Glyphosate-resistant (GR) giant ragweed has recently been identified in southwestern Ontario and has the potential to be a significant problem for regional corn producers. Eight field trials [four with preplant (PP) a...Glyphosate-resistant (GR) giant ragweed has recently been identified in southwestern Ontario and has the potential to be a significant problem for regional corn producers. Eight field trials [four with preplant (PP) and four with postemergence (POST) herbicides] were conducted from 2013 to 2014 on various Ontario farms infested with GR giant ragweed to determine the efficacy of PP and POST tank-mixes in corn. Glyphosate tank-mixed with atrazine, dicamba, dicamba/atrazine, mesotrione plus atrazine, flumetsulam, isoxaflutole plus atrazine, saflufenacil/dimethenamid-P, S-metolachlor/atrazine and rimsulfuron applied PP provided up to 54%, 95%, 93%, 95%, 40%, 89%, 91%, 50% and 93% control of GR giant ragweed and reduced dry weight 69%, 100%, 99%, 100%, 30%, 92%, 98%, 66% and 99%, respectively. POST application of glyphosate alone and tank-mixed with 2,4-D ester, atrazine, dicamba, dicamba/diflufenzopyr, dicamba/atrazine, bromoxynil plus atrazine, prosulfuron plus dicamba, mesotrione plus atrazine, topramezone plus atrazine, tembotrione/thiencarbazone-methyl and glufosinate provided up to 31%, 84%, 39%, 94%, 89%, 86%, 83%, 78%, 72%, 43%, 63% and 58% GR giant ragweed and reduced dry weight 55%, 99%, 72%, 99%, 99%, 98%, 96%, 96%, 93%, 89%, 91% and 95%, respectively. In general, PP control of GR giant ragweed was greater than POST applied herbicides evaluated. Based on these results, glyphosate tank-mixes containing dicamba or mesotrione plus atrazine applied PP, and dicamba applied POST will provide the most consistent control of GR giant ragweed in corn.展开更多
Application of a preplant or preemergence glyphosate burndown is routine in most no-tillage production systems of annual crops, however, time of application may influence overall weed control and grain yield. Six fiel...Application of a preplant or preemergence glyphosate burndown is routine in most no-tillage production systems of annual crops, however, time of application may influence overall weed control and grain yield. Six field trials were conducted over a three-year period (2008, 2009 and 2010) near Ridgetown, Ontario, Canada to determine the effect of glyphosate burndown application timing in glyphosate-resistant (GR) no-tillage soybean [Glycine max (L.) Merr.]. Soybean growth was reduced 5%, 10% and 20% when the burndown was delayed to 1, 5 and 12 days after planting (DAP), when evaluated one week after application (WAA), respectively. By 8 WAA, predicted burndown timing increased to 9, 14 and 23 DAP, and was 10, 17 and 26 DAP at 12 WAA, to reduce soybean growth by 5%, 10% and 20%, respectively. Similarly, burndown application at 14, 21 and 30 DAP corresponded to a soybean yield reduction of 5%, 10% and 20%. Seed moisture content was generally insensitive to burndown timing;80 and 140 DAP were required to increase moisture by 5% and 10%, respectively. This research indicates that delaying glyphosate burndown by up to 14 DAP, approximately VE to VC growth stage, has the potential to result in a modest reduction in soybean yield (5%).展开更多
Fenoxaprop-p-ethyl is a selective grass herbicide that if registered will provide winter wheat growers with an additional weed control option. Field experiments were established in the fall of 2011, 2012 and 2013 at R...Fenoxaprop-p-ethyl is a selective grass herbicide that if registered will provide winter wheat growers with an additional weed control option. Field experiments were established in the fall of 2011, 2012 and 2013 at Ridgetown and Exeter, Ontario, to determine the sensitivity of four market classes of winter wheat [Soft white winter wheat (SWWW), soft red winter wheat (SRWW), hard white winter wheat (HWWW) and hard red winter wheat (HRWW)] to 1X and 2X fenoxaprop-p-ethyl/safener at early-(EPOST) or late-post emergence (LPOST) application timings. Fenoxaprop-p-ethyl/safener applied LPOST at 1X and 2X the manufacturer’s proposed label rate caused 4% and 5% injury 1 week after application (WAA), respectively. The injury observed was transient with 1% injury 2 WAA. Winter wheat height ranged from 91 to 95, 76 to 77, 76 to 79 and 90 to 93 cm while grain yield was 6.2 to 6.4, 6.1 to 7.1, 5.5 to 5.8 and 5.6 to 6.2 t?ha?1 for SWWW, SRWW, HRWW and HRWW, respectively. Exeter sites were not affected by fenoxaprop-p-ethyl/ safener treatment. At Ridgetown and Exeter, no market class-specific response was identified for the cultivars evaluated. Based on this study, fenoxaprop-p-ethyl/safener has the potential to cause only minor and transient injury in winter wheat that will not decrease yield. Furthermore, this research supports the registration of fenoxaprop-p-ethyl/safener for spring POST application in winter wheat in Ontario.展开更多
文摘Glyphosate-resistant (GR) giant ragweed has recently been identified in southwestern Ontario and has the potential to be a significant problem for regional corn producers. Eight field trials [four with preplant (PP) and four with postemergence (POST) herbicides] were conducted from 2013 to 2014 on various Ontario farms infested with GR giant ragweed to determine the efficacy of PP and POST tank-mixes in corn. Glyphosate tank-mixed with atrazine, dicamba, dicamba/atrazine, mesotrione plus atrazine, flumetsulam, isoxaflutole plus atrazine, saflufenacil/dimethenamid-P, S-metolachlor/atrazine and rimsulfuron applied PP provided up to 54%, 95%, 93%, 95%, 40%, 89%, 91%, 50% and 93% control of GR giant ragweed and reduced dry weight 69%, 100%, 99%, 100%, 30%, 92%, 98%, 66% and 99%, respectively. POST application of glyphosate alone and tank-mixed with 2,4-D ester, atrazine, dicamba, dicamba/diflufenzopyr, dicamba/atrazine, bromoxynil plus atrazine, prosulfuron plus dicamba, mesotrione plus atrazine, topramezone plus atrazine, tembotrione/thiencarbazone-methyl and glufosinate provided up to 31%, 84%, 39%, 94%, 89%, 86%, 83%, 78%, 72%, 43%, 63% and 58% GR giant ragweed and reduced dry weight 55%, 99%, 72%, 99%, 99%, 98%, 96%, 96%, 93%, 89%, 91% and 95%, respectively. In general, PP control of GR giant ragweed was greater than POST applied herbicides evaluated. Based on these results, glyphosate tank-mixes containing dicamba or mesotrione plus atrazine applied PP, and dicamba applied POST will provide the most consistent control of GR giant ragweed in corn.
文摘Application of a preplant or preemergence glyphosate burndown is routine in most no-tillage production systems of annual crops, however, time of application may influence overall weed control and grain yield. Six field trials were conducted over a three-year period (2008, 2009 and 2010) near Ridgetown, Ontario, Canada to determine the effect of glyphosate burndown application timing in glyphosate-resistant (GR) no-tillage soybean [Glycine max (L.) Merr.]. Soybean growth was reduced 5%, 10% and 20% when the burndown was delayed to 1, 5 and 12 days after planting (DAP), when evaluated one week after application (WAA), respectively. By 8 WAA, predicted burndown timing increased to 9, 14 and 23 DAP, and was 10, 17 and 26 DAP at 12 WAA, to reduce soybean growth by 5%, 10% and 20%, respectively. Similarly, burndown application at 14, 21 and 30 DAP corresponded to a soybean yield reduction of 5%, 10% and 20%. Seed moisture content was generally insensitive to burndown timing;80 and 140 DAP were required to increase moisture by 5% and 10%, respectively. This research indicates that delaying glyphosate burndown by up to 14 DAP, approximately VE to VC growth stage, has the potential to result in a modest reduction in soybean yield (5%).
文摘Fenoxaprop-p-ethyl is a selective grass herbicide that if registered will provide winter wheat growers with an additional weed control option. Field experiments were established in the fall of 2011, 2012 and 2013 at Ridgetown and Exeter, Ontario, to determine the sensitivity of four market classes of winter wheat [Soft white winter wheat (SWWW), soft red winter wheat (SRWW), hard white winter wheat (HWWW) and hard red winter wheat (HRWW)] to 1X and 2X fenoxaprop-p-ethyl/safener at early-(EPOST) or late-post emergence (LPOST) application timings. Fenoxaprop-p-ethyl/safener applied LPOST at 1X and 2X the manufacturer’s proposed label rate caused 4% and 5% injury 1 week after application (WAA), respectively. The injury observed was transient with 1% injury 2 WAA. Winter wheat height ranged from 91 to 95, 76 to 77, 76 to 79 and 90 to 93 cm while grain yield was 6.2 to 6.4, 6.1 to 7.1, 5.5 to 5.8 and 5.6 to 6.2 t?ha?1 for SWWW, SRWW, HRWW and HRWW, respectively. Exeter sites were not affected by fenoxaprop-p-ethyl/ safener treatment. At Ridgetown and Exeter, no market class-specific response was identified for the cultivars evaluated. Based on this study, fenoxaprop-p-ethyl/safener has the potential to cause only minor and transient injury in winter wheat that will not decrease yield. Furthermore, this research supports the registration of fenoxaprop-p-ethyl/safener for spring POST application in winter wheat in Ontario.
