Glyphosate-resistant Canada fleabane [Conyza canadensis (L). Cronq.]: Dose response to glyphosate and control with postemergence herbicides in soybean in Ontario

2013 ◽  
Vol 93 (6) ◽  
pp. 1187-1193 ◽  
Author(s):  
Holly P. Byker ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
François J. Tardif ◽  
Mark B. Lawton ◽  
...  
Keyword(s):  
Effective Dose ◽  
Dose Response ◽  
Yield Loss ◽  
Field Studies ◽  
Conyza Canadensis ◽  
Biologically Effective Dose ◽  
Soybean Yield ◽  
And Control ◽  
Postemergence Herbicides

Byker, H. P., Soltani, N., Robinson, D. E., Tardif, F. J., Lawton, M. B. and Sikkema, P. H. 2013. Glyphosate-resistant Canada fleabane [ Conyza canadensis (L). Cronq.]: Dose response to glyphosate and control with postemergence herbicides in soybean in Ontario. Can. J. Plant Sci. 93: 1187–1193. Glyphosate-resistant (GR) Canada fleabane was first reported in Ontario in 2010. Twelve field studies were conducted over a 2-yr period (2011, 2012) to determine the biologically effective dose of glyphosate in the field and to determine the efficacy of postemergence herbicides for control of GR Canada fleabane. A dose between 1271 and 5652 g a.e. ha−1 was required for a 50% reduction in Canada fleabane biomass depending on site and year. To achieve acceptable (>95%) control with glyphosate, 18 840 to 43 200 g a.e. ha−1 of glyphosate was required across all sites. Therefore application of glyphosate at these doses for acceptable (>95%) control is not economical. None of the postemergence herbicides labeled for use in soybean provided acceptable (>95%) control, with cloransulam providing the greatest control (67%) 4 wk after application. Therefore, GR Canada fleabane must be controlled prior to soybean emergence as current herbicides registered in soybean for postemergence use do not provide sufficient control to prevent soybean yield loss.

scholarly journals Glyphosate-Resistant Giant Ragweed (<i>Ambrosia trifida</i> L.) in Ontario: Dose Response and Control with Postemergence Herbicides

2012 ◽  
Vol 03 (05) ◽  
pp. 608-617 ◽  
Author(s):  
Joseph P. Vink ◽  
Nader Soltani ◽  
Darren E. Robinson ◽  
François J. Tardif ◽  
Mark B. Lawton ◽  
...  
Keyword(s):  
Dose Response ◽  
Ambrosia Trifida ◽  
Giant Ragweed ◽  
And Control ◽  
Postemergence Herbicides

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.

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.

Herbicide-Resistant Canola (Brassica napus) Response and Weed Control with Postemergence Herbicides

2006 ◽  
Vol 20 (3) ◽  
pp. 551-557 ◽  
Author(s):  
Timothy L. Grey ◽  
Paul L. Raymer ◽  
David C. Bridges
Keyword(s):  
Weed Control ◽  
Field Studies ◽  
Italian Ryegrass ◽  
Wild Radish ◽  
Application Timing ◽  
Herbicide Resistant ◽  
Naturally Occurring ◽  
And Control ◽  
Postemergence Herbicides ◽  
Significant Injury

Field studies were conducted to evaluate weed control in herbicide-resistant canola in Georgia. The resistant canola cultivars and respective herbicides were ‘Pioneer 45A76’ and imazamox, ‘Hyola 357RR’ and glyphosate, and ‘2573 Invigor’ and glufosinate. Weed seed of Italian ryegrass and wild radish were sown simultaneously in October with canola and control of these species was evaluated along with other naturally occurring weeds. Herbicide treatments for the respective herbicide-resistant canola cultivar were imazamox at 0.035 and 0.071 kg ai/ha, glyphosate at 0.84 and 1.64 kg ae/ha, and glufosinate at 0.5 and 1.0 kg ai/ha. Herbicides were applied at one– two-leaf (LF) and three–four-LF canola stages. There was no significant injury to any canola cultivar as a result of herbicide rate or timing of application. By midseason (February), imazamox effectively controlled wild radish, henbit, and shepherd's-purse at both rates and at both timings. When applied to three–four-LF canola, the higher rates of glyphosate and glufosinate were required to provide 75% or greater control of Italian ryegrass, wild garlic, and henbit. Glufosinate did not adequately control wild radish at either rate or application timing. Greenhouse experiments provided similar results.

Glyphosate-Resistant Horseweed (Conyza canadensis) Growth, Seed Production, and Interference in Cotton

Weed Science ◽  
2009 ◽  
Vol 57 (3) ◽  
pp. 346-350 ◽  
Author(s):  
Lawrence E. Steckel ◽  
C. Owen Gwathmey
Keyword(s):  
Seed Production ◽  
Yield Loss ◽  
Maximum Yield ◽  
Field Studies ◽  
Lint Yield ◽  
Growth Stages ◽  
Conyza Canadensis ◽  
Cotton Lint ◽  
Cotton Lint Yield ◽  
A Site

Field studies were conducted to examine both density and duration of glyphosate-resistant (GR) horseweed interference in cotton. Two studies, one examining the effect of horseweed density and a second the duration of horseweed interference, were conducted on a site with a natural population of horseweed that were treated with glyphosate at 0.84 kg ae ha−1prior to planting and at the 2nd and 4th cotton node growth stages. GR horseweed density effect on cotton height, maturity, and lint yield was determined at horseweed densities of 0, 5, 10, 15, 20, and 25 plants m−2. Duration of horseweed interference was evaluated when 20 horseweed m−2were allowed to interfere with cotton from emergence to 2nd node, 6th node, 10th node, 12th node, and 1st bloom stage of cotton. The maximum cotton lint yield loss (46%) occurred when horseweed was allowed to compete with cotton from emergence to maturity at the two highest densities (20 and 25 horseweed m−2). When the data were fit to the Cousens model the estimateda(maximum yield loss) andi(yield loss per unit density as density approaches zero) were 53 ± 7.3 and 2.8 ± 0.6 SE, respectively. In both years of the study, horseweed interference from emergence to the 2nd cotton node did not reduce cotton lint yields. In 2006, cotton lint yield loss was 28% compared to 39% in 2005 when horseweed interfered with cotton from emergence until the 6th cotton node. Cotton lint yield loss was 37 and 44% when horseweed competed to the 8th cotton node in 2005 and 2006, respectively. Maximum horseweed seed production was 134,000 to 148,000 seeds m−2.

scholarly journals Halosulfuron Tank Mixtures and Adjuvants for Weed Control in Pumpkin Production

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1823-1825 ◽  
Author(s):  
Katie J. Kammler ◽  
S. Alan Walters ◽  
Bryan G. Young
Keyword(s):  
Nonionic Surfactant ◽  
Weed Control ◽  
Cucurbita Pepo ◽  
Field Studies ◽  
Digitaria Sanguinalis ◽  
Free Treatment ◽  
Herbicide Treatments ◽  
And Control ◽  
Postemergence Herbicides

Field studies were conducted to evaluate postemergence combinations of halosulfuron plus sethoxydim or clethodim with various adjuvants for effects on jack-o-lantern pumpkin (Cucurbita pepo L.) injury and yields and control of large [Digitaria sanguinalis (L.) Scop.] and smooth crabgrass [D. ischaemum (Schreb. ex Schweig.) Schreb. ex Muhl.]. Halosulfuron caused 27% and 14% pumpkin injury at 28 d after postemergence treatment (DAPT) in 2004 and 2005, respectively. Tank-mixing sethoxydim or clethodim with halosulfuron did not increase pumpkin injury compared with halosulfuron alone. Pumpkin injury from sethoxydim and clethodim alone at 28 DAPT ranged from 19% to 23% in 2004, but was only 7% to 8% in 2005. The addition of oil-based adjuvants to halosulfuron did not affect pumpkin injury compared with using a nonionic surfactant (NIS). The tank mixture of halosulfuron and sethoxydim did not affect crabgrass control regardless of adjuvant. However, the addition of halosulfuron to clethodim plus NIS reduced control of crabgrass from 89% to 77% at 28 DAPT. Crabgrass control was unaffected by the addition of halosulfuron to clethodim with crop oil concentrate (COC) or a NIS/COC blend. None of the herbicide treatments provided pumpkin yield (fruit no./ha) similar to the weed-free control. The pumpkin yield of treatments using postemergence herbicides was at least 50% less than the weed-free treatment. These low pumpkin yields were most likely the result of the combination of pumpkin injury from the herbicide applications and insufficient weed control.

ECONOMIC THRESHOLD FOR PLANT BUGS, LYGUS SPP. (HETEROPTERA: MIRIDAE), IN CANOLA

1998 ◽  
Vol 130 (6) ◽  
pp. 825-836 ◽  
Author(s):  
I.L. Wise ◽  
R.J. Lamb
Keyword(s):  
Brassica Napus ◽  
Brassica Rapa ◽  
Chemical Control ◽  
Yield Loss ◽  
Field Studies ◽  
Single Application ◽  
Economic Threshold ◽  
Bud Formation ◽  
Economic Thresholds ◽  
And Control

AbstractPlant bugs in the genus Lygus infest canola (Brassica napus L. and Brassica rapa L.) when the crop is producing buds, flowers, and pods. Field studies in cages and open plots show that plant bugs can reduce yield by 20% or more, but have little effect on seed size. A single application of a foliar insecticide when the crop has finished flowering and is beginning to produce pods will prevent most or all of the yield loss. The yield loss of canola that can be prevented by control is 0.007 t/ha per plant bug per 10 sweeps sampled at the end of flowering or the beginning of pod formation. The yield loss that can be prevented by a later application drops to 0.005 t/ha. When precipitation is greater than 100 mm from the onset of bud formation to the end of flowering, the crop may partially compensate for plant bug damage. The economic threshold for control of plant bugs in canola at the end of flowering or at the beginning of pod formation is 15 plant bugs per 10 sweeps, based on crop prices and control costs from 1989 to 1992. If plant bugs are present but control is not warranted when most flowering is complete, plant bug densities should be assessed again 5–7 days later as pods develop, but at this stage the threshold is 20 plant bugs per 10 sweeps. The use of economic thresholds for chemical control of plant bugs will maximize seed yield and minimize unnecessary or ineffectively timed insecticide applications.

Characterization of carinata tolerance to select herbicides using field dose-response studies

2021 ◽  
pp. 1-26
Author(s):  
Sandra R. Ethridge ◽  
Angela Post ◽  
Pratap Devkota ◽  
Michael J. Mulvaney ◽  
Ramon G. Leon
Keyword(s):  
Population Density ◽  
Dose Response ◽  
Field Experiments ◽  
Relative Yield ◽  
Field Studies ◽  
Yield Losses ◽  
Control Volunteer ◽  
Postemergence Herbicides ◽  
Response Field

Abstract Field experiments were conducted from 2017 to 2019 to determine the tolerance of carinata to several preemergence and postemergence herbicides. Preliminary screenings identified herbicides which caused large variation on carinata injury, indicating the potential for selectivity. Dose-response field studies were conducted to quantify the tolerance of carinata to select herbicides. Diuron applied preemergence at rates of 280 g ai ha−1 or above reduced carinata population density 54% to 84% compared to the nontreated control. In certain locations, clomazone applied preemergence caused minor injury with an acceptable level of carinata tolerance and only doses above 105 g ai ha−1 caused yield reductions. Napropamide doses of 2,856 g ai ha−1 or higher applied preemergence caused at least 25% injury to carinata; however, the damage was not severe enough to reduce yields. Simazine applied postemergence at rates above 1,594 g ai ha−1 caused 50% or more injury, resulting in yield losses ranging from 0 to 95% depending on location. Clopyralid applied postemergence at 2,512 g ai ha−1 caused 25% injury with relative yield reductions which varied across locations. The present study identified clomazone and napropamide applied preemergence, and clopyralid applied postemergence as potential herbicides for weed control in carinata. In contrast, diuron, simazine, metribuzin, imazethapyr, and chlorimuron caused high levels of carinata mortality and can be used to control volunteer carinata plants in rotational crops.

Characterization of multiple herbicide–resistant waterhemp (Amaranthus tuberculatus) populations from Illinois to VLCFA-inhibiting herbicides

Weed Science ◽  
2019 ◽  
Vol 67 (4) ◽  
pp. 369-379 ◽  
Author(s):  
Seth A. Strom ◽  
Lisa C. Gonzini ◽  
Charlie Mitsdarfer ◽  
Adam S. Davis ◽  
Dean E. Riechers ◽  
...  
Keyword(s):  
Dose Response ◽  
Field Experiments ◽  
Survival Rates ◽  
Acetolactate Synthase ◽  
Field Studies ◽  
Complete Control ◽  
Herbicide Resistant ◽  
Amaranthus Tuberculatus ◽  
Als Inhibitors ◽  
And Control

AbstractField experiments were conducted in 2016 and 2017 in Champaign County, IL, to study a waterhemp [Amaranthus tuberculatus (Moq.) J. D. Sauer] population (CHR) resistant to 2,4-D and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-, photosystem II–, acetolactate synthase (ALS)-, and protoporphyrinogen oxidase–inhibiting herbicides. Two field experiments were designed to investigate the efficacy of very-long-chain fatty-acid (VLCFA)-inhibiting herbicides, including a comparison of active ingredients at labeled use rates and a rate titration experiment. Amaranthus tuberculatus density and control were evaluated at 28 and 42 d after treatment (DAT). Nonencapsulated acetochlor, alachlor, and pyroxasulfone provided the greatest PRE control of CHR (56% to 75%) at 28 DAT, while metolachlor, S-metolachlor, dimethenamid-P, and encapsulated acetochlor provided less than 27% control. In the rate titration study, nonencapsulated acetochlor controlled CHR more than equivalent field use rates of S-metolachlor. Subsequent dose–response experiments with acetochlor, S-metolachlor, dimethenamid-P, and pyroxasulfone in the greenhouse included three multiple herbicide–resistant (MHR) A. tuberculatus populations: CHR-M6 (progeny generated from CHR), MCR-NH40 (progeny generated from Mclean County, IL), and ACR (Adams County, IL), in comparison with a sensitive population (WUS). Both CHR-M6 and MCR-NH40 are MHR to atrazine and HPPD, and ALS inhibitors and demonstrated higher survival rates (LD50) to S-metolachlor, acetochlor, dimethenamid-P, or pyroxasulfone than ACR (atrazine resistant but HPPD-inhibitor sensitive) and WUS. Based on biomass reduction (GR50), resistant to sensitive (R:S) ratios between CHR-M6 and WUS were 7.5, 6.1, 5.5, and 2.9 for S-metolachlor, acetochlor, dimethenamid-P, and pyroxasulfone, respectively. Values were greater for MCR-NH40 than CHR-M6, and ACR was the most sensitive to all VLCFA inhibitors tested. Complete control of all populations was achieved at or below a field use rate of acetochlor. In summary, field studies demonstrated CHR is not controlled by several VLCFA-inhibiting herbicides. Greenhouse dose–response experiments corroborated field results and generated R:S ratios (LD50) ranging from 4.5 to 64 for CHR-M6 and MCR-NH40 among the four VLCFA-inhibiting herbicides evaluated.

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