Efficacy of Tiafenacil Applied Preplant Alone or Mixed with Metribuzin for Glyphosate-Resistant Horseweed Control in Soybean

2021 ◽  
pp. 1-21
Author(s):  
David B. Westerveld ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Peter H. Sikkema
Keyword(s):  
Effective Dose ◽  
Management Strategy ◽  
Field Experiments ◽  
Biologically Effective Dose ◽  
Potential Utility ◽  
Industry Standard ◽  
No Till ◽  
Industry Standards ◽  
Herbicide Treatments ◽  
Chemical Class

Abstract Tiafenacil is a recently developed protoporphyrinogen IX oxidase (PPO)-inhibiting herbicide from the pyrimidinedione chemical class that is proposed for use as a preplant (PP) burndown in soybean. Glyphosate-resistant (GR) horseweed is a troublesome weed often found in no-till systems that can dramatically reduce soybean yield; control in soybean has been variable. Five field experiments were conducted over 2019 and 2020 in commercial soybean fields with GR horseweed to determine the biologically-effective-dose (BED) of tiafenacil and tiafenacil + metribuzin, and to compare their efficacy to currently accepted industry standard herbicide treatments in identity-preserved (IP, non-GMO), GR, and glyphosate/dicamba-resistant (GDR) soybean systems. There was no soybean injury with treatments evaluated. The calculated doses of tiafenacil for 50, 80, and 95% control of GR horseweed control were 21, 147 and >200 g ai ha−1, respectively, at 8 weeks after application (WAA). Lower doses were calculated with the addition of metribuzin (400 g ai ha−1) to tiafenacil for 50 and 80% control, with no dose of tiafenacil + metribuzin providing 95% control. Tiafenacil + metribuzin at 25 + 400 and 50 + 400 g ai ha−1 controlled GR horseweed 88 and 93% , respectively which was similar to the industry standards of saflufenacil + metribuzin (25 + 400 g ai ha−1) and glyphosate/dicamba + saflufenacil (1200/600 + 25 g ai ha−1) that provided 98 to 100% control, respectively at 8 WAA. This study presents the potential utility of tiafenacil + metribuzin as a GR horseweed management strategy in soybean.

Biologically-effective-dose of pyraflufen-ethyl/2,4-D, applied preplant alone or mixed with metribuzin on glyphosate-resistant horseweed in soybean

2021 ◽  
pp. 1-20
Author(s):  
David B. Westerveld ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Peter H. Sikkema
Keyword(s):  
Effective Dose ◽  
Field Experiments ◽  
Glyphosate Resistance ◽  
Biologically Effective Dose ◽  
Weed Species ◽  
Visible Injury ◽  
Industry Standards

Abstract Glyphosate resistance in weed species has presented immense challenges for farmers in Ontario. The co-application of burndown plus residual herbicides provides control of glyphosate-resistant (GR) horseweed control in soybean. Pyraflufen-ethyl/2,4-D is a premixed herbicide formulation sold under the tradename Blackhawk®. Five field experiments were conducted over a two-year period (2019, 2020) in fields in southwestern Ontario to ascertain the biologically-effective-dose of pyraflufen-ethyl/2,4-D, applied alone, or mixed with metribuzin, for GR horseweed control when applied pre-plant to soybean. Soybean visible injury for all treatments was <15%. At 8 wk after application (WAA), the calculated doses of pyraflufen-ethyl/2,4-D for 50, 80, and 95% GR horseweed control were 390, 1148, and >2108 g ha−1, respectively. The addition of metribuzin to pyraflufen-ethyl/2,4-D reduced the doses of pyraflufen-ethyl/2,4-D for 50, 80, and 95% GR horseweed control to 19, 46 and 201 g ha−1, respectively. Pyraflufen-ethyl/2,4-D + metribuzin controlled GR horseweed 97% which is comparable to the current industry standards. Based on these results, pyraflufen-ethyl/2,4-D + metribuzin (527 + 400 g ha−1) applied preplant can be used for GR horseweed control in soybean.

Biologically effective dose of bromoxynil applied alone and mixed with metribuzin for the control of glyphosate-resistant horseweed in soybean

2021 ◽  
pp. 1-6
Author(s):  
David B. Westerveld ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Peter H. Sikkema
Keyword(s):  
Photosystem Ii ◽  
Effective Dose ◽  
Weed Control ◽  
Field Experiments ◽  
Biologically Effective Dose ◽  
Soybean Yield ◽  
Industry Standards ◽  
Excellent Control

Abstract Glyphosate-resistant (GR) horseweed was first confirmed in Ontario in 2010. GR horseweed interference can reduce soybean yield by up to 97%. Bromoxynil is a photosystem II–inhibiting herbicide that is primarily used for annual broadleaf weed control in monocot crops. The objective of this study was to determine the biologically effective dose (BED) of bromoxynil applied alone and when mixed with metribuzin applied preplant for control of GR horseweed in soybean in Ontario. Five field experiments were conducted over a 2-yr period (2019–2020) to determine the predicted dose of bromoxynil with or without metribuzin that would control GR horseweed 50%, 80%, and 95%. No soybean injury was observed. The predicted doses of bromoxynil to achieve 50% and 80% control of GR horseweed were 98 and 277 g ai ha−1, respectively, at 8 wk after application (WAA). When mixed with metribuzin (400 g ai ha−1), the predicted doses of bromoxynil for 50%, 80%, and 95% control of GR horseweed were 10, 25, and 54 g ai ha−1, respectively. Bromoxynil (280 g ai ha−1) plus metribuzin (400 g ai ha−1) controlled GR horseweed 97%, a finding that was similar to the industry standards of saflufenacil + metribuzin (99% control) and glyphosate/dicamba + saflufenacil (100% control) at 8 WAA. This study concludes that bromoxynil + metribuzin applied before planting provides excellent control of GR horseweed in soybean.

Johnsongrass Control with DPX-V9360 and CGA-136872 in Corn (Zea mays) in Virginia

1990 ◽  
Vol 4 (3) ◽  
pp. 615-619 ◽  
Author(s):  
Chester L. Foy ◽  
Harold L. Witt
Keyword(s):  
Zea Mays ◽  
Field Experiments ◽  
Crop Yields ◽  
Crop Damage ◽  
Field Corn ◽  
No Till ◽  
Herbicide Treatments

Five field experiments were conducted at two locations in Virginia during 1988–89 to evaluate DPX-V9360 and CGA-136872 for postemergence control of johnsongrass in field corn grown under no-till and conventional conditions. DPX-V9360 at rates of 35 (except in no-till plots), 52, and 69 g ai ha-1applied to 8-leaf johnsongrass was 88 to 98% effective in 1988. CGA-136872 at 25, 49, and 99 g ha-1was 80% effective at the highest rate. Applications of these herbicides to 6-leaf johnsongrass resulted in 69% or less control. DPX-V9360 at 35, 52, and 69 g ha-1and CGA-136872 at 20 and 40 g ha-1applied to johnsongrass up to 48 cm in height provided 77 to 97% control at 7 WAT3in an excellent stand of conventionally planted corn during 1989. Crop yields were more than doubled with herbicide treatments relative to yields in control plots. At a second location where crop damage caused by other factors resulted in a weak stand, DPX-V9360 provided 61 to 96% control compared to 29 to 56% control with CGA-136872.

scholarly journals A linuron-free weed management strategy for carrots

2019 ◽  
Vol 33 (03) ◽  
pp. 464-474
Author(s):  
Tessa de Boer ◽  
Peter Smith ◽  
Kevin Chandler ◽  
Robert Nurse ◽  
Kristen Obeid ◽  
...  
Keyword(s):  
Effective Dose ◽  
Pest Management ◽  
Weed Management ◽  
Management Strategy ◽  
Seedling Emergence ◽  
Growing Season ◽  
Field Trials ◽  
Organic Soils ◽  
Biologically Effective Dose ◽  
And Control

AbstractThe development of a linuron-free weed management strategy for carrot production is essential as a result of the herbicide reevaluation programs launched by the Pest Management Regulatory Agency in Canada for herbicides registered before 1995 and the discovery of linuron-resistant pigweed species in Ontario. Field trials were conducted in one of Ontario’s main carrot-growing regions on high organic soils in 2016 and 2017. Pigweed species seedlings were effectively controlled with PRE treatments of prometryn, pendimethalin, S-metolachlor, or glufosinate. POST treatments of pyroxasulfone and metribuzin followed by predetermined biologically effective dose (≥90% control of pigweed seedlings) of acifluorfen, oxyfluorfen, fluthiacet-methyl, and fomesafen achieved excellent crop selectivity and commercially acceptable pigweed species seedling control under field conditions. Carfentrazone-ethyl or fomesafen applied PRE severely reduced seedling emergence and yield in the wet growing season of 2017. This study demonstrated clearly that an alternative linuron-free strategy can be developed for carrots. The strategy of exploring the potential to use the biologically effective dose of selected herbicides to achieve crop selectivity and control of pigweed species seedlings was verified.

Weed Control and Yield are Equal in Conventional, Reduced-, and No-Tillage Soybean (Glycine max) After 11 Years

1993 ◽  
Vol 7 (2) ◽  
pp. 443-451 ◽  
Author(s):  
George Kapusta ◽  
Ronald F. Krausz
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Early Spring ◽  
No Tillage ◽  
Weed Species ◽  
Tillage Systems ◽  
No Till ◽  
Giant Foxtail ◽  
Herbicide Treatments ◽  
Excellent Control

Field experiments were conducted from 1979 to 1989 to determine the influence of conventional, reduced, and no-tillage systems and different herbicide combinations on weed species and population, weed control, and soybean injury, population, and yield. In no-till (NT) non-treated plots, there was an abrupt shift from horseweed as the dominant early spring emerging weed to gray goldenrod in 1985. Following its initial observation, gray goldenrod became the dominant species within 2 yr, with giant foxtail as the only other species observed in these plots. Giant foxtail was the dominant weed species from 1980 to 1989 in conventional till (CT) and reduced-till (RT) plots. There also was a shift in the frequency of occurrence and in density of several broadleaf weed species during the 11-yr study. Most herbicides provided excellent control of all weeds in all tillage systems, especially those that included POST herbicides. There was little difference between glyphosate and paraquat in controlling weeds present at the time of planting in NT. PRE herbicides caused 2 to 9% soybean injury with slightly greater injury occurring in CT and RT than in NT. The POST broadleaf herbicides did not significantly increase soybean injury. There were no differences in soybean population or yield among the herbicide treatments regardless of tillage. There also was no difference in soybean population or yield in NT compared with CT when averaged over all herbicide treatments.

Multiple herbicide-resistant horseweed (Conyza canadensis) dose response to tolpyralate and tolpyralate plus atrazine and comparison to industry standard herbicides in corn

2019 ◽  
Vol 33 (2) ◽  
pp. 366-373 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Conyza Canadensis ◽  
Biologically Effective Dose ◽  
Herbicide Resistant ◽  
Field Crops ◽  
Industry Standard ◽  
Excellent Control ◽  
Management Challenge

AbstractHorseweed biotypes resistant to glyphosate and ALS-inhibiting herbicides are becoming more prevalent in Canada and the United States and present a significant management challenge in field crops. Tolpyralate is a recently commercialized herbicide for use in corn that inhibits 4-hydroxyphenylpyruvate dioxygenase (HPPD), and there is little information regarding its efficacy on horseweed. Six field experiments were conducted in 2017 and 2018 at four locations in Ontario, Canada, to determine the biologically effective dose of tolpyralate and tolpyralate + atrazine and to compare label rates of tolpyralate and tolpyralate + atrazine to currently accepted herbicide standards for POST control of glyphosate and cloransulam-methyl resistant (MR) horseweed. At 8 wk after application (WAA), tolpyralate at 4.8 and 22.6 g ha–1provided 50% and 80% control, respectively. When applied with atrazine at a 1:33.3 tank-mix ratio, 22.3 + 741.7 g ha–1provided 95% control of MR horseweed. The addition of atrazine to tolpyralate at label rates improved control of MR horseweed to 98%, which was similar to the control provided by dicamba:atrazine and bromoxynil + atrazine. The results of this study indicate that tolpyralate + atrazine provides excellent control of MR horseweed POST in corn.

Biologically Effective Dose and Selectivity of SAN 1269H (BAS 662H) for Weed Control in Corn (Zea mays)

1999 ◽  
Vol 13 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Peter H. Sikkema ◽  
Stevan Z. Knezevic ◽  
Allan S. Hamill ◽  
François J. Tardif ◽  
Kevin Chandler ◽  
...  
Keyword(s):  
Effective Dose ◽  
Weed Control ◽  
Field Experiments ◽  
Leaf Growth ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Biologically Effective Dose ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Wild Buckwheat

Field experiments were conducted in 1996 and 1997 at five locations in southwestern Ontario to develop dose-response curves for SAN 1269H (SAN 835H plus dicamba) for weed control and crop tolerance in corn. SAN 1269H controlled wild buckwheat (Polygonum convolvulusL.), common ragweed (Ambrosia artemisiifoliaL.), common lambsquarters (Chenopodium albumL.), pigweeds (Amaranthus retroflexusL. andA. powelliiS. Wats.), barnyardgrass [Echinochloa crus-galli(L.) Beauv.], and yellow foxtail [Setaria glauca(L.) Beauv.]. Biologically effective doses of SAN 1269H (BAS 662H) were 440, 430, 180, and 40 g/ha for yellow foxtail, barnyard grass, wild buckwheat, and common ragweed, respectively. The biologically effective dose (that which provides 90% reduction in weed dry matter) for common lambsquarters was 560 g/ha when SAN 1269H was applied preemergence (PRE) and 110 g/ha when applied postemergence (POST). When applied PRE at a rate of 420 g/ha, pigweed was controlled, whereas only 85 g/ha was required when applied POST. Grain yield increased with dose of SAN 1269H and did not differ with time of application. Temporary crop injury was observed when SAN 1269H was applied at the four- to six-leaf growth stage. Optimum corn yields were achieved with doses of 100 to 250 g/ha.

Biologically-Effective-Dose of Metribuzin, Applied Preemergence and Postemergence, for the Control of Waterhemp (Amaranthus tuberculatus) with Different Mechanisms of Resistance to Photosystem II-inhibiting herbicides

Weed Science ◽  
2021 ◽  
pp. 1-34
Author(s):  
David B. Westerveld ◽  
Nader Soltani ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
Patrick J. Tranel ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Effective Dose ◽  
Field Experiments ◽  
Target Site ◽  
Biologically Effective Dose ◽  
Ps Ii ◽  
Calculated Dose ◽  
Amaranthus Tuberculatus ◽  
Target Site Resistance ◽  
Effective Doses

Abstract Photosystem II (PS II)-inhibitor herbicide resistance in Ontario waterhemp [Amaranthus tuberculatus (Moq.) Sauer] population is conferred via target-site resistance (TSR) and non-target-site resistance (NTSR) mechanisms. Metribuzin-resistant (MR) A. tuberculatus is due to TSR,. Conversely, in other populations of PS II-resistant A. tuberculatus, plants are resistant to atrazine but metribuzin-sensitive (MS). The objective of this study was to determine the biologically-effective-dose of metribuzin applied PRE and POST for the control of MS and MR A. tuberculatus. Ten field experiments were conducted in 2019 and 2020 to determine the effective doses of metribuzin for 50, 80, and 95% control of MS and MR A. tuberculatus. Metribuzin applied PRE at the calculated doses of 133, 350, and 1070 g ai ha-1 controlled MS A. tuberculatus 50, 80, and 95%, respectively, whereas the calculated doses of 7868 and 17533 g ai ha-1 controlled MR A. tuberculatus 50 and 80%, respectively at 12 WAA. Metribuzin applied POST at the calculated doses of 245 and 1480 g ai ha-1 controlled MS A. tuberculatus 50 and 80%, respectively; the calculated dose for 50% MR A. tuberculatus control was greater than the highest dose (17920 g ai ha-1) included in this study. Metribuzin at 560 and 1120 g ha-1 and pyroxasulfone/flumioxazin (240 g ai ha-1) applied PRE controlled MS A. tuberculatus 88, 95, and 98%, respectively at 12 WAA. The aforementioned treatments controlled MR A. tuberculatus 0, 4, and 93%, respectively at 12 WAA. Metribuzin at 560 and 1120 g ha-1 and fomesafen (240 g ai ha-1) applied POST controlled MS A. tuberculatus 65, 70, and 78%, and MR A. tuberculatus 0, 1, and 49%, respectively at 12 WAA. Based on these results, NTSR PS II-resistant A. tuberculatus (enhanced metabolism) is controlled with metribuzin applied PRE and POST, in contrast TSR PS II-resistant A. tuberculatus (glycine264serine altered target site) is not controlled with metribuzin.

Herbicide Treatments for No-Till Alfalfa, Medicago sativa L., Establishment in Sod

1988 ◽  
Vol 2 (3) ◽  
pp. 327-332 ◽  
Author(s):  
Edward S. Hagood
Keyword(s):  
Nonionic Surfactant ◽  
Tall Fescue ◽  
Seedling Establishment ◽  
Field Experiments ◽  
Ground Cover ◽  
Forage Yield ◽  
No Till ◽  
Herbicide Treatments ◽  
Medicago Sativa L ◽  
Control Equivalent

Field experiments were established to evaluate the effect of herbicide treatments on control of tall fescue before spring or fall no-till alfalfa planting and to determine the effect of fescue control on alfalfa seedling establishment, forage yield, and forage quality. No treatment provided significantly greater tall fescue control than the standard two applications of paraquat at 13- to 21-day intervals. Fescue control values with this treatment ranged from 86 to 99% over experiments and were associated with maximum values for alfalfa ground-cover and alfalfa yield percentage parameters, 52 to 83% and 64 to 96%, respectively. Glyphosate and SC-0224 at 2.2 kg/ha and greater generally gave tall fescue control equivalent to the paraquat treatment in both spring and fall seedings as did sethoxydim at 0.6 kg/ha in spring seedings. Applications of fluazifop or HOE-0661 did not result in satisfactory tall fescue control or alfalfa establishment. Adding nonionic surfactant to glyphosate or SC-0224 did not increase tall fescue control. There was a direct linear relationship between tall fescue control and both alfalfa seedling establishment and yield percentage.

scholarly journals Biologically effective dose correlates with linear tumor volume changes after upfront single-fraction stereotactic radiosurgery for vestibular schwannomas

2021 ◽  
Author(s):  
Constantin Tuleasca ◽  
Mohamed Faouzi ◽  
Philippe Maeder ◽  
Raphael Maire ◽  
Jonathan Knisely ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Effective Dose ◽  
Stereotactic Radiosurgery ◽  
Tumor Volume ◽  
Vestibular Schwannomas ◽  
Benign Tumors ◽  
Biologically Effective Dose ◽  
Volume Changes ◽  
Single Fraction

AbstractVestibular schwannomas (VSs) are benign, slow-growing tumors. Management options include observation, surgery, and radiation. In this retrospective trial, we aimed at evaluating whether biologically effective dose (BED) plays a role in tumor volume changes after single-fraction first intention stereotactic radiosurgery (SRS) for VS. We compiled a single-institution experience (n = 159, Lausanne University Hospital, Switzerland). The indication for SRS was decided after multidisciplinary discussion. Only cases with minimum 3 years follow-up were included. The Koos grading, a reliable method for tumor classification was used. Radiosurgery was performed using Gamma Knife (GK) and a uniform marginal prescription dose of 12 Gy. Mean BED was 66.3 Gy (standard deviation 3.8, range 54.1–73.9). The mean follow-up period was 5.1 years (standard deviation 1.7, range 3–9.2). The primary outcome was changes in 3D volumes after SRS as function of BED and of integral dose received by the VS. Random-effect linear regression model showed that tumor volume significantly and linearly decreased over time with higher BED (p < 0.0001). Changes in tumor volume were also significantly associated with age, sex, number of isocenters, gradient index, and Koos grade. However, the effect of BED on tumor volume change was moderated by time after SRS and Koos grade. Lower integral doses received by the VSs were inversely correlated with BED in relationship with tumor volume changes (p < 0.0001). Six (3.4%) patients needed further intervention. For patients having uniformly received the same marginal dose prescription, higher BED linearly and significantly correlated with tumor volume changes after SRS for VSs. BED could represent a potential new treatment paradigm for patients with benign tumors, such as VSs, for attaining a desired radiobiological effect. This could further increase the efficacy and decrease the toxicity of SRS not only in benign tumors but also in other SRS indications.

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