The biology of Canadian weeds. 138. Kochia scoparia (L.) Schrad.

Abstract

Kochia [Kochia scoparia (L.) Schrad.] is an annual broadleaf weed species native to Eurasia and introduced as an ornamental to the Americas by immigrants in the mid- to late 1800s. Although sometimes categorized in the genus Bassia, there is no compelling reason for this classification. This naturalized species is a common and economically important weed in crop production systems and ruderal areas in semiarid to arid regions of North America, and has expanded northward in the Canadian Prairies during the past 30 yr. Although primarily self-pollinated, substantial pollen-mediated gene flow and efficient seed dispersal aids both short- and long-distance spread. The weed is morphologically highly variable, and its growth and development are markedly affected by environmental conditions. Kochia, a C4 species, is highly competitive in cropping systems because of its ability to germinate at low soil temperatures and emerge early, grow rapidly, tolerate heat, drought and salinity, and exert allelopathic effects on neighboring species. Moreover, herbicidal control has been compromised to some extent by the widespread evolution of herbicide resistance in the species. Kochia is used as a forage, is palatable to livestock with nutritional value similar to that of alfalfa (Medicago sativa), but can be toxic if it comprises the majority of the diet. Although kochia pollen is an allergen, the seed is a source of phytochemicals including mosquito pheromones and saponins that are potentially beneficial to human health; kochia also is beneficial in phytoremediation of soils contaminated by hydrocarbons or pesticides. Key words: Kochia, Kochia scoparia, Bassia scoparia, herbicide resistance, soil salinity tolerance, weed biology

Discrimination of herbicide-resistant kochia with hyperspectral imaging

“…biotypes (i.e., strains of a species) resistant to the herbicides glyphosate and dicamba. 1,2 Since 1969, kochia has been recognized as one of the most economically significant weed problems in sugar beets, as kochia densities as low as 0.1 plants m −1 of sugar beet row can cause a 10% sugar beet yield reduction. 3 Greater kochia densities can cause over 90% yield loss if left uncontrolled season long.…”

Confirmation of Glyphosate- and Acetolactate Synthase (ALS)-Inhibitor-Resistant Kochia (Kochia scoparia) in Nebraska

“…Kochia [Kochia scoparia (L.) schrad], an annual broadleaf weed species from the Chenopodiaceae family, is native to Eurasia and was introduced to the western hemisphere in the early 1900s as an ornamental plant (Dodd & Moore, 1993;Friesen et al, 2009). Commonly referred to as Fireweed (Casey, 2009), it is an economically important weed in cropland and non-crop areas including pastures, roadsides, wasteland, and ditchbanks (Forcella, 1985;Beckie et al, 2013).…”

Expression Profiles of <i>psbA, ALS, EPSPS</i>, and Other Chloroplastic Genes in Response to PSII-, ALS-, and EPSPS-Inhibitor Treatments in <i>Kochia scoparia</i>

“…Kochia also tolerates drought stress, low soil water potentials, and saline conditions. These characteristics make kochia a highly competitive weed causing extensive yield losses in several mid-western US cropping systems [1].…”

“…(a Chenopodiaceae member) is an important C4 annual broadleaf weed distributed throughout North American Great Plains [1]. Kochia can germinate and emerge early in the spring season when temperatures are low, and can also tolerate high temperatures of summer.…”