A HEAT-STABLE BLACK RASPBERRY NECROSIS VIRUS
Red raspberry plants showing symptoms typical of raspberry mosaic were heat treated at three temperatures for up to 14 weeks. At intervals during treatment, small shoot cuttings were excised and rooted in moist sand. Some cuttings developed symptoms of rubus yellow net virus (RYNV), the heat stable component of mosaic, and diagnosis was confirmed by aphid transmission to black raspberry seedlings. Others showed only a mild mottling of the foliage; aphid transmission from these plants to black raspberry seedlings caused symptoms that were indistinguishable from black raspberry necrosis virus (BRNV), a component of mosaic that was previously reported to be heat-labile. Of 80 rooted cuttings that were indexed, 52 were virus-free, 24 were infected with the BRNV-like virus, and 4 were infected with RYNV. The survival of the BRNV-like component indicates that our concept of the BRNV component of mosaic requires revision.
Mellor, F. C. and Stace-Smith, R. (1980). A HEAT-STABLE BLACK RASPBERRY NECROSIS VIRUS. Acta Hortic. 95, 71-76