The Biology of Canadian weeds. 150 Erechtites hieraciifolius (L.) Raf. ex DC.

Abstract

2012. The Biology of Canadian weeds. 150 Erechtites hieraciifolius (L.) Raf. ex DC. Can. J. Plant Sci. 92: 729Á746.Erechtites hieraciifolius, American burnweed, is a herbaceous annual in the Asteraceae native to forest zones of eastern North America, but introduced to parts of Europe and the Pacific region. Confusion sometimes arises in distinguishing it from other weedy rayless composites in Canada, such as Senecio vulgaris (common groundsel) and Conyza canadensis (Canada fleabane). A pioneer therophyte species of forest zones, it occurs in large numbers when associated with major disturbances such as forest fires, but is also common in areas of smaller scale disturbance such as shores, forest edges and wind-throws. Soil conditions may vary greatly in nutrient content, moisture content, pH and salinity. In Canada, it is generally considered a minor garden and agricultural weed. It is most common in crops such as lowbush blueberry (Vaccinium spp.), cranberry (Vaccinium macrocarpon), strawberry (Fragaria)ananassa) and vegetable crops; however, it occasionally occurs in other field and forage crops. Impacts include a variety of problems contributing to increased production costs or crop yield losses, including herbicide resistance, resource competition, and as a reservoir harbouring crop pathogens. It has been valued as a medicinal herb for treating a variety of ailments. Populations may grow rapidly in response to disturbances typical of managed landscapes, but E. hieraciifolius can usually be effectively controlled by chemical, cultural or manual weed control tactics.Darbyshire, S. J., Francis, A., DiTommaso, A. et Clements, D. R. 2012. La biologie des mauvaises herbes au Canada. 150 Erechtites hieraciifolius (L.) Raf. ex DC. Can. J. Plant Sci. 92: 729Á746. L'e´rechtite a`feuilles d'e´pervie`re (Erechtites hieraciifolius) est une herbace´e annuelle de la famille des Aste´race´es indige`ne aux re´gions forestie`res de l'est de l'Ame´rique du Nord, mais qui a e´te´introduite dans certaines parties de l'Europe et du Pacifique. On la confond parfois a`d'autres adventices a`rayons courts de la famille des Compose´es qui poussent au Canada tels le se´nec¸on vulgaire (Senecio vulgaris) et la vergette du Canada (Conyza canadensis). Espe`ce pionnie`re the´rophyte, on en retrouve de grand peuplements aux endroits qui ont subi de profondes perturbations comme un feu de foreˆt, cependant l'espe`ce colonise souvent des zones plus restreintes comme les rivages, la lisie`re des boise´s et les chablis. Les conditions du sol peuvent varier conside´rablement quant a`la concentration d'e´le´ments nutritifs, la teneur en eau, le pH et la salinite´. Au Canada, on la conside`re ge´ne´ralement comme une adventice secondaire dans les jardins et les champs. L'e´rechtite a`feuilles d'e´pervie`re se rencontre le plus souvent dans les cultures comme le bleuet nain (Vaccinium spp.), la canneberge (Vaccinium macrocarpon), la fraise (Fragaria)ananassa) et les plantes maraıˆche`res, cependant, on la de´couvre a`l'occasion dans d'autres grandes ...

Control of American Burnweed (Erechtites hieraciifolia) in Bermudagrass Turf

“…the eastern United States, from New England south to Florida and west to Minnesota and Texas, and has also been found in Washington, Oregon, and Hawaii (Darbyshire et al 2012;McCarty et al 2008). American burnweed is a phenotypically variable plant species, and three varieties are taxonomically recognized.…”

“…Growth habit is characterized as erect (up to 2.5 m tall) which disrupts turfgrass quality in unmown areas as plant height quickly reaches above the turf canopy. Plants can also be identified by grooved stems and a short taproot accompanied by fibrous secondary roots or adventitious prop roots (Darbyshire et al 2012;McCarty et al 2008). Leaves are alternate, spiraling, and decrease in size up the stem with irregularly toothed margins.…”

Investigation of Potential Seed Dormancy Mechanisms in American Burnweed (Erechtites hieraciifolius) Seeds from Wild Blueberry (Vaccinium angustifolium) fields

“…American burnweed is an annual plant in the Asteraceae family (Darbyshire et al 2012). It is native to deciduous forest regions of North America (Darbyshire et al 2012) and has been introduced to regions of Europe and Asia (Darbyshire et al 2012).…”

“…American burnweed is an annual plant in the Asteraceae family (Darbyshire et al 2012). It is native to deciduous forest regions of North America (Darbyshire et al 2012) and has been introduced to regions of Europe and Asia (Darbyshire et al 2012). The distribution in Canada is from the Maritime Provinces to western Ontario (Darbyshire et al 2012), and the plant is abundant in areas of recently cleared forest (Eaton 1824; Pursh 1814; Torrey 1843).…”

“…Although little is known about the competitive effects of American burnweed on wild blueberry, the tall growth habit and high density of this plant in typical infestations would suggest potential impacts on blueberry growth and yield, and plants also inhibit harvesting (D. Yarborough, personal communication, as cited in Darbyshire et al 2012). Increased knowledge of the basic biology of this species is therefore required to begin developing management strategies to limit the spread and impacts of this species in wild blueberry fields in Nova Scotia.…”