EFFECTS OF RASPBERRY MOSAIC VIRUSES ON YIELD AND GROWTH OF RED RASPBERRIES

Abstract

The raspberry mosaic complex (RM) and its heat-labile mosaic components (HLMC) reduced the yields of Fairview, Sumner, Newburgh and Willamette raspberry (Rubus strigosus Michx.) during the first cropping year in field tests at Abbotsford, British Columbia. The RM complex reduced yields by 43 to 78%. The HLMC reduced yields of Fairview and Newburgh by about 30% while yields of the other two cultivars were not significantly lower. In subsequent cropping years, the yield losses in Fairview and Sumner stabilized at about 14 and 11%, respectively, but Newburgh and Willamette appeared tolerant and showed no statistically significant reduction in yields. After the plants were well established there was no difference in yield between plants infected with the HLMC and those infected with the RM complex. The susceptible cultivars produced smaller fruits and shorter, thinner canes. Only 12 of the 240 originally virus-free plants were contaminated with mosaic at the conclusion of the trials. Newburgh, a cultivar that supports high populations of the aphid vector, accounted for nine of the infected plants.