Disease Note.

Introduction of the Tomato Spotted Wilt Virus and Western Flower Thrips Complex into Field Vegetables in Ontario, Canada. R. E. Pitblado, Ridgetown College of Agricultural Technology, Ridgetown, Ontario N0P 2C0. W. R. Allen, J. A. Matteoni, R. Garton, J. L. Shipp, and D. W. A. Hunt. Agriculture Canada Research Station, Vineland Station, Ontario L0R 2E0; and Agriculture Canada Research Station, Harrow, Ontario N0R 1G0. Plant Dis. 74:81. Accepted for publication 19 September 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0081B.

In early June 1989, tomato spotted wilt virus (TS WV) was detected for the first time in epidemic proportions in fields in southwestern and central Ontario planted with infected tomato (Lycopersicon lycopersicum (L.) Karst. ex Farw.) and pepper (Capsicum annuum L.) plants imported from Georgia in the United States. TSWV occurred in over 80% of the tomato fields, and field incidence varied from 0 to 85%. The virus spread within the stock from Georgia as well as to adjacent tomato, pepper, and potato (Solanum tuberosum L.) plants from Ontario. The virus was identified by ELISA, electron microscopy, and host range. An important vector, the western flower thrips (Frankliniella occidentalis (Pergande)), which is not indigenous outdoors in Ontario, was found in fields planted with stock from Georgia. This widespread introduction of the virus-thrips complex constitutes a serious threat to vegetable production in Ontario.