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Etiology

Cucumber Mosaic Virus in Weed Hosts Near Commercial Fields of Lettuce and Celery. W. L. Bruckart, Graduate Research Assistant, Department of Plant Pathology, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca 14853; J. W. Lorbeer, Professor, Department of Plant Pathology, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca 14853. Phytopathology 66:253-259. Accepted for publication 29 September 1975. DOI: 10.1094/Phyto-66-253.

Cucumber mosaic virus (CMV) was detected in 12 of 66 weed species collected during 1972 and 1973 in the vicinity of lettuce fields in Oswego County and celery fields in Orange County, New York. This is the first report of (i) natural infection by CMV for five* of the species and (ii) natural infection for three⁺ of the species in the United States. Final determination of CMV was based on the reaction of the isolates on a test host range of 16 species. Weeds found to be naturally infected were (number of plants infected/number of plants indexed - 1972 and 1973): Asclepias syriaca (3/113), Barbarea vulgaris⁺ (13/52 - 1973 only), Capsella bursapastoris⁺ (1/12), Cerastium arvense* (6/42 - 1973 only), Echinocystis lobata (11/42) , Eupatorium dubium* (1/18 - 1973 only), Galinsoga parviflora⁺ (4/10 - 1973 only), Phytolacca americana (1/35), Rorippa islandica* (21/156 - 1973 only), Solanum dulcamara* (3/41), Stellaria sp. (4/19) and Verbascum thapsus* (3/22 - 1973 only). The occurrence of broad bean wilt virus (BBWV) in the plants sampled was noted. The identity of representative isolates of CMV and BBWV was confirmed additionally by studies involving serology and electron microscopy. Lettuce mosaic virus was not recovered from any of the weed samples tested.