Herbicide Efficacy on FourAmaranthusSpecies in Soybean (Glycine max)

1998 ◽  
Vol 12 (2) ◽  
pp. 315-321 ◽  
Author(s):  
Jonathan K. Sweat ◽  
Michael J. Horak ◽  
Dallas E. Peterson ◽  
Randy W. Lloyd ◽  
John E. Boyer

Field and greenhouse studies were conducted in 1995 and 1996 in Kansas to determine the efficacy of 21 herbicide treatments for control of tumble pigweed, Palmer amaranth, redroot pigweed, and two biotypes of common waterhemp in soybean. In field studies, nine of eleven preemergence treatments controlled all four species 90% or more. However, pendimethalin and trifluralin controlled Palmer amaranth, redroot pigweed, and tumble pigweed less than the other preplant incorporated and preemergence treatments. With the exception of flumiclorac and NAF-75, postemergence treatments controlled 75 to 90% of all four species. A biotype of common waterhemp collected in Iowa was not controlled by acetolactate synthase-inhibiting herbicides. Greenhouse results were similar to field experiments. Results suggest at least 90% control of theseAmaranthusspecies is possible with proper herbicide selection.

1995 ◽  
Vol 9 (1) ◽  
pp. 141-147 ◽  
Author(s):  
Christopher M. Mayo ◽  
Michael J. Horak ◽  
Dallas E. Peterson ◽  
John E. Boyer

Acifluorfen, lactofen, chlorimuron, thifensulfuron, imazethapyr, and imazaquin were evaluated for control of Palmer amaranth, common waterhemp, redroot pigweed, and tumble pigweed at three application timings in field and greenhouse experiments. Results from field studies indicated that most herbicides provided greater than 90% control of common waterhemp, redroot pigweed, and tumble pigweed regardless of time of application. Palmer amaranth was the most difficult species to control, and only thifensulfuron and imazethapyr provided greater than 80% control at all application timings. In the greenhouse experiment, herbicides were applied when pigweeds averaged 10 cm, 20 cm, and 30 cm in height. Results were similar to the field experiment, except that common waterhemp was more difficult to control.


1990 ◽  
Vol 4 (3) ◽  
pp. 475-477 ◽  
Author(s):  
R. M. Huckaba ◽  
H. D. Coble

Field studies were conducted to determine the effect of several herbicides on soybean thrips numbers in soybean. Adult soybean thrips numbers in the preplant-incorporated and preemergent herbicide treatments were observed to be either greater than or equal to, but never less than, numbers in the control plots. Larval soybean thrips numbers were not observed to be affected by the preplant-incorporated or preemergent treatments. The postemergence herbicide treatment of naptalam plus dinoseb consistently reduced both adult and larval soybean thrips numbers. The other postemergent treatments did not affect numbers consistently.


1998 ◽  
Vol 12 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Kelly A. Nelson ◽  
Karen A. Renner

Field experiments were conducted at East Lansing and Clarksville, MI, to evaluate the efficacy of imazamox, imazethapyr, and CGA-277476 plus quizalofop applied postemergence in wide- (76-cm) and narrow- (19-cm) row soybean. Soybean injury from all herbicides was minimal 14 days after treatment (DAT), except for CGA-277476 at 79 g ai/ha plus 69 g ai/ha quizalofop, which caused 30% soybean injury at the Clarksville location. Adding 4 g ai/ha CGA-248757 to 65 g ai/ha CGA-277476 plus quizalofop reduced common ragweed control, but increased redroot pigweed control in wide rows compared to 79 g ai/ha CGA-277476 plus quizalofop. Imazamox at 35 and 45 g ai/ha provided greater common ragweed and common lambsquarters control than imazethapyr at 70 g ai/ha 28 DAT. All herbicide treatments controlled velvetleaf. Common ragweed and common lambsquarters control by all herbicide treatments was enhanced in narrow- compared to wide-row soybean 56 DAT as was redroot pigweed control by CGA-277476 treatments. Total weed biomass and soybean yield in wide-row soybean treated with imazamox at 45 g/ha was not different from the hand-weeded control. In narrow-row soybean, soybean yield was equal to the hand-weeded control for 35 and 45 g/ha imazamox and 70 g/ha imazethapyr. Postemergence herbicide treatments resulted in less weed biomass and greater soybean yield in narrow- compared to wide-row soybean.


Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 770-774 ◽  
Author(s):  
David W. Monks ◽  
Lawrence R. Oliver

Competition of weeds was characterized by determining the distance down the soybean row that a weed affects soybean biomass and yield. Field studies were conducted for 2 yr to compare competitive effects of common cocklebur, johnsongrass, Palmer amaranth, sicklepod, and tall morningglory on ‘Forrest’ and ‘Centennial’ soybeans. The weeds did not significantly reduce soybean biomass for 6 weeks after emergence. Palmer amaranth, common cocklebur, and tall morningglory had the greatest biomass by 6 weeks after emergence. However, only competition from common cocklebur and Palmer amaranth measurably reduced soybean biomass during the growing season. Biomass of Forrest and Centennial soybeans was reduced when these cultivars were growing within 12.5 and 50 cm of common cocklebur, respectively. Johnsongrass, sicklepod, and tall morningglory grew more slowly than the other weeds and had no measurable competitive effects on soybean biomass. Soybean competition reduced biomass of all weeds 90 to 97%. Soybean cultivar influenced the level and duration of competitiveness depending on the weed species present. Biomass of both soybean cultivars was reduced when they were growing within 50 cm of Palmer amaranth. Soybean seed yield was reduced when soybeans were growing within 25 cm of common cocklebur and Palmer amaranth and also when they were growing within 12.5 cm of tall morningglory. Sicklepod had no effect on soybean seed yield.


1999 ◽  
Vol 13 (3) ◽  
pp. 484-488 ◽  
Author(s):  
John W. Wilcut ◽  
John S. Richburg ◽  
F. Robert Walls

Field studies were conducted in 1992 and 1993 to evaluate AC 263,222 applied postemergence (POST) alone and as a mixture with atrazine or bentazon for weed control in imidazolinone-resistant corn. Nicosulfuron alone and nicosulfuron plus atrazine were also evaluated. Herbicide treatments were applied following surface-banded applications of two insecticides, carbofuran or terbufos at planting. Crop sensitivity to POST herbicides, corn yield, and weed control was not affected by insecticide treatments. AC 263,222 at 36 and 72 g ai/ha controlled rhizomatous johnsongrass 88 and 99%, respectively, which was equivalent to nicosulfuron applied alone or with atrazine. AC 263,222 at 72 g/ha controlled large crabgrass 99% and redroot pigweed 100%, and this level of control exceeded that obtained with nicosulfuron alone. AC 263,222 at 72 g/ha controlled sicklepod and morningglory species 99 and 98%, respectively. Nicosulfuron alone or with atrazine controlled these two species less than AC 263,222 at 72 g/ha. Addition of bentazon or atrazine to AC 263,222 did not improve control of any species compared with the higher rate of AC 263,222 at 72 g/ha applied alone. Corn yield increased over the untreated control when POST herbicide(s) were applied, but there were no differences in yield among herbicide treatments.


1988 ◽  
Vol 2 (3) ◽  
pp. 355-363 ◽  
Author(s):  
Jerome M. Green ◽  
Timothy T. Obrigawitch ◽  
James D. Long ◽  
James M. Hutchison

Metribuzin and the ethyl ester of chlorimuron were evaluated alone and in combination for preemergence broadleaf weed control in soybeans. Neither herbicide alone controlled all broadleaf weeds tested, but combinations showed both complementary and additive action. Two field studies quantified these interactions on broadleaf weeds and showed that low rates of either herbicide alone controlled Pennsylvania smartweed and redroot pigweed. Metribuzin was more effective than chlorimuron in controlling prickly sida and hemp sesbania, while chlorimuron was more effective on common cocklebur, sicklepod, and ivyleaf and pitted morningglories. Additive action was most important on velvetleaf, sicklepod, annual morningglories, and hemp sesbania. Because the components were both additive and complementary, a range of mixture rates and ratios were more effective for weed control than either herbicide alone.


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 105-110 ◽  
Author(s):  
William G. Johnson ◽  
Jeffrey S. Dilbeck ◽  
Michael S. DeFelice ◽  
J. Andrew Kendig

Field studies were conducted at three locations in 1993 and 1994 to evaluate weed control and crop response to metolachlor plus combinations of 0.5 × and 1 × label rates of imazaquin applied preplant and imazethapyr applied early postemergence or postemergence in no-till narrow-row soybean production. Giant foxtail, common ragweed, common cocklebur, and large crabgrass population reductions were greater with sequential preplant metolachlor plus imazaquin followed by early postemergence or postemergence imazethapyr than with preplant metolachlor plus imazaquin or early postemergence/postemergence imazethapyr alone. Ivyleaf morningglory was not effectively controlled by any herbicide program. Pennsylvania smartweed populations were reduced with all herbicide treatments. Soybean yields with treatments utilizing 0.5 × rates were usually equal to 1 × rates if imazethapyr was applied early postemergence or postemergence. Net income with reduced herbicide rates was equal to full-label rates and provided no greater risk to net income.


1995 ◽  
Vol 9 (4) ◽  
pp. 696-702 ◽  
Author(s):  
Chae Soon Kwon ◽  
James J. Kells ◽  
Donald Penner

Greenhouse studies were conducted to determine the response of six corn hybrids and two soybean varieties to acetolactate synthase (ALS) inhibitor herbicides applied with terbufos and/or piperonyl butoxide (PBO), a mixed function oxidase (MFO) inhibitor. Field experiments also were conducted to determine the response of six corn hybrids to the combination treatments, terbufos plus ALS inhibitor herbicides and/or PBO and/or antidote. PBO at 0.33 kg/ha tank-mixed with nicosulfuron and primisulfuron injured the Northrup King 9283 corn hybrid. Great Lakes 584 corn was less sensitive than Northrup King 9283 to these combination treatments. Pioneer 3377 IR corn hybrid was resistant to the combination of nicosulfuron or primisulfuron plus PBO at 2 kg/ha and also to the combination treatments of imazethapyr herbicide plus PBO even though terbufos was previously applied. ICI 8532 IT, ICI 8532, and Pioneer 3377 hybrids were injured by the combination of nicosulfuron or primisulfuron and/or terbufos and/or PBO at 2 kg/ha. ICI 8532 IT corn hybrid was not injured by the combination treatment of imazethapyr or thifensulfuron and terbufos. In the field studies, Pioneer 3377 IR and Ciba 4393 RSC hybrids were resistant to sulfonylurea and imidazolinone herbicides even when applied with PBO regardless of the presence of terbufos. All treatments of chlorimuron plus terbufos caused considerable injury to ICI 8532 IT, ICI 8532, Pioneer 3377, and Ciba 4393, but not Pioneer 3377 IR and Ciba 4393 RSC. The combination of thifensulfuron with PBO injured Elgin ‘87 soybean, but the W20 soybean was tolerant to this combination treatment. Combination of imazethapyr with PBO did not affect the growth of Elgin ‘87 soybean.


2015 ◽  
Vol 29 (3) ◽  
pp. 412-418 ◽  
Author(s):  
Matthew S. Wiggins ◽  
M. Angela McClure ◽  
Robert M. Hayes ◽  
Lawrence E. Steckel

Field experiments were conducted in 2013 and 2014 in Jackson, TN, to evaluate the efficacy of integrating cover crops and POST herbicides in corn to control glyphosate-resistant (GR) Palmer amaranth. Crimson clover and hairy vetch were planted in the fall and accumulated greater than 1,600 kg ha−1aboveground biomass by time of termination. Crimson clover and hairy vetch provided 62% and 58% Palmer amaranth control 14 d before application, respectively. POST herbicide treatments of glyphosate +S-metolachlor + mesotrione + atrazine, thiencarbazone-methyl + tembotrione + atrazine, and glyphosate + atrazine were applied when Palmer amaranth reached 15 cm tall. The herbicide treatments provided greater than 95% control of Palmer amaranth 28 d after application. In addition to Palmer amaranth suppression, corn was taller at V5 and V7 following a hairy vetch cover crop. Hairy vetch and crimson clover residues provided early season weed suppression because of biomass accumulation. Palmer amaranth in the nontreated control plots reached 15 cm 4 and 3 d ahead of the cover-treated plots in 2013 and 2014, respectively. This could potentially increase POST herbicide-application flexibility for producers. Results of this trial also suggest that cover crops alone are not a means of season-long control of GR Palmer amaranth. From a herbicide resistance-management perspective, the integration of cover crops with herbicide mixtures that incorporate multiple sites of action should aid in mitigating the further selection of herbicide resistance in Palmer amaranth.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Aman Chandi ◽  
David L. Jordan ◽  
Alan C. York ◽  
Susana R. Milla-Lewis ◽  
James D. Burton ◽  
...  

Palmer amaranth (Amaranthus palmeriS. Wats.) has become difficult to control in row crops due to selection for biotypes that are no longer controlled by acetolactate synthase inhibiting herbicides and/or glyphosate. Early season interference in soybean [Glycine max(L.) Merr.] for 40 days after emergence by three glyphosate-resistant (GR) and three glyphosate-susceptible (GS) Palmer amaranth biotypes from Georgia and North Carolina was compared in the greenhouse. A field experiment over 2 years compared season-long interference of these biotypes in soybean. The six Palmer amaranth biotypes reduced soybean height similarly in the greenhouse but did not affect soybean height in the field. Reduction in soybean fresh weight and dry weight in the greenhouse; and soybean yield in the field varied by Palmer amaranth biotypes. Soybean yield was reduced 21% by Palmer amaranth at the established field density of 0.37 plant m−2. When Palmer amaranth biotypes were grouped by response to glyphosate, the GS group reduced fresh weight, dry weight, and yield of soybean more than the GR group. The results indicate a possible small competitive disadvantage associated with glyphosate resistance, but observed differences among biotypes might also be associated with characteristics within and among biotypes other than glyphosate resistance.


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