Transmission of a Citrus Viroid to Avocado by Heterologous Grafting. Rivka Hadas, The S. Tolkowsky Laboratory, Department of Virology, The Volcani Center, Bet Dagan 50250, Israel. Lilach Ashulin, and M. Bar-Joseph. The S. Tolkowsky Laboratory, Department of Virology, The Volcani Center, Bet Dagan 50250, Israel. Plant Dis. 76:357-359. Accepted for publication 11 June 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0357.

A citrus viroid previously designated as CV-Ib was graft-transmitted from alimau (Citrus macrophylla) to seedlings of a West Indian avocado (Persea americana). It was found by subsequent graft transmission to have a host range limited to only a few avocado cultivars. Extracts from CV-Ib–infected avocado were infective on Etrog citron and induced a slight leaf kinking and fruit deformation. The possibilities of extending viroid host ranges as a result of heterologous grafting among noncompatible hosts are discussed.