3 results
Use of preplant sulfentrazone in no-till, narrow-row, glyphosate-resistant Glycine max
- Jeremy T. Dirks, William G. Johnson, Reid J. Smeda, William J. Wiebold, Raymond E. Massey
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- Journal:
- Weed Science / Volume 48 / Issue 5 / October 2000
- Published online by Cambridge University Press:
- 20 January 2017, pp. 628-639
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Field studies were conducted in 1998 and 1999 to evaluate crop response, weed control, Glycine max yield, and economic returns with sulfentrazone alone and tank-mixed with glyphosate, cloransulam, or chlorimuron at two preplant application timings in no-till, narrow-row, glyphosate-resistant G. max. No significant crop injury was observed. Setaria faberi and Polygonum pensylvanicum control 5 wk after planting (WAP) was generally greater with sulfentrazone applied early preplant (EPP) than with sulfentrazone applied at planting (AP). When applied AP, glyphosate plus sulfentrazone provided greater S. faberi control than sulfentrazone alone. Control of Amaranthus rudis, Ambrosia artemisiifolia, and Ipomoea hederacea was greater in 1998 than in 1999 because of more timely early-season precipitation. Sulfentrazone-based programs provided 80 to 100% control of A. rudis in 1998, but control in 1999 ranged from 72 to 95% at Columbia and 46 to 83% at Novelty. Cloransulam alone, at either application timing, was the only treatment that provided greater than 80% control of A. artemisiifolia at each site in each year. All sulfentrazone-based treatments provided greater than 80% control of I. hederacea in 1998, but control was less in 1999 and ranged from 54 to 91%. Xanthium strumarium control ranged from 5 to 94% with sulfentrazone alone; however, the addition of cloransulam or chlorimuron provided 75 to 99% control regardless of application timing. A blanket application of glyphosate was made 6 WAP over all preplant herbicide treatments, and weed control 5 wk after this treatment was greater than 79% with all sulfentrazone-based treatments. Sulfentrazone plus cloransulam or chlorimuron plus glyphosate EPP or AP followed by (fb) glyphosate postemergence (POST) generally provided the greatest weed control. Overall weed control was generally greater with the use of residual herbicides vs. glyphosate alone, although yield and net returns were not always greater. A greenhouse study was conducted to determine if altering the preplant application timing reduced sulfentrazone injury to G. max. Treatment variables included herbicide rate, temperature during a preplant incubation period, and application timing. Glycine max, Zea mays, and Sorghum bicolor were used as indicator species. Sulfentrazone caused less injury to G. max, Z. mays, and S. bicolor in soils incubated at 30 C when applied 20 d before planting compared to 0 d before planting. Equivalent amounts of crop injury were noted with sulfentrazone applied 20 or 0 d before planting in soils incubated at 5 C with all indicator species.
Management of Acetolactate Synthase (ALS)-Resistant Common Sunflower (Helianthus annuus L.) in Soybean (Glycine max)
- Jayla R. Allen, William G. Johnson, Reid J. Smeda, William J. Wiebold, Raymond E. Massey
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- Journal:
- Weed Technology / Volume 15 / Issue 3 / September 2001
- Published online by Cambridge University Press:
- 20 January 2017, pp. 571-575
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Field studies were conducted in 1998 and 1999 to evaluate the sensitivity of a common sunflower population to acetolactate synthase (ALS)-inhibiting herbicides and evaluate alternative control methods for ALS-resistant common sunflower in soybean. Imazaquin, imazethapyr, imazamox, flumetsulam, chlorimuron, cloransulam, and CGA277476 provided 35 to 73% control of common sunflower with labeled rates. Postemergence glyphosate and sequential applications of bentazon effectively controlled ALS-resistant common sunflower. Although pendimethalin + imazaquin + imazethapyr preemergence followed by glyphosate postemergence with and without cultivation provided 100% control of ALS-resistant common sunflower, sequential applications of glyphosate provided net incomes approximately $50 to $110/ha higher than the alternative control methods. Pendimethalin preemergence followed by acifluorfen + bentazon postemergence followed by bentazon 10 d later provided the lowest overall weed control and net income. In treatments with a soil-applied herbicide followed by glyphosate postemergence, cultivation generally did not improve weed control. Soybean yields were the same comparing glyphosate with a soil-applied herbicide followed by glyphosate.
Reduced rates of sulfentrazone plus chlorimuron and glyphosate in no-till, narrow-row, glyphosate-resistant Glycine max
- Jeremy T. Dirks, William G. Johnson, Reid J. Smeda, William J. Wiebold, Raymond E. Massey
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- Journal:
- Weed Science / Volume 48 / Issue 5 / October 2000
- Published online by Cambridge University Press:
- 20 January 2017, pp. 618-627
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Field studies were conducted in 1998 and 1999 to evaluate crop response, weed control, Glycine max yield, and economic returns of labeled (1×) and one-half labeled (½×) rates of early preplant (EPP) sulfentrazone plus chlorimuron and postemergence glyphosate, compared to glyphosate-alone systems in no-till, narrow-row, glyphosate-resistant G. max. Treatments containing a 1× or ½× rate of EPP sulfentrazone plus chlorimuron with glyphosate followed by (fb) a postemergence treatment of glyphosate provided 80 to 100% control of Xanthium strumarium, Ambrosia artemisiifolia, and Polygonum pensylvanicum and 82 to 100% control of Setaria faberi and Amaranthus rudis if glyphosate was applied mid-postemergence (MPOST) or late postemergence (LPOST). Glyphosate alone EPP fb glyphosate postemergence or sequential postemergence treatments of glyphosate provided 77 to 100% control of S. faberi, A. artemisiifolia, and P. pensylvanicum. Glycine max yield did not significantly differ between treatments that contained 1× or ½× rates of sulfentrazone plus chlorimuron EPP with postemergence glyphosate or sequential glyphosate. Residual herbicides fb glyphosate reduced overall weed control variability but did not reduce the overall yield variability compared to glyphosate alone. Greater weed control, G. max yield, net incomes, and lower coefficient of variation (CV) of net incomes were generally associated with treatments that included both EPP and postemergence treatments vs. single herbicide applications. A greenhouse study was conducted to determine the optimal spray additive to maximize the foliar activity of sulfentrazone on three annual weeds. Sulfentrazone alone and in combination with a nonionic surfactant (NIS), methylated seed oil (MSO), crop oil concentrate (COC), and a silicone-based surfactant (SBS), with and without ammonium sulfate (AMS), were applied on two sizes of Abutilon theophrasti, P. pensylvanicum, and S. faberi. AMS provided little additional efficacy of sulfentrazone on S. faberi, but improved efficacy on A. theophrasti and P. pensylvanicum. SBS or MSO plus AMS with sulfentrazone generally provided the greatest efficacy on all species.