Jacob Fleming, J. Norsworthy, M. Bagavathiannan, T. Barber
Postemergence selective monocot control in grain sorghum is an issue due to the limited number of herbicides available. The herbicides currently labeled in grain sorghum have strict use restrictions, low efficacy on johnsongrass, or weed resistance issues. To introduce a new effective herbicide mode of action for monocot control, multiple companies and universities have been developing herbicide-resistant grain sorghum that would allow producers to utilize either acetolactate synthase (ALS) or acetyl coenzyme A carboxylase (ACCase) inhibitors for postemergence monocot control. An experiment was conducted in Fayetteville, AR, in 2020 and 2021 to determine the effectiveness of two ALS-inhibiting herbicides and nine ACCase-inhibiting herbicides on TamArkTM grain sorghum, conventional grain sorghum, and problematic monocot weed species. Grain sorghum and monocot weeds (johnsongrass, broadleaf signalgrass, barnyardgrass, and Texas panicum) were sprayed when TamArkTM grain sorghum reached the 2- to 3-leaf stage. TamArkTM grain sorghum was tolorant to all ACCase-inhibiting herbicides tested exhibiting ≤10% injury at all evaluation timings, except clethodim and sethoxydim, and had no resistance to the ALS-inhibiting herbicides evaluated. Additionally, all ACCase inhibitors except diclofop and pinoxaden controlled all monocots tested >91% by 28 days after application (DAA). Conversely, the two ALS inhibitors, imazamox and nicosulfuron had ≤81% control of broadleaf signalgrass 28 DAA but still controlled all other monocots >95%. TamArkTM grain sorghum 'has low sensitivity to multiple ACCase-inhibiting herbicides thus providing an effective POST option for monocot weed control and unwanted volunteer TamArkTM plants can be controlled with cledthodim, sethoxydim, nicosulfuron, or imazamox has low sensitivity to multiple ACCase-inhibiting herbicides. Imazamox and nicosulfuron, both ALS-inhibiting herbicides, while not useful on TamArkTM grain sorghum, are effective options for monocot control in IgrowthTM and InzenTM grain sorghum, respectively.
{"title":"Sensitivity of TamArkTM Grain Sorghum and Monocot Weed Species to ACCase- and ALS-inhibiting Herbicides","authors":"Jacob Fleming, J. Norsworthy, M. Bagavathiannan, T. Barber","doi":"10.1017/wet.2023.51","DOIUrl":"https://doi.org/10.1017/wet.2023.51","url":null,"abstract":"\u0000 Postemergence selective monocot control in grain sorghum is an issue due to the limited number of herbicides available. The herbicides currently labeled in grain sorghum have strict use restrictions, low efficacy on johnsongrass, or weed resistance issues. To introduce a new effective herbicide mode of action for monocot control, multiple companies and universities have been developing herbicide-resistant grain sorghum that would allow producers to utilize either acetolactate synthase (ALS) or acetyl coenzyme A carboxylase (ACCase) inhibitors for postemergence monocot control. An experiment was conducted in Fayetteville, AR, in 2020 and 2021 to determine the effectiveness of two ALS-inhibiting herbicides and nine ACCase-inhibiting herbicides on TamArkTM grain sorghum, conventional grain sorghum, and problematic monocot weed species. Grain sorghum and monocot weeds (johnsongrass, broadleaf signalgrass, barnyardgrass, and Texas panicum) were sprayed when TamArkTM grain sorghum reached the 2- to 3-leaf stage. TamArkTM grain sorghum was tolorant to all ACCase-inhibiting herbicides tested exhibiting ≤10% injury at all evaluation timings, except clethodim and sethoxydim, and had no resistance to the ALS-inhibiting herbicides evaluated. Additionally, all ACCase inhibitors except diclofop and pinoxaden controlled all monocots tested >91% by 28 days after application (DAA). Conversely, the two ALS inhibitors, imazamox and nicosulfuron had ≤81% control of broadleaf signalgrass 28 DAA but still controlled all other monocots >95%. TamArkTM grain sorghum 'has low sensitivity to multiple ACCase-inhibiting herbicides thus providing an effective POST option for monocot weed control and unwanted volunteer TamArkTM plants can be controlled with cledthodim, sethoxydim, nicosulfuron, or imazamox has low sensitivity to multiple ACCase-inhibiting herbicides. Imazamox and nicosulfuron, both ALS-inhibiting herbicides, while not useful on TamArkTM grain sorghum, are effective options for monocot control in IgrowthTM and InzenTM grain sorghum, respectively.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41904887","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}
Glyphosate-resistant (GR) horseweed is a problematic weed for Michigan soybean growers. Additionally, rosette- and upright- horseweed growth types have been observed co-emerging during mid- to late-summer in several Michigan fields. In the greenhouse, shade levels from 35 to 92% reduced rosette and upright horseweed biomass 31 to 99% compared with the upright growth type grown under 0% shade. Greater reductions in biomass occurred under 69 and 92% shade. Thus, increased shading by planting in narrow rows and/or planting green into cereal rye may improve horseweed suppression. A field experiment conducted over three site-years compared the effect of fall-planted cereal rye terminated with glyphosate 1 wk after planting (planting green) with a preemergence (PRE) residual herbicide program (glyphosate + 2,4-D + flumioxazin + metribuzin) on horseweed control in soybean planted in three row widths (19-, 38-, and 76-cm). Planting green or applying a residual herbicide program across all row widths reduced horseweed biomass 86 to 91% and 95 to 99%, respectively, compared with soybean planted with no cover in 76 cm rows, 4 to 6 wk after planting (WAP). At soybean harvest, when a noneffective postemergence (POST) herbicide (glyphosate) was applied horseweed biomass was 42 and 81% lower by planting green or applying a residual herbicide program compared with no cover, respectively. Similarly, planting soybean in 19 cm rows reduced horseweed biomass compared with 38- and 76-cm rows. When an effective POST program was applied, similar horseweed biomass reductions were observed by planting green or applying a residual herbicide across all row widths. Additionally, soybean yield and economic returns were similar between planting green and applying a residual herbicide in 1 of 2 site-years. Integrating planting green and an effective POST herbicide program offers an alternative horseweed management strategy to applying a residual preemergence herbicide program.
{"title":"Contributions of shading, soybean row-width, and planting green on horseweed management compared with soil-applied residual herbicides","authors":"Justin D. L. Fisher, Christy L. Sprague","doi":"10.1017/wet.2023.49","DOIUrl":"https://doi.org/10.1017/wet.2023.49","url":null,"abstract":"\u0000 Glyphosate-resistant (GR) horseweed is a problematic weed for Michigan soybean growers. Additionally, rosette- and upright- horseweed growth types have been observed co-emerging during mid- to late-summer in several Michigan fields. In the greenhouse, shade levels from 35 to 92% reduced rosette and upright horseweed biomass 31 to 99% compared with the upright growth type grown under 0% shade. Greater reductions in biomass occurred under 69 and 92% shade. Thus, increased shading by planting in narrow rows and/or planting green into cereal rye may improve horseweed suppression. A field experiment conducted over three site-years compared the effect of fall-planted cereal rye terminated with glyphosate 1 wk after planting (planting green) with a preemergence (PRE) residual herbicide program (glyphosate + 2,4-D + flumioxazin + metribuzin) on horseweed control in soybean planted in three row widths (19-, 38-, and 76-cm). Planting green or applying a residual herbicide program across all row widths reduced horseweed biomass 86 to 91% and 95 to 99%, respectively, compared with soybean planted with no cover in 76 cm rows, 4 to 6 wk after planting (WAP). At soybean harvest, when a noneffective postemergence (POST) herbicide (glyphosate) was applied horseweed biomass was 42 and 81% lower by planting green or applying a residual herbicide program compared with no cover, respectively. Similarly, planting soybean in 19 cm rows reduced horseweed biomass compared with 38- and 76-cm rows. When an effective POST program was applied, similar horseweed biomass reductions were observed by planting green or applying a residual herbicide across all row widths. Additionally, soybean yield and economic returns were similar between planting green and applying a residual herbicide in 1 of 2 site-years. Integrating planting green and an effective POST herbicide program offers an alternative horseweed management strategy to applying a residual preemergence herbicide program.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45501334","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}
Jacob Fleming, J. Norsworthy, M. Bagavathiannan, T. Barber
Genetic similarities between johnsongrass and grain sorghum leave producers with limited herbicide options for postemergence johnsongrass control. TamArkTM grain sorghum with resistance to acetyl CoA carboxylase-inhibiting herbicides was developed through a collaboration between the University of Arkansas System Division of Agriculture and Texas A&M AgriLife Research. Two field experiments were conducted in 2021 in two locations each Keiser and Marianna, AR or Fayetteville and Marianna, AR. The objective of the first was to determine the optimal rate and application timing of fluazifop-butyl for control of natural johnsongrass populations in a non-crop setting, and of the second was to evaluate johnsongrass control and TamArkTM grain sorghum tolerance in response to fluazifop-butyl applied at different timings and rates based on crop growth stage. The highest levels of johnsongrass control occurred when sequential applications of fluazifop-butyl were utilized. All sequential treatments provided at least 80% johnsongrass control at any rate or application timing tested. A single application of fluazifop-butyl provided greater than 90% johnsongrass control when applied at 210 g ai ha-1 to johnsongrass with less than 6 leaves. Weed size played a role in achieving high levels of johnsongrass control. Greater than 90% control was achieved when johnsongrass had 6-leaves or less at the initial application for the sequential application treatments. A single application of fluazifop-butyl at 105 g ai ha-1 resulted in no more than 82% johnsongrass mortality at any application timing. TamArk TM grain sorghum injury did not exceed 6% at any application timing or rate. It was, therefore, considered to be safe even if the initial application was made before the 6-leaf crop stage. Since no unacceptable levels of injury were observed with TamArkTM grain sorghum for fluazifop-butyl, johnsongrass size at the time of application should be the most critical aspect for control with this herbicide.
约翰逊草和高粱之间的遗传相似性使得生产者在约翰逊草出现后控制除草剂的选择有限。TamArkTM谷物高粱具有抗乙酰辅酶a羧化酶抑制剂的抗性，是由阿肯色大学农业系统部和德克萨斯农工大学农业生物研究所合作开发的。研究人员于2021年在德克萨斯州Keiser和Marianna或Fayetteville和Marianna两个地点分别进行了两项田间试验。第一项试验的目的是确定在非作物环境下控制天然强johngrass种群的最佳用量和施用时间，第二项试验是根据作物生长阶段，评估在不同的施用时间和施用剂量下，fluazifp -butyl对强johngrass的控制和TamArkTM谷物高粱的耐药性。当连续使用氟唑磷-丁基时，约翰逊草的控制水平最高。所有顺序处理在任何速率或施用时间测试下都提供了至少80%的约翰逊草控制。当剂量为210 g / ha-1时，单次施用氟唑磷-丁基对6片以下强生草的防治效果大于90%。杂草大小在实现高水平的约翰逊草控制方面发挥了作用。按顺序施用，初施6片或6片以下的约翰逊草防治效果大于90%。在任何施用时间，单次施用105 g / ha-1的氟唑磷-丁基导致约翰逊草死亡率不超过82%。TamArk TM籽粒高粱在任何施用时间和施用速率下的伤害均不超过6%。因此，即使在6叶作物阶段之前进行初始施用，也被认为是安全的。由于在TamArkTM高粱上没有观察到对氟唑磷-丁基的不可接受程度的伤害，因此施用时的约翰逊草大小应该是该除草剂控制的最关键方面。
{"title":"Influence of Fluazifop Timing and Rate on Johnsongrass (Sorghum halepense (L.)) Control in ACCase Resistant Grain Sorghum (Sorghum bicolor (L.) Moench)","authors":"Jacob Fleming, J. Norsworthy, M. Bagavathiannan, T. Barber","doi":"10.1017/wet.2023.47","DOIUrl":"https://doi.org/10.1017/wet.2023.47","url":null,"abstract":"\u0000 Genetic similarities between johnsongrass and grain sorghum leave producers with limited herbicide options for postemergence johnsongrass control. TamArkTM grain sorghum with resistance to acetyl CoA carboxylase-inhibiting herbicides was developed through a collaboration between the University of Arkansas System Division of Agriculture and Texas A&M AgriLife Research. Two field experiments were conducted in 2021 in two locations each Keiser and Marianna, AR or Fayetteville and Marianna, AR. The objective of the first was to determine the optimal rate and application timing of fluazifop-butyl for control of natural johnsongrass populations in a non-crop setting, and of the second was to evaluate johnsongrass control and TamArkTM grain sorghum tolerance in response to fluazifop-butyl applied at different timings and rates based on crop growth stage. The highest levels of johnsongrass control occurred when sequential applications of fluazifop-butyl were utilized. All sequential treatments provided at least 80% johnsongrass control at any rate or application timing tested. A single application of fluazifop-butyl provided greater than 90% johnsongrass control when applied at 210 g ai ha-1 to johnsongrass with less than 6 leaves. Weed size played a role in achieving high levels of johnsongrass control. Greater than 90% control was achieved when johnsongrass had 6-leaves or less at the initial application for the sequential application treatments. A single application of fluazifop-butyl at 105 g ai ha-1 resulted in no more than 82% johnsongrass mortality at any application timing. TamArk TM grain sorghum injury did not exceed 6% at any application timing or rate. It was, therefore, considered to be safe even if the initial application was made before the 6-leaf crop stage. Since no unacceptable levels of injury were observed with TamArkTM grain sorghum for fluazifop-butyl, johnsongrass size at the time of application should be the most critical aspect for control with this herbicide.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42376332","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}
Sachin Dhanda, Vipan Kumar, P. Geier, R. Currie, J. Dille, A. Obour, E. Yeager, J. Holman
Multiple herbicide-resistant (MHR) kochia is a serious concern in the U.S. Great Plains and warrants alternative herbicide mixtures for its control. Greenhouse and field experiments were conducted at Kansas State University Research and Extension Centers near Hays and Garden City, KS to investigate the interactions of 2,4-D, dichlorprop-p, dicamba, and halauxifen/fluroxypyr premix in various combinations for MHR kochia control. Two previously confirmed MHR (resistant to glyphosate, dicamba, and fluroxypyr) populations and a susceptible (SUS) population were tested in a greenhouse study. Kochia at the Hays field site was resistant to glyphosate and chlorsulfuron, whereas the population at Garden City was resistant to glyphosate, dicamba, fluroxypyr, and atrazine. Results from greenhouse study indicated that 2,4-D, dicamba, dichlorprop-p, and premix of halauxifen/fluroxypyr provided 26 to 69% control of both MHR populations at 28 days after treatment (DAT). However, the control increased to 85 to 97% when these herbicides were applied in three-way mixtures. Synergistic interactions were observed when dicamba was mixed with dichlorprop-p, 2,4-D, dichlorprop-p + 2,4-D, and halauxifen/fluroxypyr + 2,4-D for shoot dry weight reductions (86 to 92%) of both MHR populations. Results from field study also indicated synergistic interactions when dicamba was mixed with dichlorprop-p + 2,4-D, halauxifen/fluroxypyr + dichlorprop-p, and halauxifen/ fluroxypyr + 2,4-D, resulting in 84 to 95% control of MHR kochia at 28 DAT across both sites. These results indicate that synergistic effects of mixing dicamba with other auxinic herbicides in two- or three-way mixtures can help control MHR kochia.
{"title":"Synergistic Interactions of 2,4-D, Dichlorprop-p, Dicamba, and Halauxifen/Fluroxypyr for Controlling Multiple Herbicide-Resistant Kochia (Bassia scoparia L.)","authors":"Sachin Dhanda, Vipan Kumar, P. Geier, R. Currie, J. Dille, A. Obour, E. Yeager, J. Holman","doi":"10.1017/wet.2023.48","DOIUrl":"https://doi.org/10.1017/wet.2023.48","url":null,"abstract":"Multiple herbicide-resistant (MHR) kochia is a serious concern in the U.S. Great Plains and warrants alternative herbicide mixtures for its control. Greenhouse and field experiments were conducted at Kansas State University Research and Extension Centers near Hays and Garden City, KS to investigate the interactions of 2,4-D, dichlorprop-p, dicamba, and halauxifen/fluroxypyr premix in various combinations for MHR kochia control. Two previously confirmed MHR (resistant to glyphosate, dicamba, and fluroxypyr) populations and a susceptible (SUS) population were tested in a greenhouse study. Kochia at the Hays field site was resistant to glyphosate and chlorsulfuron, whereas the population at Garden City was resistant to glyphosate, dicamba, fluroxypyr, and atrazine. Results from greenhouse study indicated that 2,4-D, dicamba, dichlorprop-p, and premix of halauxifen/fluroxypyr provided 26 to 69% control of both MHR populations at 28 days after treatment (DAT). However, the control increased to 85 to 97% when these herbicides were applied in three-way mixtures. Synergistic interactions were observed when dicamba was mixed with dichlorprop-p, 2,4-D, dichlorprop-p + 2,4-D, and halauxifen/fluroxypyr + 2,4-D for shoot dry weight reductions (86 to 92%) of both MHR populations. Results from field study also indicated synergistic interactions when dicamba was mixed with dichlorprop-p + 2,4-D, halauxifen/fluroxypyr + dichlorprop-p, and halauxifen/ fluroxypyr + 2,4-D, resulting in 84 to 95% control of MHR kochia at 28 DAT across both sites. These results indicate that synergistic effects of mixing dicamba with other auxinic herbicides in two- or three-way mixtures can help control MHR kochia.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43090054","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}
Postemergence herbicides to control weeds in the space between raised, plastic-covered beds in plasticulture production systems are typically banded and herbicides are applied to weeds as well as where weeds do not occur. To reduce the incidence of off-targeted applications, the University of Florida developed smart spray technology for row middles in plasticulture systems. The technology detects weed categories and applies herbicides only where they occur. Field experiments were conducted at the Gulf Coast Research and Education Center in Balm, FL, in the Fall 2021 and Spring 2022. The objective was to evaluate the efficacy of postemergence applications of diquat and glyphosate in row middles in jalapeno pepper fields when banded or applied with smart spray technology. The overall precision of the weed detection model was 0.92 and 0.89 for fall and spring respectively. The actuation precision achieved was 0.86 and 1 for fall and spring respectively. No significant differences were observed between banded and targeted applications either with glyphosate or diquat in terms of broadleaf, grass, and nutsedge weed density. No significant pepper damage was observed with either herbicides or application techniques. The smart spray technology reduced herbicide application volume by 26% and 42% for fall and spring respectively, with no reduction in weed control or pepper yield compared to a banded application. Overall, the smart spray technology reduced the herbicide volume applied with no reductions in weed control and no significant effects on crop yield.
{"title":"Evaluation of Smart Spray Technology for Post-Emergence Herbicide Application in Row Middles of Plasticulture Production","authors":"Ana C. Buzanini, A. Schumann, N. Boyd","doi":"10.1017/wet.2023.44","DOIUrl":"https://doi.org/10.1017/wet.2023.44","url":null,"abstract":"\u0000 Postemergence herbicides to control weeds in the space between raised, plastic-covered beds in plasticulture production systems are typically banded and herbicides are applied to weeds as well as where weeds do not occur. To reduce the incidence of off-targeted applications, the University of Florida developed smart spray technology for row middles in plasticulture systems. The technology detects weed categories and applies herbicides only where they occur. Field experiments were conducted at the Gulf Coast Research and Education Center in Balm, FL, in the Fall 2021 and Spring 2022. The objective was to evaluate the efficacy of postemergence applications of diquat and glyphosate in row middles in jalapeno pepper fields when banded or applied with smart spray technology. The overall precision of the weed detection model was 0.92 and 0.89 for fall and spring respectively. The actuation precision achieved was 0.86 and 1 for fall and spring respectively. No significant differences were observed between banded and targeted applications either with glyphosate or diquat in terms of broadleaf, grass, and nutsedge weed density. No significant pepper damage was observed with either herbicides or application techniques. The smart spray technology reduced herbicide application volume by 26% and 42% for fall and spring respectively, with no reduction in weed control or pepper yield compared to a banded application. Overall, the smart spray technology reduced the herbicide volume applied with no reductions in weed control and no significant effects on crop yield.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41828275","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}
J. M. Craft, Navdeep Godara, Jeffrey F Derr, Adam D. Nichols, J. McCurdy, Michael P Richard, S. Askew
Turfgrass managers apply nonselective herbicides to control winter annual weeds during dormancy of warm-season turfgrass. Zoysiagrass subcanopies, however, retain green leaves and stems during winter dormancy, especially in warmer climatic regions. The partially green zoysiagrass often deters the use of nonselective herbicides due to variable injury concerns in transition and southern climatic zones. This study evaluated zoysiagrass response to glyphosate and glufosinate applied at four different growing-degree-day (GDD) based application timings during post-dormancy transition under different geographic regions, including Blacksburg, VA; Starkville, MS; and Virginia Beach, VA, in 2018 and 2019. GDD was calculated using a 5C base temperature with accumulation beginning January 1 each yr, and targeted application timings were 125, 200, 275, and 350 GDD5C. Zoysiagrass injury response to glyphosate and glufosinate was consistent across a broad growing region from northern Mississippi to coastal Virginia but varied by application timing. Glyphosate application at 125 and 200 GDD5C can be utilized safely for weed control during post-dormancy period of zoysiagrass, while glufosinate caused unacceptable turf injury regardless of application timings. Glyphosate and glufosinate exhibited a stepwise increase to maximum injury with increasing targeted GDD5C application timings. Glyphosate applied at 125 or 200 GDD5C did not injure zoysiagrass above a threshold of 30%, while glufosinate caused greater than 30% injury for 28 and 29 d when applied at 125 and 200 GDD5C, respectively. Likewise, glyphosate application at 125 or 200 GDD5C did not affect the zoysiagrass green cover area under progress curve d-1, while later application timings reduced it. Glyphosate and glufosinate caused higher injury to zoysiagrass when applied at greater cumulative heat units and were attributed to increasing turfgrass green leaf density, as heat unit accumulation is positively correlated with green leaf density. Accumulated heat unit-based application timing will allow practitioners to apply nonselective herbicides with reduced injury concerns.
{"title":"Regional response of zoysiagrass turf to glufosinate and glyphosate applied during post-dormancy transition based on accumulated heat units","authors":"J. M. Craft, Navdeep Godara, Jeffrey F Derr, Adam D. Nichols, J. McCurdy, Michael P Richard, S. Askew","doi":"10.1017/wet.2023.46","DOIUrl":"https://doi.org/10.1017/wet.2023.46","url":null,"abstract":"\u0000 Turfgrass managers apply nonselective herbicides to control winter annual weeds during dormancy of warm-season turfgrass. Zoysiagrass subcanopies, however, retain green leaves and stems during winter dormancy, especially in warmer climatic regions. The partially green zoysiagrass often deters the use of nonselective herbicides due to variable injury concerns in transition and southern climatic zones. This study evaluated zoysiagrass response to glyphosate and glufosinate applied at four different growing-degree-day (GDD) based application timings during post-dormancy transition under different geographic regions, including Blacksburg, VA; Starkville, MS; and Virginia Beach, VA, in 2018 and 2019. GDD was calculated using a 5C base temperature with accumulation beginning January 1 each yr, and targeted application timings were 125, 200, 275, and 350 GDD5C. Zoysiagrass injury response to glyphosate and glufosinate was consistent across a broad growing region from northern Mississippi to coastal Virginia but varied by application timing. Glyphosate application at 125 and 200 GDD5C can be utilized safely for weed control during post-dormancy period of zoysiagrass, while glufosinate caused unacceptable turf injury regardless of application timings. Glyphosate and glufosinate exhibited a stepwise increase to maximum injury with increasing targeted GDD5C application timings. Glyphosate applied at 125 or 200 GDD5C did not injure zoysiagrass above a threshold of 30%, while glufosinate caused greater than 30% injury for 28 and 29 d when applied at 125 and 200 GDD5C, respectively. Likewise, glyphosate application at 125 or 200 GDD5C did not affect the zoysiagrass green cover area under progress curve d-1, while later application timings reduced it. Glyphosate and glufosinate caused higher injury to zoysiagrass when applied at greater cumulative heat units and were attributed to increasing turfgrass green leaf density, as heat unit accumulation is positively correlated with green leaf density. Accumulated heat unit-based application timing will allow practitioners to apply nonselective herbicides with reduced injury concerns.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43818482","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}
Ethofumesate is a broad spectrum, soil-applied herbicide for control of broadleaf and grass weeds in sugarbeet. Ethofumesate is commonly applied preemergence at rates ranging from 1.25 to 4.2 kg ai ha−1, or applied postemergence, up to 0.38 kg ai ha−1. Generic Crop Science has developed a new Ethofumesate 4SC label that increased ethofumesate postemergence rates up to 4.48 kg ha−1 in sugarbeet with more than two true leaves per plant. Field and greenhouse experiments were conducted in 2018 and 2019 to evaluate sugarbeet tolerance and herbicide efficacy. Field tolerance experiments indicated sugarbeet stature from ethofumesate postemergence at 0.28, 0.56, and 1.12 kg ha−1 was the same as the non-treated control, but ethofumesate at 2.24 kg ha−1 reduced sugarbeet stature; however, did not affect yield components. Ethofumesate postemergence at 4.48 kg ha−1 reduced sugarbeet stature and affected sugarbeet yield components. Ethofumesate alone postemergence provided weed control of up to 85, 76, and 84% on common lambsquarters, redroot pigweed, and waterhemp, respectively, in field efficacy experiments. Mixing ethofumesate at 1.12 kg ha−1 with glyphosate does not provide a second effective herbicide for postemergence control of common lambsquarters and redroot pigweed, but does provide residual control of these weeds when at least one-half inch of penetrating rainfall occurs, following application. In greenhouse experiments, ethofumesate alone or ethofumesate plus glyphosate timed to common lambsquarters, redroot pigweed, or waterhemp less than 2.5-cm provided the best combination of burndown and soil residual control compared with 2.5- to 5-cm tall weeds. Ethofumesate postemergence at 1.12 kg ha−1 plus glyphosate provided the best combination of tolerance and efficacy, especially on waterhemp.
乙氧膦酸盐是一种广谱土壤除草剂，用于甜菜阔叶杂草和草籽杂草的防治。乙氧膦酸酯通常在出生前施用，用量范围为1.25 - 4.2 kg /公顷- 1，或在出生前施用，用量为0.38 kg /公顷- 1。通用作物科学公司开发了一种新的Ethofumesate 4SC标签，在每株真叶超过两片的甜菜中，该标签可将Ethofumesate发芽后率提高到4.48 kg ha - 1。在2018年和2019年进行了田间和温室试验，以评估甜菜的耐受性和除草剂功效。田间耐受性试验表明，0.28、0.56和1.12 kg ha - 1处理后的甜菜身高与未处理对照相同，但2.24 kg ha - 1处理后的甜菜身高降低;但不影响产量成分。羽化后施用4.48 kg ha - 1的乙氧膦酸盐会降低甜菜的身高，并影响甜菜的产量成分。在田间药效试验中，羽化后单独使用乙硫马酯对普通羔羊、重根藜和水麻的防效分别高达85%、76%和84%。将1.12 kg ha - 1的乙氧膦酸盐与草甘膦混合，并不能提供第二种有效的除草剂来控制常见的羊窝和重根杂草，但在施用后发生至少半英寸的穿透性降雨时，确实可以对这些杂草进行残留控制。在温室试验中，与2.5 ~ 5厘米高的杂草相比，在2.5厘米以下的普通羔羊窝、重根藜或水麻中单独施用或施用草甘膦加草甘膦能提供最佳的燃烧和土壤残留控制组合。羽化后1.12 kg ha - 1的乙氧膦加草甘膦提供了最佳的耐受性和有效性组合，特别是对水麻。
{"title":"Ethofumesate Applied at Greater than Labeled Rates Postemergence in Sugarbeet","authors":"Alexa L. Lystad, T. J. Peters","doi":"10.1017/wet.2023.42","DOIUrl":"https://doi.org/10.1017/wet.2023.42","url":null,"abstract":"\u0000 Ethofumesate is a broad spectrum, soil-applied herbicide for control of broadleaf and grass weeds in sugarbeet. Ethofumesate is commonly applied preemergence at rates ranging from 1.25 to 4.2 kg ai ha−1, or applied postemergence, up to 0.38 kg ai ha−1. Generic Crop Science has developed a new Ethofumesate 4SC label that increased ethofumesate postemergence rates up to 4.48 kg ha−1 in sugarbeet with more than two true leaves per plant. Field and greenhouse experiments were conducted in 2018 and 2019 to evaluate sugarbeet tolerance and herbicide efficacy. Field tolerance experiments indicated sugarbeet stature from ethofumesate postemergence at 0.28, 0.56, and 1.12 kg ha−1 was the same as the non-treated control, but ethofumesate at 2.24 kg ha−1 reduced sugarbeet stature; however, did not affect yield components. Ethofumesate postemergence at 4.48 kg ha−1 reduced sugarbeet stature and affected sugarbeet yield components. Ethofumesate alone postemergence provided weed control of up to 85, 76, and 84% on common lambsquarters, redroot pigweed, and waterhemp, respectively, in field efficacy experiments. Mixing ethofumesate at 1.12 kg ha−1 with glyphosate does not provide a second effective herbicide for postemergence control of common lambsquarters and redroot pigweed, but does provide residual control of these weeds when at least one-half inch of penetrating rainfall occurs, following application. In greenhouse experiments, ethofumesate alone or ethofumesate plus glyphosate timed to common lambsquarters, redroot pigweed, or waterhemp less than 2.5-cm provided the best combination of burndown and soil residual control compared with 2.5- to 5-cm tall weeds. Ethofumesate postemergence at 1.12 kg ha−1 plus glyphosate provided the best combination of tolerance and efficacy, especially on waterhemp.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57584239","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}
Tatiane Severo Silva, N. Arneson, Ryan DeWerff, Daniel H. Smith, D. V. Silva, R. Werle
Widespread occurrence of herbicide-resistant weeds and more variable weather conditions across the US has made weed control in many crops more challenging. Preemergence (PRE) herbicides with soil residual activity have resurged as the foundation for early-season weed control in many crops. Field experiments were conducted at Janesville and Lancaster, WI in 2021 and 2022 (4 site-years) to evaluate the weed control efficacy of solo (single site of action [SOA]) and premix (two or more SOAs) PRE herbicides in conventional tillage corn. Treatments consisted of 18 PRE herbicides plus a non-treated check. At Janesville-2021, S-metolachlor + bicyclopyrone + mesotrione, atrazine + S-metolachlor + bicyclopyrone + mesotrione, and clopyralid + acetochlor + mesotrione provided >72% giant ragweed control. At Janesville-2022, none of the PRE herbicides evaluated provided >70% giant ragweed control due to the high giant ragweed density and the lack of timely rainfall. At Lancaster-2021, atrazine, dicamba, and flumetsulam + clopyralid provided <45% waterhemp control, but the remaining treatments provided >90% control. At Lancaster-2022, the efficacy of some PRE herbicides was reduced due to the high waterhemp density; however, most herbicides provided >75% control. At Lancaster-2021 and 2022, only dicamba and S-metolachlor did not provide >75% common lambsquarters control. PRE herbicides containing SOA group 15 provided >75% control of giant foxtail. Across weed species, PRE herbicides with two (78%) and three (81%) SOAs provided higher weed control than PRE herbicides with a single SOA (68%), indicating that at least two SOAs PRE result in better early-season weed control. The efficacy of the PRE herbicide treatments evaluated herein varied according to the soil seed bank weed community composition and environmental conditions (i.e., rainfall following application), but the premixes were a more reliable option to improve early-season weed control in conventional tillage corn.
在美国，抗除草剂杂草的广泛存在和多变的天气条件使得许多作物的杂草控制更具挑战性。具有土壤残留活性的孕前除草剂已重新成为许多作物早季杂草防治的基础。于2021年和2022年(4个站点年)在威斯康星州简斯维尔和兰开斯特进行了现场试验，以评估常规耕作玉米中单独(单点作用[SOA])和预混(两种或多种SOA) PRE除草剂的杂草控制效果。处理包括18种PRE除草剂和一种未经处理的检查。在Janesville-2021, s -甲草胺+双环吡酮+中三甲酮，阿特拉津+ s -甲草胺+双环吡酮+中三甲酮，氯吡胺+乙草胺+中三甲酮的控制效果为0.72%。在Janesville-2022，由于巨型豚草密度高且缺乏及时降雨，评估的PRE除草剂都没有提供70%的巨型豚草控制。在兰开斯特-2021年，阿特拉津、麦草畏和氟美舒仑+氯吡酯提供了90%的控制。在Lancaster-2022上，由于水麻密度高，一些PRE除草剂的药效降低;然而，大多数除草剂的控制效果为75%。在兰开斯特-2021年和2022年，只有麦草畏和s -甲草胺没有提供75%的常见羔羊窝控制。含有SOA组15的PRE除草剂对巨型狐尾草的控制效果为75%。在杂草种类中，含有两个(78%)和三个(81%)SOA的PRE除草剂比含有单个SOA的PRE除草剂(68%)具有更高的杂草控制效果，这表明至少有两个SOA PRE除草剂可以更好地控制早季杂草。PRE除草剂处理的效果根据土壤种子库杂草群落组成和环境条件(即施用后的降雨量)而有所不同，但预混料是改善常规耕作玉米早季杂草控制的更可靠选择。
{"title":"Preemergence Herbicide Premixes Reduce the Risk of Soil Residual Weed Control Failure in Corn","authors":"Tatiane Severo Silva, N. Arneson, Ryan DeWerff, Daniel H. Smith, D. V. Silva, R. Werle","doi":"10.1017/wet.2023.45","DOIUrl":"https://doi.org/10.1017/wet.2023.45","url":null,"abstract":"\u0000 Widespread occurrence of herbicide-resistant weeds and more variable weather conditions across the US has made weed control in many crops more challenging. Preemergence (PRE) herbicides with soil residual activity have resurged as the foundation for early-season weed control in many crops. Field experiments were conducted at Janesville and Lancaster, WI in 2021 and 2022 (4 site-years) to evaluate the weed control efficacy of solo (single site of action [SOA]) and premix (two or more SOAs) PRE herbicides in conventional tillage corn. Treatments consisted of 18 PRE herbicides plus a non-treated check. At Janesville-2021, S-metolachlor + bicyclopyrone + mesotrione, atrazine + S-metolachlor + bicyclopyrone + mesotrione, and clopyralid + acetochlor + mesotrione provided >72% giant ragweed control. At Janesville-2022, none of the PRE herbicides evaluated provided >70% giant ragweed control due to the high giant ragweed density and the lack of timely rainfall. At Lancaster-2021, atrazine, dicamba, and flumetsulam + clopyralid provided <45% waterhemp control, but the remaining treatments provided >90% control. At Lancaster-2022, the efficacy of some PRE herbicides was reduced due to the high waterhemp density; however, most herbicides provided >75% control. At Lancaster-2021 and 2022, only dicamba and S-metolachlor did not provide >75% common lambsquarters control. PRE herbicides containing SOA group 15 provided >75% control of giant foxtail. Across weed species, PRE herbicides with two (78%) and three (81%) SOAs provided higher weed control than PRE herbicides with a single SOA (68%), indicating that at least two SOAs PRE result in better early-season weed control. The efficacy of the PRE herbicide treatments evaluated herein varied according to the soil seed bank weed community composition and environmental conditions (i.e., rainfall following application), but the premixes were a more reliable option to improve early-season weed control in conventional tillage corn.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43464796","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}
The goal of weed science extension efforts are to encourage and accelerate adoption of diverse, effective, and economical management tactics. To be most successful and efficient, extension personnel need to be aware of growers’ preferred information sources, delivery format, and areas of focus for future research. To this end, surveys were distributed at crop and forage extension meetings in Virginia. The results from 249 responses indicate that both crop and forage producers have similar influences as well as preferences for both programming and future research. Agribusiness personnel (e.g. co-ops, suppliers, vendors, crop consultants, sales reps) had the greatest influence on herbicide-purchasing decisions and the primary source of information for weed management decisions, and thus should be a target audience of extension. Respondents said that economic assessments, weed control data, and yield data are most likely to influence changes in management and that they would prefer to get that information through traditional extension formats (presentations, publications, and on-farm demonstrations). Generally, respondents also indicated that they wanted extension to focus on evaluating new herbicides for weed control and crop safety in the future over alternative non-herbicidal weed control methods. Therefore, extension is likely to be more successful by including herbicides in the integrated weed management approach rather than solely non-chemical approaches.
{"title":"Preferred Information and Delivery Methods for Weed Management Extension in Virginia","authors":"K. B. Pittman, Elisabeth Russell, M. Flessner","doi":"10.1017/wet.2023.43","DOIUrl":"https://doi.org/10.1017/wet.2023.43","url":null,"abstract":"\u0000 The goal of weed science extension efforts are to encourage and accelerate adoption of diverse, effective, and economical management tactics. To be most successful and efficient, extension personnel need to be aware of growers’ preferred information sources, delivery format, and areas of focus for future research. To this end, surveys were distributed at crop and forage extension meetings in Virginia. The results from 249 responses indicate that both crop and forage producers have similar influences as well as preferences for both programming and future research. Agribusiness personnel (e.g. co-ops, suppliers, vendors, crop consultants, sales reps) had the greatest influence on herbicide-purchasing decisions and the primary source of information for weed management decisions, and thus should be a target audience of extension. Respondents said that economic assessments, weed control data, and yield data are most likely to influence changes in management and that they would prefer to get that information through traditional extension formats (presentations, publications, and on-farm demonstrations). Generally, respondents also indicated that they wanted extension to focus on evaluating new herbicides for weed control and crop safety in the future over alternative non-herbicidal weed control methods. Therefore, extension is likely to be more successful by including herbicides in the integrated weed management approach rather than solely non-chemical approaches.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41825180","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：