scholarly journals Time of Day Effects on Peanut Herbicide Efficacy

2019 ◽  
Vol 46 (2) ◽  
pp. 174-181
Author(s):  
O.W. Carter ◽  
E.P. Prostko

ABSTRACT Recent research on the effects of time of d (TOD) when glufosinate is applied to cotton (Gossypium hirsutum L.) and several protoporphyrinogen-inhibiting herbicides in soybean (Glycine max L.) has growers concerned about potential TOD effects on peanut weed control. Consequently, research was conducted in 2015, 2016, and 2017 to determine if TOD influences the performance of peanut herbicides acifluorfen, bentazon, imazapic, lactofen, paraquat, and 2,4-DB. Both non- (bare-ground) and in-crop (peanut) studies were conducted. For non-crop, paraquat plus bentazon plus acifluorfen plus S-metolachlor, imazapic plus S-metolachlor plus 2,4-DB, and lactofen plus S-metolachlor plus 2,4-DB were applied to Palmer amaranth and a non-uniform mixture of annual grasses including Urochloa texana (Buckley), Dactyloctenium aegyptium (L.), Eleusine indica (L.), Digitaria spp. at 7:00, 12:00, 17:00, and 22:00 hr. For in-crop studies, two peanut weed control programs were used and herbicide programs were applied at the same TOD. Herbicides were paraquat plus acifluorfen plus bentazon plus S-metolachlor (EPOST) followed by imazapic plus S-metolachlor plus 2,4-DB, or lactofen plus S-metolachlor plus 2,4-DB (POST). For the non-crop studies, a significant interaction between TOD and herbicide program was observed for the 7 d after treatment (DAT) rating of Palmer amaranth control. Control was reduced with imazapic applied at 22:00 hr. At 14 DAT, there was no TOD effect and control was reduced with all imazapic treatments due to ALS resistance. There was no interaction between TOD and herbicide program for annual grass control. Annual grass control was unacceptable (<50%) with lactofen. For in-crop studies, there was no interaction between TOD or herbicide program. Peanut injury was lower at 7:00 hr and 22:00 hr when compared to other timings. Lactofen was more injurious to peanut than imazapic. Palmer amaranth control was not influenced by timing or herbicide program. A reduction in sicklepod control was observed at the 22:00 hr timing and with lactofen. While TOD influenced peanut injury and weed control, peanut yield was not affected.

2019 ◽  
Vol 33 (03) ◽  
pp. 411-425
Author(s):  
Andrea Smith ◽  
Nader Soltani ◽  
Allan J. Kaastra ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

AbstractTransgenic crops are being developed with herbicide resistance traits to expand innovative weed management solutions for crop producers. Soybean with traits that confer resistance to the hydroxyphenylpyruvate dioxygenase herbicide isoxaflutole is under development and will provide a novel herbicide mode of action for weed management in soybean. Ten field experiments were conducted over 2 years (2017 and 2018) on five soil textures with isoxaflutole-resistant soybean to evaluate annual weed control using one- and two-pass herbicide programs. The one-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, at a low rate (52.5 + 210 g ai ha−1), medium rate (79 + 316 g ai ha−1), and high rate (105 + 420 g ai ha−1); and glyphosate applied early postemergence (EPOST) or late postemergence (LPOST). The two-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, followed by glyphosate applied LPOST, and glyphosate applied EPOST followed by LPOST. At 4 weeks after the LPOST application, control of common lambsquarters, pigweed species, common ragweed, and velvetleaf was variable at 25% to 69%, 49% to 86%, and 71% to 95% at the low, medium, and high rates of isoxaflutole plus metribuzin, respectively. Isoxaflutole plus metribuzin at the low, medium, and high rates controlled grass species evaluated (i.e., barnyardgrass, foxtail, crabgrass, and witchgrass) 85% to 97%, 75% to 99%, and 86% to 100%, respectively. All two-pass weed management programs provided 98% to 100% control of all species. Weed control improved as the rate of isoxaflutole plus metribuzin increased. Two-pass programs provided excellent, full-season annual grass and broadleaf weed control in isoxaflutole-resistant soybean.


2010 ◽  
Vol 24 (1) ◽  
pp. 1-5 ◽  
Author(s):  
W. Carroll Johnson ◽  
Eric P. Prostko ◽  
Benjamin G. Mullinix

In strip-tillage peanut production, situations occur when dinitroaniline herbicides are not applied in a timely manner. In these cases, dinitroaniline herbicides would be applied days or weeks after seeding. However, there is no information that documents the effects of delayed applications on weed control. Trials were conducted in 2004, 2005, and 2007 in Georgia to determine the weed control efficacy of delayed applications of pendimethalin in strip-tillage peanut production. Treatments included seven timings of pendimethalin application and three pendimethalin-containing herbicide combinations. Timings of application were immediately after seeding (PRE), vegetative emergence of peanut (VE), 1 wk after VE (VE+1wk), VE+2wk, VE+3wk, VE+4wk, and a nontreated control. Pendimethalin containing herbicide programs included pendimethalin plus paraquat, pendimethalin plus imazapic, and pendimethalin alone. Among the possible treatment combinations was a current producer standard timing for nonpendimethalin weed control programs in peanut, which was either imazapic or paraquat alone applied VE+3wk. Pendimethalin alone did not effectively control Texas millet regardless of time of application (69 to 77%), whereas southern crabgrass was controlled by pendimethalin alone PRE (87%). Delayed applications of pendimethalin controlled Texas millet and southern crabgrass when combined with either paraquat or imazapic, with imazapic being the preferred combination due to better efficacy on southern crabgrass than paraquat at most delayed applications. Peanut yield was improved when any of the herbicide combinations were applied PRE compared to later applications. Across all times of application, pendimethalin plus imazapic effectively maximized peanut yield with interference from annual grasses.


2017 ◽  
Vol 44 (2) ◽  
pp. 93-99 ◽  
Author(s):  
O.W. Carter ◽  
E.P. Prostko ◽  
J.W. Davis

ABSTRACT The increase in herbicide-resistant weeds over the past decade has led to the introduction of crops that are resistant to auxin herbicides. Strict application procedures are required for the use of auxin herbicides in auxin-resistant crops to minimize off-target movement. One requirement for application is the use of nozzles that will minimize drift by producing coarse droplets. Generally, an increase in droplet size can lead to a reduction in coverage and efficacy depending upon the herbicide and weed species. In studies conducted in 2015 and 2016, two of the potential required auxin nozzle types [(AIXR11002 (coarse) and TTI11002 (ultra-coarse)] were compared to a conventional flat-fan drift guard nozzles [DG11002 (medium)] for weed control in peanut herbicide systems. Nozzle type did not influence annual grass or Palmer amaranth control in non-crop tests. Results from in-crop tests indicated that annual grass control was 5% to 6% lower when herbicides were applied with the TTI nozzle when compared to the AIXR or DG nozzles. However, Palmer amaranth control and peanut yield was not influenced by coarse-droplet nozzles. Peanut growers using the coarse-droplet nozzles need to be aware of potential reduced grass control.


2018 ◽  
Vol 32 (3) ◽  
pp. 273-283
Author(s):  
Christopher E. Rouse ◽  
Nilda Roma-Burgos ◽  
Leopoldo E. Estorninos ◽  
Teal M. Penka

Cowpea is a major specialty crop in the southern US. In recent years, no new herbicide programs have been evaluated for cowpea despite additional herbicide registrations. Studies were conducted from 2014 to 2016 at Fayetteville and Kibler, Arkansas to assess new herbicide programs for cowpea production. The herbicide programs included: three commercial standard programs; fomesafen (PPL, 0.21 kgha−1)-, flumioxazin (PPL, 0.21 kgha−1)-, and halosulfuron (PPL, 0.054 kgha−1)-based programs with or withoutS-metolachlor (1.12 kgha−1) fb imazethapyr (0.07 kgha−1); and two sets of sulfentrazone (PPL/PRE)-based programs applied alone (0.21 kgha−1) or as a pre-mixture with carfentrazone (0.11 kgha−1+0.01 kgha−1) with or withoutS-metolachlor (1.12 kgha−1). The sulfentrazone-based programs included POST applications of imazethapyr fb sethoxydim (0.32 kgha−1) or fluthiacet-methyl (0.0067 kgha−1) and sethoxydim as necessary. In 2014 and 2015, crop stand loss was minimal and crop injury was generally low (<20%). Weed control from sulfentrazone- and flumioxazin-based programs was excellent (>90%). In 2016, with heavy rainfall around planting time, sulfentrazone-containing programs reduced cowpea yield 45% to 60%. Flumioxazin-based programs caused >85% injury at Kibler early-season, which lasted until harvest. Heavy rainfall also reduced efficacy of residual herbicides. In general, the sulfentrazone- and flumioxazin-based treatments consistently yielded similar to the weed-free controls. The majority of the programs had <60% weed control in Fayetteville early in the season. POST herbicides improved weed control to >90% in most treatments. Palmer amaranth and annual grass control was generally better in Kibler, with >80% control at harvest. Sulfentrazone is registered for cowpea and is effective on Palmer amaranth, but growers need to be careful about where and when to use it. Flumioxazin should be considered for registration in cowpea once its use pattern and location-specific recommendations are well defined.


2011 ◽  
Vol 25 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Jared R. Whitaker ◽  
Alan C. York ◽  
David L. Jordan ◽  
A. Stanley Culpepper

Glyphosate-resistant (GR) Palmer amaranth has become a serious pest in parts of the Cotton Belt. Some GR cotton cultivars also contain the WideStrike™ insect resistance trait, which confers tolerance to glufosinate. Use of glufosinate-based management systems in such cultivars could be an option for managing GR Palmer amaranth. The objective of this study was to evaluate crop tolerance and weed control with glyphosate-based and glufosinate-based systems in PHY 485 WRF cotton. The North Carolina field experiment compared glyphosate and glufosinate alone and in mixtures applied twice before four- to six-leaf cotton. Additional treatments included glyphosate and glufosinate mixed withS-metolachlor or pyrithiobac applied to one- to two-leaf cotton followed by glyphosate or glufosinate alone on four- to six-leaf cotton. All treatments received a residual lay-by application. Excellent weed control was observed from all treatments on most weed species. Glyphosate was more effective than glufosinate on glyphosate-susceptible (GS) Palmer amaranth and annual grasses, while glufosinate was more effective on GR Palmer amaranth. Annual grass and GS Palmer amaranth control by glyphosate plus glufosinate was often less than control by glyphosate alone but similar to or greater than control by glufosinate alone, while mixtures were more effective than either herbicide alone on GR Palmer amaranth. Glufosinate caused minor and transient injury to the crop, but no differences in cotton yield or fiber quality were noted. This research demonstrates glufosinate can be applied early in the season to PHY 485 WRF cotton without concern for significant adverse effects on the crop. Although glufosinate is often less effective than glyphosate on GS Palmer amaranth, GR Palmer amaranth can be controlled with well-timed applications of glufosinate. Use of glufosinate in cultivars with the WideStrike trait could fill a significant void in current weed management programs for GR Palmer amaranth in cotton.


Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 762-767 ◽  
Author(s):  
N. C. Glaze ◽  
C. C. Dowler ◽  
A. W. Johnson ◽  
D. R. Sumner

Six multiple-cropping systems composed of: a) turnip (Brassica campestrisspp.rapifera), corn (Zea maysL.), and snapbean (Phaseolus vulgarisL.); b) turnip, peanut (Arachis hypogaeaL.), and snapbean; c) turnip, corn, and turnip; d) turnip, peanut, and turnip; e) snapbean, soybean [Glycine max(L.) Merr.], and cabbage (Brassica oleraceaL.); and f) turnip, cucumber (Cucumis sativusL.), cowpea [Vigna unguiculata(L.) Walp.], and turnip were subjected to nematicide and weed control programs of cultivation or herbicides. Herbicide programs were superior to cultivation in control of weeds. Weeds remaining in the row following cultivation competed severely with crops. Weed species remaining were altered depending on the method of control and crop. Yellow nutsedge (Cyperus esculentusL. ♯3CYPES) increased rapidly in all herbicide programs but not in cultivated plots. Pigweeds (Amaranthusspp.) were controlled by herbicides but increased in cultivated plots. Corn, peanut, soybean, and spring snapbean yields were higher in herbicide treatments than in cultivated treatments. Cucumber was the only crop that had increased yields for both main effects, herbicide and nematicide. Turnip was consistently injured in herbicide treatments, which was believed to be caused by residues from previous crops interacting with pathogens and possible allelopathic effects of decaying organic matter.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Michael M. Houston ◽  
L. Tom Barber ◽  
Jason K. Norsworthy ◽  
Trent L. Roberts

Protoporphyrinogen oxidase- (PPO-) resistant Amaranthus palmeri (S.) Wats. (Palmer amaranth) was confirmed in Arkansas in 2015. Field trials were conducted in Crawfordsville, Gregory, and Marion, Arkansas in 2016, and Crawfordsville and Marion in 2017, assessing PPO-resistant Palmer amaranth control options in Glycine max (L.) Merr. (soybean). Twelve trials consisted of 26 preemergence (PRE) treatments, evaluated for Palmer amaranth control and density reduction at 28 days after treatment (DAT). Treatments that consisted of PPO- or acetolactate synthase- (ALS-) inhibiting herbicides such as flumioxazin (72 g ai ha−1) or sulfentrazone + cloransulam (195 g ha−1 + 25 g ha−1) controlled Palmer amaranth <60%. At 28 DAT, treatments including mixtures of a very-long-chain fatty acid (VLCFA) plus the photosystem II- (PSII-) inhibiting herbicide metribuzin provided increased control over single herbicide sites of action (SOA) or herbicides mixtures to which Palmer amaranth was resistant. Pyroxasulfone + metribuzin (149 g ha−1 + 314 g ha−1) controlled Palmer amaranth 91% control across twelve trials at 28 DAT. S-metolachlor alone did not provide consistent, acceptable control of PPO-resistant Palmer amaranth (55–77%); subsequent research has determined that these populations are resistant to S-metolachlor. A minimum of two effective herbicides should be included in soybean PRE programs for control of PPO-resistant Palmer amaranth.


2007 ◽  
Vol 17 (1) ◽  
pp. 102-106
Author(s):  
Russell W. Wallace ◽  
John C. Hodges

Herbicides were applied pre-emergence (PRE) and early post-directed (EP-DIR) to determine their effects on crop injury and control of palmer amaranth (Amaranthus palmeri) and nutsedge (Cyperus spp.) in field-grown cannas (Canna ×generalis). Results indicate that PRE-applied s-metolachlor + pendimethalin was the most effective treatment for controlling palmer amaranth. All other PRE-applied treatments failed to adequately control palmer amaranth. While moderate and temporary stunting was visible, in general, no herbicides (except trifloxysulfuron) significantly decreased canna rhizome yields. EP-DIR s-metolachlor or s-metolachlor + pendimethalin did not improve nutsedge control unless halosulfuron was included in the tank mixture. Addition of halosulfuron did not increase crop injury or decrease canna yields but did significantly reduce the number of nutsedge tubers found in the canna rhizomes at harvest. Results suggest that all PRE-applied herbicides tested were safe for cannas, but the lack of adequate palmer amaranth and nutsedge control prohibits their use as stand-alone herbicides for canna production in the midsouth. Post-directing applications of halosulfuron significantly improved nutsedge control and reduced tuber infestation and, therefore, should be included in all nutsedge management programs for canna rhizome production.


1994 ◽  
Vol 8 (2) ◽  
pp. 338-343 ◽  
Author(s):  
Windsor Griffiths

During the early years of herbicide use, the total amount of ai applied per ha increased in attempts to obtain season-long weed control, peaking in the decade of the mid-1970's to mid-1980's. Since then, the chemical load applied for broadleaf weed control has shown a consistent, if not dramatic, decline. A much more significant reduction has occurred in grass weed control. Main reasons for the reduction are a move from PPI and PRE treatments to POST, the development of repeat low-dose herbicide techniques, and the introduction of more active postemergence grass herbicides. In general, this change has been achieved with a concomitant improvement in crop safety. These developments occurred as a coincident benefit in pursuing the target objective of giving growers more convenient and flexible weed control and not as a specific attempt to reduce chemical use. This paper discusses the evolution of weed control programs in the U.K., France, Germany, and the U.S.A. All show a similar trend, though the pace of change has been slower in the U.S.A.


2019 ◽  
Vol 33 (5) ◽  
pp. 651-657
Author(s):  
J. Drake Copeland ◽  
Garret B. Montgomery ◽  
Lawrence E. Steckel

AbstractStudies to evaluate the effect of application time of day (TOD) and protoporphyrinogen IX oxidase (PPO)-inhibiting herbicide–resistant Palmer amaranth on the efficacy of commonly used herbicides was conducted in Tennessee in 2017 and 2018. Treatments of fomesafen, lactofen, acifluorfen, paraquat, glufosinate, glufosinate plus fomesafen, paraquat plus fomesafen, and paraquat plus metribuzin were applied to PPO-resistant (PPO-R) and PPO-susceptible (PPO-S) Palmer amaranth at sunrise and midday. Control of Palmer amaranth with acifluorfen, glufosinate, and glufosinate plus fomesafen was greater with the midday application. However, control of Palmer amaranth with paraquat-based treatments was greater with the sunrise application. TOD effects on PPO-inhibiting herbicides and paraquat-based treatments were more prominent for the PPO-R Palmer amaranth biotype. The TOD effect observed when applying glufosinate in early morning hours on PPO-S Palmer amaranth can be minimized by adding fomesafen to the tank mix. However, this strategy did not provide consistent performance on PPO-R Palmer amaranth. The percentages of living Palmer amaranth plants and control were greater when paraquat plus metribuzin was applied to both biotypes. These results highlight the necessity of at least two effective herbicide sites of action for POST applications intended for controlling PPO-R Palmer amaranth. In addition, the timing of herbicide applications can affect their activity in both PPO-R and PPO-S Palmer amaranth populations.


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