Effect of Bud vs Rosette Growth Stage on Translocation of14C-Glyphosate in Canada Thistle (Cirsium arvense)

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 347-351 ◽  
Author(s):  
James H. Hunter

The effect of photoperiod and growth stage on translocation of14C-glyphosate was compared in Canada thistle plants at the bud and rosette stage of growth. Canada thistle plants grown under controlled environment conditions with a 10 h photoperiod remained as low growing rosettes and developed a mature root system. When the photoperiod for half of these plants was increased to 16 h, stem elongation occurred and flowering was initiated. Growth stage at the time of application affected the distribution of14C-glyphosate within the elongated shoot and between the shoot and root. The shoot tissue of the bud stage plants contained 25.9% of the14C-glyphosate recovered, while the rosette plants contained only 3.6%; a seven-fold difference.14C-glyphosate was applied to leaves 19 and 20, which corresponded to the mid-point of the elongated stem of the bud-stage plants. In the bud-stage plants,14C-glyphosate moved preferentially into the apical portion of the stem, with three to four times as much in the apical portion of the elongated stem as in the basal portion. In the roots, the effect of growth stage on distribution of14C-glyphosate was reversed, application at the rosette stage resulted in a four-fold increase in the amount of14C-glyphosate in the root. When applied in the rosette stage, 19.1% of the14C-glyphosate detected was in the root compared to only 4.9% when applied at the bud stage. Although the root of the rosette plants was larger than in bud-stage plants, the concentration of14C-glyphosate in the root tissue of the rosette plants was three times greater. Photoperiod indirectly affected the distribution of14C-glyphosate in Canada thistle by its effect on growth.

Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Ray S. McAllister ◽  
Lloyd C. Haderlie

Translocation of14CO2-labeled photoassimilates was compared to movement of14C-glyphosate [N-(phosphonomethyl)glycine] in Canada thistle [Cirsium arvense(L.) Scop. ♯ CIRAR] under field and controlled-environment conditions. Field-grown Canada thistle plants were treated on mature upper leaves at the midflower stage in mid-June and harvested 8 days later. No differences were found in glyphosate and assimilate distribution, and movement was primarily basipetal. Of the glyphosate and photoassimilates translocated from the treated leaves, 25 and 31%, respectively, were recovered from the roots, while 59 and 58%, respectively, were found in the shoot tissue below the treated leaf. Concentration of labeled glyphosate in the roots as much as 95 cm from the treated shoot was as high as at the base of the treated shoot. Photoperiods that induce flowering (15 h) or maintain vegetative growth (13 h) did not differentially affect the distribution of photoassimilates or glyphosate in 7-week-old Canada thistle plants in the growth chamber. In growth chamber-grown plants equivalent amounts of glyphosate and assimilates were translocated out of treated leaves; however, relatively more glyphosate than photoassimilates accumulated in the roots.


1987 ◽  
Vol 1 (2) ◽  
pp. 168-170
Author(s):  
J. P. Sterrett

The response of yellow nutsedge (Cyperus esculentusL. #3CYPES) and Canada thistle [Cirsium arvense(L.) Scop. # CIRAR] to combinations of low rates of fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone} and bentazon [3-(1-methylethyl)-(1H)-2,l,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was determined in a controlled environment chamber and on Canada thistle in the field. In the growth chamber, injury to yellow nutsedge was increased with 24 g ai/ha fluridone combined with 323 g ai/ha bentazon. Either 2.7 or 5.4 g/ha fluridone combined with 27 g/ha bentazon caused uniform injury to Canada thistle. In the field, the combinations of 5.6 g/ha fluridone with either 28 or 2800 g/ha bentazon was phytotoxic to Canada thistle.


Weed Science ◽  
1992 ◽  
Vol 40 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Thomas Tworkoski

Under field conditions, more photoassimilate moved to roots of Canada thistle at the bolt than at the bud, flower, or postflower stages. Similarly, greater photoassimilate accumulated in roots of Canada thistle in the greenhouse at the rosette and bolt than at the flower bud stage. Growth chamber experiments indicated that environmental conditions typical of fall, and possibly early spring, favored photoassimilate movement to the root and superseded growth stage control of assimilate partitioning. Allocation of assimilate within the root was strongly influenced by growth stage, with most assimilate being utilized for growth at the rosette stage and for fructan reserves in bolt and flower bud stages.


1987 ◽  
Vol 1 (1) ◽  
pp. 10-13 ◽  
Author(s):  
Nancy K. Zuris ◽  
Robert G. Wilson ◽  
Lenis A. Nelson

Field research was conducted to evaluate the performance of chlorsulfuron {2-chloro-N-[[4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} applied to established Canada thistle plants [Cirsium arvenseL. scop. # CIRAR] in the spring or fall to young vegetative shoots, and in June to plants in the bud growth stage. Canada thistle shoot densities measured in the spring following chlorsulfuron applications the previous year were lower when chlorsulfuron was applied in the bud and fall growth stage as compared to applications made in the spring to young vegetative shoots. Suppression of Canada thistle shoots from chlorsulfuron application during the bud and fall growth stage increased with rate, and was greatest at 269 g ai/ha. Chlorsulfuron applied at 269 g/ha at the fall growth stage only partially controlled the root system of Canada thistle.


1973 ◽  
Vol 105 (12) ◽  
pp. 1489-1494 ◽  
Author(s):  
D. P. Peschken ◽  
R. W. Beecher

AbstractCeutorhynchus litura (F.) laid an average of 123 eggs per female. Development from egg to adult took about 6 weeks at room temperature, followed by an obligatory diapause of 3–4 months. In laboratory rearings a maximum of only an 8-fold increase over the original breeding stock was achieved in one generation. The weevil was released against the weed Canada thistle (Cirsium arvense (L.) Scop.) near Belleville, Ont., in 1967. Near the centre of the release site on about 400 m2, thistle shoots have decreased to 4% of their former density of about 3–7 shoots per 0.25 m2. Circumstantial evidence indicates that the weevil aided in the spread of thistle rust Puccinia punctiformis (Str.) Rohl.


2002 ◽  
Vol 82 (3) ◽  
pp. 625-628 ◽  
Author(s):  
E. Zand ◽  
H. J. Beckie ◽  
C. D. Myhre ◽  
H. A. Loeppky

Field observations suggested that control of Canada thistle variety horridumby hexazinone was greater than that of variety integrifolium. To confirm these observations, the response of these two varieties to hexazinone and 13 other herbicides was examined under controlled environment conditions. The tolerance of the variety integrifoliumto hexazinone was 40% greater compared with the variety horridum. Differences in shoot growth response between the two varieties were not detected from any of the other herbicides. Key words: Canada thistle, Cirsium arvense, variety horridum, variety integrifolium, hexazinone


Weed Science ◽  
1996 ◽  
Vol 44 (4) ◽  
pp. 934-938 ◽  
Author(s):  
James H. Hunter

The interaction of cultivation and photoperiod on the initiation of Canada thistle rosettes, and the effect of growth stage on control of Canada thistle with glyphosate were determined in a series of field experiments. Under the natural photoperiod occurring in the southern Canadian Prairies, rosettes of Canada thistle were initiated by cultivation to remove the shoot growth during the last week of July. Regrowth remained as rosettes without any stem elongation and formed dense clusters of leaves. Application at the “August rosette stage” improved the effectiveness of the glyphosate treatment and resulted in consistent control of Canada thistle with less than half as much herbicide as recommended for control when applied at the bud-stage. The number of shoots of Canada thistle on plots treated with glyphosate was less than on the intensively summer-fallowed check plot. Check plots received 5 cultivations during the summer-fallow season. One year after application of glyphosate at the rosette stage, the reduction in shoot density was 99% compared to the summer-fallowed check. By year three, without glyphosate applications in years two and three, the benefits of applying glyphosate at the rosette stage rather than the bud-stage were very evident. When applied at the bud-stage the shoot density on plots treated with glyphosate at 2.25 kg ha−1was 24 m−2compared to only 10 shoots m−2when applied at the rosette stage, (35% vs 72% control). Glyphosate at 0.9 kg ha−1or less than half of the rate recommended for application at the bud-stage, applied to Canada thistle in the rosette stage, resulted in consistently fewer shoots 2 and 3 yr after treatment. Physical removal of shoot top growth, simulating an in-crop herbicide treatment, improved the consistency of control. Two years after application of 0.9 kg ha−1of glyphosate at the rosette stage, the control of Canada thistle was 98% compared to the summer-fallowed checks.


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.


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