R. 2001. The biology of Canadian weeds. 112. Ulex europaeus L. Can. J. Plant Sci. 81: 325-337. Gorse (Ulex europaeus L.) is a leguminous shrub native to western Europe and North Africa. During the past century it has greatly expanded its adventive range in Australia, New Zealand, Chile and Europe, and along the Pacific and Atlantic coasts of North America. In Canada, it is found in British Columbia (Vancouver, Vancouver Island, the Gulf Islands and Queen Charlotte Islands) where it is classed as a noxious weed. Gorse is also found from Virginia to Massachusetts on the east coast of North America. The shrub rapidly invades dry and disturbed areas, forming dense thickets that can suppress and inhibit native vegetation, including economically important conifer seedlings. It can occupy the same habitats as Scotch broom [Cytisus scoparius (L.) Link] but usually occurs on drier sites. Both of these legumes threaten native plant communities but U. europaeus persists longer and possesses conspicuous spines. Invasive characteristics of gorse include its evergreen habit, prolific seed production, longevity of seeds in the soil and nitrogen fixation. Human activities such as agriculture and construction of logging roads have accelerated the spread of gorse in British Columbia, but there is still an historic opportunity to restrict the population expansion that this species has exhibited in many other countries. Various methods of control (chemical, manual, biological and integrated) are evaluated. , mais il préfère habituellement des endroits plus secs. Ces deux légumineuses menacent les peuplements d'espèces indigènes, quoique la première persiste plus longtemps et présente des épines très évidentes. Parmi les caractéristiques qui font de l'ajonc d'Europe une plante envahissante, mentionnons un port semblable à celui des conifères, une production abondante de semences, la longévité des graines dans le sol et la capacité de fixer l'azote. Les activités humaines comme l'agriculture et la construction de chemins d'exploitation ont accéléré la propagation de l'ajonc d'Europe en Colombie-Britannique, mais on pourrait encore freiner son expansion, ce qui n'est plus le cas dans d'autres pays. Suit une évaluation de diverses méthodes de lutte (chimique, manuelle, biologique et intégrée).

) is an exotic perennial, leguminous, deciduous shrub, which during the past century has greatly expanded its range along the Pacific and Atlantic coasts of North America, and in Australia, New Zealand, South Africa, Chile, Iran, and India. This shrub rapidly invades disturbed areas, forming dense thickets, which can suppress and inhibit native vegetation, including economically important conifer seedlings. The developmental characteristics whereby Scotch broom invades new sites include specialized stem photosynthesis, prolific seed production, longevity of seeds in the soil, and nitrogen fixation. Human activities such as planting along highways for beautification and prevention of soil erosion have accelerated the problem of rapid geographical dispersal. Various methods of control (chemical, manual, and biological) together with habitat, morphology, reproductive biology, growth and development are discussed. L'arbuste colonise rapidement les habitats perturbés où il forme des fourrés denses qui peuvent étouffer et éliminer la végétation naturelle en place, notamment les jeunes semis de conifères de grande importance économique. Parmi les caractères physiologiques qui le rendent apte à envahir de nouveaux emplacements, mentionnons un régime photosynthétique caulinaire spécialisé, une abondante production semencière, la longévité des graines dans le sol et la fixation azotée. Les activités humaines comme la plantation le long des routes pour des fins esthétiques ou comme moyen de lutte contre l'érosion du sol ont contribué à accélérer la dispersion de l'arbuste. Les auteurs passent en revue diverses méthodes de lutte possibles, chimique, manuelle, biologique, ainsi que les données actuelles sur l'habitat, la morphologie, la biologie de la reproduction, la croissance et la différenciation c hez cette légumineuse. (Fig. 1) is a perennial deciduous shrub, up to 4 m tall plant, glabrous or pubescent. Stems unarmed, green and strongly angled, becoming woody as plant matures. Leaves alternate, tri-foliate at the base of branches, becoming simple above, appressed close to the branches; leaflets 4-8 mm long, obovate, acute or mucronate-tipped; upper leaves sessile, stipules none. Flowers perfect, bright yellow, sometimes red or purplish-tinged, about 2 cm long, solitary or two or three together in the axils of the leaves, or in elongated terminal leafy racemes; styles slender, very strongly curved, longer than the keel; upper and lower calyx lobes equally twotoothed and three-toothed respectively; pedicels 6-0 mm long; wings oblong or obovate; keel straight or curved, stamens monadelphous, anthers alternately smaller and larger. Ovary sessile, many-ovuled. Fruits black when mature, flattened pods, 2-5 cm in length, ciliate on the margins, otherwise glabrous, containing an average of five to nine seeds. As pod matures and dries, two pod halves split and wrap in alternate directions, audibly snapping apart and catapulting the seeds. The seeds are strophiolate, meaning the seeds have an enlargement or outgrowth like a cre...

Persistence, mobility, and degradation studies of glyphosate, AT-(phosphonomethyl)glycine, under actual field conditions of boreal forest soils of Ontario, were undertaken after spraying Roundup at the rate of 2 kg of active ingredient (AI)/ha. Soils at three depths were collected and analyzed for residues of

A national research program was established to test the field efficacy of the native fungal pathogen Chondrostereum purpureum (Pers. ex Fr.) Pouzar) for control of hardwood vegetation. During 1995, two fungal isolates were applied as a biocontrol agent to the cut stumps of Populus tremuloides Michx. (trembling aspen) and Alnus viridis ssp. sinuata (Regel) Á. Löve & D. Löve (Sitka alder). Treatments consisted of two formulations (BC, ON) in combination with two fungal isolates (2139, JAM6), blank formulations, cutting only, triclopyr herbicide application, and an uncut control. Analysis of Sitka alder clump mortality indicated isolates JAM6 and 2139 in combination with the BC formulation caused clump mortality of 90 and 88%, respectively. The blank formulation treatments caused the lowest clump mortality and appeared to promote sprouting and growth of Sitka alder when compared with cutting alone. At the aspen installation, the BC formulation with isolate 2139 was found to be the most effective fungal treatment resulting in 84% aspen stem mortality. The results from both installations suggest that C. purpureum efficacy appears to be dependent on the virulence of the isolate and the formulation.

The effects of droplet size and numerical deposit density on herbicide efficacy differed among investigations that relied on commercial nozzles to produce droplets strictly within small, medium, or large sizes. A droplet generator capable of producing uniform and homogeneous droplets was therefore used in a greenhouse experiment. Four droplet size classes (150, 350, 450, and 650 μm) using glyphosate, hexazinone, and triclopyr on red alder, aspen, and white birch were studied. Herbicides applied in small (150 to 450-μm) droplets were more phytotoxic than large (660-μm) ones because of their greater numerical coverage and translocation. Leaf age, weed species, herbicide type, and mixture of droplet sizes were not critical in modifying the effects of droplet behavior; however, the concentrations of herbicide used had a positive effect. When the herbicides were applied at high concentrations, the influence of droplet size was nullified. These findings may help reduce the cost of application and the chemical burden in a forest environment.