Evaluation of Postemergence Weed Control Strategies in Herbicide-Resistant Isolines of Corn (Zea mays)

2006 ◽  
Vol 20 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Karen A. Zuver ◽  
Mark L. Bernards ◽  
James J. Kells ◽  
Christy L. Sprague ◽  
Case R. Medlin ◽  
...  

Herbicide-resistant corn hybrids offer additional options for POST weed control in corn, and growers may benefit from information on the consistency of these weed-control strategies. Studies were conducted in Indiana, Illinois, Michigan, and Ohio, in 2000 and 2001, to evaluate weed control among herbicide strategies for imidazolinone-resistant, glufosinate-resistant, glyphosate-resistant, and conventional corn. Isogenic hybrids were utilized to minimize variation in growth and yield potential among hybrids. The glyphosate-resistant corn postemergence (glyphosate-POST) treatment provided more consistent control of giant foxtail than the PRE, conventional corn postemergence (conventional-POST), glufosinate-resistant corn postemergence (glufosinate-POST), and imidazolinone-resistant corn postemergence (imi-POST) treatments. All four POST treatments were more consistent and provided greater control than the PRE treatment of the large-seeded broadleaf weeds velvetleaf, giant ragweed, common cocklebur, and morningglory species. Conventional-POST and imi-POST were more consistent than glufosinate-POST and glyphosate-POST treatments in controlling giant ragweed. There were no statistical differences in the variability of PRE or POST treatments for control of common lambsquarters, common ragweed, and redroot pigweed. Corn yield varied among locations and years. The glyphosate-POST treatment did not reduce yield relative to the weed-free treatment, the imi-POST and glufosinate-POST treatments each reduced yield in one of eight locations, and the conventional-POST treatment reduced yield in three of eight locations.

2008 ◽  
Vol 26 (3) ◽  
pp. 585-594 ◽  
Author(s):  
I.M. El-Metwally ◽  
M.T. Abdelhamid

Two field experiments were conducted in two successive seasons, 2005/2006 and 2006/2007, to determine whether management can improve faba bean competitiveness with weeds, thus helping to achieve its yield potential. The experiment included five treatments, composed of organic and mineral fertilizers, alone and mixed at different rates, along with a control and six weed control treatments, including oxadiargyl, prometryn, hand hoeing treatments alone or mixed with the herbicides, and a nonweeded treatment (control).The herbicide treatments were not superior to the two hand-hoeing treatments. Using compost favored growth and yield of faba bean more than of weeds. Adding fertilizer also improved most yield parameters. Application of compost alone or combined with 50 or 100% of the recommended NPK rate improved faba bean growth in terms of net assimilation rate, specific leaf area, and leaf weight ratio as components of relative growth rate. This improvement in growth resulted in increase of seed yield, yield components and protein of faba bean. Faba bean yield performance improved under interactive fertilizer effects and weed control treatments as growth improved, as a result of nutrient release from fertilizers and weed control.


Weed Science ◽  
2019 ◽  
Vol 67 (1) ◽  
pp. 57-67 ◽  
Author(s):  
O. Adewale Osipitan ◽  
J. Anita Dille ◽  
Muthukumar V. Bagavathiannan ◽  
Stevan Z. Knezevic

AbstractKochia [Bassia scoparia(L.) A. J. Scott] is a problematic weed species across the Great Plains, as it is spreading fast and has developed herbicide-resistant biotypes. It is imperative to understand key life-history stages that promote population expansion ofB. scopariaand control strategies that would provide effective control of these key stages, thereby reducing population growth. Diversifying weed control strategies has been widely recommended for the management of herbicide-resistant weeds. Therefore, the objectives of this study were to develop a simulation model to assess the population dynamics ofB. scopariaand to evaluate the effectiveness of diverse weed control strategies on long-term growth rates ofB. scopariapopulations. The model assumed the existence of a glyphosate-resistant (GR) biotype in theB. scopariapopulation, but at a very low proportion in a crop rotation that included glyphosate-tolerant corn (Zea maysL.) and soybean [Glycine max(L.) Merr.]. The parameter estimates used in the model were obtained from various ecological and management studies onB. scoparia. Model simulations indicated that seedling recruitment and survival to seed production were more important than seedbank persistence forB. scopariapopulation growth rate. Results showed that a diversified management program, including glyphosate, could provide excellent control ofB. scopariapopulations and potentially eliminate already evolved GRB. scopariabiotypes within a given location. The most successful scenario was a diverse control strategy that included one or two preplant tillage operations followed by preplant or PRE application of herbicides with residual activities and POST application of glyphosate; this strategy reduced seedling recruitment, survival, and seed production during the growing season, with tremendous negative impacts on long-term population growth and resistance risk inB. scoparia.


2015 ◽  
Vol 29 (3) ◽  
pp. 464-471 ◽  
Author(s):  
Ross A. Recker ◽  
Joseph G. Lauer ◽  
David E. Stoltenberg ◽  
Paul D. Mitchell ◽  
Vince M. Davis

Atrazine is an important herbicide for broadleaf weed control in corn. Use rates have declined in many corn production systems due to environmental concerns and the availability of other effective herbicides, especially glyphosate in glyphosate-resistant hybrids. However, using multiple effective herbicide modes of action is ever more important because occurrence of herbicide-resistant weeds is increasing. An experiment to compare application timings of reduced rates of atrazine to benefit resistance management in broadleaf weeds while protecting corn yield was conducted in Wisconsin across four site-years in 2012 and 2013. Herbicide treatments consisted of five atrazine rate and timing combinations and three POST base herbicides: glyphosate, glufosinate, and tembotrione. Metolachlor was applied PRE at 2.1 kg ai ha−1 for grass control in all treatments. A linear regression model estimated that atrazine rates ≥ 1.0 kg ai ha−1 applied PRE would prevent exposure of common lambsquarters plants to POST herbicides, but giant ragweed and velvetleaf exposure was not influenced by timing. Corn yield was also not influenced by atrazine rate and timing combinations at the α = 0.05 level; however, at P = 0.06, corn yield was greater for atrazine applied PRE at 1.1 kg ha−1 than for atrazine applied PRE at 0.5 kg ha−1, POST at 1.1 kg ha−1, or not at all. In summary, higher rates of atrazine applied PRE may improve yield, as reported by others, but this study concludes reduced rates of atrazine (i.e., ≤ 1.1 kg ha−1) applied to corn in a POST tank mixture combination provided more consistent control of giant ragweed, velvetleaf, and common lambsquarters compared with atrazine applied PRE. This information should help direct atrazine application timing applied POST when applied at low rates to improve proactive herbicide resistance management.


2003 ◽  
Author(s):  
Radi Aly ◽  
James H. Westwood ◽  
Carole L. Cramer

Our overall goal was to engineer crop plants with enhanced resistance to Orobanche (broomrape) based on the inducible expression of sarcotoxin-like peptide (SLP). A secondary objective was to localize small proteins such as SLP in the host-parasite union in order to begin characterizing the mechanism of SLP toxicity to Orobanche. We have successfully accomplished both of these objectives and have demonstrated that transgenic tobacco plants expressing SLP under control of the HMG2 promoter show enhanced resistance to O. aegyptiaca and O. ramosa . Furthermore, we have shown that proteins much larger than the SLP move into Orobanche tubercles from the host root via either symplastic or apoplastic routes. This project was initiated with the finding that enhanced resistance to Orobanche could be conferred on tobacco, potato, and tomato by expression of SLP (Sarcotoxin IA is a 40-residue peptide produced as an antibiotic by the flesh fly, Sarcophaga peregrina ) under the control of a low-level, root-specific promoter. To improve the level of resistance, we linked the SLP gene to the promoter from HMG2, which is strongly inducible by Orobanche as it parasitizes the host. The resulting transgenic plants express SLP and show increased resistance to Orobanche. Resistance in this case is manifested by increased growth and yield of the host in the presence of the parasite as compared to non-transgenic plants, and decreased parasite growth. The mechanism of resistance appears to operate post-attachment as the parasite tubercles attached to the transgenic root plants turned necrotic and failed to develop normally. Studies examining the movement of GFP (approximately 6X the size of SLP) produced in tobacco roots showed accumulation of green fluorescence in tubercles growing on transformed plants but not in those growing on wild-type plants. This accumulation occurs regardless of whether the GFP is targeted to the cytoplasm (translocated symplastically) or the apoplastic space (translocated in xylem). Plants expressing SLP appear normal as compared to non-transgenic plants in the absence of Orobanche, so there is no obvious unintended impact on the host plant from SLP expression. This project required the creation of several gene constructs and generation of many transformed plant lines in order to address the research questions. The specific objectives of the project were to: 1. Make gene constructs fusing Orobanche-inducible promoter sequences to either the sarcotoxin-like peptide (SLP) gene or the GFP reporter gene. 2. Create transgenic plants containing gene constructs. 3. Characterize patterns of transgene expression and host-to-parasite movement of gene products in tobacco ( Nicotiana tabacum L.) and Arabidopsis thaliana (L.). 4. Characterize response of transgenic potato ( Solanum tuberosum L.) and tomato ( Lycopersicon esculentum Mill .) to Orobanche in lab, greenhouse, and field. Objectives 1 and 2 were largely accomplished during the first year during Dr. Aly's sabbatical visit to Virginia Tech. Transforming and analyzing plants with all the constructs has taken longer than expected, so efforts have concentrated on the most important constructs. Work on objective 4 has been delayed pending the final results of analysis on tobacco and Arabidopsis transgenic plants. The implications of this work are profound, because the Orobanche spp. is an extremely destructive weed that is not controlled effectively by traditional cultural or herbicidal weed control strategies. This is the first example of engineering resistance to parasitic weeds and represents a unique mode of action for selective control of these weeds. This research highlights the possibility of using this technique for resistance to other parasitic species and demonstrates the feasibility of developing other novel strategies for engineering resistance to parasitic weeds.


1990 ◽  
Vol 5 (3) ◽  
pp. 114-119 ◽  
Author(s):  
Jeffrey L. Gunsolus

AbstractMany farmers and consumers are reevaluating chemical weed control because of the environmental risks of herbicides and their influence on farm size and diversity. This paper reviews research of the last 35 years on mechanical and cultural weed control in corn(Zea maysL.)and soybeans(Glycine maxL.).Soybeans can better use the weed control advantages of late planting and narrow row spacing and are less affected by early stand losses from mechanical weed control. In Minnesota, delaying planting to early June allows early germinating weeds to be controlled by preplant tillage but reduces the maximum yield potential of corn by approximately 25 percent and soybeans by approximately 10 percent. Narrow rows allow the crop canopy to close earlier, preventing emerging weeds from developing. However, in a nonchemical weed control system, the row spacing should allow for inter-row cultivation to control weeds that emerge with the crop. Up to a 10 percent reduction in crop stand may be expected in fields that have been rotary hoed. In Minnesota, a 10 percent stand loss results in a 2 percent loss of corn yield potential and no loss of soybean yield potential. Successful mechanical weed control is directly related to the timeliness of the operation. Rotary hoeing is effective on weeds that have germinated but not yet emerged but not on weeds that germinate from deeper than 5 cm, on no-till fields, or on fields with more than 20 to 30 percent crop residue. Inter-row cultivation is most effective on weeds up to 10 to 15 cm tall. Successful nonchemical weed control requires highly refined management skills and is as much an art as a science.


2011 ◽  
Vol 12 (2) ◽  
Author(s):  
Alvadi Antonio BALBINOT JUNIOR ◽  
Gilcimar Adriano VOGT ◽  
Michelangelo Muzell TREZZI

As práticas de manejo do solo e de culturas podem afetar diretamente a infestação de plantas daninhas na cultura do milho. O objetivo desse trabalho foi avaliar o efeito da integração de práticas culturais e químicas na infestação de plantas daninhas e na produtividade da cultura do milho. Foi conduzido um experimento em Papanduva, SC, em delineamento experimental de blocos ao acaso, com três repetições e parcelas subdivididas. Nas parcelas foram avaliados dois sistemas de manejo cultural de plantas daninhas: S1 (cultivo de consórcio de espécies para cobertura do solo no inverno, uso de sementes de milho com elevada massa e espaçamento entre fileiras de 0,45 m) e S2 (pousio no inverno, uso de sementes de milho com baixa massa e espaçamento entre fileiras de 0,90 m). Nas subparcelas foram avaliadas quatro estratégias de controle de plantas daninhas no milho (sem controle, atrazine, atrazine+mesotrione e capina). Avaliaram-se a quantidade de palha no momento da semeadura do milho, a velocidade de decomposição da palha, a densidade e a massa seca da parte aérea de plantas daninhas e o desempenho da cultura de milho. O uso de práticas culturais para o manejo de plantas daninhas promoveu redução da infestação dessas plantas na cultura de milho, além de aumentar a produtividade da cultura. A aplicação de atrazine + mesotrione proporcionou melhor controle de plantas daninhas e maior produtividade de grãos em relação à aplicação isolada de atrazine. ABSTRACT Soil and crop management can affect the weed population in corn. The experiment was carried out to evaluate the effect of cultural and chemical management practices on weed infestation and corn yield. The experiment was carried out in Papanduva, SC, Brazil. The experimental design was a randomized complete blocks with three replications in a split-plot arrangement. In plots were evaluated two cultural weed management systems: S1 (multicropping of winter cover crops, corn seeds with high weight and narrow row of 0.45 m) and S2 (winter fallow, corn seeds with low weight and narrow row of 0.90 m). In subplots were evaluated four weed control strategies (no-control, atrazine, atrazine + mesotrione and weeding). The parameters evaluated were the straw quantity, residue decomposition, weed plant density and shoot dry mass and corn performance. The use of cultural weed management practices reduced the weed infestation on corn and improved the crop yield. The association of atrazine + mesotrione herbicides showed more efficient weed control than atrazine.


2017 ◽  
Vol 31 (4) ◽  
pp. 496-502 ◽  
Author(s):  
Daniel O. Stephenson ◽  
Jason A. Bond ◽  
James L. Griffin ◽  
Randall L. Landry ◽  
Brandi C. Woolam ◽  
...  

Field experiments were conducted in Louisiana and Mississippi from 2011 through 2013 to evaluate crop injury, weed control, and yield in field corn following pyroxasulfone applied PRE and POST. Pyroxasulfone PRE or POST did not injure corn at any evaluation. Barnyardgrass control was not improved with the addition of any POST treatment to pyroxasulfone alone or atrazine plus pyroxasulfone PRE; however, all POST treatments increased barnyardgrass control to at least 95% at all evaluations following atrazine PRE. All treatments that contained a PRE followed by POST application controlled browntop millet ≥90% at all evaluations. All POST treatments increased ivyleaf morningglory control to ≥92% following atrazine or pyroxasulfone alone PRE. However, control with atrazine plus pyroxasulfone PRE was similar or greater 28 d after POST than all treatments that received a POST application. In the absence of a POST treatment, pyroxasulfone or atrazine plus pyroxasulfone PRE controlled Palmer amaranth 93 to 96% at all evaluations, but atrazine alone PRE provided 84, 82, and 66% control 7, 14, and 28 d after POST, respectively. All programs that contained a PRE followed by POST herbicide treatment controlled Palmer amaranth >90% at all evaluations. Corn yield following all treatments except atrazine alone PRE and the nontreated were similar and ranged from 10990 to 12330 kg ha−1. This research demonstrated that pyroxasulfone can be a valuable tool for weed management in a corn weed management program.


2011 ◽  
Vol 29 (4) ◽  
pp. 793-802 ◽  
Author(s):  
P.S.L Silva ◽  
P.I.B Silva ◽  
K.M.B Silva ◽  
V.R Oliveira ◽  
F.S.T Pontes Filho

Although labor is intensive, evaluating the growth of crops may allow a better understanding of crop performance, including the reasons why certain cultivars can compete better with weeds. This study aims at evaluating growth, green ear yield, and grain yield in corn when in competition with weeds. Cultivars AG 1051 and BRS 106 were grown with (two hoeings, at 20 and 40 days after sowing) or without weed control. In order to evaluate crop growth, six collections of the above-ground part and the root system of corn were performed, every 15 days, with the first collection made 30 days after sowing. A randomized complete block design was adopted, with split-split plots (weed control in plots, cultivars in subplots, and collections in sub-subplots) and ten replicates. Eighteen weed species were found in the experiment area. Increased values of corn leaf area, above-ground part and root system, due to plant age function, were smaller in non-hoed plots than in hoed plots and were dependent upon cultivar. The lack of weed control increased dry matter of weeds aboveground part and decreased green ear yield and grain yield. Cultivar AG 1051 had higher increases in leaf area, above-ground part of the plant and root system, due to plant age function, and controlled weeds better than cultivar BRS 106. In addition, cultivar AG 1051 was superior to other cultivars with respect to most traits used for green corn yield and grain yield assessment.


2008 ◽  
Vol 22 (4) ◽  
pp. 571-579 ◽  
Author(s):  
Ian C. Burke ◽  
Walter E. Thomas ◽  
Jayla R. Allen ◽  
Jim Collins ◽  
John W. Wilcut

Experiments were conducted at three North Carolina research stations in 2003 to evaluate weed control and corn yield in glyphosate-resistant, glufosinate-resistant, imidazolinone-tolerant, and conventional corn weed management systems. Late-season control of common lambsquarters, large crabgrass, and yellow nutsedge increased with metolachlor PRE compared with no PRE herbicide treatment. Common lambsquarters, pitted morningglory, entireleaf morningglory, spurred anoda, and tropic croton control was improved by a single early POST (EPOST) application regardless of herbicide system. Control of common lambsquarters, pitted morningglory, entireleaf morningglory, and spurred anoda was similar for glyphosate and glufosinate systems for each POST over-the-top (POT) herbicide system. A single EPOST application of imazethapyr plus imazapyr to imidazolinone-tolerant corn controlled common lambsquarters, pitted morningglory, entireleaf morningglory, and spurred anoda and was better than a single EPOST application of glyphosate, glufosinate, or nicosulfuron. Tropic croton was controlled ≥ 95% with glufosinate or glyphosate, applied once or twice, or in mixture with metolachlor. A single EPOST application of imazethapyr plus imazapyr or nicosulfuron did not control tropic croton. Common lambsquarters, entireleaf morningglory, large crabgrass, Palmer amaranth, and yellow nutsedge control was greater with a late-POST–directed (LAYBY) of ametryn than no LAYBY. Systems that did not include a POT herbicide system had the lowest percentage in the weed-free yield and the lowest yield. Treatments that included a POT system with or without a PRE treatment of metolachlor yielded within 5% of the weed-free treatment, regardless of herbicide system.


2012 ◽  
Vol 26 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Daniel O. Stephenson ◽  
Jason A. Bond

Field studies were conducted in Louisiana and Mississippi in 2009 and 2010 to evaluate PRE herbicide treatments containing isoxaflutole or a prepackaged mixture of thiencarbazone-methyl : isoxaflutole (TCM : isoxaflutole) for weed control in corn. PRE treatments included the premix of TCM : isoxaflutole alone (30 : 80 g ai ha−1) and with atrazine (1,120 g ai ha−1), isoxaflutole alone (90 g ai ha−1) and with atrazine (1,120 g ai ha−1), and the premix of atrazine plus S-metolachlor (1,820 plus 1,410 g ai ha−1). POST treatments included glufosinate (450 g ai ha−1) or glyphosate (870 g ae ha−1) applied to 30-cm corn along with a no POST treatment. All PRE treatments controlled barnyardgrass, entireleaf morningglory, rhizomatous johnsongrass, Palmer amaranth, and velvetleaf 87 to 95% 4 wk after planting (WAP) and browntop millet and hophornbeam copperleaf were controlled 86 to 95% 8 WAP. Weed control was improved 8 and 20 WAP when either POST treatment was applied. TCM : isoxaflutole plus atrazine controlled barnyardgrass, entireleaf morningglory, Palmer amaranth, and velvetleaf at least 90% 20 WAP regardless of POST treatment. TCM : isoxaflutole plus atrazine provided greater control of browntop millet (90%) than isoxaflutole alone or with atrazine and atrazine plus S-metolachlor where control was 86% 20 WAP. Pooled across POST treatments, all PRE treatments containing isoxaflutole or TCM : isoxaflutole controlled rhizomatous johnsongrass better (74 to 76%) than atrazine plus S-metolachlor (67%). Corn yield following herbicide treatments ranged from 9,280 to 11,040 kg ha−1 compared with 9,110 kg ha−1 for the nontreated. Results indicate that TCM : isoxaflutole or isoxaflutole PRE is an option for use in a corn weed management program and may prolong the use of atrazine where weed resistance may be an issue. Where rhizomatous johnsongrass is a problem, TCM : isoxaflutole or isoxaflutole PRE can provide better control than atrazine plus S-metolachlor PRE. Without PRE treatments, glufosinate or glyphosate was needed for season-long weed control.


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