The biology of Canadian weeds. 130. Amaranthus retroflexus L., A. powellii S. Watson and A. hybridus L.

2004 ◽  
Vol 84 (2) ◽  
pp. 631-668 ◽  
Author(s):  
M. Costea ◽  
S. E. Weaver ◽  
F. J. Tardif

A review of the biological information published after 1980 is provided for three species of the genus Amaranthus: A. retroflexus L., A. powellii S. Watson and A. hybridus L. The three species are noxious weeds introduced to Canada from southern North America. Their geographical distribution has remained almost unchanged since the original paper published in 1980. The plants exhibit a high phenotypic plasticity and genetic variability and they easily adapt to a multitude of agrestal and ruderal habitats. The seeds contribute to a persistent seed bank; they exhibit a variable dormancy and polymorph germination as a result of maternal, genetic and environmental factors. Growth is rapid and plants produce a large number of viable seeds. The three species have developed multiple resistance to triazine and acetolactate-synthase-inhibiting herbicides. They are alternate hosts to many insects, nematodes, viruses, bacteria and fungi that affect cultivated plants. Key words: Amaranthus retroflexus, Amaranthus powellii, Amaranthus hybridus, weed biology, ecology, taxonomy, herbicide resistance

2003 ◽  
Vol 83 (4) ◽  
pp. 1039-1066 ◽  
Author(s):  
M. Costea and F. J. Tardif

A review of biological information is provided for three species of the genus Amaranthus: A. albus L., A. blitoides S. Watson and A. blitum L. The last species has been revised taxonomically and a new subspecies for Canada is presented-A. blitum subsp. emarginatus (Moq. ex Uline & Bray) Carretero, Munoz Garmendia & Pedrol. Amaranthus albus and A. blitoides are native to the U.S.A. and introduced to Canada. Both species are annual ruderal and agrestal weeds. During the past 100 yr the two species have spread across most provinces of Canada, but the greatest frequency and abundance have been recorded in Saskatchewan. Originating from Europe, Asia and North Africa, A. blitum was initially considered a non-persistent species. The present study shows that A. blitum especially, subsp. emarginatus, has continued to spread in Québec. The three species are alternate hosts to many insects, nematodes, viruses, bacteria and fungi that affect cultivated plants. In other areas (U.S.A., Europe and Asia), the three species have developed multiple resistance to triazine and acetolactate-synthase-inhibiting herbicides. Key words: Amaranthus albus, Amaranthus blitoides, Amaranthus blitum, weed biology, ecology, taxonomy, herbicide resistance


2005 ◽  
Vol 85 (2) ◽  
pp. 507-522 ◽  
Author(s):  
Mihai Costea ◽  
Susan E Weaver ◽  
François J. Tardif

This annual dioecious weed was found in 2002 and 2003 infesting soybean fields in southwestern Ontario, and it was collected in 1992 from waste places in British Columbia. It is a major weed problem in field crops in the mid-western United States, where it has become increasingly difficult to control during the past 10 yr. Morphological differences between Amaranthus tuberculatus var. rudis and var. tuberculatus are presented. A review of the biological information published is provided. Plants exhibit high phenotypic plasticity and genetic variability. Emergence is prolonged, growth rapid, and female plants produce a large number of viable seeds that contribute to a persistent seed bank. Amaranthus tuberculatus var. rudis has developed multiple resistance to triazine and acetolactate synthase- and protoporphyrinogen-inhibiting herbicides. Airborne pollen can travel significant distances and A. tuberculatus var. rudis may hybridize with other noxious Amaranthus spp. transferring herbicide resistance or other traits. Key words: Amaranthus tuberculatus var. rudis, AMATA, Amaranthus rudis, common waterhemp, weed biology, invasive alien


2005 ◽  
Vol 85 (2) ◽  
pp. 481-506 ◽  
Author(s):  
Mihai Costea ◽  
François J. Tardif

A review and assessment of biological information as well as personal data are provided for Polygonum aviculare in Canada. The species has been revised taxonomically and the six subspecies that occur in Canada are presented. Three of the subspecies, P. aviculare subsp. aviculare, P. aviculare subsp. neglectum and P. aviculare subsp. depressum are weeds introduced to Canada from Europe. A fourth subspecies, P. aviculare subsp. buxiforme is apparently native to North America. The geographical distribution of the latter four subspecies is very wide. Plants exhibit a high phenotypic plasticity and genetic variability, and they easily adapt to a multitude of agrestal and ruderal habitats. The seeds have a variable dormancy and polymorphic germination as a result of heterocarpy, genetic and environmental factors. In other areas (Europe), the species has developed resistance to triazines. Plants are hosts to nematodes, viruses, and fungi that also affect cultivated plants. Key words: POLAV, ecology, distribution, taxonomy


2003 ◽  
Vol 83 (2) ◽  
pp. 441-451 ◽  
Author(s):  
A. Francis ◽  
S. I. Warwick

A review of biological information is provided for Neslia paniculata. Native to central Eurasia, this species is naturalized in other temperate regions of the northern hemisphere. In North America it is most abundant in Canada’s prairie provinces, but has spread west and north to British Columbia, Alaska, Yukon and the Northwest Territories, and to scattered locations in eastern Canada and the northern United States. It is typically a summer annual weed of disturbed soils. Its growth habit and persistence in the seed bank have enabled it to spread as an adventive and to maintain its presence in cultivated areas. While it is present in relatively low frequency as a weed in most crops, its indehiscent seed pods can contaminate harvested crops and spread in seed commodities. The small size of its seed pods and the similarity of its seeds to those of canola and condiment mustard have led to its regulation as a significant contaminant of commercial seed. It is generally well controlled by herbicides (e.g., sulfonylureas, glyphosate, MCPA, bromoxynil, and 2, 4-D); however, a population resistant to metsulfuron-methyl, one of the Group 2 herbicides that inhibit acetolactate synthase (ALS), was found at a site in Alberta in 1998. Key words: Ball mustard, Neslia paniculata, weed biology, herbicide resistance, seed contaminant


2002 ◽  
Vol 82 (4) ◽  
pp. 803-823 ◽  
Author(s):  
S. I. Warwick ◽  
A. Francis ◽  
D. J. Susko

An updated review of biological information is provided for Thlaspi arvense. Native to Eurasia, the species is naturalized and widely spread in temperate regions of the northern hemisphere, including all of Canada's provinces and territories, and has recently spread to temperate regions in the southern hemisphere. It is an annual pioneer of disturbed soils and is an important weed of grain, oilseed, and forage crops in Canada, particularly in the prairies. High levels of erucic acid and glucosinolates can contaminate canola. When present in hay or other fodder, its seeds or leaves can be toxic to animals, as well as contaminate milk and meat with unpleasant flavors. It can serve as a host for insect, nematode, fungal and viral pests of canola and mustard crops. A persistent seed bank, high fecundity, and the growth habit of a hardy winter annual with early- (EF) and late-flowering (LF) strains, all contribute to its ability to compete with crops. Effective herbicides include the sulfonylureas, chlorsulfuron and ethametsulphuron, MCPA, tribenuronmethyl, phenocyacetic acid, flurtamone, 2,4-D, 2,4-D + dicamba, and 2,4-D + picloram. A resistant biotype to Group 2 herbicides, which inhibit acetolactate synthase (ALS), has been found at two to five sites in Alberta in 2001. The potential of T. arvense as an industrial oilseed crop is being investigated. Key words: Stinkweed, Thlaspi arvense, weed biology, field pennycress, fanweed, oilseed potential


1998 ◽  
Vol 78 (1) ◽  
pp. 155-165 ◽  
Author(s):  
Suzanne I. Warwick ◽  
David A. Wall

A review of biological information is provided for Erucastrum gallicum (Willd.) O.E. Schulz. A European native, it was introduced into Canada and the United States in the early 1900s and spread rapidly along the railroads. The species occurs in all the provinces and the Northwest Territories and is particularly abundant in the Prairie provinces and mid-western United States. It is a summer annual, rarely a winter annual or biennial species, and is characterized by high reproductive output. Plants occur most commonly on waste ground and along roadsides and railroads, followed by agricultural fields. Erucastrum gallicum is of allopolyploid origins (n = 15, 7 + 8 chromosomes), and contains a single multi-locus isozyme genotype. The species is a close relative of Brassica and is capable of limited genetic exchange with the canola species, B. rapa and B. napus. The possible transfer of genes from transgenic canola varieties to Erucastrum gallicum poses a remote, but potential, environmental risk. Populations of Erucastrum gallicum, including both Old World and North American populations, constitute a valuable germplasm resource as potential sources of beneficial agronomic traits, such as disease resistance for canola crop improvement. Key words: Dog mustard, Erucastrum gallicum, weed biology, risk assessment, germplasm, canola


2020 ◽  
pp. 69-82
Author(s):  
Rainer W. Bussmann ◽  
Ketevan Batsatsashvili ◽  
Zaal Kikvidze ◽  
Narel Y. Paniagua-Zambrana ◽  
Manana Khutsishvili ◽  
...  

Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 510-514 ◽  
Author(s):  
G. H. Egley

The effects of ethylene upon germination of common cocklebur (Xanthium pensylvanicumWallr.) and redroot pigweed (Amaranthus retroflexusL.) seeds were studied. In laboratory tests with seeds in sealed flasks in the dark, 10 μl/L ethylene increased germination of redroot pigweed seeds from 7% to 52% at 30 C, and increased germination of large and small common cocklebur seeds from 30% and 0% to 100% and 90% respectively, at 25 C. At least 12 h of exposure to ethylene was necessary for appreciable stimulation of germination. In growth chamber studies with known numbers of seeds in pots of soil, ethylene at 11 kg/ha was injected into the soil, and the pots were enclosed in plastic bags for 24 h. One such injection at 2 weeks after planting, and successive injections at 2, 3, and 4 weeks, significantly increased redroot pigweed seedling emergence, and significantly decreased the numbers of dormant, viable seeds remaining in the soil. When pots were not enclosed, injections did not significantly effect redroot pigweed seeds, but significantly increased common cocklebur seedling emergence and decreased the number of viable common cocklebur seeds remaining in the soil.


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