STUDIES ON RUBUS VIRUS DISEASES IN BRITISH COLUMBIA: VIII. RASPBERRY LEAF CURL

A virus disease that occurs on red raspberry in the Okanagan Valley in British Columbia was identified as raspberry leaf curl. Under experimental conditions the virus was transmitted by the aphid Aphis idaci V. d.G. Test plants included red raspberry, Rubus idaeus L.; black raspberry, Rubus occidentalis L.; wineberry, Rubus phoenicolasius Maxim.; Rubus henryi Hemsl. & Kuntse; and the Alpine strawberry, Fragaria vesca L. The virus did not infect black raspberry and caused only transitory symptoms on Alpine strawberry. Root cuttings of red raspberry, leaf-bud cuttings of R. henryi, and seedlings of wineberry provided satisfactory indicator plants. Wineberry and R. henryi were more readily inoculated by aphids than red raspberry. Non-viruliferous aphids required a feed of at least 1 day on the virus source to acquire an infective charge. When viruliferous aphids were transferred to a series of healthy indicator plants, some plants became infected after a test access time of 20 minutes, although transmissions were increased if the time was increased to 1 hour. The virus was found to persist in viruliferous aphids for at least 11 days. Leaf curl virus was not eliminated from infected plants held at an air temperature of 37 °C for periods up to 4 weeks.