The biology of Canadian weeds. 65. Salsola tragus L. (updated)

Abstract

This account updates that published by Crompton and Bassett in 1985 (classified then as Salsola pestifer A. Nels.). The taxonomy of this species has been controversial and confusing. Salsola tragus is an annual broadleaf weed species native to Eurasia and inadvertently introduced to the Americas in crop seed in 1873. This naturalized species is a common and economically important weed in crop production systems and non-cropped disturbed areas in semiarid to arid regions of western North America; in eastern North America, S. tragus commonly occurs along roadsides, railways, and other dry, stony, and sandy areas. Pollen-mediated gene flow and efficient seed dispersal aids both short- and long-distance spread. As a C4 species, S. tragus is highly competitive in semiarid and arid small-grain cropping systems because of its ability to emerge early, efficiently extract soil available water by its extensive root system, and tolerate heat, drought, and salinity. Moreover, the evolution of acetolactate synthase-inhibitor resistance has impacted herbicidal control of the species. The weed has been used as an emergency forage during drought, and is palatable when immature and non-toxic to livestock. Key words: Salsola tragus, Salsola pestifer, Salsola iberica, Salsola kali, Russian thistle, weed biology