Weed Technology最新文献

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"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":null,"pages":null},"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}

{"title":"Effects of 2,4-D choline on fruiting in sensitive cotton","authors":"Kyle R. Russell, P. Dotray, G. Ritchie, Brendan R. Kelly","doi":"10.1017/wet.2023.38","DOIUrl":"https://doi.org/10.1017/wet.2023.38","url":null,"abstract":"\u0000 With the increase in hectares planted to auxin-resistant cotton, the number of preplant, at-plant, and post plant applications of dicamba and 2,4-D choline to aid in the control of troublesome broadleaf weeds including glyphosate-resistant Palmer amaranth has increased. More dicamba and 2,4-D choline applications means an increased risk of off-target movement. Field studies were conducted in 2019-2021 at the Texas Tech University New Deal Research Farm to evaluate dicamba-resistant cotton response to various rates of 2,4-D choline when applied at four growth stages [first square (FS) + 2 weeks (wk), first bloom (FB), FB + 2 wk, and FB + 4 wk]. Applications of 2,4-D choline were applied at 1060 (1x), 106 (1/10x), 21 (1/50x), 10.6 (1/100x), 2.1 (1/500x), and 1.06 (1/1000x) g ae ha-1 to Deltapine 1822 XF cotton. Relative to the non-treated control, yield losses were observed in all years at FS + 2 wk and FB from rates of 2,4-D choline ≥ 1/100x. At the FB + 4 wk application, only the 1x rate of 2,4-D choline resulted in a yield reduction in all three years. Micronaire, fiber length, and uniformity were negatively influenced by the 1/10X and 1X rates of 2,4-D choline at various timings in 2019, 2020, and 2021. In addition, short fiber content, neps, and seed coat neps increased where micronaire, fiber length, and uniformity were negatively impacted.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44407305","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":"Preemergence and postemergence weed control in sweet corn on organic soils","authors":"Alex G. Rodriguez, H. Sandhu, A. Wright, D. Odero","doi":"10.1017/wet.2023.35","DOIUrl":"https://doi.org/10.1017/wet.2023.35","url":null,"abstract":"Abstract Atrazine and S-metolachlor are the herbicides most relied on by growers to control weeds in sweet corn crops grown in the Everglades Agricultural Area (EAA) in southern Florida. Alternative weed management programs are needed. Field experiments were conducted in 2021 and 2022 to evaluate the efficacy of 1) pyroxasulfone (183 and 237 g ha–1) alone or as a premix with carfentrazone-ethyl (13 and 17 g ha–1) or fluthiacet-methyl (6 and 7 g ha–1), S-metolachlor (1,790 g ha–1) alone or in combination with atrazine (3,360 g ha–1) applied preemergence(PRE); 2) mesotrione (105 g ha–1), topramezone (25 g ha–1), and tembotrione (92 g ha–1) applied postemergence alone or in combination with atrazine (560 and 2,240 g ha–1) or bentazon (1,120 g ha–1); and 3) mechanical cultivation alone at the fourth and the fourth followed by the sixth leaf stages of sweet corn. PRE-applied herbicides did not provide acceptable control of fall panicum, common lambsquarters, or common purslane probably due to a lack of incorporation into the soil because of limited rainfall. POST-applied topramezone alone or in combination with atrazine or bentazon resulted in effective fall panicum control (>91%). Topramezone alone provided 83% and 88% control of common lambsquarters and common purslane, respectively, whereas atrazine added to topramezone resulted in >94% control of both weed species. Mesotrione and tembotrione plus atrazine provided excellent control (>93%) of both broadleaf weed species but poor fall panicum control (<72%). Mechanical cultivation alone did not effectively control any weeds. Overall, treatments that contained topramezone resulted in greater sweet corn yield. These results show that a combination of topramezone, mesotrione, and tembotrione with atrazine resulted in improved broadleaf weed control. Fall panicum control was improved only with the combination of topramezone with atrazine, showing that atrazine is an important mixture component of these herbicides to provide effective POST weed control in sweet corn on organic soils of the EAA. Nomenclature: Atrazine; bentazon; mesotrione; pyroxasulfone; S-metolachlor; tembotrione; topramezone; common lambsquarters; Chenopodium album L. CHEAL; common purslane; Portulaca oleracea L. POROL; fall panicum; Panicum dichotomiflorum Michx. PANDI; sweet corn; Zea mays spp. saccharata","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49013015","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":"Planting into a living cover crop alters preemergence herbicide dynamics and can reduce soybean yield","authors":"J. Nunes, N. Arneson, Ryan DeWerff, M. Ruark, S. Conley, Damon L. Smith, R. Werle","doi":"10.1017/wet.2023.41","DOIUrl":"https://doi.org/10.1017/wet.2023.41","url":null,"abstract":"Abstract Cereal rye cover crop (cereal rye) and preemergence (PRE) herbicides are becoming common practices for managing herbicide-resistant weeds in soybean production. Adopting these two practices in combination raises concerns regarding herbicide fate in soil, given that the cereal rye biomass can intercept the herbicide spray solution, preventing it from reaching the soil. Delaying cereal rye termination until soybean planting (planting green) optimizes biomass accumulation but might also increase PRE interception. To better understand the dynamics between cereal rye and PRE herbicides, a field experiment was conducted to evaluate two soil management practices (tillage and no-till) and two cereal rye termination practices in the planting-green system (glyphosate [1,260 g ae ha–1] and roller-crimper) on the spray deposition and fate of PRE herbicides and soybean yield. The spray deposition was assessed by placing water-sensitive paper cards on the soil surface before spraying the PRE herbicides (sulfentrazone [153 g ai ha–1] + S-metolachlor [1,379 g ai ha–1]). Herbicide concentration in soil (0 to 7.6 cm) was quantified 25 d after treatment (DAT). The presence of no-till stubble and cereal rye biomass reduced the spray coverage compared to tillage at PRE application, which reflected in a reduction in the concentration of both herbicides in soil 25 DAT. Soybean yield was reduced in all three years when the cereal rye was terminated with a roller-crimper but only reduced in one year when terminated with glyphosate. Our findings indicate that mainly cereal rye biomass reduced the concentration of PRE herbicides in the soil due to the interception of the spray solution during application. Although higher cereal rye biomass accumulation can provide better weed suppression according to the literature, farmers should be aware that the biomass can lower the concentration of PRE herbicides reaching the soil, thus intensifying field scouting to ensure that weed control is not being negatively affected. Nomenclature: sulfentrazone; glyphosate; S-metolachlor; cereal rye, Secale cereale L.; soybean, Glycine max (L.) Merr.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41433670","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":"Efficacy of herbicides for selective control of an invasive liana, old man's beard (Clematis vitalba)","authors":"Brenda Jarvis-Lowry, K. Harrington, H. Ghanizadeh, A. Robertson","doi":"10.1017/wet.2023.40","DOIUrl":"https://doi.org/10.1017/wet.2023.40","url":null,"abstract":"Abstract Old man's beard is a woody liana that has become an invasive weed in many areas of its introduction, through its vigorous spread and negative impacts on the tree hosts it climbs. Control techniques that improve precision and reduce non-target damage are increasingly preferred for weed control yet have not been compared in published research for use against old man's beard. Field experiments in New Zealand were conducted to: (i) assess targeted herbicide techniques for control of this weed's climbing stems when growing among trees and (ii) assess foliar herbicides for control of creeping stems in ruderal sites. For climbing stems, triclopyr in oil was applied around the circumference of woody stems near their base, which was compared with cutting the stems and applying concentrated glyphosate gel (45% ai) to each cut end. Herbicides were applied in autumn directly to individual stem bases of the weed, thereby protecting tree hosts and other non-target vegetation. The basal application of triclopyr to intact stems was highly effective (>95% mortality) with no damage to nearby trees noted. The glyphosate gel applications to cut stems were less effective (56% mortality by 2 yr after treatment). For creeping stems in grass-dominated ruderal sites, selective foliar herbicide sprays had not been previously juxtaposed to compare control of old man's beard. Three selective sprays that do not damage existing grass cover were applied in autumn at their recommended rates: (i) metsulfuron; (ii) triclopyr; and (iii) a mixture of triclopyr, picloram, and aminopyralid. All herbicide treatments provided effective control, although metsulfuron had a negative effect on grass vigor, which might allow new establishment of old man's beard seedlings by competitive release. These results provide effective options that reduce non-target damage for control of both climbing and creeping old man's beard stems. Nomenclature: Aminopyralid; glyphosate; metsulfuron-methyl; picloram; triclopyr butoxyethyl ester; old man's beard, Clematis vitalba L.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43137101","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":"Rush skeletonweed (Chondrilla juncea) control and winter wheat injury with picloram applied in fallow","authors":"D. Lyon, M. Thorne","doi":"10.1017/wet.2023.37","DOIUrl":"https://doi.org/10.1017/wet.2023.37","url":null,"abstract":"Abstract Rush skeletonweed is an invasive weed in the winter wheat–fallow production regions of the inland Pacific Northwest. The objectives of this study were to determine the dose response of rush skeletonweed to picloram applied in the fall or spring of the fallow year with either a broadcast or weed-sensing sprayer, and to evaluate injury and grain yield in the subsequent winter wheat crop from these fallow treatments. Field studies were conducted between 2019 and 2022. Fall treatments were applied at one site in 2019, and one site in 2020. Spring treatments were applied at two sites in 2021. Four picloram herbicide rates (0, 140, 280, and 560 g ae ha–1), were applied with either a weed-sensing precision applicator or with a standard broadcast spray applicator. Rush skeletonweed densities in the wheat crop following fall-applied treatments declined with increasing picloram rates at both sites. Treatments applied with the weed-sensing sprayer achieved similar efficacy to broadcast treatments with an average of 37% and 26% of the broadcast rate applied. Spring-applied broadcast treatments resulted in reduced rush skeletonweed densities in wheat with increasing picloram rates. Picloram rate had no apparent effect on rush skeletonweed density when applied in the spring with a weed-sensing sprayer; however, the weed-sensing sprayer applied just 16% and 9% of the broadcast rate. Winter wheat grain yields were not reduced by fall picloram applications. Grain yields were not reduced by spring applications of picloram with the weed-sensing sprayer; however, grain yields were reduced by spring broadcast applications of picloram at both locations, and grain yields declined as the picloram rate increased. Applying picloram in the fall of the fallow phase with a weed-sensing sprayer provides effective and economical control of rush skeletonweed with a low risk for crop injury and yield loss in the following winter wheat crop. Nomenclature: Picloram; rush skeletonweed, Chondrilla juncea L.; wheat, Triticum aestivum L.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44214524","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}