Occurrence of an Aphid-Transmissible Sweet Potato Feathery Mottle Virus in Ontario, Canada. L. W. Stobbs, Agriculture Canada, Vineland Station, Box 6000, Ontario L0R 2E0. R. F. Cerkauskas, L. B. Reynolds, and A. W. McKeown. Agriculture Canada, Vineland Station, Box 6000, Ontario L0R 2E0; Agriculture Canada, Delhi, Ontario N4B 2W9; and O.M.A.F., Horticultural Station, Simcoe, Ontario N3Y 4N5. Plant Dis. 75:430. Accepted for publication 7 December 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0430C.
Sweet potato (Ipomoea batatas (L.) Lam.) has been introduced as an alternative crop to tobacco in southern Ontario. Seed tubers for plantings were imported from a supplier in North Carolina. In 1988, sweet potato feathery mottle virus (FMV) was identified in eight locations, with moderate to high incidences of infection. Symptoms on the cultivars Jewel and Georgia Jet were generally mild and often transient. Symptoms included chlorotic leaf spots, often with purple borders, and mild stunting. Root abnormalities were absent. The virus was detected by electron microscopy in tubers, stem, and leaf tissue triturates and confirmed using convergent immunoelectrophoresis and ELISA with antiserum from J. W. Moyer (North Carolina State University, Raleigh). FMV was transmitted mechanically and in a nonpersistent manner by the green peach aphid (Myzus persicae (Sulzer» between Jewel and Georgia Jet, but it was not transmissible to either Chenopodium quinoa Willd. or C. amaranticolor Coste & Reyn. Virus particles had a mean length of 850-900 nm. The present strain of FMV differs from the damaging strain previously observed in Ontario (1) by being both aphid-transmissible and oflittle economic importance. Weeds that may serve as reservoirs for the virus in Ontario, as well as sources of virus-free certified seed tubers, need to be identified.