Influence of application timing and herbicide rate on the efficacy of tolpyralate plus atrazine

2019 ◽  
Vol 33 (03) ◽  
pp. 448-458 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Integrated Weed Management ◽  
Herbicide Application ◽  
Weed Species ◽  
Common Ragweed ◽  
Application Timing ◽  
Common Lambsquarters ◽  
Green Foxtail ◽  
Equivalent Control

AbstractEffective POST herbicides and herbicide mixtures are key components of integrated weed management in corn; however, herbicides vary in their efficacy based on application timing. Six field experiments were conducted over 2 yr (2017–2018) in southwestern Ontario, Canada, to determine the effects of herbicide application timing and rate on the efficacy of tolpyralate, a new 4-hydroxyphenyl pyruvate dioxygenase inhibitor. Tolpyralate at 15, 30, or 40 g ai ha−1 in combination with atrazine at 500 or 1,000 g ai ha−1 was applied PRE, early POST, mid-POST, or late POST. Tolpyralate + atrazine at rates ≥30 + 1,000 g ha−1 provided equivalent control of common lambsquarters and Powell amaranth applied PRE or POST, whereas no rate applied PRE controlled common ragweed, velvetleaf, barnyardgrass, or green foxtail. Common ragweed, common lambsquarters, velvetleaf, and Powell amaranth were controlled equally regardless of POST timing. In contrast, control of barnyardgrass and green foxtail declined when herbicide application was delayed to the late-POST timing, irrespective of herbicide rate. Similarly, corn grain yield declined within each tolpyralate + atrazine rate when herbicide applications were delayed to late-POST timing. Overall, the results of this study indicate that several monocot and dicot weed species can be controlled with tolpyralate + atrazine with an early to mid-POST herbicide application timing, before weeds reach 30 cm in height, and Powell amaranth and common lambsquarters can also be controlled PRE. Additionally, this study provides further evidence highlighting the importance of effective, early-season weed control in corn.

Environment and Soil Conditions Influence Pre- and Postemergence Herbicide Efficacy in Soybean

2010 ◽  
Vol 24 (3) ◽  
pp. 234-243 ◽  
Author(s):  
Christie L. Stewart ◽  
Robert E. Nurse ◽  
Allan S. Hamill ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Environmental Conditions ◽  
Soil Conditions ◽  
Herbicide Application ◽  
Common Ragweed ◽  
Application Timing ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Green Foxtail ◽  
Before And After

Deciding on the most efficacious PRE and POST herbicide options and their ideal application timing can be challenging for soybean producers. Climatic events during the 14 d before and after herbicide application can further complicate decisions because of their influence on herbicide effectiveness. Nine field trials were conducted at three locations in southwestern Ontario from 2003 to 2006, to determine the most effective PRE and POST soybean herbicides for control of common lambsquarters, common ragweed, green foxtail, and redroot pigweed. When precipitation was low at least 7 d before and after herbicide application weed control was reduced in treatments that included imazethapyr (PRE or POST) or flumetsulam/S-metolachlor (a premix formulation) (PRE). Cumulative precipitation during the 12 d after PRE application that exceeded the monthly average by at least 60% reduced common lambsquarters control when metribuzin was applied and green foxtail control when imazethapyr was applied. Delaying application of imazethapyr + bentazon to a later soybean growth stage decreased control of common lambsquarters and green foxtail; however, environmental conditions appeared to influence these results. Precipitation on the day of application decreased control of common ragweed and redroot pigweed more with quizalofop-p-ethyl + thifensulfuron-methyl + bentazon compared with imazethapyr + bentazon. Soybean yield varied among POST herbicide treatments because of reduced weed control. This research confirms that environmental conditions pre- and postapplication, as well as application timing, influence herbicide efficacy and should be considered by growers when selecting an herbicide program.

Postemergence Control of Weeds in Winter Rapeseed,Brassica napus, by DPX-A7881

Weed Science ◽  
1990 ◽  
Vol 38 (4-5) ◽  
pp. 389-395 ◽  
Author(s):  
Finlay S. Buchanan ◽  
Clarence J. Swanton ◽  
Terry J. Gillespie
Keyword(s):  
Brassica Napus ◽  
Growth Stage ◽  
Field Experiments ◽  
Seed Quality ◽  
Herbicide Application ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Winter Rapeseed

Field experiments were established to determine the dose and timing of DPX-A7881 applied postemergence for control of weeds in winter rapeseed. Wild mustard and shepherdspurse were effectively controlled by DPX-A7881. Control of these weeds by DPX-A7881 was dependent upon growth stage. The later the growth stage at time of herbicide application the poorer the control. Fall applications of DPX-A7881 provided greater control of wild mustard and shepherdspurse seedlings compared to spring applications. The 0.010 kg ai ha-1dose was as effective in controlling susceptible weed species as 0.030 kg ai ha-1. Control of common lambsquarters and redroot pigweed by DPX-A7881 was poor. Regardless of timing or amount of herbicide applied, DPX-A7881 did not significantly reduce dry weights of either barnyardgrass or green foxtail. Doses of DPX-A7881 ranging from 0.010 to 0.030 kg ai ha-1did not injure or adversely affect winter survival of rapeseed seedlings. Rapeseed yield and seed quality were not affected by DPX-A7881 applied postemergence.

scholarly journals Weed Management in White Bean With Pre-plant Incorporated Herbicides

2021 ◽  
Vol 13 (10) ◽  
pp. 1
Author(s):  
Nader Soltani ◽  
Christy Shropshire ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Design Factor ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Green Foxtail ◽  
White Bean ◽  
Bean Yield

Five field experiments were conducted in Ontario Canada during 2018-2020 to determine the level of crop injury, weed control and white bean yield with up to four-way mixtures of herbicides applied preplant incorporated (PPI). The trials were arranged in a factorial design: Factor 1 was “Grass herbicide” including no grass herbicide, trifluralin, S-metolachlor and trifluralin + S-metolachlor and Factor 2 was “Broadleaf herbicide” including no broadleaf herbicide, halosulfuron, imazethapyr and halosulfuron + imazethapyr. At 2 and 4 weeks after emergence (WAE), there was minimal (≤ 4%) white bean injury. At 8 weeks after herbicide application (WAA), trifluralin, S-metolachlor or trifluralin + S-metolachlor averaged across Factor 2 controlled velvetleaf 69, 71 and 62%, respectively; halosulfuron, imazethapyr and halosulfuron + imazethapyr averaged across Factor 1 controlled velvetleaf 75, 95 and 97%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled pigweed 93, 90 and 97%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled pigweed 97, 79 and 98%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor provided poor (≤ 32%) control of common ragweed while halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled common ragweed 86, 53 and 87%, respectively. The 4-way tankmix of trifluralin, S-metolachlor, halosulfuron + imazethapyr controlled common ragweed 95%. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled common lambsquarters 81, 38 and 91%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled common lambsquarters 94, 97 and 99%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor provided poor (≤ 46%) control of wild mustard while halosulfuron, imazethapyr and halosulfuron + imazethapyr provided excellent (≥ 97%) wild mustard control. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled barnyardgrass 70, 85 and 94%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled barnyardgrass 9, 50 and 59%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled green foxtail 89 to 98% and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled green foxtail 19, 69 and 67%, respectively. Weed interference reduced white bean yield 76%. Generally, white bean yield reflected the level of weed control. Based on these results, the 2- and 3-way tankmixes of herbicides evaluated generally provide similar weed control as the 4-way tankmixes.

Halauxifen-methyl controls glyphosate-resistant horseweed (Conyza canadensis) but not giant ragweed (Ambrosia trifida) in winter wheat

2020 ◽  
Vol 34 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Jessica Quinn ◽  
Nader Soltani ◽  
Jamshid Ashigh ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Field Experiments ◽  
The United States ◽  
Integrated Weed Management ◽  
Conyza Canadensis ◽  
Limited Information ◽  
Weed Species ◽  
Ambrosia Trifida ◽  
Giant Ragweed

AbstractHorseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.

Tolpyralate Efficacy: Part 1. Biologically Effective Dose of Tolpyralate for Control of Annual Grass and Broadleaf Weeds in Corn

2018 ◽  
Vol 32 (6) ◽  
pp. 698-706 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Effective Dose ◽  
Weed Management ◽  
Field Studies ◽  
Biologically Effective Dose ◽  
Limited Information ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Low Field ◽  
Green Foxtail

AbstractTolpyralate is a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)-inhibiting herbicide for POST weed management in corn; however, there is limited information regarding its efficacy. Six field studies were conducted in Ontario, Canada, over 3 yr (2015 to 2017) to determine the biologically effective dose of tolpyralate for the control of eight annual weed species. Tolpyralate was applied POST at six doses from 3.75 to 120 g ai ha−1and tank mixed at a 1:33.3 ratio with atrazine at six doses from 125 to 4,000 g ha−1. Regression analysis was performed to determine the effective dose (ED) of tolpyralate, and tolpyralate+atrazine, required to achieve 50%, 80%, or 90% control of eight weed species at 1, 2, 4, and 8 wk after application (WAA). The ED of tolpyralate for 90% control (ED90) of velvetleaf, common lambsquarters, common ragweed, redroot pigweed or Powell amaranth, and green foxtail at 8 WAA was ≤15.5 g ha−1; however, tolpyralate alone did not provide 90% control of wild mustard, barnyardgrass, or ladysthumb at 8 WAA at any dose evaluated in this study. In contrast, the ED90for all species in this study with tolpyralate+atrazine was ≤13.1+436 g ha−1, indicating that tolpyralate+atrazine can be highly efficacious at low field doses.

Tolpyralate Efficacy: Part 2. Comparison of Three Group 27 Herbicides Applied POST for Annual Grass and Broadleaf Weed Control in Corn

2018 ◽  
Vol 32 (6) ◽  
pp. 707-713 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Effective Dose ◽  
Weed Control ◽  
Biologically Effective Dose ◽  
Annual Grass ◽  
Weed Species ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Wild Mustard ◽  
Percentage Points ◽  
Green Foxtail

AbstractTolpyralate is a new Group 27 pyrazolone herbicide that inhibits the 4-hydroxyphenyl-pyruvate dioxygenase enzyme. In a study of the biologically effective dose of tolpyralate from 2015 to 2017 in Ontario, Canada, tolpyralate exhibited efficacy on a broader range of species when co-applied with atrazine; however, there is limited published information on the efficacy of tolpyralate and tolpyralate+atrazine relative to mesotrione and topramezone, applied POST with atrazine at label rates, for control of annual grass and broadleaf weeds. In this study, tolpyralate applied alone at 30 g ai ha−1 provided >90% control of common lambsquarters, velvetleaf, common ragweed, Powell amaranth/redroot pigweed, and green foxtail at 8 weeks after application (WAA). Addition of atrazine was required to achieve >90% control of wild mustard, ladysthumb, and barnyardgrass at 8 WAA. Tolpyralate+atrazine (30+1,000 g ai ha−1) and topramezone+atrazine (12.5+500 g ai ha−1) provided similar control at 8 WAA of the eight weed species in this study; however, tolpyralate+atrazine provided >90% control of green foxtail by 1 WAA. Tolpyralate+atrazine provided 18, 68, and 67 percentage points better control of common ragweed, green foxtail, and barnyardgrass, respectively, than mesotrione+atrazine (100+280 g ai ha−1) at 8 WAA. Overall, tolpyralate+atrazine applied POST provided equivalent or improved control of annual grass and broadleaf weeds compared with mesotrione+atrazine and topramezone+atrazine.

Weed control in soybean using pyroxasulfone and sulfentrazone

2015 ◽  
Vol 95 (6) ◽  
pp. 1199-1204 ◽  
Author(s):  
Kimberly D. Belfry ◽  
Kristen E. McNaughton ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Chenopodium Album ◽  
Ambrosia Artemisiifolia ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Industry Standard ◽  
Control Option ◽  
Green Foxtail ◽  
Glycine Max L

Belfry, K. D., McNaughton, K. E. and Sikkema, P. H. 2015. Weed control in soybean using pyroxasulfone and sulfentrazone. Can. J. Plant Sci. 95: 1199–1204. Pyroxasulfone and sulfentrazone are new herbicides currently being evaluated for weed control in soybean [Glycine max (L.) Merr.] in Ontario, Canada. Seven experiments were conducted over a 3-yr period (2011 to 2013) at Ridgetown and Exeter, Ontario, to evaluate weed management using pyroxasulfone, sulfentrazone and their tank-mixes relative to the industry standard, imazethapyr plus metribuzin. Tank-mixing pyroxasulfone and sulfentrazone provided up to 97, 46, 60, 100 and 71% control of common lambsquarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), green foxtail [Setaria viridis (L.) Beauv.], Powell amaranth [Amaranthus powellii (S.) Wats.] and velvetleaf (Abutilon theophrasti Medic.), respectively, at 2 wk after treatment. Control with pyroxasulfone and sulfentrazone was improved when tank-mixed, relative to application of each herbicide separately. Although control was variable across weed species, no difference in control was identified between pyroxasulfone plus sulfentrazone and imazethapyr plus metribuzin. Soybean yield was up to 2.7, 2.4 and 2.9 t ha−1 for pyroxasulfone, sulfentrazone and pyroxasulfone plus sulfentrazone application, yet imazethapyr plus metribuzin provided the highest yield (3.3 t ha−1). This research demonstrates that pyroxasulfone plus sulfentrazone may be used as a valuable weed control option in soybean; however, weed community composition may limit herbicidal utility.

Weed Management in Conventional- and No-Till Soybean Using Flumioxazin/Pyroxasulfone

2014 ◽  
Vol 28 (2) ◽  
pp. 298-306 ◽  
Author(s):  
Kris J. Mahoney ◽  
Christy Shropshire ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Conventional Tillage ◽  
Common Ragweed ◽  
No Till ◽  
Giant Foxtail ◽  
Green Foxtail ◽  
Excellent Control ◽  
Almost All

Eleven field experiments were conducted over a 3-yr period (2010, 2011, and 2012) in conventional- and no-till soybean with a flumioxazin and pyroxasulfone premix. PRE and preplant applications were evaluated for soybean injury, weed control, and yield compared to standard herbicides. Early-season soybean injury from flumioxazin/pyroxasulfone ranged from 1 to 19%; however, by harvest, soybean yields were similar across labeled rates (160 and 200 g ai ha−1), standard treatments, and the nontreated control. Flumioxazin/pyroxasulfone provided excellent control (99 to 100%) of velvetleaf, pigweed species (redroot pigweed and smooth pigweed), and common lambsquarters across almost all rates tested (80 to 480 g ai ha−1). Common ragweed, green foxtail, and giant foxtail control increased with flumioxazin/pyroxasulfone rate. The biologically effective rates varied between tillage systems. The flumioxazin/pyroxasulfone rate required to provide 80% control (R80) of pigweed was 3 and 273 g ai ha−1under conventional- and no-till, respectively. For common ragweed, the R80was 158 g ai ha−1under conventional tillage; yet, under no-till, the rate was nonestimable. The results indicate that flumioxazin/pyroxasulfone can provide effective weed control as a setup for subsequent herbicide applications.

scholarly journals Weed Control in White Bean with Pethoxamid Tank-Mixes Applied Preemergence

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Nader Soltani ◽  
Lynette R. Brown ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Weed Species ◽  
Navy Bean ◽  
Visible Injury ◽  
Common Lambsquarters ◽  
Weed Interference ◽  
Green Foxtail ◽  
White Bean ◽  
Bean Yield

Six field experiments were conducted during 2015 to 2017 in Ontario, Canada, to determine the efficacy of pethoxamid applied alone, and in combination with broadleaf herbicides, for the control of annual grass and broadleaved weeds in white navy bean. Visible injury was generally minimal (0 to 8%) with herbicide treatments evaluated. Weed control was variable depending on the weed species evaluated. Pethoxamid,S-metolachlor, halosulfuron, imazethapyr, sulfentrazone, pethoxamid + halosulfuron, pethoxamid + imazethapyr, and pethoxamid + sulfentrazone controlled redroot pigweed 82 to 98%; common ragweed 19 to 93%; common lambsquarters 49 to 84%; and green foxtail 47 to 92% in white bean. Weed biomass and weed density reductions were similar to visible control ratings for herbicides evaluated. Weed interference delayed white bean maturity and reduced yield by 50% in this study. Weed interference in plots sprayed with pethoxamid,S-metolachlor, and sulfentrazone reduced white bean yield 36%. White bean yield was similar to the weed-free with other herbicides evaluated. This study concludes that there is potential for the tank-mix of pethoxamid with halosulfuron, imazethapyr, or sulfentrazone for weed control in white bean production.

Seed Dormancy and Seed Morphology Related to Weed Susceptibility to Biofumigation

Weed Science ◽  
2017 ◽  
Vol 66 (2) ◽  
pp. 199-214 ◽  
Author(s):  
Maxime Lefebvre ◽  
Maryse L. Leblanc ◽  
Alan K. Watson
Keyword(s):  
Seed Dormancy ◽  
Weed Management ◽  
Relative Weight ◽  
Indian Mustard ◽  
Petri Dish ◽  
Seed Morphology ◽  
Weed Species ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Wild Carrot

Biofumigation is practiced to control soilborne pests and weeds in agronomic fields. The objectives of this research were to assess the dose response of weed seeds to Indian mustard biofumigation and associate responses to seed dormancy state, initial dormancy, and seed parameters. A petri dish biofumigation methodology was developed to expose seeds of common lambsquarters, bird vetch, wild carrot, common ragweed, green foxtail, velvetleaf, hairy galinsoga, and red clover to allelochemicals produced after rehydrating 0 (control), 1.94, 2.90, 5.81, 11.61, and 17.41 mg cm−2of dried mustard powder. Weed species expressed specific dose responses, estimated ED50, LD50, and maximal mortality. Hairy galinsoga and wild carrot were consistently the most affected by biofumigation, with maximal mortality reaching 97% and 95%, ED50values for germination were 1.91 and 2.68 mg cm−2, and LD50values were 3.31 and 3.69 mg cm−2of dried mustard tissue, respectively. Initial dormancy was assessed by germination and tetrazolium tests. Seed parameters such as testa thickness, relative weight of the testa, and seed size were measured directly by manual dissection, weighing seed structures, and stereomicroscopic imaging software measurements. Linear regression analyses revealed initial dormancy to be positively related to ED50and LD50values with a significant interaction with seed surface and seed width, respectively. Exposure to 5.81 mg cm−2of dried mustard powder increased common ragweed seed mortality for after-ripened seeds by 293% and by 58% for primary dormant seeds compared with untreated seeds. Mortality of common lambsquarters secondary and primary dormant seeds increased by 730% and 106%, respectively, and for wild carrot by 1,193 and 156%, respectively. Results underline the potential to incorporate biofumigation into weed management programs for repression of susceptible weed species.

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