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Glyphosate Resistant Palmer Amaranth Amaranthus Palmeri In Arkansas
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Book Synopsis Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Arkansas by : Griff Michael Griffith
Download or read book Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Arkansas written by Griff Michael Griffith and published by . This book was released on 2013 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 2000, there have been thirteen weed species confirmed resistant (R) to glyphosate in the United States, six of those resistant species are present in Arkansas. The goal of this research was to confirm and to determine the level of resistance in two R Palmer amaranth biotypes from Mississippi (MC-R) and Lincoln (LC-R) Counties, Arkansas, and one susceptible (S) biotype from Clarendon County, South Carolina, which had never been exposed to glyphosate. Shikimic acid concentration over time was significantly greater in the S biotype than both the MC-R and LC-R biotypes. The lethal dose required to kill 50% (LD50) of the population was 2,255 and 3,223 g ae ha -1 for the MC-R and LC-R biotypes, respectively, and it was hypothesized that the two Arkansas biotypes each had a different resistance mechanism. Results indicate metabolism of glyphosate to its major metabolite, aminomethylphosphonic acid (AMPA), was not responsible for resistance in any biotype. Reduced absorption in the LC-R and limited translocation from the treated leaf in the MC-R were at least partially responsible for the observed resistance to glyphosate. The LC-R biotype effectively colonized a field within two years of a single resistant female producing ̃20,000 seed. Cotton lint yield was reduced over 100 kg ha-1 by some densities of LC-R Palmer, depending on the soil and relative elevation in that region. Several resistant management options exist in cotton; however, results indicate that timely herbicide applications based off of Palmer amaranth size are required for effective season-long control and management of the soil seedbank.
Book Synopsis Resistance Screening and Control Options for Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Cotton (gossypium Hirsutum) by : Ryan Christopher Doherty
Download or read book Resistance Screening and Control Options for Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Cotton (gossypium Hirsutum) written by Ryan Christopher Doherty and published by . This book was released on 2012 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the mid-2000's, glyphosate-resistant Palmer amaranth biotypes began to emerge in many southern states. In 2006, glyphosate-resistant Palmer amaranth was identified in a field in Mississippi County, Arkansas. A greenhouse experiment was conducted in 2008 to screen Palmer amaranth accessions, collected in this survey, for glyphosate resistance. Inflorescence were collected from a total of 276 plants from fields were glyphosate failure occurred, representing 74 accessions in 14 counties, including Clay, Craighead, Crittenden, Greene, Jackson, Jefferson, Lawrence, Lee, Mississippi, Phillips, Poinsett, Randolph, St. Francis, and White Counties. Eight of the 74 accessions did not produce viable seed. In the greenhouse, 32 of the 66 Palmer amaranth accessions screened were at least 10% glyphosate-resistant. Two counties (Lee and St. Francis) contained Palmer amaranth accessions that were greater than 80% glyphosate-resistant. Every accession tested had at least one survivor following glyphosate at 0.86 kg ae/ha. Three field experiments were conducted in 2006 and 2007 to determine if preplant-applied fomesafen and postemergence-applied glufosinate would provide control of Palmer amaranth without causing cotton injury. A total of, 28 preplant (PPL) and preemergence (PRE) herbicide treatments and 27 herbicide programs were evaluated for Palmer amaranth control. The 28 PPL and PRE treatments were also evaluated for cotton injury. The 28 PPL and PRE treatments were fomesafen, flumioxazin, fluometuron, prometryn, diuron, and pendimethalin applied at four preplant timings (21, 14, 7, and 0 days). The Liberty Link herbicide programs, utilized glufosinate, S-metolachlor, fomesafen, fluometuron, prometryn, flumioxazin, diuron, and pendimethalin to control Palmer amaranth. At 7 days after emergence (DAE) of cotton, fomesafen applied at 0.21 and 0.28 kg ai/ha, flumioxazin at 0.071 kg ai/ha, prometryn at 1.12 kg ai/ha, diuron at 0.56 kg ai/ha, and pendimethalin at 1.12 kg ai/ha applied at 21, 14, 7, and 0 DPP all controlled Palmer amaranth 90 to 100%. Fomesafen at 0.21 kg ai/ha and flumioxazin at 0.071 kg ai/ha applied at 0 days prior to planting (DPP) reduced stand by 22 and 58%, respectively, when compared to those same treatments applied 21 DPP. Application timing was the only significant factor to affect cotton yield in the PPL and PRE study.
Book Synopsis Characterization of Glyphosate-resistant Amaranthus Palmeri (Palmer Amaranth) Tolerance to ALS- and HPPD-inhibiting Herbicides by : Shilpa Singh
Download or read book Characterization of Glyphosate-resistant Amaranthus Palmeri (Palmer Amaranth) Tolerance to ALS- and HPPD-inhibiting Herbicides written by Shilpa Singh and published by . This book was released on 2017 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth is a principal weed problem across the United States and is resistant to several herbicide modes of action. By 2008, Palmer amaranth in Arkansas was reported to be resistant to both ALS- and EPSPS-inhibitors, but the predominant resistance mechanisms are yet to be explored. Herbicide options with different modes of action are needed to provide effective Palmer amaranth control and HPPD-inhibitors (e.g. mesotrione) are among these. The goal of this research was to elucidate the resistance profile of Palmer amaranth in Arkansas to ALS herbicides and glyphosate (EPSPS-inhibitor) as well as evaluate the differential tolerance of Palmer amaranth to mesotrione. This research aimed to (1) evaluate the response of Palmer amaranth populations to the full dose of glyphosate and mesotrione; (2) determine if tolerance to mesotrione is heritable; (3) determine the mechanism of resistance to glyphosate in selected accessions; and (4) verify the target-site as the mechanism of resistance in ALS-resistant Palmer amaranth. For objective 1, a total of 119 accessions were collected from crop fields in Arkansas between 2008 and 2014. Overall, 55% of the accessions (115) were glyphosate-resistant (GR). Mesotrione controlled 74% of the accessions (119); the remaining accessions had survivors with high injury (61%-90%). For objective 2, low level of tolerance to mesotrione (3- to 5-fold) was observed in four recalcitrant accessions. For objective 3, 20 accessions were selected. GR accessions had ED50 494 g ha-1 to 1355 g ha-1 and for susceptible accessions ED50 ranged from 28 g ha-1 to 207 g ha-1. EPSPS gene amplification was the primary mechanism of resistance. For objective 4, Palmer amaranth accessions were cross-resistant to pyrithiobac and trifloxysulfuron. Out of 20 accessions, 19 showed 21- to 56-fold resistance to trifloxysulfuron than the susceptible. Four and seven increased ALS copies were observed in a single plant from White and Mississippi counties, respectively, indicating the elevated ALS copies as potential mechanism of resistance in these accessions. Although, all accessions but susceptible had Trp574Ser mutation along with Ala122Thr, Pro197Ala and Ser653Asn present in a few plants, confirming mutations at the target-site as the main mechanism of resistance to ALS-inhibitors.
Book Synopsis Alternative Herbicide Control Options for Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) by : George Macmillan Botha
Download or read book Alternative Herbicide Control Options for Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) written by George Macmillan Botha and published by . This book was released on 2012 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The occurrence of glyphosate-resistant (GR) Palmer amaranth has prompted a shift in weed management strategies worldwide. Studies were conducted with the aim to (1) establish and compare the degree of tolerance of GR Palmer amaranth populations; (2) assess the efficacy of glufosinate, tembotrione, 2,4-D or dicamba, applied alone or tank-mixed, on Palmer amaranth with higher tolerance to glufosinate in the greenhouse and corn field, and (3) establish the mechanism involved in the tolerance of Palmer amaranth to glufosinate. Tembotrione, 2,4-D, dicamba, and glufosinate applied at 1x controlled 80 to 100%, 98 to 100%, 84 to 100%, and 94 to 100% Palmer amaranth, respectively. Differential response of Palmer amaranth populations to the test herbicides existed. The potential of selecting for resistance was highest in tembotrione, followed by dicamba. In the tank mixture test, all herbicides applied individually at 1x rate controlled Pra-C population 99 to 100% in the greenhouse and 91 to 100% in the field study. In corn, the control in Pra-C, Mis-C, and STF-C populations was 33 to 54% for tembotrione, 68 to 89% for 2,4-D, and 96 to 100% for glufosinate applied at their commercial rates. The study showed that half rates of 2,4-D and glufosinate can be applied, only in combination, without significantly compromising Palmer amaranth control. The majority of glufosinate + tembotrione and some glufosinate + dicamba mixtures were not compatible; glufosinate + 2,4-D mixtures were generally additive and in few cases, synergistic. The reduced efficacy from antagonism was overcome by mixing 1x rates of the herbicides. Pra-C (tolerant) had 2-folds higher tolerance than Lee-A (susceptible), with LD50 values of 344 and 141 g ha-1, respectively. The basal activity of the tolerant population was 20% higher than that of the susceptible. Tolerance to glufosinate is certainly due to higher baseline activity of GS in the tolerant plants, which would require more herbicide molecule to cause substantial inhibition.
Book Synopsis Integration of Herbicide Programs with Cultural and Mechanical Practices for Managing Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Soybean (glycine Max) by : Holden Douglas Bell
Download or read book Integration of Herbicide Programs with Cultural and Mechanical Practices for Managing Glyphosate-resistant Palmer Amaranth (amaranthus Palmeri) in Soybean (glycine Max) written by Holden Douglas Bell and published by . This book was released on 2014 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Herbicide-resistant Palmer amaranth is the most troublesome weed in Arkansas row crops, causing producers to rely heavily on multiple mechanisms of action to reduce selection pressure for further evolution of herbicide resistance and to successfully produce a profitable crop. It is critical for the sustainability of weed management not only to adequately control this weed but also to reduce the soil seedbank using both non-chemical and chemical practices. Studies were conducted to determine the effect of soybean row spacing, seeding rate, and herbicide program on Palmer amaranth emergence, survival, and seed production in soybean, the effect of drill-seeded soybean population on Palmer amaranth emergence with and without a residual preemergence (PRE)-applied herbicide, and the impact of integrating cover crops and deep tillage with herbicide programs for glyphosate-resistant Palmer amaranth control in glyphosate- and glufosinate-resistant soybean. Herbicide application timing and choice of herbicide had more of an impact on Palmer amaranth control than either row spacing or seeding rate and greater control was observed in PRE plus postemergence (POST)-applied residual programs compared to POST-only residual programs, regardless of seeding rate and row spacing. Narrow-row soybean reached 95% canopy formation quicker than plants in wide rows, in turn resulting in greater suppression of Palmer amaranth emergence. In drill-seeded soybean, a PRE-applied residual herbicide was more beneficial in reducing Palmer amaranth emergence than increasing soybean density. Using a combination of cover crop and deep tillage along with the addition of a PRE followed by POST-applied residual herbicide program, Palmer amaranth was effectively controlled throughout the season with limited weed seed return to the soil seedbank in both glufosinate- and glyphosate-resistant soybean. Overall, herbicide programs were the strongest factor influencing Palmer amaranth control; however, the addition of a cover crop, deep tillage, and narrow row spacing play a vital role in reducing selection pressure on herbicides, thus reducing risks for new cases of herbicide resistance.
Book Synopsis Use of Fluridone for Control of Palmer Amaranth (amaranthus Palmeri) in Cotton (gossypium Hirsutum) and on Ditchbanks by : Zachary Thornton Hill
Download or read book Use of Fluridone for Control of Palmer Amaranth (amaranthus Palmeri) in Cotton (gossypium Hirsutum) and on Ditchbanks written by Zachary Thornton Hill and published by . This book was released on 2015 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 2006, glyphosate-resistant Palmer amaranth has been considered the most problematic weed in agronomic crops across the Midsouth. As a result of glyphosate resistance, producers began to again utilize a diverse herbicide program for management of this weed, which consists of several soil-residual herbicides most notably diuron, fluometuron, fomesafen, and metolachlor. Fluridone inhibits phytoene desaturase in plants, and is unique in that its mechanism of action (MOA) is not currently registered for use in cotton. Studies were conducted to determine the length of residual that fluridone provides in controlling Palmer amaranth in Arkansas glyphosate- and glufosinate-resistant cotton programs and along field margins in comparison to other soil-residual herbicides. Furthermore, studies were conducted to assess the persistence of fluridone in Arkansas soils and the risk for injury to crops subsequently planted following fluridone use in cotton. Regardless of the cotton program, fluridone failed to provide season-long control of Palmer amaranth; hence, reducing the number of postemergence applications will not be recommended when applying fluridone at cotton planting. Additionally, fluridone failed to provide season-long control of Palmer amaranth along ditchbanks over that of other labeled soil-residual herbicides; however, when applied under favorable conditions fluridone applied preplant incorporated provided extended control of Palmer amaranth with or without a sequential application. Injury to wheat as a rotational crop from an application of fluridone to cotton was greater than that of other crops commonly rotated with cotton; albeit, injury was not severe enough to result in wheat yield reductions. Although fluridone did not provide season-long control of Palmer amaranth, introducing a herbicide with a unique MOA into current cotton would be beneficial for reducing the risk of resistance to herbicides that are currently used in cotton.
Book Synopsis Palmer Amaranth (Amaranthus Palmeri) Control in Double-crop Dicamba/glyphosate Resistant Soybean (Glycine Max) and Dicamba and 2,4-D Efficacy on Palmer Amaranth and Common Waterhemp (Amaranthus Rudis) by : Nathaniel Russell Thompson
Download or read book Palmer Amaranth (Amaranthus Palmeri) Control in Double-crop Dicamba/glyphosate Resistant Soybean (Glycine Max) and Dicamba and 2,4-D Efficacy on Palmer Amaranth and Common Waterhemp (Amaranthus Rudis) written by Nathaniel Russell Thompson and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Auxin herbicides have been widely used for broadleaf weed control since the mid-1940's. With new auxinic herbicide-resistant traits in corn, soybean, and cotton, use of these herbicides is likely to increase. Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) and common waterhemp (Amaranthus rudis) are two primary problematic weed species that will be targeted with dicamba and 2,4-D in the new systems. No-till double-crop soybean after winter wheat harvest is a popular cropping system in central and eastern Kansas, however, management of glyphosate resistant Palmer amaranth has become a serious issue. Field experiments were established near Manhattan and Hutchinson, KS, in 2016 and 2017, to compare seventeen herbicide treatments for control of Palmer amaranth and large crabgrass (Digitaria sanguinalis) in dicamba/glyphosate resistant no-till double-crop soybean after winter wheat. Herbicide programs that included a residual preemergence (PRE) treatment followed by a postemergence (POST) treatment offered greater Palmer amaranth control 8 weeks after planting when compared to PRE-only, POST-only and burndown-only treatments. All treatments that contained glyphosate POST provided complete control of large crabgrass compared to less than 43% control with PRE-only treatments. Soybean grain yield was greater in programs that included PRE followed by POST treatments, compared to PRE-only and burndown-only treatments. A second set of field experiments were established in 2017 near Manhattan and Ottawa, KS to evaluate dicamba and 2,4-D POST efficacy on Palmer amaranth and common waterhemp. Five rates of dicamba (140, 280, 560, 1121, and 2242 g ae ha−1) and 2,4-D (140, 280, 560, 1121, and 2242 g ae ha−1) were used to evaluate control of the Amaranthus spp. Each experiment was conducted twice at each location. Dicamba provided better Palmer amaranth and common waterhemp control than 2,4-D across the rates evaluated. Control of Palmer amaranth was 94% and 99% with dicamba rates of 1121 and 2242 g ae ha−1, respectively, but 2,4-D never provided more than 80% control at any rate. The highest rates of both dicamba and 2,4-D provided greater than 91% common waterhemp control, but control was less than 78% with all other rates of both herbicides. Palmer amaranth and common waterhemp control did not exceed 73% with the highest labelled POST rates of either dicamba or 2,4-D. Auxinic herbicide-resistant traits in corn, soybean, and cotton offer new options for controlling glyphosate-resistant Palmer amaranth and common waterhemp, however proper stewardship is vital to maintain their effectiveness.
Book Synopsis Postemergence and Residual Control of Glyphosate-resistant Palmer Amaranth (Amaranthus Palmeri) with Dicamba by : Clifford Blake Edwards
Download or read book Postemergence and Residual Control of Glyphosate-resistant Palmer Amaranth (Amaranthus Palmeri) with Dicamba written by Clifford Blake Edwards and published by . This book was released on 2013 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: On-farm research was conducted in 2011 and 2012 to determine the postemergence and residual control by dicamba of glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Wats.). Preemergence dicamba at 0, 0.28, 0.56, and 1.1 kg ae ha−1 and 0.07 kg ae ha−1 flumioxazin was applied at 30, 15 and 0 days prior to planting. Postemergence dicamba at 0.28, 0.56, and 1.1 kg ae ha−1 with and without 0.84 kg ae ha−1 glyphosate was applied to 5, 10 and 15 cm Palmer amaranth. In addition, a greenhouse experiment was conducted in 2012 to evaluate and confirm the optimum rate for control of Palmer amaranth with a new formulation of dicamba (BAS 18322H). In the greenhouse, dicamba at 0.14, 0.28, 0.56, 1.1, and 2.2 kg ae ha−1 was applied to 5, 10, and 15 cm Palmer amaranth.
Book Synopsis Physiological, and Genetic Characterization of 2,4-D-resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) and Its Management by : Chandrima Shyam
Download or read book Physiological, and Genetic Characterization of 2,4-D-resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) and Its Management written by Chandrima Shyam and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth (Amaranthus palmeri S. Watson) is one of the topmost troublesome, C4 dioecious weeds in the US. Biological traits such as aggressive growth habits, prolific seed production, and the ability to withstand environmental stresses hinder control of this weed. Additionally, numerous Palmer amaranth populations across the US have been found to have evolved resistance to multiple herbicides. In 2018, a population of Palmer amaranth from a conservation tillage study from Riley County, Kansas was suspected to have evolved resistance to multiple herbicides including 2,4-dichlorophenoxyacetic acid (2,4-D) and was designated as Kansas Conservation Tillage Resistant (KCTR). 2,4-D, a synthetic auxin herbicide, is widely used for controlling broadleaf weeds in cereal crops. However, over-reliance on 2,4-D to control other herbicide-resistant weeds, along with the commercialization of 2,4-D-tolerant crop technology, has resulted in increased usage of this herbicide. The objectives of this dissertation were to 1) characterize the evolution of multiple herbicide resistance including 2,4-D in KCTR Palmer amaranth; 2) investigate the physiological mechanism of 2,4-D resistance in KCTR compared to two known susceptible Palmer amaranth populations i.e., Kansas Susceptible (KSS) and Mississippi Susceptible (MSS); 3) assess the genetic basis of 2,4-D resistance in KCTR; and 4) evaluate herbicide programs that can manage glyphosate-resistant Palmer amaranth in 2,4-D tolerant soybean. Experiments were conducted under either greenhouse or controlled growth chamber conditions. Standard herbicide dose-response, physiological, biochemical (using radiolabeled herbicides), breeding, and field experiments were designed and conducted. The results of these experiments found that KCTR Palmer amaranth had evolved resistance to six herbicide modes of action, including acetolactate synthase (ALS)-, photosystem II (PS II)-, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS)-, 4-hydroxyphenylpyruvate dioxygenase (HPPD)-, protoporphyrinogen oxidase (PPO)- inhibitors, and synthetic auxins (2,4-D). Sequencing and analyses of genes coding for the herbicide targets indicated absence of all known mutations that confer resistance, except for EPSPS-inhibitor, with a massive amplification of EPSPS gene (up to 88 copies). Investigation of non-target site resistance mechanism(s) in KCTR confirmed the predominance of metabolic resistance to multiple herbicides mediated by either cytochrome P450 (P450) or glutathione S-transferase enzyme activity. Whole-plant dose-response analyses confirmed a 6- to 11- fold resistance to 2,4-D in KCTR compared to two susceptible populations (KSS or MSS). [14C] 2,4-D uptake and translocation studies indicated a 10% less and 3 times slower translocation of [14C] 2,4-D in KCTR compared to susceptible populations, while there was no difference in the amount of [14C] 2,4-D absorbed. However, KCTR plants metabolized [14C] 2,4-D much faster than the susceptible KSS and MSS, suggesting that enhanced metabolism bestows resistance to this herbicide in KCTR. Further, use of P450-inhibitor (e.g., malathion) indicated that the metabolism of 2,4-D in KCTR is mediated by P450 activity. Genetic analyses of F1 and F2 progenies, derived from crossing between KCTR and KSS, revealed that 2,4-D resistance in KCTR Palmer amaranth is an incompletely dominant, nuclear trait. Segregation of F2 progenies did not follow the Mendelian single gene inheritance model (3:1), suggesting the involvement of multiple genes in mediating 2,4-D resistance in KCTR. Evaluation of herbicide programs for Palmer amaranth management in the field suggested that pre-emergence herbicides with residual activity followed by post-emergence application of either 2,4-D or glufosinate or 2,4-D and glufosinate can control glyphosate-resistant Palmer amaranth in 2,4-D-tolerant soybean. Overall, the outcome of this dissertation documents the first case of a six-way resistance in a single Palmer amaranth population and also for the first time characterizes the physiological and genetic basis of 2,4-D resistance in this weed. These findings will help in predicting and minimizing further evolution and spread of 2,4-D resistance in Palmer amaranth.
Book Synopsis Glyphosate-resistant Palmer Amaranth and Ryegrass Management by : Kenneth L. Smith
Download or read book Glyphosate-resistant Palmer Amaranth and Ryegrass Management written by Kenneth L. Smith and published by . This book was released on 2009 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The growth of glyphosate-resistant Amaranthus Palmeri in response to increased temperature and water stress by : Hannah M. Parks
Download or read book The growth of glyphosate-resistant Amaranthus Palmeri in response to increased temperature and water stress written by Hannah M. Parks and published by . This book was released on 2018 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluation of Rescue Applications on Glyphosate-resistant Palmer Amaranth by : Andrew Boyette Denton
Download or read book Evaluation of Rescue Applications on Glyphosate-resistant Palmer Amaranth written by Andrew Boyette Denton and published by . This book was released on 2016 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: Options for glyphosate-resistant (GR) Palmer amaranth [Amaranthus palmeri (S. Wats)] control are becoming limited. Research was conducted in 2014 and 2015 to evaluate the effectiveness of rescue herbicide applications on glyphosate-resistant Palmer amaranth. Research was established to evaluate efficacy provided by new and current herbicide programs on GR Palmer amaranth that was larger than recommended at the time of herbicide application. Studies included a postemergence application of different herbicides used singly and in combination at differentinitial application timings; sequential postemergence application timing evaluating herbicide tank mix combinations at five different time intervals between applications; and postemergence evaluation of herbicide tank mix combinations at multiple application timings.
Download or read book Herbicides written by Andrew Price and published by BoD – Books on Demand. This book was released on 2015-11-26 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Herbicides are one of the most widely used groups of pesticides worldwide for controlling weedy species in agricultural and non-crop settings. Due to the extensive use of herbicides and their value in weed management, herbicide research remains crucial for ensuring continued effective use of herbicides. Presently, a wide range of research continues to focus on improved herbicide use and weed biology. The authors of Herbicides, Agronomic Crops and Weed Biology cover multiple topics concerning current valuable herbicide research.
Book Synopsis Response of Glyphosate Resistant Palmer Amaranth (Amaranthus Palmeri) to Protoporphyrinogen Oxidase Inhibiting Herbicides in Tennessee by : Alinna Marie Umphres
Download or read book Response of Glyphosate Resistant Palmer Amaranth (Amaranthus Palmeri) to Protoporphyrinogen Oxidase Inhibiting Herbicides in Tennessee written by Alinna Marie Umphres and published by . This book was released on 2017 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: In many agronomic cropping systems across the United States, Palmer amaranth (Amaranthus palmeri) is the most economic and troublesome weed for producers. The introduction of glyphosate resistant (GR) crops gave producers the benefit of controlling Palmer amaranth as well as other weeds, a broad window of application, and reduced tillage practices. With the confirmation of GR Palmer amaranth, producers implemented protoporphyrinogen oxidase (PPO or Protox)-inhibiting herbicides to control these populations in crops such as soybean [Glycine max (L.) Merr.] and cotton [Gossypium hirsutum (L.)]. However the continuous use of PPO herbicides has caused a shift in Palmer amaranth populations for PPO resistance. Therefore the scope of this study was to observe fomesafen response to four Palmer amaranth populations, determine the fomesafen resistance level, evaluate the effect of Palmer amaranth size on fomesafen efficacy, determine susceptibility to other foliar-applied herbicides, and evaluate the efficacy of four soil-applied PPO-inhibiting herbicides on PPO-resistant (PPO-R) and PPOsusceptible (PPO-S) Palmer amaranth populations. The PPO-S population was observed with 98% control however, fomesafen efficacy was reduced in SPA, LPA, and WPA populations with 24%, 4%, and 2% control, respectively at 14 days after treatment (DAT). The level of resistance for the PPO-R population SPA was 4-fold relative to the PPO-S population KPA. When determining the height of Palmer amaranth on fomesafen efficacy, control of SPA Sm, Md, and Lg sized plants was 62%, 49%, and 18%, respectively. Atrazine, glufosinate, and mesotrione were observed to have the greatest control (>70%) of the SPA population but resistant to glyphosate and chlorimuron. When subjected to soil-applied PPO herbicides, SPA showed reduced control with fomesafen and saflufenacil however greater control was observed with flumioxazin and sulfentrazone at 35 DAT.
Book Synopsis Distribution and Management of Herbicide-resistant Palmer Amaranth in Arkansas by : Thomas R. Butts
Download or read book Distribution and Management of Herbicide-resistant Palmer Amaranth in Arkansas written by Thomas R. Butts and published by . This book was released on 2020 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Resistance to Herbicides Conferred by Amaranthus Palmeri Protoporphyrinogen IX Oxidase Mutations by : Pamela Carvalho de Lima
Download or read book Resistance to Herbicides Conferred by Amaranthus Palmeri Protoporphyrinogen IX Oxidase Mutations written by Pamela Carvalho de Lima and published by . This book was released on 2020 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palmer amaranth (Amaranthus palmeri S. Wats.) is one of the most problematic agronomic weeds to control in fields across Arkansas. Thus far, this species has evolved resistance to several herbicides, including protoporphyrinogen IX oxidase (PPO) inhibitors. The majority of PPO-resistant Palmer amaranth populations harbor a target-site mutation (substitution or deletion of amino acids). The objective of this thesis was to identify the level of fomesafen resistance conferred by PPO2 mutations from Palmer amaranth. The experiments conducted aimed to (1) characterize the level of resistance conferred by the transgene Palmer amaranth ppo2 carrying EG210 mutation into the wild type rice (Oryza sativa cv. 'Nipponbare'); and (2) study the resistance level of Palmer amaranth plants having a single mutation (EG210 or G399A) or a combination. For objective 1, 'Nipponbare' rice was transformed with Palmer amaranth ppo2 EG210 gene via particle bombardment. The presence of the transgene in T0 plants was confirmed, and seeds (T1) were harvested. After selection with foliar treatment of fomesafen (0.78 kg ai ha-1), T1 plants carrying the mutation and showing low injury were maintained to produce T2 seeds. Soil-based assay was conducted with T2 seeds and the survivors were cultured to produce T3 seeds. Seeds from each surviving plant were kept as a separate line. The insertion of Palmer amaranth ppo2 EG210 conferred resistance to fomesafen in rice. The data suggests that only homozygous transgenic plants had full resistance to fomesafen. For objective 2, one susceptible and six resistant accessions were used to conduct dose response assay with the PPO-herbicide, fomesafen, and to test cross resistance or multiple resistance. Selected survivors from these tests were genotyped for the two expected mutations. Homozygosity of EG210 was correlated with high fomesafen resistance. At higher fomesafen rates, survivors carrying EG210 in both alleles or accumulating EG210+G399A recovered better than heterozygous EG210 plants. Populations with higher frequency of individuals with these mutation profiles were also less sensitive to the other two PPO-herbicides tested, saflufenacil and trifludimoxazin.
Book Synopsis Resistance to Glyphosate in Palmer Amaranth (Amaranthus Palmeri) Populations from New Mexico Pecan Orchards by : Mohsen Mohseni Moghadam
Download or read book Resistance to Glyphosate in Palmer Amaranth (Amaranthus Palmeri) Populations from New Mexico Pecan Orchards written by Mohsen Mohseni Moghadam and published by . This book was released on 2013 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
