Cirsium arvense (L.) Scopoli, Canada thistle (Asteraceae).

Author(s):  
A. S. McClay ◽  
R. S. Bourchier ◽  
R. A. Butts ◽  
D. P. Peschken
Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 524-530 ◽  
Author(s):  
Malcolm D. Devine ◽  
William H. Vanden Born

Both14C-clopyralid (3,6-dichloropicolinic acid) and14C-chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]benzensulfonamide} were readily absorbed by Canada thistle [Cirsium arvense(L.) Scop. ♯ CIRAR] leaves, with 99 and 75%, respectively, of the applied doses absorbed 144 h after application. Absorbed14C-clopyralid was rapidly exported from the treated leaves, whereas14C-chlorsulfuron was translocated much more slowly. After 144 h, 29% of the applied14C-clopyralid and 5% of the applied14C-chlorsulfuron were recovered in the roots and developing root buds of Canada thistle plants. Smaller amounts of the two herbicides were absorbed and translocated in perennial sowthistle (Sonchus arvensisL. ♯ SONAR) than in Canada thistle. More14C-clopyralid than14C-chlorsulfuron was absorbed and translocated out of treated leaves of perennial sowthistle, but equal amounts, 3 to 4% of the applied doses, were recovered in the roots and root buds 144 h after application. Foliar applications of clopyralid, followed by removal of the treated shoot 24, 72, or 144 h after application, markedly reduced shoot regrowth in both Canada thistle and perennial sowthistle. Similar treatment with chlorsulfuron did not prevent shoot regrowth in either species.


1988 ◽  
Vol 2 (4) ◽  
pp. 445-455 ◽  
Author(s):  
Steven J. Carlson ◽  
William W. Donald

Effects of repeated late-fall applications of the isopropylamine salt of glyphosate at 1.7 kg ae/ha plus 0.5% (v/v) surfactant on adventitious root buds, thickened propagative roots (> 1.3 mm diam), and shoot density of Canada thistle were studied in continuous hard red spring wheat over a 4-yr period. Glyphosate suppressed Canada thistle shoot density more quickly and to a greater extent than thickened root fresh weight or root bud number. A single fall application of glyphosate drastically decreased Canada thistle shoot density for 1 yr after treatment. However, shoot density was the same as the untreated control by 2 yr after a single fall treatment. Two consecutive late-fall applications of glyphosate in 2 yr decreased Canada thistle shoot density 94% in the fall 1 yr after the last treatment. Glyphosate reduced Canada thistle thickened root fresh weight 70% in the first fall 1 yr after a single fall treatment. However, 2 yr after a single fall application of glyphosate, root fresh weight equalled the controls. Two consecutive fall applications of glyphosate reduced thickened root fresh weight 77% 1 yr after the second treatment.


1982 ◽  
Vol 114 (4) ◽  
pp. 349-357 ◽  
Author(s):  
D. P. Peschken ◽  
D. B. Finnamore ◽  
A. K. Watson

AbstractThe gall fly Urophora cardui (L.) (Diptera: Tephritidae), native to Europe, was released at 24 locations across Canada beginning in 1974. It became established in Ontario, Quebec, and New Brunswick but died out in all but one location in western Canada. Evidence for winter mortality in the west does not explain the failure of these colonies. Although galls, in particular those on the main shoot, reduce the height of Canada thistle, so far the impact on the host weed, Canada thistle (Cirsium arvense) (L.) Scop., is slight.


Weed Science ◽  
1984 ◽  
Vol 32 (1) ◽  
pp. 42-50 ◽  
Author(s):  
William W. Donald

The effect of 67 g ai/ha chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-amino] carbonyl] benzenesulfonamide} on Canada thistle [Cirsium arvense (L.) Scop. ♯ CIRAR] root bud growth was examined in a series of greenhouse trials in which potted plants were treated with foliar sprays. Injury to root buds was assayed by determining their ability to form secondary shoots. Added surfactant, 0.2% (v/v) oxysorbic [oxysorbic (20 POE) polyethylene sorbitan monooleate], did not enhance chlorsulfuron-induced inhibition of parent shoot growth, but it increased root bud injury from foliarly applied chlorsulfuron. Cuttings taken from controls formed more secondary shoots than did chlorsulfuron-treated plants 2 weeks following spraying. However, root fresh weight and final secondary shoot growth from cut roots were unchanged 3 weeks after chlorsulfuron treatment compared to the time of spraying. Foliar treatment or a combination of foliar and soil treatment inhibited root fresh weight accumulation and secondary shoot growth equally 1 month following treatment relative to harvest controls. Soil treatment alone did not reduce either root fresh weight gains or secondary shoot outgrowth from root buds. Foliar treatment of vegetative Canada thistle with chlorsulfuron inhibited subsequent secondary shoot outgrowth from root buds more than did treatment at flowering.


Weed Science ◽  
1981 ◽  
Vol 29 (2) ◽  
pp. 159-164 ◽  
Author(s):  
R. G. Wilson

Field and greenhouse experiments were established to determine the phytotoxicity of Canada thistle [Cirsium arvense(L.) Scop.] residue on crop growth. Field examination of infestations showed that as Canada thistle shoots increased in an area, the number of kochia [Kochia scoparia(L.) Schrad.], marshelder (Iva xanthifoliaNutt.) and foxtail barley (Hordeum jubatumL.) plants decreased. Conversely, as Canada thistle shoots decreased, the aforementioned annual and perennial plants increased. In greenhouse studies, roots and shoots of Canada thistle that were mixed with soil reduced the growth of sugarbeet (Beta vulgarisL. ‘Mono Hy D2’), wheat (Triticum aestivumL. ‘Centurk’), alfalfa (Medicago sativaL. ‘Dawson’), and Canada thistle seedlings. Corn (Zea maysL. ‘Jacques No. 1004’) and dry edible beans (Phaseolus vulgarisL. ‘Great Northern No. 59’) grown in soil treated with Canada thistle residue were affected to a lesser extent. When Canada thistle residue was mixed with soil, crop growth was inversely proportional to the amount of Canada thistle residue added to the soil. Both roots and shoots of Canada thistle were toxic to crops when mixed with the soil. The effects of Canada thistle residue on crop growth lasted for about 60 days. Neither autoclaving residue and soil nor fertilization of soil had any effect on residue toxicity. Canada thistle leaf leachate inhibited the growth of sugarbeets watered daily with the leachate.


Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 418-425 ◽  
Author(s):  
Malcolm D. Devine ◽  
Hank D. Bestman ◽  
Chris Hall ◽  
William H. Vanden Born

Three wash techniques, each with 1, 10, or 95% (v/v) ethanol:water were used to measure foliar absorption of14C-glyphosate [N-(phosphonomethyl)glycine],14C-3,6-dichloropicolinic acid, and14C-chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} in Tartary buckwheat [Fagopyrum tataricum(L.) Gaertn. ♯3FAGTA], Canada thistle [Cirsium arvense(L.) Scop. ♯ CIRAR], and barley (Hordeum vulgareL. ‘Galt’). For the herbicides and species tested, the most suitable common procedure for determining absorption consisted of a double or triple rinse with or immersion in 10% ethanol. Wiping the treated leaves with cotton balls moistened with the solvent was much less effective. Efficiency of herbicide removal by a given solvent was not related consistently to solubility of the herbicide in the solvent.


Weed Science ◽  
1972 ◽  
Vol 20 (2) ◽  
pp. 163-167 ◽  
Author(s):  
James H. Hunter ◽  
Leon W. Smith

Root sections of seven Canada thistle(Cirsium arvense(L.) Scop.) ecotypes were grown under 8, 12, 14, and 16-hr photoperiods at 16, 21, and 27 C. Flowering occurred in all ecotypes under a 16-hr photoperiod. At the 14-hr photoperiod five ecotypes flowered; flowering in three of them was temperature-dependent. Shoot and root development and plant height varied with ecotype. Both the root-to-shoot ratios and the number of shoot buds formed on the roots were inversely related to temperature and length of photoperiod. Herbicides tested for their effects on Canada thistle were 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro-o-anisic acid (dicamba), and (2,4-dichlorophenoxy)acetic acid (2,4-D). Control of top growth increased with increasing temperature. Similarly, root control was maximum at 27 C, at which temperature there were few fleshy roots. Picloram, unlike 2,4-D and dicamba, caused little leaf damage but completely destroyed the root system.


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