Weed Technology最新文献

{"title":"Effect of herbicide programs on control and seed production of multiple herbicide-resistant Palmer amaranth (Amaranthus palmeri) in corn resistant to 2,4-D/glufosinate/glyphosate","authors":"Ramandeep Kaur, Rachel Rogers, Nevin C. Lawrence, Yeyin Shi, Parminder S. Chahal, Stevan Z. Knezevic, Amit J. Jhala","doi":"10.1017/wet.2024.23","DOIUrl":"https://doi.org/10.1017/wet.2024.23","url":null,"abstract":"Multiple herbicide-resistant (MHR) Palmer amaranth is among the most problematic summer annual broadleaf weeds in Nebraska and several other states in the United States. A new multiple herbicide-resistant corn cultivar (2,4-D/glufosinate/glyphosate-resistant, also known as Enlist corn) has been commercially available in the United States since 2018. Growers are searching for herbicide programs for control and reducing seed production of MHR Palmer amaranth in Enlist corn. The objectives of this study were to evaluate herbicide programs applied preemergence (PRE), early-postemergence (EPOST), or PRE followed by (fb) late-POST (LPOST) for the management of MHR Palmer amaranth in Enlist corn and their effect on Palmer amaranth biomass, density, seed production, and corn yield. Field experiments were conducted near Carleton, Nebraska, in 2020 and 2021 in a grower’s field infested with acetolactate synthase-inhibitor/atrazine/glyphosate-resistant Palmer amaranth in Enlist corn. Herbicides applied PRE, such as flufenacet/isoxaflutole/thiencarbazone-methyl, acetochlor/clopyralid/flumetsulam, or acetochlor/clopyralid/mesotrione provided 75% to 99% control of Palmer amaranth 30 d after PRE (DA-PRE). PRE fb LPOST herbicides resulted in 94% Palmer amaranth control 90 DA-LPOST, reduced weed density to 0 to 8 plants m<jats:sup>−2</jats:sup> 30 DA-LPOST, and biomass to 2 to 14 g m<jats:sup>−2</jats:sup> 15 DA-LPOST compared to PRE-only (59% control, 0 to 15 plants m<jats:sup>−2</jats:sup>, and 4 to 123 g m<jats:sup>−2</jats:sup>) and EPOST-only herbicides (78% control, 6 to 30 plants m<jats:sup>−2</jats:sup>, and 8 to 25 g m<jats:sup>−2</jats:sup>). Based on contrast analysis, Palmer amaranth seed production was reduced to 14,050 seed m<jats:sup>–2</jats:sup> in PRE fb LPOST herbicide programs compared with 325,490 seed m<jats:sup>–2</jats:sup> in PRE-only and 376,750 seed m<jats:sup>–2</jats:sup> in EPOST-only programs. Based on orthogonal contrast, higher corn yield of 12,340 and 11,730 kg ha<jats:sup>−1</jats:sup> was obtained with PRE fb LPOST herbicide programs compared to PRE-only (10,840 and 11,510 kg ha<jats:sup>−1</jats:sup>) and EPOST-only programs (10,850 and 10,030 kg ha<jats:sup>−1</jats:sup>) in 2020 and 2021, respectively.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140613903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of management practices to optimize cereal rye cover crop-based weed mitigation in Canadian sweet corn production","authors":"Hayley L. Brackenridge, Jichul Bae, Marie-Josée Simard, François J. Tardif, Kerry Bosveld, Robert E. Nurse","doi":"10.1017/wet.2024.19","DOIUrl":"https://doi.org/10.1017/wet.2024.19","url":null,"abstract":"Fall sown cereal rye has gained popularity as a cover crop in vegetable production due to its weed-suppressive capabilities. However, previous research has shown that replacing preemergence and/or postemergence herbicide applications with roller-crimped rye has variable success at controlling weeds and maintaining vegetable cash crop yields. The objective of this research was to test roller-crimped rye in sweet corn production to determine whether it can provide season-long weed control and maintain sweet corn yield. Two rye cultivars (early vs. standard maturity) were compared at three seeding rates (150, 300, and 600 seeds m<jats:sup>-2</jats:sup>) for their effect on weed control and sweet corn yield. The trial was conducted at Harrow, ON, and St. Jean-sur-Richelieu, QC, from 2019 to 2021 and at Agassiz, BC, in 2019 and 2021. Results suggest that, although the early maturing cultivar allowed for earlier roller crimping in some locations, it was inferior at weed control and resulted in lower sweet corn yield than local standard cultivars. The average rye biomass was lower than the current literature recommendations, and the resulting level of weed control was not high enough to prevent sweet corn yield loss in cover crop treatments. Weed control provided by roller-crimped rye peaked between crimping and eight weeks after crimping and was highest in the standard cultivars sown at 300 and 600 seeds m<jats:sup>-2</jats:sup>. Preliminary testing of supplemental postemergence weed control showed evidence for sweet corn yields comparable to the weed-free no-cover crop check. However, more research is needed. Overall, it was found that with the cultivars and seeding rates tested, roller-crimped rye is not a suitable stand-alone weed control option in sweet corn. Given the benefits of cover crops, further research should evaluate its potential as a component of an integrated weed management program.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140600771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water-Seeded Rice Response to Pendimethalin Applied at Different Rates and Timings","authors":"Aaron Becerra-Alvarez, Kassim Al-Khatib","doi":"10.1017/wet.2024.18","DOIUrl":"https://doi.org/10.1017/wet.2024.18","url":null,"abstract":"Currently, there is a limited number of herbicides available in California water-seeded rice, with widespread resistance to most of these herbicides. Because no resistant grasses showed resistance to pendimethalin, a series of studies were conducted to evaluate water-seeded rice response to pendimethalin. In a field study conducted at the Rice Experiment Station at Biggs, California, in 2020 and 2021, three pendimethalin formulations, a granule (GR), emulsifiable concentrate (EC), and capsule suspension (CS), were applied at 1.1, 2.3, and 3.4 kg ai ha<jats:sup>-1</jats:sup> rates, and at 5, 10, and 15 days after seeding onto water-seeded rice. In addition, a greenhouse study was conducted to examine the response of five common California rice cultivars to GR and CS formulation applications. <jats:italic>Echinochloa</jats:italic> control levels were reduced at the 15 days after seeding timing after use of EC and CS formulations compared to earlier timings. In both years, rice grain yields were increased by 3,014 kg ha<jats:sup>-1</jats:sup> after application of pendimethalin at 3.4 kg ai ha<jats:sup>-1</jats:sup> when applied at 15 days after seeding compared to 5 and 10 days after seeding, and similar to 1.1 kg ai ha<jats:sup>-1</jats:sup> applications. The GR and CS were safer formulations based on a reduction in injury and an increase in grain yields compared to the EC. Differences in seedling vigor across cultivars appeared to incur an advantage after a pendimethalin application. However, most cultivars evaluated for stand reduction and dry biomass demonstrated tolerance to GR and CS formulation applications only after rice reached the 3-leaf stage. In contrast, an application at 1-leaf stage rice reduced stand up to 68%. Application rate, timing, and formulation are important factors to consider if the use of pendimethalin in water-seeded rice is to be pursued.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140600755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Control of multiple-herbicide-resistant waterhemp with acetochlor-based herbicide mixtures in soybean","authors":"Hannah E. Symington, Nader Soltani, Allan C. Kaastra, David C. Hooker, Darren E. Robinson, Peter H. Sikkema","doi":"10.1017/wet.2024.14","DOIUrl":"https://doi.org/10.1017/wet.2024.14","url":null,"abstract":"<p>Waterhemp has evolved resistance to Group 2, 5, 9, 14, and 27 herbicides in Ontario, Canada, making control of this challenging weed even more difficult. Acetochlor is a Group 15, chloroacetanilide herbicide that has activity on many small-seeded annual grasses and some small-seeded annual broadleaf weeds, including waterhemp. The objective of this study was to ascertain if acetochlor mixtures with broadleaf herbicides (dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin), applied preemergence (PRE), increase multiple-herbicide-resistant (MHR) waterhemp control in soybean. Five trials were conducted over 2 yr (2021 and 2022). The acetochlor mixtures caused ≤7% soybean injury, except acetochlor + flumioxazin, which caused 19% soybean injury. Acetochlor applied PRE controlled MHR waterhemp 89% at 4 wk after application (WAA). Dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin controlled MHR waterhemp 59%, 67%, 58%, 64%, and 86%, respectively, at 4 WAA. Acetochlor applied in a mixture with dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin provided good to excellent control of MHR waterhemp; control ranged from 91% to 98% but was similar to acetochlor applied alone. Acetochlor alone reduced MHR waterhemp density and biomass 98% and 93%; acetochlor + flumioxazin reduced waterhemp density and biomass by an additional 2% and 7%, respectively. This research concludes that acetochlor applied in a mixture with flumioxazin was the most efficacious mixture evaluated for MHR waterhemp control.</p>","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140600648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EPSPS Gene Amplification Confers Glyphosate Resistance in Palmer Amaranth in Connecticut","authors":"Jatinder S. Aulakh, Vipan Kumar, Caio A. C. G. Brunharo, Adrian Veron, Andrew J. Price","doi":"10.1017/wet.2024.17","DOIUrl":"https://doi.org/10.1017/wet.2024.17","url":null,"abstract":"A Palmer amaranth biotype (CT-Res) with resistance to glyphosate was recently confirmed from a pumpkin field in Connecticut. However, the underlying mechanism (s) conferring glyphosate resistance in this biotype is not known. The main objectives of this research were (1) to determine the effect of plant height (10-, 20-, and 30-cm tall) on glyphosate resistance levels in CT-Res Palmer amaranth biotype, and (2) to investigate if the target-site-based mechanisms confer glyphosate resistance. To achieve these objectives, progeny seeds of CT-Res biotype after two generations of recurrent selection with glyphosate (6,720 g ae ha<jats:sup>-1</jats:sup>) were used. Similarly, known glyphosate-susceptible Palmer amaranth biotypes from Kansas (KS-Sus) and Alabama (AL-Sus) were included. Results from greenhouse dose-response studies revealed that CT-Res Palmer amaranth biotype had 69-, 64-, and 54-fold resistance to glyphosate as compared to KS-Sus biotype when treated at 10-, 20-, and 30-cm tall, respectively. Sequence analysis of the <jats:italic>EPSPS</jats:italic> gene revealed no point mutations at the Pro<jats:sub>106</jats:sub> and Thr<jats:sub>102</jats:sub> residues in the CT-Res Palmer amaranth biotype. The qPCR analysis revealed that CT-Res biotype had 33 to 111 relative copies of the <jats:italic>EPSPS</jats:italic> gene compared to AL-Sus biotype. All these results suggest that the <jats:italic>EPSPS</jats:italic> gene amplification endows a high level of glyphosate resistance in the GR Palmer amaranth biotype from Connecticut. Because of the lack of control with glyphosate, growers should adopt effective alternative preemergence and postemergence herbicides in conjunction with other cultural and mechanical tactics to mitigate the further spread of GR Palmer amaranth in Connecticut.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140170671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Control of multiple herbicide-resistant waterhemp (Amaranthus tuberculatus) with acetochlor-based herbicide mixtures in corn","authors":"Hannah E. Symington, Nader Soltani, Allan C. Kaastra, David C. Hooker, Darren E. Robinson, Peter H. Sikkema","doi":"10.1017/wet.2024.16","DOIUrl":"https://doi.org/10.1017/wet.2024.16","url":null,"abstract":"Waterhemp is a summer annual, broadleaf weed with high fecundity, short seed longevity in the soil, and wide genetic diversity. Populations have evolved resistance to five herbicide modes of action (Groups 2, 5, 9, 14, and 27), which are present across southern Ontario; this has increased the challenge of controlling this competitive weed species in corn, the most important grain crop produced worldwide, and the highest value agronomic crop in Ontario. Acetochlor is a Group 15 soil-applied residual herbicide that has activity on many grass and broadleaf weeds but has yet to be registered in Canada. The objective of this study was to ascertain whether mixtures of acetochlor with flumetsulam, dicamba, atrazine, isoxaflutole/diflufenican, or mesotrione + atrazine applied preemergence would increase the control of multiple herbicide-resistant (MHR) waterhemp in corn. Five field trials were conducted between 2022 and 2023. No corn injury was observed. Acetochlor applied alone controlled MHR waterhemp 97% 12 weeks after application (WAA). All herbicide mixtures controlled MHR waterhemp similarly at ≥98% 12 WAA; there were no differences among herbicide mixtures. Flumetsulam, dicamba, and atrazine provided lower MHR waterhemp control than all other herbicide treatments and did not reduce density or biomass. Acetochlor reduced waterhemp density 98%, while the acetochlor mixtures reduced density similarly at 99 to 100%. This study concludes that the acetochlor mixtures evaluated provide excellent waterhemp control; however, control was not greater than acetochlor alone. Herbicides herbicide mixtures should be used as a best management practice to mitigate the evolution of herbicide resistance.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140154192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Common ragweed (Ambrosia artemisiifolia L.) accession in the Mid-Atlantic region resistant to ALS-, PPO-, and EPSPS-inhibiting herbicides","authors":"Frank D’Amico, Thierry Besançon, Alyssa Koehler, Lovreet Shergill, Melissa Ziegler, Mark VanGessel","doi":"10.1017/wet.2024.11","DOIUrl":"https://doi.org/10.1017/wet.2024.11","url":null,"abstract":"Common ragweed is a troublesome weed in many crops. Farmers and crop advisors in the coastal Mid-Atlantic region have reported inadequate control of common ragweed in soybean with glyphosate and other herbicide modes of action. To determine if herbicide resistance was one of the causes of poor herbicide performance, twenty-nine accessions from four states (DE, MD, NJ, VA) where common ragweed plants survived herbicide applications and produced viable seeds were used for greenhouse screening. Common ragweed seedlings from those accessions were treated with multiple rates of cloransulam, fomesafen, or glyphosate, applied as a single postemergence (POST) herbicide application. All accessions except one demonstrated resistance to at least one of the herbicides applied at twice the effective rate (2X), seventeen accessions were two-way resistant (glyphosate- and cloransulam-resistant; glyphosate- and fomesafen-resistant) and three-way resistance was present in eight accessions collected from three different states. Based on the POST study, five accessions were treated preemergence (PRE) with acetolactate synthase (ALS)-inhibiting PRE herbicides, and two accessions were treated with protoporphyrinogen oxidase (PPO)-inhibiting herbicides. All accessions treated PRE with the ALS-inhibitors chlorimuron or cloransulam demonstrated resistance at the 2X rates. Both accessions treated PRE with the PPO-inhibitor sulfentrazone, had survivors at the 2X rate. When the same accessions were treated PRE with fomesafen, one had survivors at the 2X rate, and one had survivors at the 1X rate. Results from these tests confirmed common ragweed with three-way resistance to POST herbicides is widespread in the region. In addition, this is the first confirmation that common ragweed accessions in the region are also resistant to ALS- or PPO-inhibiting herbicides when applied PRE.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantifying changes in the environmental impact of in-crop herbicide use in Saskatchewan","authors":"Elisabeta Lika, Chelsea Sutherland, Savannah Gleim, Stuart J. Smyth","doi":"10.1017/wet.2024.15","DOIUrl":"https://doi.org/10.1017/wet.2024.15","url":null,"abstract":"The sustainable management of herbicides is critical to modern agriculture and the environment. This article examines the evolution and environmental implications of herbicide use in Saskatchewan agriculture. It quantifies changes in herbicide use and their environmental impacts by analyzing farm-level herbicide use data from 1991-1994 and 2016-2019 through the Environmental Impact Quotient. Results confirm significant reductions in both the environmental and toxicological impacts of herbicides used, underlining the pivotal shift from tillage-based weed control to herbicide-resistant cropping systems. The environmental impact of the top five herbicides used from 2016-19 is 65% lower than those used from 1991-94, with a 45% reduction in the active ingredient applied per acre. Despite increased herbicide usage due to more crop acres being seeded, the findings highlight a marked improvement in the sustainability of herbicide use, affirming the importance of technological advancements in agriculture. This research contributes valuable insights into long-term trends in herbicide use, offering a practical framework for informed decisions aligning with sustainable agricultural practices as well as reduced biodiversity impacts.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140071097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxyfluorfen-Resistant Rice Tolerance and Weed Control when using Oxyfluorfen","authors":"Casey H. Arnold, Jason K. Norsworthy, Thomas R. Butts, Trenton L. Roberts, Nick R. Bateman, Chad W Shelton","doi":"10.1017/wet.2024.6","DOIUrl":"https://doi.org/10.1017/wet.2024.6","url":null,"abstract":"Herbicide-resistant barnyardgrass and weedy rice control, without crop injury, is a challenge for rice producers in the United States. Herbicides, such as oxyfluorfen, that were not initially labeled for rice, are now being evaluated as a new tool for weed control. The Roxy<jats:sup>®</jats:sup> trait allows for the use of oxyfluorfen in rice for weed control preemergence and postemergence. Experiments were initiated in 2021 and 2022 to evaluate 1) the effectiveness of preemergence- and postemergence-applied oxyfluorfen on barnyardgrass and weedy rice, 2) the sensitivity of oxyfluorfen-resistant rice to oxyfluorfen as a function of application timing, and 3) the influence of soil moisture on oxyfluorfen-resistant rice sensitivity to oxyfluorfen. In the field, a rate response was observed for oxyfluorfen applied to weedy rice when averaged over application timings of 1-leaf, 2-leaf, 3-leaf, and tillering, with oxyfluorfen at 1,680 g ai ha<jats:sup>-1</jats:sup> resulting in 81 and 72% control 7 d after application (DAA) in 2021 and 2022, respectively. Under greenhouse conditions, barnyardgrass and weedy rice control averaged by the rate of oxyfluorfen was ≥85 and ≥70%, respectfully, 7 DAA for the 1-, 2-, and 3-leaf rice growth stage timings. Preemergence applications of oxyfluorfen under 100% soil saturation resulted in 75% injury to oxyfluorfen-resistant rice, greater than all other soil moisture at 7 DAA. All postemergence applications of oxyfluorfen resulted in 63 to 70% injury to oxyfluorfen-resistant rice at 7 DAA, regardless of soil moisture. Barnyardgrass and weedy rice control with oxyfluorfen are achieved with timely applications; however, injury to oxyfluorfen-resistant rice is likely.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140002325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification, mapping, and chemical control of fleabane resistant to glyphosate, chlorimuron, paraquat and 2,4-D","authors":"Juliano Bortoluzzi Lorenzetti, Maikon Tiago Yamada Danilussi, Alfredo Junior Paiola Albrecht, Arthur Arrobas Martins Barroso, Leandro Paiola Albrecht, André Felipe Moreira Silva, Guilherme Rossano dos Santos, Giuzeppe Augusto Maram Caneppele","doi":"10.1017/wet.2024.10","DOIUrl":"https://doi.org/10.1017/wet.2024.10","url":null,"abstract":"Monitoring herbicide-resistant weeds makes it possible to study the evolution and spread of resistance, providing important information for management. The objective of this study was to map fleabane accessions in the states of Paraná (PR) and Mato Grosso do Sul (MS), Brazil, to identify herbicide-resistant accessions and their response to soybean pre-plant chemical burndown management strategies. Fleabane seeds were collected in agricultural areas in PR and MS, in 2018, 2019, and 2020. Initial screening was performed for glyphosate, chlorimuron, paraquat, 2,4-D, saflufenacil, and glufosinate efficacy. Subsequently, dose-response experiments were conducted. Field experiments were carried out in three locations, where accessions of multiple-resistant Sumatran fleabane were identified. Herbicides were used in single or sequential (seq.) applications at three plant heights (&lt;5 cm, 5 to 10 cm, and &gt;10 cm). After preliminary screening, accessions were classified as putative resistant (&lt;80% control for all 4 replicates), segregated (&lt;80% control for 1 to 3 replicates), or susceptible (&gt;80% control for all 4 replicates). There was no evidence of resistance to glufosinate or saflufenacil in any of the 461 accessions, while 65 showed possible resistance or segregation only for glyphosate, 235 for glyphosate + chlorimuron, 79 to glyphosate + chlorimuron + paraquat, 59 to glyphosate + chlorimuron + 2,4-D, and 23 with 4-way resistance (glyphosate, chlorimuron, paraquat and 2,4-D). Of these 23 accessions, 7 were analyzed using dose-response curves (F2 generation), all from PR, confirming 4-way resistance to glyphosate, chlorimuron, paraquat, and 2,4-D. To control resistant Sumatran fleabane, an application should prioritize smaller plants. Despite resistance to 2,4-D, double mixtures containing this herbicide were among the most effective treatments in plants &lt;5 cm in height. Sequential application is needed for plants &gt;5 cm in height, it was recommended glyphosate + synthetic auxin followed by glufosinate or glyphosate + saflufenacil.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140002047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}