The biology of Canadian weeds. 123. Senecio vulgaris L.

Abstract

Senecio vulgaris L. is a native of Eurasia, and has been introduced to and become naturalized in North America, South America, Africa and Australia. In Canada, it is found in all provinces and the Northwest and Yukon Territo ries. High fecundity, rapid wind dispersal, continuous germination under a wide range of growing conditions, rapid growth rate, ability to set seed a number of times per growing season and lack of chemical control options has made this species an importan t weed of some horticultural crops. This species produces pyrrolizidine alkaloids that have been implicated as a cause of liver toxicity in livestock. Populations of S. vulgaris have displayed resistance to Group 5, 6 and 7 herbicides (triazines, uracils, substituted ureas and nitriles) and other photosynthetic-transport-inhibiting herbicides. Triazine resistance in S. vulgaris was the first reported case of herbicide resistance worldwide. A rust pathogen, Puccinia lagenophorae Cooke, is currently being evaluated for control of S. vulgaris in Europe. Key words: