Glyphosate resistant giant ragweed is an increasing problem in glyphosate resistant cropping systems in southwestern Ontario. The postemergence herbicides registered for use in soybean in Ontario do not provide consis...Glyphosate resistant giant ragweed is an increasing problem in glyphosate resistant cropping systems in southwestern Ontario. The postemergence herbicides registered for use in soybean in Ontario do not provide consistent control of glyphosate resistant giant ragweed. There is limited research on the lowest effective rate of 2,4-D for the control of glyphosate resistant giant ragweed. Consequently, the objectives of this study were a) to determine the efficacy of herbicides applied postemergence for the control of glyphosate resistant giant ragweed in glyphosate resistant soybean, and b) to determine the lowest effective rate of 2,4-D for the control of glyphosate-resistant giant ragweed. Ten postemergence herbicide combinations and seven rates of 2,4-D were evaluated in field studies conducted in 2011 and 2012 at six locations confirmed with glyphosate-resistant giant ragweed. The post emergence herbicides evaluated did not provide acceptable/consistent control. Of the herbicides evaluated, glyphosate plus cloransulam-methyl provided 26% to 70% control 8 WAA of glyphosate resistant giant ragweed, which was the best of the herbicides combinations evaluated. The doses of 2,4-D required to reduce giant ragweed shoot dry weight by 50, 80 and 95% were 142, 310 and 1048 g a.e. ha-1, respectively.展开更多
[Objective]The paper was to study efficacy and phytotoxicity of different dosages of 4% nicosulfuron on weeds in corn fields.[Method]With summer corn variety Zhengdan 958commonly used in field production in Hengshui a...[Objective]The paper was to study efficacy and phytotoxicity of different dosages of 4% nicosulfuron on weeds in corn fields.[Method]With summer corn variety Zhengdan 958commonly used in field production in Hengshui area of Hebei Province of China as the test material,different dosages（1 050,1 500 and 1 950mL/hm2）of corn postemergence herbicide 4% nicosulfuron SC were sprayed during five-leaf stage of corn,and the treatments with water spraying and manual weeding were set as controls.The effects of different dosages of 4% nicosulfuron SC on weed control efficacy and safety and yield of corn were analyzed in order to determine the optimal dosage.[Result]Spraying 4% nicosulfuron SC with dosage of 1 500mL/hm2 during five-leaf stage of corn not only had better control effect against various weeds,but also did not produce phytotoxicity on corn,and the yield of corn was higher.[Conclusion]The study provided scientific information for using 4% nicosulfuron to eradicate weeds in corn fields.展开更多
基金Funding for this project was provided in part by Monsanto Canada Inc.,the Grain Farmers of Ontario and the Agricultural Adaptation Council through the Canadian Agricultural Adaptation Program.
文摘Glyphosate resistant giant ragweed is an increasing problem in glyphosate resistant cropping systems in southwestern Ontario. The postemergence herbicides registered for use in soybean in Ontario do not provide consistent control of glyphosate resistant giant ragweed. There is limited research on the lowest effective rate of 2,4-D for the control of glyphosate resistant giant ragweed. Consequently, the objectives of this study were a) to determine the efficacy of herbicides applied postemergence for the control of glyphosate resistant giant ragweed in glyphosate resistant soybean, and b) to determine the lowest effective rate of 2,4-D for the control of glyphosate-resistant giant ragweed. Ten postemergence herbicide combinations and seven rates of 2,4-D were evaluated in field studies conducted in 2011 and 2012 at six locations confirmed with glyphosate-resistant giant ragweed. The post emergence herbicides evaluated did not provide acceptable/consistent control. Of the herbicides evaluated, glyphosate plus cloransulam-methyl provided 26% to 70% control 8 WAA of glyphosate resistant giant ragweed, which was the best of the herbicides combinations evaluated. The doses of 2,4-D required to reduce giant ragweed shoot dry weight by 50, 80 and 95% were 142, 310 and 1048 g a.e. ha-1, respectively.
文摘[Objective]The paper was to study efficacy and phytotoxicity of different dosages of 4% nicosulfuron on weeds in corn fields.[Method]With summer corn variety Zhengdan 958commonly used in field production in Hengshui area of Hebei Province of China as the test material,different dosages（1 050,1 500 and 1 950mL/hm2）of corn postemergence herbicide 4% nicosulfuron SC were sprayed during five-leaf stage of corn,and the treatments with water spraying and manual weeding were set as controls.The effects of different dosages of 4% nicosulfuron SC on weed control efficacy and safety and yield of corn were analyzed in order to determine the optimal dosage.[Result]Spraying 4% nicosulfuron SC with dosage of 1 500mL/hm2 during five-leaf stage of corn not only had better control effect against various weeds,but also did not produce phytotoxicity on corn,and the yield of corn was higher.[Conclusion]The study provided scientific information for using 4% nicosulfuron to eradicate weeds in corn fields.
