Martin Ignes, J. C. Ferguson, T. Tseng, Barry R. Stewart, E. Castro, J. McCurdy
Annual bluegrass is a troublesome weed in turfgrass, with reported resistance to at least 12 herbicide sites of action. The mitotic-inhibiting herbicide pronamide has both pre- and postemergence activity on susceptible annual bluegrass populations. Previous studies suggest that postemergence activity may be compromised due to lack of root-uptake, as well as target-site- and translocation-based mechanisms. Research was conducted to determine the effects of spray droplet spectra on spray coverage and control of annual bluegrass with pronamide, flazasulfuron, and the mixture of pronamide plus flazasulfuron. Herbicides were delivered to annual bluegrass plants having two to three leaves via five different spray spectra based on volume median diameters (VMD) of 200, 400, 600, 800, and 1000 µm. Fluorescent tracer dye was added to each treatment solution to quantify the effects of herbicide and spray droplet spectra on herbicide deposition. In another experiment, efficacy of 0.58, 1.16, and 2.32 kg pronamide ha-1; 0.022, 0.044, and 0.088 kg flazasulfuron ha-1, or the combination, were assessed in iteration with droplet spectrum sprays of 400 and 1000 µm on two pronamide-resistant and two pronamide-susceptible annual bluegrass populations. Spray droplet spectrum affected deposition of pronamide and flazasulfuron, applied alone and in combination. Pronamide foliar deposition decreased with increasing droplet spectra. Pronamide efficacy was affected by droplet spectrum, with the largest (1000 µm) showing improved control. Flazasulfuron efficacy and pronamide plus flazasulfuron efficacy were not affected by droplet spectra. Pronamide plus flazasulfuron mixture controlled all four populations more effectively than pronamide alone, regardless of droplet spectra. Pronamide plus flazasulfuron mixture applied with relatively large droplets may be optimal for annual bluegrass control, which offers valuable insights for optimizing herbicide application and combatting herbicide resistance. However, applications in this controlled growth pot study may not mimic conditions where thatch and turfgrass canopy limit soil deposition of pronamide.
一年生蓝草是草坪上的一种麻烦的杂草，据报道它对至少12种除草剂有抗性。抑制有丝分裂的除草剂pronamide在蓝草易感群体中具有出生前和出后活性。先前的研究表明，由于缺乏根吸收，以及基于目标位点和易位的机制，出现后的活动可能受到损害。研究了吡虫胺、氟唑磺隆和吡虫胺与氟唑磺隆混用对一年生蓝草喷雾覆盖和防治效果的影响。根据200、400、600、800和1000µm的体积中值直径(VMD)，通过五种不同的喷雾光谱，将除草剂施用于有2到3片叶子的一年生蓝草植物。在每个处理溶液中加入荧光示踪染料，量化除草剂和喷雾液滴光谱对除草剂沉积的影响。在另一项实验中，原酰胺的功效分别为0.58、1.16和2.32 kg ha-1;以0.022、0.044和0.088 kg氟唑虫隆(ha-1)或混合剂量，分别以400µm和1000µm滴谱喷雾对2个虫酰胺抗性和2个虫酰胺敏感的年生蓝草种群进行迭代评价。喷雾液滴谱对单药和联合用药时原酰胺和氟唑脲沉积的影响。原酰胺叶面沉积随液滴光谱的增加而减少。Pronamide的药效受液滴谱的影响，最大的液滴(1000µm)具有较好的控制效果。滴剂光谱不影响氟唑脲的药效和丙酰胺加氟唑脲的药效。无论液滴光谱如何，Pronamide + flazasulfuron混合物都比单独使用Pronamide更有效地控制所有四种种群。Pronamide + flazasulfuron的大液滴混合施用可能是蓝草年度控制的最佳选择，为优化除草剂施用和对抗除草剂抗性提供了有价值的见解。然而，在这个受控生长盆栽研究中的应用可能不会模拟茅草和草坪草冠层限制原酰胺土壤沉积的条件。
{"title":"Effect of spray droplet spectra on control of Poa annua with pronamide","authors":"Martin Ignes, J. C. Ferguson, T. Tseng, Barry R. Stewart, E. Castro, J. McCurdy","doi":"10.1017/wet.2023.54","DOIUrl":"https://doi.org/10.1017/wet.2023.54","url":null,"abstract":"\u0000 Annual bluegrass is a troublesome weed in turfgrass, with reported resistance to at least 12 herbicide sites of action. The mitotic-inhibiting herbicide pronamide has both pre- and postemergence activity on susceptible annual bluegrass populations. Previous studies suggest that postemergence activity may be compromised due to lack of root-uptake, as well as target-site- and translocation-based mechanisms. Research was conducted to determine the effects of spray droplet spectra on spray coverage and control of annual bluegrass with pronamide, flazasulfuron, and the mixture of pronamide plus flazasulfuron. Herbicides were delivered to annual bluegrass plants having two to three leaves via five different spray spectra based on volume median diameters (VMD) of 200, 400, 600, 800, and 1000 µm. Fluorescent tracer dye was added to each treatment solution to quantify the effects of herbicide and spray droplet spectra on herbicide deposition. In another experiment, efficacy of 0.58, 1.16, and 2.32 kg pronamide ha-1; 0.022, 0.044, and 0.088 kg flazasulfuron ha-1, or the combination, were assessed in iteration with droplet spectrum sprays of 400 and 1000 µm on two pronamide-resistant and two pronamide-susceptible annual bluegrass populations. Spray droplet spectrum affected deposition of pronamide and flazasulfuron, applied alone and in combination. Pronamide foliar deposition decreased with increasing droplet spectra. Pronamide efficacy was affected by droplet spectrum, with the largest (1000 µm) showing improved control. Flazasulfuron efficacy and pronamide plus flazasulfuron efficacy were not affected by droplet spectra. Pronamide plus flazasulfuron mixture controlled all four populations more effectively than pronamide alone, regardless of droplet spectra. Pronamide plus flazasulfuron mixture applied with relatively large droplets may be optimal for annual bluegrass control, which offers valuable insights for optimizing herbicide application and combatting herbicide resistance. However, applications in this controlled growth pot study may not mimic conditions where thatch and turfgrass canopy limit soil deposition of pronamide.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46722695","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}
M. L. Zaccaro-Gruener, J. Norsworthy, L. Piveta, L. Barber, Andy Mauromoustakos
Off-target movement of 2,4-D and dicamba are sometimes to blame as the cause of symptoms observed in weeds growing in production fields. Pesticide regulatory authorities routinely sample tissue of weeds or crops from fields under investigation for potential illegal use of auxin herbicides. This research aimed to determine if analytical tests of herbicide residue on soybean or Palmer amaranth vegetation treated with dicamba or 2,4-D could be used to differentiate between rates applied and how the residue levels decay over a one-month interval. Four rates of each herbicide (1X, 0.1X, 0.01X, and 0.001X) were applied, with a 1X rate of dicamba and 2,4-D assumed to be 560 and 1065 g ae ha-1, respectively. Experiments included dicamba- and 2,4-D-resistant soybean (Xtend and Enlist traits, respectively) and Palmer amaranth categorized by size (8-15 cm, 20-30 cm, and 35-50 cm in height). Analytical results showed that herbicide residues were detected above detection limits of 0.04 µg g-1 for dicamba and 0.004 µg g-1 for 2,4-D, respectively, particularly for samples treated with a 1X and 0.1X rate of dicamba or 2,4-D. Non-detections were frequent, even as early as 2 to 3 days after treatment (DAT), with 0.01X and 0.001X rates of 2,4-D or dicamba. Dicamba residues declined rapidly on Xtend soybean treated with dicamba, and 2,4-D residue in Enlist soybean. The severity of auxin symptomology generally agreed with the ability to detect dicamba or 2,4-D residue in plant tissue for Palmer amaranth, while, for soybean, this was not always the case. Hence, detecting dicamba or 2,4-D residues in both Palmer amaranth and soybean vegetation, along with visible symptoms on both plants during investigations, would generally indicate an earlier direct application of the auxin herbicide rather than off-target movement being the cause of detection.
2，4-D和麦草畏的脱靶运动有时被认为是生产田杂草出现症状的原因。农药监管机构经常从被调查可能非法使用生长素除草剂的田地中抽取杂草或作物的组织样本。这项研究旨在确定用麦草畏或2，4-D处理的大豆或帕尔默苋植被上除草剂残留的分析测试是否可以用来区分施用速率和残留水平如何在一个月内衰减。每种除草剂施用四种速率（1X、0.1X、0.01X和0.001X），麦草畏和2,4-D的1X速率分别假定为560和1065 g ae ha-1。实验包括抗麦草畏和2,4-D的大豆（分别为Xtend和Enlist性状）和按大小分类的Palmer苋（高度分别为8-15厘米、20-30厘米和35-50厘米）。分析结果表明，麦草畏和2,4-D的除草剂残留量分别高于0.04µg g-1和0.004µg g-2的检测限，尤其是用1倍和0.1倍麦草畏或2,4-D处理的样品。即使早在治疗后2至3天（DAT），未检测到的情况也很常见，2，4-D或麦草畏的检出率分别为0.01X和0.001X。麦草畏处理的Xtend大豆中麦草畏残留量迅速下降，Enlist大豆中2,4-D残留量迅速减少。生长素症状的严重程度通常与检测植物组织中麦草畏或2,4-D残留的能力一致，而对于大豆，情况并非总是如此。因此，在调查期间，在Palmer苋和大豆植被中检测到麦草畏或2,4-D残留，以及在这两种植物上的明显症状，通常表明检测的原因是生长素除草剂的早期直接施用，而不是脱靶运动。
{"title":"Assessment of Dicamba and 2,4-D Residues in Palmer amaranth and Soybean","authors":"M. L. Zaccaro-Gruener, J. Norsworthy, L. Piveta, L. Barber, Andy Mauromoustakos","doi":"10.1017/wet.2023.60","DOIUrl":"https://doi.org/10.1017/wet.2023.60","url":null,"abstract":"\u0000 Off-target movement of 2,4-D and dicamba are sometimes to blame as the cause of symptoms observed in weeds growing in production fields. Pesticide regulatory authorities routinely sample tissue of weeds or crops from fields under investigation for potential illegal use of auxin herbicides. This research aimed to determine if analytical tests of herbicide residue on soybean or Palmer amaranth vegetation treated with dicamba or 2,4-D could be used to differentiate between rates applied and how the residue levels decay over a one-month interval. Four rates of each herbicide (1X, 0.1X, 0.01X, and 0.001X) were applied, with a 1X rate of dicamba and 2,4-D assumed to be 560 and 1065 g ae ha-1, respectively. Experiments included dicamba- and 2,4-D-resistant soybean (Xtend and Enlist traits, respectively) and Palmer amaranth categorized by size (8-15 cm, 20-30 cm, and 35-50 cm in height). Analytical results showed that herbicide residues were detected above detection limits of 0.04 µg g-1 for dicamba and 0.004 µg g-1 for 2,4-D, respectively, particularly for samples treated with a 1X and 0.1X rate of dicamba or 2,4-D. Non-detections were frequent, even as early as 2 to 3 days after treatment (DAT), with 0.01X and 0.001X rates of 2,4-D or dicamba. Dicamba residues declined rapidly on Xtend soybean treated with dicamba, and 2,4-D residue in Enlist soybean. The severity of auxin symptomology generally agreed with the ability to detect dicamba or 2,4-D residue in plant tissue for Palmer amaranth, while, for soybean, this was not always the case. Hence, detecting dicamba or 2,4-D residues in both Palmer amaranth and soybean vegetation, along with visible symptoms on both plants during investigations, would generally indicate an earlier direct application of the auxin herbicide rather than off-target movement being the cause of detection.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43872720","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}
Vipan Kumar, R. Liu, Deepika Chauhan, Ramasamy Perumal, Sarah Morran, T. Gaines, Prashant Jha
Shattercane is a problematic summer annual grass weed species in grain sorghum producing regions, including Kansas. Three shattercane populations (DC8, GH4, and PL8) collected from sorghum fields from northwestern Kansas survived the field-use rate (52 g ha-1) of postemergence applied imazamox. The main objectives of this research were to (1) confirm and characterize the level of resistance to imazamox in those putative imazamox-resistant (IMI-R) shattercane populations, (2) investigate the underlying mechanism of resistance, and (3) determine the effectiveness of postemergence herbicides for controlling IMI-R populations. A previously known imazamox susceptible (SUS) shattercane population from Rooks County, KS was used. All three putative populations exhibited a 4.1- to 6.0-fold resistance to imazamox compared to the SUS population. The ALS gene sequences from all IMI-R populations did not reveal any known target-site resistance mutations. A pretreatment of the cytochrome P450-inhibiting insecticide malathion followed by imazamox at various doses reversed the resistance phenotype of PL8 population. In a separate greenhouse study, the postemergence treatments of nicosulfuron, quizalofop, clethodim, and glyphosate provided ≥96% injury to all IMI-R populations. The lack of known ALS target-site mutations and the reversal of resistance phenotype by malathion suggest the possibility of metabolism-based resistance to imazamox in PL8 shattercane population.
在包括堪萨斯州在内的高粱产区，沙藤是一种有问题的夏季一年生杂草。从美国堪萨斯州西北部高粱田采集的3个穗状甘蔗种群(DC8、GH4和PL8)在出苗后施用imazamox的田间使用率(52 g ha-1)下存活。本研究的主要目的是:(1)确认和表征对伊马唑莫抗性(IMI-R)的甘蔗种群的抗性水平;(2)探讨抗性的潜在机制;(3)确定出苗期除草剂对IMI-R种群的控制效果。先前已知的易感人群(SUS)是来自堪萨斯州鲁克斯县的散蔗种群。与SUS种群相比，所有三个假定种群对imazamox的抗性均为4.1- 6.0倍。来自所有IMI-R群体的ALS基因序列未显示任何已知的靶位点耐药突变。用抑制细胞色素p450的杀虫剂马拉硫磷预处理后，再用不同剂量的伊马唑莫(imazamox)可逆转PL8种群的抗性表型。在一项单独的温室研究中，nico磺隆、quizalofop、clethodim和草甘膦的出苗后处理对所有IMI-R种群造成了≥96%的伤害。缺乏已知的ALS靶位点突变和马拉硫磷对耐药表型的逆转表明，PL8沙地种群对伊马唑莫的耐药可能是基于代谢的。
{"title":"Characterization of Imazamox-Resistant Shattercane (Sorghum bicolor L.) Populations from Kansas","authors":"Vipan Kumar, R. Liu, Deepika Chauhan, Ramasamy Perumal, Sarah Morran, T. Gaines, Prashant Jha","doi":"10.1017/wet.2023.55","DOIUrl":"https://doi.org/10.1017/wet.2023.55","url":null,"abstract":"\u0000 Shattercane is a problematic summer annual grass weed species in grain sorghum producing regions, including Kansas. Three shattercane populations (DC8, GH4, and PL8) collected from sorghum fields from northwestern Kansas survived the field-use rate (52 g ha-1) of postemergence applied imazamox. The main objectives of this research were to (1) confirm and characterize the level of resistance to imazamox in those putative imazamox-resistant (IMI-R) shattercane populations, (2) investigate the underlying mechanism of resistance, and (3) determine the effectiveness of postemergence herbicides for controlling IMI-R populations. A previously known imazamox susceptible (SUS) shattercane population from Rooks County, KS was used. All three putative populations exhibited a 4.1- to 6.0-fold resistance to imazamox compared to the SUS population. The ALS gene sequences from all IMI-R populations did not reveal any known target-site resistance mutations. A pretreatment of the cytochrome P450-inhibiting insecticide malathion followed by imazamox at various doses reversed the resistance phenotype of PL8 population. In a separate greenhouse study, the postemergence treatments of nicosulfuron, quizalofop, clethodim, and glyphosate provided ≥96% injury to all IMI-R populations. The lack of known ALS target-site mutations and the reversal of resistance phenotype by malathion suggest the possibility of metabolism-based resistance to imazamox in PL8 shattercane population.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44714714","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}
F. H. Oreja, D. Lyon, Jennifer A. Gourlie, Henry C. Wetzel, Judit Barroso
Russian thistle is one of the most important broadleaf weeds in the semi-arid US Pacific Northwest (PNW). It consumes soil water after wheat harvest, compromising the yield of the following crop. The objectives of this work were to determine the impact of post wheat harvest herbicide application timing on Russian thistle control, and stubble height on Russian thistle post-harvest control and plant dispersal. For the first objective, experiments were conducted at the Columbia Basin Agricultural Research Center (CBARC, Adams, OR) and the Lind Dryland Research Station (LDRS, Lind, WA) in 2020 and 2021. Herbicides evaluated included paraquat, glyphosate, and either bromoxynil + pyrasulfotole (CBARC) or bromoxynil + metribuzin (LDRS). The different post wheat harvest application timings were 24 h, 1, 2, and 3 wk after harvest. For the second objective, two stubble heights (short and tall) were compared for their impact on control at CBARC and in a production field near Ione, OR. Paraquat provided the greatest control in all scenarios, with no differences in application timings or stubble height. Impacts of application timings were not clear for glyphosate or bromoxynil mixtures. For glyphosate treatments, control in short stubble was 11% greater than in tall stubble in both years. Control was also greater in short stubble for the bromoxynil + pyrasulfotole in 2020. However, Russian thistle plant dispersal was greater in short stubble at both locations. At CBARC, plant dispersal in short stubble was 58% compared to 18% in tall stubble. Near Ione, plant dispersal in flattened stubble was 88% compared to 43% in non-flattened short stubble. Leaving tall stubble at harvest should be considered to reduce Russian thistle plant dispersal if the infestation is going to be left untreated after harvest. Otherwise, short stubble might result in better Russian thistle control when using systemic herbicides, such as glyphosate.
{"title":"Russian thistle (Salsola tragus) post-harvest control and plant dispersal","authors":"F. H. Oreja, D. Lyon, Jennifer A. Gourlie, Henry C. Wetzel, Judit Barroso","doi":"10.1017/wet.2023.58","DOIUrl":"https://doi.org/10.1017/wet.2023.58","url":null,"abstract":"\u0000 Russian thistle is one of the most important broadleaf weeds in the semi-arid US Pacific Northwest (PNW). It consumes soil water after wheat harvest, compromising the yield of the following crop. The objectives of this work were to determine the impact of post wheat harvest herbicide application timing on Russian thistle control, and stubble height on Russian thistle post-harvest control and plant dispersal. For the first objective, experiments were conducted at the Columbia Basin Agricultural Research Center (CBARC, Adams, OR) and the Lind Dryland Research Station (LDRS, Lind, WA) in 2020 and 2021. Herbicides evaluated included paraquat, glyphosate, and either bromoxynil + pyrasulfotole (CBARC) or bromoxynil + metribuzin (LDRS). The different post wheat harvest application timings were 24 h, 1, 2, and 3 wk after harvest. For the second objective, two stubble heights (short and tall) were compared for their impact on control at CBARC and in a production field near Ione, OR. Paraquat provided the greatest control in all scenarios, with no differences in application timings or stubble height. Impacts of application timings were not clear for glyphosate or bromoxynil mixtures. For glyphosate treatments, control in short stubble was 11% greater than in tall stubble in both years. Control was also greater in short stubble for the bromoxynil + pyrasulfotole in 2020. However, Russian thistle plant dispersal was greater in short stubble at both locations. At CBARC, plant dispersal in short stubble was 58% compared to 18% in tall stubble. Near Ione, plant dispersal in flattened stubble was 88% compared to 43% in non-flattened short stubble. Leaving tall stubble at harvest should be considered to reduce Russian thistle plant dispersal if the infestation is going to be left untreated after harvest. Otherwise, short stubble might result in better Russian thistle control when using systemic herbicides, such as glyphosate.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48874530","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}
Delaying cover crop termination until cash crop planting (i.e., planting green) is an emerging no-till practice. Improved management recommendations are needed for optimizing weed suppression benefits while minimizing other pest, fertility, and crop management risks when planting green in corn production systems. In a 2-yr field experiment, we evaluated the interaction between cereal rye residue management tactics (standing residue, roll-crimping, roll-crimping with row cleaners) and herbicide programs (1-pass PRE, 2-pass POST) when planting green on weed recruitment spatial patterns and corn performance compared to standard termination (14 d pre-plant; 14 DPP) and ryelage harvest (14 DPP) practices. In a 2-yr on-farm experiment, we evaluated corn performance in response to the same residue management tactics. Cereal rye biomass production varied significantly across years in on-station experiments, with average (4.9 Mg ha-1) and anomalous (9.9 Mg ha-1) levels observed in 2020 and 2021, respectively. In 2020, planting green with an integrated roll-crimper/row cleaner system resulted in greater intra-row weed density compared to planting green into standing cereal rye. Inter-row weed density was lower when employing roll-crimping compared to early-termination (14 DPP). Planting green into standing cereal rye resulted in greater mean corn height (V5 stage) compared to other treatments but corn population and yield did not differ. In 2021, few differences in weed recruitment patterns were observed, but corn population and yield were significantly lower in planting green treatments compared to early termination. Across years, late-season weed biomass was lower in two-pass POST programs compared to one-pass PRE programs. On-farm trials showed that planting green into standing residue increases corn height, and can reduce corn populations, which may lead to reduce yields. Our results suggest that management recommendations for optimizing herbicide application timing should consider intra- and inter-row weed recruitment dynamics associated with residue management tactics needed to optimize corn performance.
{"title":"Cereal rye residue management tactics influence inter- and intra- row weed recruitment dynamics in field corn when planting green","authors":"John M. Wallace, Tosh Mazzone, Zachary Larson","doi":"10.1017/wet.2023.56","DOIUrl":"https://doi.org/10.1017/wet.2023.56","url":null,"abstract":"\u0000 Delaying cover crop termination until cash crop planting (i.e., planting green) is an emerging no-till practice. Improved management recommendations are needed for optimizing weed suppression benefits while minimizing other pest, fertility, and crop management risks when planting green in corn production systems. In a 2-yr field experiment, we evaluated the interaction between cereal rye residue management tactics (standing residue, roll-crimping, roll-crimping with row cleaners) and herbicide programs (1-pass PRE, 2-pass POST) when planting green on weed recruitment spatial patterns and corn performance compared to standard termination (14 d pre-plant; 14 DPP) and ryelage harvest (14 DPP) practices. In a 2-yr on-farm experiment, we evaluated corn performance in response to the same residue management tactics. Cereal rye biomass production varied significantly across years in on-station experiments, with average (4.9 Mg ha-1) and anomalous (9.9 Mg ha-1) levels observed in 2020 and 2021, respectively. In 2020, planting green with an integrated roll-crimper/row cleaner system resulted in greater intra-row weed density compared to planting green into standing cereal rye. Inter-row weed density was lower when employing roll-crimping compared to early-termination (14 DPP). Planting green into standing cereal rye resulted in greater mean corn height (V5 stage) compared to other treatments but corn population and yield did not differ. In 2021, few differences in weed recruitment patterns were observed, but corn population and yield were significantly lower in planting green treatments compared to early termination. Across years, late-season weed biomass was lower in two-pass POST programs compared to one-pass PRE programs. On-farm trials showed that planting green into standing residue increases corn height, and can reduce corn populations, which may lead to reduce yields. Our results suggest that management recommendations for optimizing herbicide application timing should consider intra- and inter-row weed recruitment dynamics associated with residue management tactics needed to optimize corn performance.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47653574","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}
Monochoria is an introduced weed to Iran. Two field experiments were conducted to identify soil-applied and foliar-applied herbicides for monochoria control in transplanted rice. Pre-packaged herbicides triafamone plus ethoxysulfuron applied at 40 g ai ha-1, pyrazosulfuron-ethyl plus pretilachlor at 382.5 g ai ha-1, and pendimethalin plus clomazone at 1200 g ai ha-1 reduced monochoria biomass by 100%, 100%, and 14%, respectively, and a single application of flucetosulfuron at 30 g ai ha-1, pendimethalin at 990 g ai ha-1, thiobencarb at 2750 g ai ha-1, and pretilachlor at 1000 g ai ha-1 by 100%, 99%, 75%, and 56%, respectively, compared with the nontreated control. Tank-mixed bensulfuron-methyl at 45 g ai ha-1 with pretilachlor, thiobencarb, or pendimethalin provided 100% control of monochoria. Rice height, and straw and grain yield were greater in herbicide treatments than in the nontreated and hand-weeded control, indicating the advantages of chemical monochoria control over manual weeding. Full-season monochoria interference reduced rice grain yield by 32%. In the second study, foliar-applied herbicides triafamone plus ethoxysulfuron, flucetosulfuron, 2,4-D at 1080 g ai ha-1, dicamba plus 2,4-D at 928 g ai ha-1, bispyribac-sodium at 31.25 g ai ha-1, bentazon plus MCPA at 1150 g ai ha-1, pyribenzoxim at 30 g ai ha-1, and propanil at 5400 g ai ha-1 applied at 4-5 leaf seedlings of monochoria provided ≥97% control and prevented 100% of its regrowth, with the exception of propanil. This study shows that monochoria control can be achieved by many residual and foliar-applied herbicides with different mechanisms of action.
Monochoria是一种引入伊朗的杂草。进行了两个田间试验，以确定土壤施用和叶面施用的除草剂用于控制移植水稻的单子叶枯病。预包装除草剂三甲硫酮加乙氧基磺隆（40 g ai ha-1）、吡唑磺隆乙基加丙二甲草胺（382.5 g ai ha-）和戊二甲灵加氯马宗（1200 g ai ha-2）分别使单壳虫生物量减少了100%、100%和14%，与未处理的对照相比，1000 g ai ha-1的预甲草胺分别提高了100%、99%、75%和56%。将45 g ai ha-1的甲基苄磺隆与预甲草胺、硫本卡伯或二甲灵罐混合，可100%控制单孢菌。除草剂处理的水稻株高、秸秆产量和粮食产量均高于未处理和人工除草处理，这表明化学单孢控制比人工除草具有优势。全季单子叶植物干扰使水稻产量下降32%。在第二项研究中，叶面施用除草剂三唑酮加乙氧基磺隆、氟嘧磺隆、2,4-D（1080 g ai ha-1）、麦草畏加2,4-D（928 g ai ha-1）、双嘧菌素钠（31.25 g ai ha-）、苯达松加MCPA（1150 g ai ha-2）、吡苯并肟（30 g ai ha-3）和丙醇（5400 g ai ha-1）对单子叶菊4-5叶苗的生长提供了≥97%的控制，并阻止了其100%的再生，除了丙醇。本研究表明，通过多种不同作用机制的残留除草剂和叶面施用除草剂，可以实现单孢菌的控制。
{"title":"Herbicides for Monochoria (Monochoria vaginalis) Control in Transplanted Rice","authors":"Zahra Hazrati, Bijan Yaghoubi, Pershang Hosseini, Bhagirath Singh Chauhan","doi":"10.1017/wet.2023.50","DOIUrl":"https://doi.org/10.1017/wet.2023.50","url":null,"abstract":"\u0000 Monochoria is an introduced weed to Iran. Two field experiments were conducted to identify soil-applied and foliar-applied herbicides for monochoria control in transplanted rice. Pre-packaged herbicides triafamone plus ethoxysulfuron applied at 40 g ai ha-1, pyrazosulfuron-ethyl plus pretilachlor at 382.5 g ai ha-1, and pendimethalin plus clomazone at 1200 g ai ha-1 reduced monochoria biomass by 100%, 100%, and 14%, respectively, and a single application of flucetosulfuron at 30 g ai ha-1, pendimethalin at 990 g ai ha-1, thiobencarb at 2750 g ai ha-1, and pretilachlor at 1000 g ai ha-1 by 100%, 99%, 75%, and 56%, respectively, compared with the nontreated control. Tank-mixed bensulfuron-methyl at 45 g ai ha-1 with pretilachlor, thiobencarb, or pendimethalin provided 100% control of monochoria. Rice height, and straw and grain yield were greater in herbicide treatments than in the nontreated and hand-weeded control, indicating the advantages of chemical monochoria control over manual weeding. Full-season monochoria interference reduced rice grain yield by 32%. In the second study, foliar-applied herbicides triafamone plus ethoxysulfuron, flucetosulfuron, 2,4-D at 1080 g ai ha-1, dicamba plus 2,4-D at 928 g ai ha-1, bispyribac-sodium at 31.25 g ai ha-1, bentazon plus MCPA at 1150 g ai ha-1, pyribenzoxim at 30 g ai ha-1, and propanil at 5400 g ai ha-1 applied at 4-5 leaf seedlings of monochoria provided ≥97% control and prevented 100% of its regrowth, with the exception of propanil. This study shows that monochoria control can be achieved by many residual and foliar-applied herbicides with different mechanisms of action.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44592813","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 first textbooks focused on weed identification published in the United States are reviewed. Those weeds considered the most troublesome weeds in agriculture are discussed. Common and scientific names written in the texts have been cross referenced to current common and scientific names.
{"title":"The first weed science textbooks in the United States (Part 1)","authors":"J. Byrd, David P. Russell, Kayla Broster","doi":"10.1017/wet.2023.64","DOIUrl":"https://doi.org/10.1017/wet.2023.64","url":null,"abstract":"\u0000 The first textbooks focused on weed identification published in the United States are reviewed. Those weeds considered the most troublesome weeds in agriculture are discussed. Common and scientific names written in the texts have been cross referenced to current common and scientific names.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49109616","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}
Smooth scouringrush is a creeping perennial with a high silica content in stems that may impede herbicide uptake. Smooth scouringrush has become a troublesome weed in no-till cropping systems across eastern Washington. In previous field studies, glyphosate provided inconsistent control of smooth scouringrush. The objective of this study was to determine if the addition of an organosilicone surfactant to glyphosate would improve the efficacy and consistency of control through stomatal flooding. To test this hypothesis, glyphosate was applied at three field sites at 3.78 kg ae ha-1 alone, with an organosilicone surfactants (OS1 and OS2), an organosilicone plus nonionic surfactant blend, or an alcohol-based surfactant applied during the day or at night. Stem counts were taken one year after herbicide applications. Five of the six effective treatments observed across the three study sites included organosilicone surfactant or an organosilicone plus nonionic surfactant blend. At two sites, when there was a difference in efficacy between application times, daytime applications were more effective than nighttime applications. These results support the hypothesis of stomatal flooding as a likely mechanism for enhanced efficacy of glyphosate with the addition of an organosilicone surfactant. However, at one site, the treatments containing organosilicone surfactant were more efficacious when applied at night than during the day. At this site, high daytime temperatures and low relative humidity may have resulted in rapid evaporation of spray droplets. The addition of an organosilicone surfactant to glyphosate is recommended for smooth scouringrush control and daytime treatments are preferred but should be applied when temperatures and humidity are not conducive to rapid droplet drying. Further research is necessary to confirm that stomatal flooding is responsible for improved glyphosate efficacy.
顺草是一种匍匐多年生植物，茎中硅含量高，可能会阻碍除草剂的吸收。在华盛顿东部的免耕种植系统中，草鞭草已经成为一种麻烦的杂草。在以前的实地研究中，草甘膦对光滑的鞭毛病的控制效果不一致。本研究的目的是确定在草甘膦中加入有机硅表面活性剂是否会提高通过气孔淹水控制的有效性和一致性。为了验证这一假设，草甘膦在三个现场以3.78 kg ae - ha-1单独施用，与有机硅表面活性剂(OS1和OS2)，有机硅加非离子表面活性剂混合物，或醇基表面活性剂在白天或晚上施用。使用除草剂一年后进行茎干计数。在三个研究地点观察到的六种有效处理方法中，有五种包括有机硅表面活性剂或有机硅加非离子表面活性剂的混合物。在两个地点，当使用时间不同时，白天使用比夜间使用更有效。这些结果支持了气孔泛洪可能是添加有机硅表面活性剂增强草甘膦功效的机制的假设。然而，在一个部位，含有有机硅表面活性剂的处理在夜间比在白天更有效。在这个地点，白天的高温和较低的相对湿度可能导致喷雾液滴迅速蒸发。建议在草甘膦中添加有机硅表面活性剂，以平滑控制刷毛，首选白天处理，但应在温度和湿度不利于快速干燥的情况下应用。需要进一步的研究来证实气孔淹水是提高草甘膦功效的原因。
{"title":"Smooth scouringrush (Equisetum laevigatum) control with glyphosate is affected by surfactant choice and application time","authors":"Marija Savic, M. Thorne, D. Lyon","doi":"10.1017/wet.2023.57","DOIUrl":"https://doi.org/10.1017/wet.2023.57","url":null,"abstract":"\u0000 Smooth scouringrush is a creeping perennial with a high silica content in stems that may impede herbicide uptake. Smooth scouringrush has become a troublesome weed in no-till cropping systems across eastern Washington. In previous field studies, glyphosate provided inconsistent control of smooth scouringrush. The objective of this study was to determine if the addition of an organosilicone surfactant to glyphosate would improve the efficacy and consistency of control through stomatal flooding. To test this hypothesis, glyphosate was applied at three field sites at 3.78 kg ae ha-1 alone, with an organosilicone surfactants (OS1 and OS2), an organosilicone plus nonionic surfactant blend, or an alcohol-based surfactant applied during the day or at night. Stem counts were taken one year after herbicide applications. Five of the six effective treatments observed across the three study sites included organosilicone surfactant or an organosilicone plus nonionic surfactant blend. At two sites, when there was a difference in efficacy between application times, daytime applications were more effective than nighttime applications. These results support the hypothesis of stomatal flooding as a likely mechanism for enhanced efficacy of glyphosate with the addition of an organosilicone surfactant. However, at one site, the treatments containing organosilicone surfactant were more efficacious when applied at night than during the day. At this site, high daytime temperatures and low relative humidity may have resulted in rapid evaporation of spray droplets. The addition of an organosilicone surfactant to glyphosate is recommended for smooth scouringrush control and daytime treatments are preferred but should be applied when temperatures and humidity are not conducive to rapid droplet drying. Further research is necessary to confirm that stomatal flooding is responsible for improved glyphosate efficacy.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42066120","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}
Cynthia Sias, K. Bamber, Vipin Kumar, Vijay Singh, M. Flessner
Successful cover crop (CC) establishment in the fall is important to maximize CC production, which is critical for achieving many objectives of CCs. Competition from winter weeds may reduce CC establishment and biomass production. A preplant herbicide, such as paraquat, at the time of CC planting in the fall will reduce winter weed pressure resulting in better establishment and growth. An experiment was conducted between 2019-2021 to test this hypothesis by evaluating a no CC check, cereal rye, hairy vetch, crimson clover, and cereal rye + hairy vetch drilled with and without paraquat applied at planting (mid-October to mid-November) following either a corn or soybean crop. Visible weed suppression ratings were collected in mid-April and total CC and weed biomass was collected in late April. More CC biomass was accumulated following corn than soybean, regardless of preplant herbicide application because corn is typically harvested before soybeans. Therefore, CC should be planted early to accumulate more biomass. Weed suppression varied by weed species from all factors, but in general weed suppression was best from CC mixture containing cereal rye and paraquat applied at planting. If weed suppression is the main goal of the CC, then a preplant herbicide at CC planting is recommended. However, if CC weed suppression goals can be achieved through biomass accumulation, no preplant herbicide is needed. This information is useful for producers to achieve various CC objectives while managing costs.
{"title":"Effects of paraquat application at cover crop planting on cover crop biomass and weed suppression","authors":"Cynthia Sias, K. Bamber, Vipin Kumar, Vijay Singh, M. Flessner","doi":"10.1017/wet.2023.59","DOIUrl":"https://doi.org/10.1017/wet.2023.59","url":null,"abstract":"\u0000 Successful cover crop (CC) establishment in the fall is important to maximize CC production, which is critical for achieving many objectives of CCs. Competition from winter weeds may reduce CC establishment and biomass production. A preplant herbicide, such as paraquat, at the time of CC planting in the fall will reduce winter weed pressure resulting in better establishment and growth. An experiment was conducted between 2019-2021 to test this hypothesis by evaluating a no CC check, cereal rye, hairy vetch, crimson clover, and cereal rye + hairy vetch drilled with and without paraquat applied at planting (mid-October to mid-November) following either a corn or soybean crop. Visible weed suppression ratings were collected in mid-April and total CC and weed biomass was collected in late April. More CC biomass was accumulated following corn than soybean, regardless of preplant herbicide application because corn is typically harvested before soybeans. Therefore, CC should be planted early to accumulate more biomass. Weed suppression varied by weed species from all factors, but in general weed suppression was best from CC mixture containing cereal rye and paraquat applied at planting. If weed suppression is the main goal of the CC, then a preplant herbicide at CC planting is recommended. However, if CC weed suppression goals can be achieved through biomass accumulation, no preplant herbicide is needed. This information is useful for producers to achieve various CC objectives while managing costs.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42275001","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}
Several Echinochloa P. Beauv. species, introduced at multiple events, have established themselves as a persistent concern for US rice production. In this review, we highlight the key biological characteristics of economically relevant Echinochloa in US rice, revisit their historical trajectory, and put forward research directions for their management with special reference to barnyardgrass. Ecologically-differentiated Echinochloa species have a distinct association with rice culture methods that have been practiced in a region, barnyardgrass being historically predominant in drill-seeded rice in the mid-South, and early watergrass and late watergrass in water-seeded California rice for the last few decades. However, the emerging evidence challenges the dogma that other Echinochloa species for the specific regions are of less importance. Primarily managed by the water-seeding method of rice culture in the early years, Echinochloa species have persisted in the sophisticated US rice culture through the evolution of resistance to herbicides in the later course. Accumulating knowledge, including those of recent genomic insights, suggests the rapid adaptability of Echinochloa. The last decade has seen a (re)emergence of non-chemical methods as a key component of a sustainable management approach, among which use of harvest weed seed control (HWSC) methods and cover crops in the mid-South and stale-drill seeding in California are being considered as potential tools for management of Echinochloa. In recent years, furrow-irrigated rice has rapidly supplanted a significant proportion of conventionally flooded rice in the mid-South, whereas the propensity for compromised continuous submergence is increasing in California rice. On the cusp of this shift, the question at the forefront is how this will affect Echinochloa interference in rice and how this change will dictate the management efforts. Future research will develop a clear understanding of the impact of the changing agroecosystems on Echinochloa species as well as their response to the prospective integrated control interventions.
{"title":"Echinochloa in mid-southern US and California Rice: What is Known and What are the Knowledge Gaps?","authors":"Amar S. Godar, J. Norsworthy","doi":"10.1017/wet.2023.52","DOIUrl":"https://doi.org/10.1017/wet.2023.52","url":null,"abstract":"\u0000 Several Echinochloa P. Beauv. species, introduced at multiple events, have established themselves as a persistent concern for US rice production. In this review, we highlight the key biological characteristics of economically relevant Echinochloa in US rice, revisit their historical trajectory, and put forward research directions for their management with special reference to barnyardgrass. Ecologically-differentiated Echinochloa species have a distinct association with rice culture methods that have been practiced in a region, barnyardgrass being historically predominant in drill-seeded rice in the mid-South, and early watergrass and late watergrass in water-seeded California rice for the last few decades. However, the emerging evidence challenges the dogma that other Echinochloa species for the specific regions are of less importance. Primarily managed by the water-seeding method of rice culture in the early years, Echinochloa species have persisted in the sophisticated US rice culture through the evolution of resistance to herbicides in the later course. Accumulating knowledge, including those of recent genomic insights, suggests the rapid adaptability of Echinochloa. The last decade has seen a (re)emergence of non-chemical methods as a key component of a sustainable management approach, among which use of harvest weed seed control (HWSC) methods and cover crops in the mid-South and stale-drill seeding in California are being considered as potential tools for management of Echinochloa. In recent years, furrow-irrigated rice has rapidly supplanted a significant proportion of conventionally flooded rice in the mid-South, whereas the propensity for compromised continuous submergence is increasing in California rice. On the cusp of this shift, the question at the forefront is how this will affect Echinochloa interference in rice and how this change will dictate the management efforts. Future research will develop a clear understanding of the impact of the changing agroecosystems on Echinochloa species as well as their response to the prospective integrated control interventions.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41847494","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}
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