Is There a Benefit of Adding Atrazine to HPPD-Inhibiting Herbicides for Control of Multiple-Herbicide-Resistant, Including Group 5-Resistant, Waterhemp in Corn?

2021 ◽  
Vol 13 (7) ◽  
pp. 21
Author(s):  
Christian Willemse ◽  
Nader Soltani ◽  
Lauren Benoit ◽  
Amit J. Jhala ◽  
David C. Hooker ◽  
...  

The evolution of multiple-herbicide-resistant (MHR) waterhemp (resistant to Groups 2, 5, 9, and 14) in Ontario, Canada is challenging for growers. The complementary activity of the co-application of hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides with atrazine has been well documented. The objective of this research was to determine if the addition of atrazine to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides applied postemergence improves their consistency of MHR waterhemp (including Group 5 resistance) in corn. Five field trials were conducted over a two-year period (2018, 2019) in Ontario, Canada. Five HPPD-inhibiting herbicides [isoxaflutole (105 g ha-1), mesotrione (100 g ha-1), topramezone (12.5 g ha-1), tembotrione (90 g ha-1), and tolpyralate (30 g ha-1)] were applied postemergence with and without atrazine to 10-cm-tall waterhemp. Corn injury (≤ 10%) was observed at specific sites where the application of tembotrione, isoxaflutole and isoxaflutole + atrazine resulted in characteristic white bleaching of corn foliage; however, yield was not affected. Averaged across field sites, the addition of atrazine to isoxaflutole, mesotrione, topramezone, or tembotrione improved MHR waterhemp control 15%, 11%, 7%, and 7%, respectively at 4 weeks after application (WAA). Averaged across herbicide treatments and sites, the addition of atrazine reduced the standard error of MHR waterhemp control by 13% to 100%. This study concludes that the co-application of atrazine with HPPD-inhibitors applied postemergence reduced the risk of herbicide failure and resulted in greater and more consistent control of MHR waterhemp.

Weed Science ◽  
2021 ◽  
pp. 1-36
Author(s):  
Christian Willemse ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Amit J. Jhala ◽  
Darren E. Robinson ◽  
...  

Abstract The complementary activity of 4-hydroxphenylpyruvate dioxygenase (HPPD)-inhibitors and atrazine is well documented, but the use of atrazine is restricted in some geographical areas including the province of Quebec in Canada necessitating the evaluation of atrazine alternatives and their interactions with HPPD inhibitors. The objectives of this study were to determine if mixing HPPD-inhibitors with atrazine alternative photosystem II (PS II)-inhibitors, such as metribuzin and linuron applied PRE, or bromoxynil and bentazon applied POST, results in similar control of multiple-herbicide-resistant (MHR) waterhemp [Amaranthus tuberculatus (Moq.) Sauer] in corn. Ten field trials, five with herbicides applied PRE and five with herbicides applied POST, were conducted in Ontario, Canada in fields infested with MHR A. tuberculatus. Isoxaflutole, applied PRE, controlled MHR A. tuberculatus 58% to 76%; control increased 17% to 34% with the addition of atrazine, metribuzin, or linuron at three of five sites across 2, 4, 8, and 12 weeks after application (WAA). The interaction between isoxaflutole and PS II-inhibitors, applied PRE, was additive for MHR A. tuberculatus control, and biomass and density reduction. Mesotrione, tolpyralate, and topramezone, applied POST, controlled MHR A. tuberculatus 54% to 59%, 61%, and 44% to 45%, respectively, at two of five sites across 4, 8, and 12 WAA. The addition of atrazine, bromoxynil, or bentazon to mesotrione improved MHR A. tuberculatus control 29%, 34%, and 22%, to tolpyralate improved control 2%, 20%, and 10%, and to topramezone improved control 3%, 14%, and 8%, respectively. Interactions between HPPD- and PS II-inhibitors were mostly additive; however, synergistic responses were observed with mesotrione + bromoxynil or bentazon, and tolpyralate + bromoxynil. Mixing atrazine alternatives, metribuzin or linuron with isoxaflutole, applied PRE, and bromoxynil or bentazon with mesotrione or tolpyralate, applied POST, resulted in similar or better control of MHR A. tuberculatus in corn (Zea mays L.).


2013 ◽  
Vol 27 (3) ◽  
pp. 454-458 ◽  
Author(s):  
Kelly A. Barnett ◽  
Thomas C. Mueller ◽  
Lawrence E. Steckel

The development of crops resistant to 2,4-D, dicamba, and glufosinate may provide new options for the management of glyphosate-resistant (GR) giant ragweed and other herbicide-resistant weeds. A fallow field study was conducted in 2011 and 2012 to determine the control of GR giant ragweed with 2,4-D and dicamba applied alone and in combination with glufosinate or fomesafen. Dicamba and 2,4-D tank-mixed with glufosinate or fomesafen provided the highest level of control at 10 or 20 days after application (DAA). At 30 DAA, all herbicide treatments provided > 88% control of giant ragweed except glyphosate, glufosinate, and 2,4-D alone at 0.56 kg ae ha−1. Glyphosate, glufosinate, and 2,4-D alone at 0.56 kg ae ha−1also had the highest number of giant ragweed plants (> 5.8 plants m−2) and highest biomass (> 19.2 g m−2). Contrast statements between 2,4-D and dicamba indicated no differences among treatments containing these herbicides. However, contrast analysis indicated that herbicides applied alone resulted in 56, 58, and 61% control while tank-mix combinations of 2,4-D or dicamba with glufosinate or fomesafen resulted in 86, 91, and 93% control, respectively. Herbicides applied alone also had more giant ragweed plants and biomass per m−2than herbicides applied in tank-mix combinations. Tank-mixing combinations of 2,4-D and dicamba will be important for effective control of GR giant ragweed.


2021 ◽  
pp. 1-23
Author(s):  
Michael J. Walsh ◽  
Peter Newman ◽  
Paul Chatfield

Abstract Wild radish is the most problematic broadleaf weed of Australian grain production. The propensity of wild radish to evolve resistance to herbicides has led to high frequencies of multiple herbicide resistant populations present in these grain production regions. The objective of this study was to evaluate the potential of mesotrione to selectively control wild radish in wheat. The initial dose response pot trials determined that at the highest mesotrione rate of 50 g ha−1, PRE application was 30% more effective than POST on wild radish. This same rate of mesotrione POST resulted in a 30% reduction in wheat biomass compared to 0% for the PRE application. Subsequent, mesotrione PRE dose response trials identified a wheat selective rate range of >100 and < 300 g ai ha−1 that provided greater than 85% wild radish control with less than 15% reduction in wheat growth. Field evaluations confirmed the efficacy of mesotrione at 100 to 150 g ai ha−1 in reducing wild radish populations by greater than 85% following PRE application and incorporation by wheat planting. Additionally, these field trials demonstrated the opportunity for season-long control of wild radish when mesotrione PRE was followed by bromoxynil POST. The sequential application of mesotrione, an HPPD-inhibiting herbicide, PRE followed by bromoxynil, a PS II-inhibiting herbicide POST has the potential to provide 100% wild radish control with no effect on wheat growth.


2010 ◽  
Vol 90 (6) ◽  
pp. 933-938 ◽  
Author(s):  
N. Soltani ◽  
C. Shropshire ◽  
P.H. Sikkema

Nine field trials (five with PRE and four with POST herbicides) were conducted in 2006 to 2009 on various Ontario farms with heavy common cocklebur infestations to determine the effectiveness of PRE and POST herbicides for the control of common cocklebur in corn. There was no commercially significant corn injury from the PRE herbicides evaluated. Saflufenacil, saflufenacil/dimethenamid-p, isoxaflutole + atrazine, mesotrione + atrazine and dicamba/atrazine, applied PRE provided 85, 85, 76, 73 and 67% control of common cocklebur in corn 8 wk after emergence (WAE), respectively. Common cocklebur shoot dry weight was reduced 84, 80, 79, 75 and 68% with saflufenacil/dimethenamid-p, isoxaflutole + atrazine, mesotrione + atrazine, saflufenacil and dicamba/atrazine, respectively. There was no effect on corn yield compared with the weedy control with the PRE herbicides evaluated. The application of 2,4-D/atrazine POST resulted in unacceptable injury (28%) in corn. Dicamba/atrazine, dicamba/diflufenzopyr, dicamba and mesotrione + atrazine provided up to 98, 95, 90 and 90% control of common cocklebur 8 wk after application (WAA), respectively. All POST herbicide treatments increased corn yield compared with the non-treated control. Saflufenacil and saflufenacil/dimethenamid-p applied PRE and dicamba, dicamba/diflufenzopyr, dicamba/atrazine or mesotrione + atrazine applied POST have potential to provide good to excellent control of common cocklebur in corn under Ontario environmental conditions.


1994 ◽  
Vol 8 (3) ◽  
pp. 441-444 ◽  
Author(s):  
Eric P. Prostko ◽  
Joseph Ingerson-Mahar ◽  
Brad A. Majek

Field trials were conducted in New Jersey during 1991 and 1992 to evaluate the efficacy of nicosulfuron, primisulfuron, dicamba, and clopyralid on horsenettle control in field corn. Horsenettle biomass was reduced 74%, 68%, 64%, 61%, 48%, and 40% by primisulfuron + dicamba, primisulfuron, nicosulfuron + dicamba, dicamba, clopyralid, and nicosulfuron, respectively. No treatment was statistically more effective than dicamba. Corn yields were not influenced by the herbicide treatments. Horsenettle populations were not reduced by any treatment.


2018 ◽  
Vol 64 (No. 10) ◽  
pp. 479-483
Author(s):  
Tichý Lukáš ◽  
Jursík Miroslav ◽  
Kolářová Michaela ◽  
Hejnák Václav ◽  
Andr Jiří ◽  
...  

The aim of this work was to verify and assess the tolerance of the PR63E82 (ExpressSun) sunflower cultivar to tribenuron, propaquizafop and their tank-mix combination in two rates under various weather conditions. Three small-plot field trials were carried out on sunflower in Prague, Czech Republic, from 2015 to 2017. High phytotoxicity (25–56%) of tribenuron (TBM) + non-ionic surfactant was observed in 2015 and 2016 when the sunflower was sown in mid-April. In 2017, phytotoxicity was significantly lower (4–6%), probably due to a later sowing of sunflower (May), and hence higher temperatures. The main symptoms of TBM phytotoxicity were leaf chlorosis, necrosis and growth retardation. Propaquizafop (PQF) injury was minimal in 2015 and 2017. A higher phytotoxicity (10–13%) was recorded in 2016, probably due to a hail which occurred 2 days after T2 (second application term (sunflower BBCH 14)) application. Plant injury had puckered leaves and also made more side branches. TBM + PQF damaged sunflower plants most of the tested herbicide treatments (phytotoxicity 3–62%). High phytotoxicity caused stem branching, increased number of sunflower heads and decreased yield.  


2004 ◽  
Vol 18 (2) ◽  
pp. 443-453 ◽  
Author(s):  
Jerry L. Corbett ◽  
Shawn D. Askew ◽  
Walter E. Thomas ◽  
John W. Wilcut

Thirteen field trials were conducted in 1999 and 2000 to evaluate postemergence (POST) weed control with single applications of bromoxynil at 420 or 560 g ai/ha, glufosinate at 291 or 409 g ai/ha, glyphosate at 1,120 g ai/ha, pyrithiobac at 36 or 72 g ai/ha, or sulfosate at 1,120 g ai/ha. Additional treatments evaluated included two applications with glufosinate at both rates in all possible combinations, two applications of glyphosate, and two applications of sulfosate. Weeds were 2 to 5 cm or 8 to 10 cm tall for annual grass and broadleaf weeds whereas yellow nutsedge and glyphosate-resistant corn were 8 to 10 cm tall. All herbicide treatments controlled 2- to 5-cm common cocklebur, Florida beggarweed, jimsonweed, ladysthumb smartweed, Pennsylvania smartweed, pitted morningglory, prickly sida, redroot pigweed, smooth pigweed, and velvetleaf at least 90%. All herbicide treatments except pyrithiobac at either rate controlled 2- to 5-cm common lambsquarters, common ragweed, and tall morningglory at least 90%; pyrithiobac at the lower rate was the only treatment that failed to control entireleaf and ivyleaf morningglory at least 90%. Bromoxynil and pyrithiobac at either rate controlled 2- to 5-cm sicklepod 33 to 68% whereas glufosinate, glyphosate, and sulfostate controlled ≥99%. Glyphosate and sulfosate applied once or twice controlled hemp sesbania less than 70% and volunteer peanut less than 80%. Bromoxynil and pyrithiobac were the least effective treatments for control of annual grass species and bromoxynil controlled Palmer amaranth less than 80%. Glufosinate controlled broadleaf signalgrass, fall panicum, giant foxtail, green foxtail, large crabgrass, yellow foxtail, seedling johnsongrass, Texas panicum, and glyphosate-resistant corn at least 90% but controlled goosegrass less than 60%. Glyphosate and sulfosate controlled all grass species except glyphosate-resistant corn at least 90%. In greenhouse research, goosegrass could be controlled with glufosinate POST plus a late POST-directed treatment of prometryn plus monosodium salt of methylarsonic acid.


2013 ◽  
Vol 27 (3) ◽  
pp. 492-496 ◽  
Author(s):  
Holly P. Byker ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
François J. Tardif ◽  
Mark B. Lawton ◽  
...  

Herbicide-resistant crops, such as glyphosate-resistant (GR) soybean, allow for broad-spectrum, flexible weed control with minimal crop injury; however, the development of GR weeds, such as horseweed, has forced reliance on alternative herbicides for control of these weeds. While preplant (PP) herbicides provide excellent control of GR-horseweed, there are currently no POST herbicide control options within soybean. The objective of this study was to evaluate the efficacy of dicamba for the control of GR-horseweed when applied PP, POST, and sequentially in dicamba-resistant soybean. Dicamba applied PP at 600 g a.e. ha−1provided 90 to 100% control of GR-horseweed 8 wk after application (WAA) across three field trials conducted in Ontario in 2011 and 2012. Similarly, sequential applications provided 91 to 100% control. This technology provides a much-needed POST option of dicamba to be applied as a rescue treatment to control weed escapes caused by late emergence or poor initial control following a PP herbicide application.


2009 ◽  
Vol 23 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Scott L. Bollman ◽  
Christy L. Sprague

Field trials were conducted to determine if tillage and soil-applied herbicides had an effect on weed control and sugarbeet growth with a micro-rate herbicide program. Sugarbeet emergence was earlier in the moldboard plowed system compared with the chisel plowed system at three of four sites. Conditions were dry and sugarbeets emerged 5 d later in the moldboard plowed system compared with the chisel plowed system at the fourth site. Even though the rate of sugarbeet emergence differed between tillage systems at all four sites, final sugarbeet populations did not differ at two of the four sites. Sugarbeet injury from PRE treatments ofS-metolachlor, ethofumesate, and ethofumesate plus pyrazon, followed by four POST micro-rate applications, ranged from 11 to 27% and 1 to 18% in the chisel and moldboard plowed systems, respectively, 6 wk after planting (WAP). Under wet conditions, sugarbeet stand was reduced and injury was greatest from PRE applications ofS-metolachlor. Common lambsquarters, pigweed (redroot pigweed and Powell amaranth), and giant foxtail control in mid-August was consistently higher when a PRE herbicide was applied prior to micro-rate herbicide treatments. Even though there were differences between PRE and no-PRE treatments with respect to sugarbeet injury and weed control, recoverable white sucrose yield did not differ between herbicide treatments. However, recoverable white sucrose yield was greater in the moldboard plowed treatments compared with the chisel plowed treatments at three out of the four sites.


2014 ◽  
Vol 94 (7) ◽  
pp. 1239-1244 ◽  
Author(s):  
Kimberly D. Walsh ◽  
Nader Soltani ◽  
Lynette R. Brown ◽  
Peter H. Sikkema

Walsh, K. D., Soltani, N., Brown, L. R. and Sikkema, P. H. 2014. Weed control with postemergence glyphosate tank mixes in glyphosate-resistant soybean. Can. J. Plant Sci. 94: 1239–1244. Six field trials were conducted over a 3-yr period (2011, 2012 and 2013) in Ontario, Canada, to evaluate various postemergence (POST) glyphosate tank mixes for weed management in glyphosate-resistant (GR) soybean. Herbicide treatments included glyphosate applied alone or mixed with acifluorfen, fomesafen, bentazon and thifensulfuron-methyl. Glyphosate tank mixtures with acifluorfen, fomesafen, bentazon and thifensulfuron-methyl caused GR soybean injury of up to 21, 11, 4 and 14% at 7 d after treatment (DAT), which was reduced to 5, 0, 0 and 2% by 28 DAT, respectively. Velvetleaf, green pigweed, common ragweed and common lambsquarters control ranged from 55 to 95, 93 to 100, 70 to 92 and 81 to 98% at 28 DAT respectively. Relative to glyphosate alone, tank mixtures with thifensulfuron-methyl provided equivalent to increased weed control, while acifluorfen, fomesafen and bentazon provided equivalent to reduced weed control. All herbicide tank mixtures resulted in higher yields (3.8–4.0 t ha−1) than the untreated check (2.7 t ha−1), and were generally equivalent to glyphosate alone (4.1 t ha−1). Results from this study indicate that the glyphosate tank mixtures evaluated did not provide a benefit over glyphosate alone.


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