) by Heat Therapy and Apical...

The incidence of aphid-transmitted blueberry scorch carlavirus (BBSCV) has been increasing in recent years through the blueberry production areas of Oregon and Washington (1). Several infected plants were detected by enzyme-linked immunosorbent assay (ELISA) and removed from the blueberry germ plasm collection at the USDA/ARS National Clonal Germplasm Repository (NCGR) in Corvallis, OR. A virus-free replacement was not available from other sources for one of the infected cultivars. Plants of a highbush blueberry cultivar (Vaccinium corymbosum L. 'Gem'), infected with BBSCV, were grown at temperatures alternating every 4 h between 30 and 38°C. After 16 or 58 days of heat therapy, apical shoot tips were removed and meristems ranging in size from 0.2 to 1.0 mm were dissected and grown in vitro. Eight plants were successfully regenerated from these meristems: five from shoots that had been heat treated for 16 days and three from shoots heat treated for 58 days. These eight plants were tested for BBSCV by ELISA during the first growing season, and again after growth resumed following winter dormancy. All eight plants consistently tested negative for the virus and Gem is now among the 400 virus-tested Vaccinium clones available at NCGR Corvallis. This is the first report of the successful elimination of BBSCV from infected blueberry plants. Reference: (1) R. R. Martin and P. R. Bristow. Phytopathology 78:1636, 1988.