Compendium of plant disease and decay fungi in Canada, 1960-1980

. 2008. The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa. Can. J. Plan Sci. 88: 951Á996. 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, herbicideresistant 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 Gulden, R. H., Warwick, S. I. et Thomas, A. G. 2008. La biologie des mauvaises herbes au Canada. 137. Brassica napus L. et B. rapa L. Can. J. Plant Sci. 88: 951Á996. Brassica napus et B. rapa sont des plantes originaires d'Eurasie. Au Canada, on les de´signe souvent sous l'expression « canola spontane´», tandis que les peuplements sauvages de B. rapa sont appele´s « navette ». Dans l'Ouest canadien, Brassica napus et B. rapa sont cultive´s commercialement pour l'huile que renferment leurs graines depuis le milieu du sie`cle dernier et les repousses spontane´es sont devenues monnaie courante dans les champs. On observe des peuplements des deux espe`ces le long des routes et des voies ferre´es ainsi que dans les terrains vagues, cependant on sait que seule B. rapa s'est acclimate´e pour donner des populations sauvages et stables dans les meˆmes habitats, dans l'est du pays. Malgre´cela, B. napus et B. rapa demeurent surtout pre´occupants dans les cultures, oul eur abondance relative, une fois combine´s, s'est accrue au cours des dernie`res de´cennies. Au milieu des anne´e 1990, des ge´notypes de B. napus re´sistants aux herbicides ont e´te´homologue´s pour la culture commerciale. Cette re´sistance et l'accumulation des ge`nes qui la codent dans les peuplements spontane´s ont concouru a`compliquer la lutte contre les repousses de B. napus dans certaines cultures. Quoi qu'il en soit, les pertes de rendement qui en re´sultent sont mal e´taye´es au Canada.

Section: Response To Other Human Manipulationsmentioning

confidence: 99%

The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa L.

Gulden¹,

Warwick²,

Thomas³

2008

“…In studies in Mexico, Rosado-May (1992) Ismail and Hasabo (1995) found that the root diffusates of S. arvensis stimulated the hatchability of the corn cyst nematode, Heterodera zeae Koshy, Swarup, and Sethi. Diseases (a) Fungi - Ginns (1986) Minogue and Friesen (1984) reported that S. arvensis can contribute to an increase in the incidence of Sclerotinia wilt in sunflower fields in North Dakota by acting as an alternate host for the pathogen. Storck and Sacristan (1995) examined the role of phytoalexins in seedling resistance to Leptosphaeria maculans in resistant lines of S. arvensis and Brassica spp., B. juncea, B. carinata and B. napus.…”

Section: Response To Parasitesmentioning

confidence: 99%

The biology of Canadian weeds. 8. Sinapis arvensis. L. (updated)

Warwick¹,

Beckie²,

Thomas³

et al. 2000

. 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.

“…Aphids were moving about inside the flowers and presumably feeding on nectar collected at the petal bases. Ginns (1986). Hydrocharis morsusranae is reported as a host to a number of rusts, smuts and molds (including Aecidium hydrocharidis Rab., Doassansia For personal use only.…”

Section: Response To Herbivory Disease and Higherplant Parasitesmentioning

confidence: 99%

The biology of Canadian weeds. 124. Hydrocharis morsus-ranae L.

Catling¹,

Mitrow²,

Haber³

et al. 2003

Catling, P. M., Mitrow, G., Haber, E., Posluszny, U. and Charlton, W. A. 203. The biology of Canadian weeds. 124. Hydrocharis morsus-ranae L. Can. J. Plant Sci. 83: 1001-1016. European frog-bit (Hydrocharis morsus-ranae L.), a free-floating, stoloniferous aquatic, is native to Europe and parts of Asia and Africa. It was discovered in Canada in 1932 in Ottawa, but earlier introduction is possible. By 1955 its North American distribution extended from Ottawa to Montreal. By 1980 it had extended southwest to Lake Ontario and northeast to Quebec City. Recently it has spread throughout much of the central and southwestern parts of southern Ontario, and further into northern New York and Vermont and eastern Michigan. The maximum rate of spread has been 15.6 km yr -1 . Reproduction by seeds is rarely reported but vegetative reproduction is very important in spread and colonization. In the fall, turions separate from the plant, sinking to the bottom where they overwinter. In the spring, these turions grow into small floating rosettes. Extremely rapid stoloniferous growth during the summer months results in the formation of large masses of interlocking plants that diminish native submerged aquatic plant communities by reducing available light. It is also of importance in limiting water flow in irrigation systems and restricting water traffic, thereby hindering recreational activity. Management has been largely mechanical. Hydrocharis morsus-ranae is a food plant for several water birds, rodents, fish and insects.