Cucumber Mosaic Virus in Weed Hosts Near Commercial Fields of Lettuce and Celery

Abstract

Cucumber mosaic virus (CMV) was detected in 12 of 66 weed species collected during 1972 and 1973 in the vicinity of lettuce [Lactuca sativa] fields in Oswego County and celery [Apium graveolens var. dulce] fields in Orange County, New York [USA]. This is the 1st report of natural infection by CMV for 5* of the species and natural infection for 3+ of the species in the USA. Final determination of CMV was based on the reaction of the isolates on a test host range of 16 spp. Weeds 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 bursa-pastoris+ (1/12), Cerastium arvense* (6/42 - 1973 only), Echinocystis lobata (11/42), Eupatorium dubium* (1/8 - 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 visus was not recovered from any of the weed samples tested.