Symptoms Incited by Apple Type II Virus Isolates in Virginia Crabapple Trees. H. E. Water Worth, Research Plant Pathologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Plant Introduction Station, Glenn Dale, MD 20769. J. K. Uyemoto, Professor of Plant Pathology, Department of Plant Pathology, Kansas State University, Manhattan 66506. Plant Dis. 64:562-563. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/PD-64-562.

Isolates of Type II viruses from four apple cultivars were, in earlier work, mechanically transmitted to squash and from squash to apple seedlings. These seedlings have now been used to transmit these isolates by budding to virus indicators Virginia crabapple K-6, R-12740-7A (Russian), and Spy 227 to relate symptoms to the characterized virus. After 3 yr, some Virginia crabapple trees were yellowed and in decline; all had necrosis at the graft union, but some isolates caused more severe necrosis than others. No grooving symptoms appeared after 4 yr on the stocks or scions within 15 cm of the graft union with any of the four virus isolates. These isolates also did not incite symptoms in the Russian or Spy 227 trees or in five pear virus indicator cultivars.