The biology of Canadian weeds. 126. Amaranthus albus L., A. blitoides S. Watson and A. blitum L.

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

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


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


2008 ◽  
Vol 88 (5) ◽  
pp. 951-996 ◽  
Author(s):  
R. H. Gulden ◽  
S. I. Warwick ◽  
A. G. Thomas

Brassica napus and B. rapa are native to Eurasia. In Canada, these species are commonly referred to as volunteer canola, while feral populations of B. rapa are referred to as birdrape. Brassica napus and B. rapa have been grown commercially for their seed oil content in western Canada since the middle of the last century and volunteer populations are common in fields. Escaped populations of both species are also found along roadways, railways and in waste areas; however, only B. rapa is known to have naturalized, self-sustaining feral populations in these habitats in eastern Canada. Despite these escaped and feral populations, B. napus and B. rapa are mainly a concern in agricultural fields where their combined relative abundance has increased over the past few decades. In the mid 1990s, herbicide-resistant genotypes of B. napus were released for commercial production. Herbicide-resistance and the stacking of genes in volunteer populations conferring resistance to multiple herbicides have contributed to increased difficulties in controlling volunteer B. napus in some crops. However, yield loss resulting from volunteer populations is not well documented in Canada. Key words: Brassica napus, Brassica rapa, herbicide resistance, transgene escape, volunteer canola, weed biology


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


2019 ◽  
Vol 37 ◽  
Author(s):  
A. FRANCISCHINI ◽  
J. CONSTANTIN ◽  
R.S. OLIVEIRA JR ◽  
H.K. TAKANO ◽  
R.R. MENDES

ABSTRACT: Herbicide resistance in Amaranthus genus occurs frequently around the word and has become a big problem in cotton producing areas. The objective of this work was to evaluate cross-and multiple-resistance of redroot pigweed (A. retroflexus) to herbicides used in preemergence in cotton fields in Brazil. Seven dose-response experiments were conducted with herbicides atrazine, prometryn, diuron, S-metolachlor, trifluralin, trifloxysulfuron-sodium and pyrithiobac-sodium, and the treatments consisted of application rates of 0, ¼, ½, 1, 2 and 4 times the recommended label rate. Eight A. retroflexus byotipes with suspect of resistance were sampled for experiments in three brazilian states of cotton producing. Resistance to prometryn was confirmed for one biotype in Goiás (GO), and one biotype from Mato Grosso (MT) showed cross-resistance to atrazine and prometryn. One byotipe from GO was identified with cross-resistance to trifloxysulfuron-sodium and pyrithiobac-sodium. One of the GO samples was identified with multiple resistance to prometryn and ALS inhibitors, another one to atrazine and ALS inhibitors, while MT byotipe was confirmed with multiple resistance to triazines and pyrithiobac. The herbicides S-metolachlor, diuron, and trifluralin were efficient for control of this species, therefore, they can be used as managment alternative in those regions.


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


2000 ◽  
Vol 80 (4) ◽  
pp. 939-961 ◽  
Author(s):  
Suzanne I. Warwick ◽  
Hugh J. Beckie ◽  
A. Gordon Thomas ◽  
Tracey McDonald

An updated review of biological information is provided for Sinapis arvensis L. Native to the Old World, the species is widely introduced and naturalized in temperate regions around the world. The species occurs in all the provinces, the Northwest Territories, and the Yukon. It is an important weed of field crops in the Canadian prairies. A strongly persistent seedbank, competitive annual growth habit and high fecundity all contribute to its weedy nature and ensure that it will be a continuing problem. Several cases of herbicide resistance have been documented for natural populations of S. arvensis in Canada, including biotypes resistant to: i) Group 2 herbicides, which inhibit acetolactate synthase (ALS), from Manitoba in 1992 and Alberta in 1993; ii) Group 4 herbicides or synthetic auxins from Manitoba in 1991; and iii) Group 5 herbicides, which inhibit photosynthesis at photosystem II, from Ontario in 1983. The species is a close relative of Brassica nigra (L.) Koch, black mustard, and is capable of limited genetic exchange with the Brassica crop species under laboratory hybridization conditions either by conventional crossing or with the aid of ovary/embryo recovery techniques. Key words: Wild mustard, Sinapis arvensis, weed biology, herbicide resistance, risk assessment


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


STUDIUM ◽  
2018 ◽  
pp. 189-208
Author(s):  
Patricia Aguirre

El siguiente artículo ejemplifica con tres elementos del servicio de mesa (la olla, la fuente y el plato) las formas características en que se despliega la comensalidad en diferentes sectores de ingresos, sexos y edades, en Argentina. Diferencia las prácticas, los actores y los sentidos ligados al repartir y al compartir, en cada sector, señalando que el reparto es una obligación ligada a las jerarquías mientras que compartir es una elección libre y afectuosa basada en la amistad y la confianza de la cual se espera reciprocidad. Se señala que tal como muestran el asado y el mate en el pasado, se puede compartir tanto con el alimento más prestigioso (la carne asada) como sin comida: en la ronda del mate. Palabras clave: Comensalidad, ingresos, compartir, repartir, representaciones   Abstract Through the pot, the platter and the dish —three objects used at meal times— this article exemplifies typical ways of commensality in Argentina, among groups whose income, sex, and age differ. The article points to the differences between practices, actors, and senses involved in distributing and sharing in each sector. It shows that distribution is an obligation related to hierarchy, whereas sharing is a free, loving decision based on trust and friendship and that reciprocity is expected. As shown by asado and mate in the past, it is possible to share regardless of what is being shared. In the example, asado stands for prestigious meat done on a charcoal grill, whereas the mate circle is not about food. Key words: commensality, income, share, distribute, representations


Author(s):  
Charles F. Briggs

This chapter looks at Latin Christendom's evolution of historical writing, which had issued forth from a few, mostly monastic, centers, and eventually swelled into a substantial river fed by many and diverse tributaries. This expansionary trend in historiography was itself but one small manifestation of a protracted phase of accelerated growth in Europe, beginning in roughly the year 1000 and continuing until the early decades of the fourteenth century. The politically atomized, sparsely populated, and economically nonintegrated society that survived the inner turmoil attending the breakup of the Frankish Empire and the incursions of peoples from North Africa, the Eurasian Steppes, and Scandinavia during the ninth through early eleventh centuries, demonstrated a renewed vitality — spurred in part by the new political and economic conditions, as well as a period of improved climate.


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