L. M. 2012. The Biology of Canadian Weeds. 27. Avena fatua L. (Updated). Can. J. Plant Sci. 92:1329Á1357. An updated review of biological information is provided for Avena fatua. A widespread species originating in Eurasia, A. fatua is one of the 10 worst annual weeds of temperate agricultural regions of the world. Key weediness traits of this highly selfing species include fecundity, seed shatter, and a large and persistent seed bank with variable degrees of primary seed dormancy. The species occurs in all Canadian provinces and most states in the USA. In Canada, it is most troublesome as a weed in the prairies, where it has spread throughout crop areas in all climatic zones. Depending upon plant density and relative time of emergence, A. fatua competition may reduce annual crop yields by as much as 70%. First cohort emergence of A. fatua coincides with planting and emergence of spring-seeded crops, although additional cohorts can emerge throughout the growing season. Avena fatua is more abundant in zerothan intensive-tillage systems; the former regime promotes earlier and greater emergence because of a shallower and less persistent seed bank. Despite the introduction of highly efficacious herbicides in the 1970s and 1980s, abundance of the species has not declined across the Canadian prairies or elsewhere. The continual evolution of herbicide-resistant A. fatua populations, seed spread via farm machinery, and limited herbicide modes of action for its control threaten sustained annual field crop production in many temperate agricultural areas. Further adoption and integration of multiple non-herbicidal weed management practices, such as enhanced crop seeding rate, competitive crops and cultivars, and precision fertilizer placement, should help mitigate A. fatua interference. The species has some beneficial uses as an alternative feed and food constituent or industrial feedstock, as well as potential in cultivated oat (Avena sativa L.) improvement. Key words: Avena fatua, wild oat, folle avoine, weed biology Beckie, H. J., Francis, A. et Hall, L. M. 2012. La biologie des mauvaises herbes au Canada. 27. Avena fatua L. (mise aj our). Can. J. Plant Sci. 92: 1329Á1357. L'article propose une mise au point sur la biologie d'Avena fatua. Espe`ce d'Eurasie largement re´pandue, la folle avoine figure parmi les dix pires adventices annuelles dans les re´gions agricoles ac limat tempe´re´du monde.Les principaux caracte`res qui font de cette espe`ce autofe´conde´e une mauvaise herbe sont la fe´condite´, l'e´gre`nement et un important re´servoir de graines persistantes a`dormance primaire de degre´variable. La folle avoine existe dans toutes les provinces du Canada et dans la majorite´des É tats ame´ricains. Au Canada, elle s'ave`re particulie`rement proble´matique dans les Prairies, ou`elle a gagne´les re´gions cultive´es de toutes les zones climatiques. Selon la densite´du peuplement et le moment relatif ou`a lieu la leve´e, A. fatua peut re´duire le rendement des cultures annuelles de jusqu'a`70 %. La germination de la pre...

Francis, A., Darbyshire, S. J., Légère, A. and Simard, M.-J. 2012. The Biology of Canadian Weeds. 151. Erodium cicutarium (L.) L'Hér. ex Aiton. Can. J. Plant Sci. 92: 1359–1380. Stork's bill, Erodium cicutarium, is an annual weed of the geranium family (Geraniaceae), native to Mediterranean Europe, North Africa and western Asia. It has spread widely to temperate regions of both hemispheres, in particular to semi-arid ranges and prairies where it is frequently a dominant weed. In western Canada, it has increased in importance as a weed of cereal, canola, legume, sugarbeet and potato crops, particularly with the adoption of conservation tillage, and is both a field weed and seed contaminant of forage crops. The species had been sporadically collected in Québec since 1874 from cultivated fields (oats, potatoes, corn), but it recently appeared in experimental plots grown in corn, soybean, and red clover in eastern Québec, suggesting its potential as a serious weed. Outside of Canada, it is found in a range of crops, and has been host to viral, fungal and insect pathogens that can cause damage to crops and pastures. The plant's early germination, rapid growth and prolific seed production give it a competitive advantage in crops. In spring crops, the weed may be past the stage for optimal control by the time that the crop has reached the stage when herbicides are normally applied. Control may consequently require an extensive and often costly integrated weed management system. In semi-arid grazing areas it probably displaced some native vegetation, but has also become an important forage plant and a source of food for native wildlife. Its antioxidant and other chemical properties have drawn attention to potential medicinal and other beneficial uses.