STUDIES OF VIRUS DISEASES OF STRAWBERRIES IN BRITISH COLUMBIA: II THE SEPARATION OF THE COMPONENT VIRUSES OF YELLOWS

Abstract

Progressive transfers of Capitophorus fragaefolii Ckll. from yellows-infected Marshall plants through a succession of Fragaria vesca L. plants resulted in the separation of at least two component viruses. One was of the nonpersistent type; it caused reduction in leaf size, mottle, crinkle, and leaf distortion, but the severity and dominance of these symptoms varied so widely that it is assumed that this component itself is a complex of viruses or strains. The other was of the persistent type; its principal effect was to reduce the vigor of the plant although there was some cupping of the leaves, and in the fall, under green-house conditions, a transitory yellow mottling of the tips and margins of some of the younger leaves.