Abstract Mexican devil [ Ageratina adenophora (Spreng.) R.M. King & H. Rob.], a globally invasive weed with destructive effects on forests, has spread to numerous countries. To elucidate the inhibition of tree growth by A. adenophora , a study was conducted using the fungi ( Lactarius deliciosus , Ceriporia lacerat and Fomitopsis palustris ) involved in the recycling of carbon and nutrients in forests. The focus was on investigating soil nitrogen and phosphorus availability, in response to aqueous extracts from uncomposted and aerobically composted A. adenophora (EUA and ECA, respectively). The samples of CA from different sites exhibited a significant reduction in the concentration of allelochemicals 4,7-dimethyl-1-(propan-2-ylidene)-1,4,4a,8a-tetrahydronaphthalene-2,6(1H, 7H)-dione and 6-hydroxy-5-isopropyl-3,8-dimethyl-4a,5,6,7,8,8a-hexahydronaphthalen-2(1H)-one. This reduction more than 94% when compared to the concentration of these allelochemicals in CA. The EUA solutions at 5.0 and 10 mg L -1 (oven-dried plant biomass base) minimized Lactarius deliciosus and Ceriporia lacerate growth, and significantly decreased Fomitopsis palustris growth on the soil surface and within the soil. However, soil with ECA had no effect or promoting effect on the fungal growth. Compared to CK (only fungal inoculation in tested soil), the EUA solution reduced soil nitrogen and phosphorus, while ECA had the opposite effect; soil pH was increased by 0.01-0.08 under EUA treatment, while decreased by 0.5-0.41under ECA treatment. Nitrogen and phosphorus availability were positively correlated with protease and phosphatase activity ( r = 0.723-0.944), while available phosphorus was inversely correlated with pH in tested soils ( r = -(0.809-0.978)). As such, the EUA solution decreased soil nitrogen and phosphorus supplies by inhibiting the liberation of proteases, phosphatases, and protons, which may lead to poor growth or even mortality of three fungal species. The in situ aerobically composted A. adenophora residues left may directly supply fungal specie with nutrients and indirectly increase soil nutrient availability via the promotion of nitrogen and phosphorus mobilization.
{"title":"Allelopathic effects of aqueous extracts from uncomposted and composted Mexican devel (<i>Ageratina Adenophora</i>) plants on forest fungal growth and soil nitrogen and phosphorus mobilization","authors":"Yujie Jiao, Jianguo Huang","doi":"10.1017/wsc.2023.56","DOIUrl":"https://doi.org/10.1017/wsc.2023.56","url":null,"abstract":"Abstract Mexican devil [ Ageratina adenophora (Spreng.) R.M. King & H. Rob.], a globally invasive weed with destructive effects on forests, has spread to numerous countries. To elucidate the inhibition of tree growth by A. adenophora , a study was conducted using the fungi ( Lactarius deliciosus , Ceriporia lacerat and Fomitopsis palustris ) involved in the recycling of carbon and nutrients in forests. The focus was on investigating soil nitrogen and phosphorus availability, in response to aqueous extracts from uncomposted and aerobically composted A. adenophora (EUA and ECA, respectively). The samples of CA from different sites exhibited a significant reduction in the concentration of allelochemicals 4,7-dimethyl-1-(propan-2-ylidene)-1,4,4a,8a-tetrahydronaphthalene-2,6(1H, 7H)-dione and 6-hydroxy-5-isopropyl-3,8-dimethyl-4a,5,6,7,8,8a-hexahydronaphthalen-2(1H)-one. This reduction more than 94% when compared to the concentration of these allelochemicals in CA. The EUA solutions at 5.0 and 10 mg L -1 (oven-dried plant biomass base) minimized Lactarius deliciosus and Ceriporia lacerate growth, and significantly decreased Fomitopsis palustris growth on the soil surface and within the soil. However, soil with ECA had no effect or promoting effect on the fungal growth. Compared to CK (only fungal inoculation in tested soil), the EUA solution reduced soil nitrogen and phosphorus, while ECA had the opposite effect; soil pH was increased by 0.01-0.08 under EUA treatment, while decreased by 0.5-0.41under ECA treatment. Nitrogen and phosphorus availability were positively correlated with protease and phosphatase activity ( r = 0.723-0.944), while available phosphorus was inversely correlated with pH in tested soils ( r = -(0.809-0.978)). As such, the EUA solution decreased soil nitrogen and phosphorus supplies by inhibiting the liberation of proteases, phosphatases, and protons, which may lead to poor growth or even mortality of three fungal species. The in situ aerobically composted A. adenophora residues left may directly supply fungal specie with nutrients and indirectly increase soil nutrient availability via the promotion of nitrogen and phosphorus mobilization.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135476650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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{"title":"Tuber development and propagation are inhibited by GA<sub>3</sub> effects on the DELLA-dependent pathway in purple nutsedge (<i>Cyperus rotundus</i>) – CORRIGENDUM","authors":"Chen-Yang Wei, Dan-Li Fan, Shu-Yu Liu, Shan-Chi Yi, Shi-Xian Yu, Guo-Chao Zhao, Xiao-Liang Liu, Wen-Wei Tang","doi":"10.1017/wsc.2023.58","DOIUrl":"https://doi.org/10.1017/wsc.2023.58","url":null,"abstract":"An abstract is not available for this content. As you have access to this content, full HTML content is provided on this page. A PDF of this content is also available in through the ‘Save PDF’ action button.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135820989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Thailand’s northeast (NE) region is an area of high-quality cultivated rice ( Oryza sativa L.) production. However, an outbreak of weedy rice has recently spread throughout the region. Weedy rice is phenotypically and morphologically similar to cultivated rice, making identification difficult. The prospective management of weedy rice in the future will involve the study of its genetic diversity and population structure in this region. This study assesses the genetic diversity and population structure of 380 weedy rice samples in the northeast of Thailand through simple sequence repeat (SSR) markers. Thirty-one SSR markers generated 213 alleles with an average of 6.87 per locus and an overall gene diversity of 0.723. Based on its geographical origin, weedy rice in the Southern NE showed greater gene diversity than that in the Central NE and Northern NE areas. The out-crossing rate in all regions was relatively high, with the highest being in the Southern NE at 9.769%. According to genetic distance analysis, the clustering of weedy rice samples in Northeast Thailand was not associated with the geographical region. Neighbor-joining and principal coordinate analysis revealed that the 380 weedy rice samples fell into two major clusters. Cluster I contained three weedy rice samples and four wild. In Cluster II, 377 weedy rice samples were closely related to the four cultivated rice cultivars as well as brownbeard rice ( Oryza rufipogon Griffiths) wild species. The results suggest that weedy rice in Northeast Thailand may have originated as a cross between cultivated and wild rice, as seen in the closely related species, O. rufipogon . Overall, the findings of this study demonstrate the high genetic diversity of weedy rice in this region. Notably, some samples adapted, performing more like cultivated rice, which may be problematic for the future production of high-quality rice in this region. The prevention of weedy rice should, therefore, be given greater consideration in future studies.
{"title":"The genetic diversity and population structure of weedy rice in Northeast Thailand accessed by SSR markers","authors":"Monchita Ponsen, Kularb Loasatit, Tidarat Monkham, Jirawat Sanitchon, Peerapon Moung-ngam, Sompong Chankaew","doi":"10.1017/wsc.2023.60","DOIUrl":"https://doi.org/10.1017/wsc.2023.60","url":null,"abstract":"Abstract Thailand’s northeast (NE) region is an area of high-quality cultivated rice ( Oryza sativa L.) production. However, an outbreak of weedy rice has recently spread throughout the region. Weedy rice is phenotypically and morphologically similar to cultivated rice, making identification difficult. The prospective management of weedy rice in the future will involve the study of its genetic diversity and population structure in this region. This study assesses the genetic diversity and population structure of 380 weedy rice samples in the northeast of Thailand through simple sequence repeat (SSR) markers. Thirty-one SSR markers generated 213 alleles with an average of 6.87 per locus and an overall gene diversity of 0.723. Based on its geographical origin, weedy rice in the Southern NE showed greater gene diversity than that in the Central NE and Northern NE areas. The out-crossing rate in all regions was relatively high, with the highest being in the Southern NE at 9.769%. According to genetic distance analysis, the clustering of weedy rice samples in Northeast Thailand was not associated with the geographical region. Neighbor-joining and principal coordinate analysis revealed that the 380 weedy rice samples fell into two major clusters. Cluster I contained three weedy rice samples and four wild. In Cluster II, 377 weedy rice samples were closely related to the four cultivated rice cultivars as well as brownbeard rice ( Oryza rufipogon Griffiths) wild species. The results suggest that weedy rice in Northeast Thailand may have originated as a cross between cultivated and wild rice, as seen in the closely related species, O. rufipogon . Overall, the findings of this study demonstrate the high genetic diversity of weedy rice in this region. Notably, some samples adapted, performing more like cultivated rice, which may be problematic for the future production of high-quality rice in this region. The prevention of weedy rice should, therefore, be given greater consideration in future studies.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135411508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Weeds are a significant threat to the production of agronomic, horticultural, and ornamental crops, as direct competition for resources can result in substantial yield shortfalls (WSSA 2023). A review of research data generated across the United States and Canada indicated that unmanaged weeds have the potential to reduce corn and soybean production by approximately 50%, even when other best management practices are applied (Soltani et al. 2016, 2017). The associated economic losses, which were estimated at 26.7 and 17.2 billion USD for corn and soybeans, respectively, would be catastrophic. Weeds can also interfere with crops, indirectly. For example, weeds may impede or delay harvest operations (Smith et al. 2000), reduce crop quality because of contamination (Moore et al. 2004), and serve as alternate hosts for pests and pathogens (Chen et al. 2011; Wisler and Norris 2005). Other habitats, such as rangelands, wetlands, and other natural and urban areas, are also affected by weedy and invasive plant species. Impacts of unwanted vegetation can include damage to infrastructure, damage to recreational space, altered water flow, degraded natural resources, reduced biodiversity and species displacement, and a loss of ecosystem services, among other effects (DiTomaso 2000; Jetter et al. 2021; Neal 2023; Vilà et al. 2011).
杂草是对农艺、园艺和观赏作物生产的重大威胁，因为对资源的直接竞争可能导致大量产量不足(WSSA 2023)。对美国和加拿大研究数据的回顾表明，即使采用其他最佳管理措施，未经管理的杂草也有可能使玉米和大豆产量减少约50% (Soltani et al. 2016, 2017)。玉米和大豆的相关经济损失估计分别为267亿美元和172亿美元，这将是灾难性的。杂草也会间接地干扰农作物。例如，杂草可能阻碍或延迟收获作业(Smith et al. 2000)，因污染而降低作物质量(Moore et al. 2004)，并作为害虫和病原体的替代宿主(Chen et al. 2011;威斯勒和诺里斯2005)。其他生境，如牧场、湿地和其他自然和城市地区，也受到杂草和入侵植物物种的影响。不需要的植被的影响包括对基础设施的破坏、对娱乐空间的破坏、水流的改变、自然资源的退化、生物多样性的减少和物种迁移、生态系统服务的丧失以及其他影响(DiTomaso 2000;Jetter et al. 2021;尼尔2023;vilou et al. 2011)。
{"title":"Implications of weakening of the United States Geological Survey Pesticide National Synthesis Project for Weed Scientists","authors":"Lynn M. Sosnoskie, Stephen O. Duke","doi":"10.1017/wsc.2023.59","DOIUrl":"https://doi.org/10.1017/wsc.2023.59","url":null,"abstract":"Abstract Weeds are a significant threat to the production of agronomic, horticultural, and ornamental crops, as direct competition for resources can result in substantial yield shortfalls (WSSA 2023). A review of research data generated across the United States and Canada indicated that unmanaged weeds have the potential to reduce corn and soybean production by approximately 50%, even when other best management practices are applied (Soltani et al. 2016, 2017). The associated economic losses, which were estimated at 26.7 and 17.2 billion USD for corn and soybeans, respectively, would be catastrophic. Weeds can also interfere with crops, indirectly. For example, weeds may impede or delay harvest operations (Smith et al. 2000), reduce crop quality because of contamination (Moore et al. 2004), and serve as alternate hosts for pests and pathogens (Chen et al. 2011; Wisler and Norris 2005). Other habitats, such as rangelands, wetlands, and other natural and urban areas, are also affected by weedy and invasive plant species. Impacts of unwanted vegetation can include damage to infrastructure, damage to recreational space, altered water flow, degraded natural resources, reduced biodiversity and species displacement, and a loss of ecosystem services, among other effects (DiTomaso 2000; Jetter et al. 2021; Neal 2023; Vilà et al. 2011).","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135412284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jose Nunes, Nicholas J. Arneson, John Wallace, Karla Gage, Eric Miller, Sarah Lancaster, Thomas Mueller, Rodrigo Werle
Abstract Preemergence herbicides associated with cereal rye ( Secale cereale L.) cover crop (cereal rye) can be an effective waterhemp [ Amaranthus tuberculatus (Moq.) Sauer.] and Palmer amaranth ( Amaranthus palmeri S. Watson) management strategy in soybean [ Glycine max (L.) Merr.] production. Delaying cereal rye termination until soybean planting (planting green) optimizes biomass production and weed suppression but might further impact the fate of preemergence herbicides. Limited research is available on the fate of preemergence herbicides applied over living cereal rye in the planting green system. Field experiments were conducted in Illinois, Kansas, Pennsylvania, and Wisconsin to evaluate the fate of flumioxazin and pyroxasulfone and Amaranthus spp. residual control under different cover crop management practices in soybean in 2021 and 2022 (8 site-years). A flumioxazin + pyroxasulfone herbicide premix was applied preemergence at soybean planting under no-till without cereal rye, cereal rye early terminated before soybean planting, and cereal rye terminated at soybean planting. Flumioxazin and pyroxasulfone concentrations in the soil were quantified at 0, 7, and 21 d after treatment (DAT) and Amaranthus spp. density was determined at postemergence herbicide application. The presence of cereal rye biomass intercepted flumioxazin and pyroxasulfone at preemergence application and reduced concentration in the soil when compared to no-till, mainly at 0 DAT. Main differences in herbicide concentration were observed between no-till and cereal rye treatments rather than cereal rye termination times. Despite reducing herbicide concentration in the soil, early-season residual Amaranthus spp. control was not affected by the presence of the cereal rye biomass. The adoption of effective preemergence herbicides associated with a properly managed cereal rye cover crop is an effective option for integrated Amaranthus spp. management programs in soybean production systems.
小麦黑麦(Secale cereale L.)覆盖作物(谷类黑麦)的出苗期除草剂可以作为一种有效的水麻[Amaranthus tuberculatus (Moq.)]。萨奥尔。大豆中苋菜(Amaranthus palmeri S. Watson)的管理策略[j]。稳定。)生产。将谷物黑麦的终止推迟到大豆种植(绿色种植)可以优化生物量生产和杂草抑制，但可能进一步影响出生前除草剂的命运。在种植绿色系统中，对活的谷物黑麦施用发芽前除草剂的影响研究有限。在伊利诺斯州、堪萨斯州、宾夕法尼亚州和威斯康星州进行了田间试验，评估了2021年和2022年(8个立地年)不同覆盖作物管理措施下氟恶嗪、吡啶砜和苋属残留防治的效果。采用免耕不播黑麦条件下大豆播种前施用氟恶嗪+焦唑砜除草剂预混剂、黑麦播种前提前终止大豆、黑麦播种后终止大豆。测定了处理后0、7、21 d土壤中氟恶嗪和pyroxasulfone的浓度，并测定了出苗期施用除草剂时苋菜的密度。谷物黑麦生物量的存在在苗期前施用时拦截了氟恶嗪和焦唑砜，并且与免耕相比降低了土壤中的浓度，主要是在0 DAT。除草剂浓度在免耕和黑麦处理之间存在主要差异，而不是在黑麦终止时间之间。尽管降低了土壤中除草剂的浓度，但小麦黑麦生物量的存在对苋属早季残留的控制没有影响。在大豆生产系统中，采用有效的孕前除草剂和适当管理的黑麦覆盖作物是苋属植物综合管理方案的有效选择。
{"title":"Impact of Cereal Rye Cover Crop on the Fate of Preemergence Herbicides Flumioxazin and Pyroxasulfone and Control of <i>Amaranthus</i> spp. in Soybean","authors":"Jose Nunes, Nicholas J. Arneson, John Wallace, Karla Gage, Eric Miller, Sarah Lancaster, Thomas Mueller, Rodrigo Werle","doi":"10.1017/wsc.2023.46","DOIUrl":"https://doi.org/10.1017/wsc.2023.46","url":null,"abstract":"Abstract Preemergence herbicides associated with cereal rye ( Secale cereale L.) cover crop (cereal rye) can be an effective waterhemp [ Amaranthus tuberculatus (Moq.) Sauer.] and Palmer amaranth ( Amaranthus palmeri S. Watson) management strategy in soybean [ Glycine max (L.) Merr.] production. Delaying cereal rye termination until soybean planting (planting green) optimizes biomass production and weed suppression but might further impact the fate of preemergence herbicides. Limited research is available on the fate of preemergence herbicides applied over living cereal rye in the planting green system. Field experiments were conducted in Illinois, Kansas, Pennsylvania, and Wisconsin to evaluate the fate of flumioxazin and pyroxasulfone and Amaranthus spp. residual control under different cover crop management practices in soybean in 2021 and 2022 (8 site-years). A flumioxazin + pyroxasulfone herbicide premix was applied preemergence at soybean planting under no-till without cereal rye, cereal rye early terminated before soybean planting, and cereal rye terminated at soybean planting. Flumioxazin and pyroxasulfone concentrations in the soil were quantified at 0, 7, and 21 d after treatment (DAT) and Amaranthus spp. density was determined at postemergence herbicide application. The presence of cereal rye biomass intercepted flumioxazin and pyroxasulfone at preemergence application and reduced concentration in the soil when compared to no-till, mainly at 0 DAT. Main differences in herbicide concentration were observed between no-till and cereal rye treatments rather than cereal rye termination times. Despite reducing herbicide concentration in the soil, early-season residual Amaranthus spp. control was not affected by the presence of the cereal rye biomass. The adoption of effective preemergence herbicides associated with a properly managed cereal rye cover crop is an effective option for integrated Amaranthus spp. management programs in soybean production systems.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135883602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vijaya Bhaskar Alwarnaidu Vijayarajan, Charlotte Morgan, Nawaporn Onkokesung, Sarah K Cook, Trevor R Hodkinson, Susanne Barth, Michael Hennessy, Patrick D Forristal
Abstract Herbicide-resistant annual bluegrass ( Poa annua L.) has become a problem in non-arable land areas. In arable fields, P. annua is frequently of lower priority in weed control programmes due to the variety of control options available and the relatively modest impact on crop yield than other species. In Ireland, postemergence herbicides are not primarily intended for P. annua control, but some herbicides, including acetolactate synthase (ALS)-inhibitor mesosulfuron-methyl + iodosulfuron-methyl, exhibit P. annua -activity. In this study, a suspected P. annua population (POAAN-R) that survived mesosulfuron-methyl + iodosulfuron-methyl at 0.75 of field-recommended rate was sampled from a wheat field in County Dublin, Ireland. Single-dose testing confirmed that the suspected POAAN-R had evolved resistance to mesosulfuron-methyl + iodosulfuron-methyl and additionally, to pyroxsulam (not registered in Ireland for P. annua control), but was sensitive to clethodim, glyphosate, pendimethalin and flufenacet. Dose-response experiments indicated that POAAN-R was more resistant (GR 50 resistance index) to both mesosulfuron-methyl + iodosulfuron-methyl (47.8 times) and pyroxsulam (38.0 times) than sensitive POAAN-S and this was associated with the mutation at tryptophan (Trp)-574 in ALS protein. Malathion (a cytochrome P450 inhibitor) pre-treatment did not reverse POAAN-R resistance to mesosulfuron-methyl + iodosulfuron-methyl or pyroxsulam at field rate or above. The natural inherent mutation at isoleucine (Ile)-1781 in ACCase protein had no effect on both POAAN-R and POAAN-S sensitivity to clethodim. The glyphosate sensitivity of POAAN-R also corresponded with no known mutation in EPSPS protein. Based on field histories, poor early-season weed control coupled with intensive use of mesosulfuron-methyl + iodosulfuron-methyl (often at reduced rates) has unintentionally selected for ALS-inhibitor-resistant POAAN-R. This is the first report to characterize resistance in P. annua to ALS-mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam in an arable setting. There is an opportunity to effectively control POAAN-R using herbicides, but this needs a wide-ranging and varied approach, coupled with cultural/non-chemical practices.
{"title":"Characterization of Mesosulfuron-Methyl + Iodosulfuron-Methyl and Pyroxsulam-Resistant Annual Bluegrass (<i>Poa annua</i>) in an Annual Cropping System","authors":"Vijaya Bhaskar Alwarnaidu Vijayarajan, Charlotte Morgan, Nawaporn Onkokesung, Sarah K Cook, Trevor R Hodkinson, Susanne Barth, Michael Hennessy, Patrick D Forristal","doi":"10.1017/wsc.2023.55","DOIUrl":"https://doi.org/10.1017/wsc.2023.55","url":null,"abstract":"Abstract Herbicide-resistant annual bluegrass ( Poa annua L.) has become a problem in non-arable land areas. In arable fields, P. annua is frequently of lower priority in weed control programmes due to the variety of control options available and the relatively modest impact on crop yield than other species. In Ireland, postemergence herbicides are not primarily intended for P. annua control, but some herbicides, including acetolactate synthase (ALS)-inhibitor mesosulfuron-methyl + iodosulfuron-methyl, exhibit P. annua -activity. In this study, a suspected P. annua population (POAAN-R) that survived mesosulfuron-methyl + iodosulfuron-methyl at 0.75 of field-recommended rate was sampled from a wheat field in County Dublin, Ireland. Single-dose testing confirmed that the suspected POAAN-R had evolved resistance to mesosulfuron-methyl + iodosulfuron-methyl and additionally, to pyroxsulam (not registered in Ireland for P. annua control), but was sensitive to clethodim, glyphosate, pendimethalin and flufenacet. Dose-response experiments indicated that POAAN-R was more resistant (GR 50 resistance index) to both mesosulfuron-methyl + iodosulfuron-methyl (47.8 times) and pyroxsulam (38.0 times) than sensitive POAAN-S and this was associated with the mutation at tryptophan (Trp)-574 in ALS protein. Malathion (a cytochrome P450 inhibitor) pre-treatment did not reverse POAAN-R resistance to mesosulfuron-methyl + iodosulfuron-methyl or pyroxsulam at field rate or above. The natural inherent mutation at isoleucine (Ile)-1781 in ACCase protein had no effect on both POAAN-R and POAAN-S sensitivity to clethodim. The glyphosate sensitivity of POAAN-R also corresponded with no known mutation in EPSPS protein. Based on field histories, poor early-season weed control coupled with intensive use of mesosulfuron-methyl + iodosulfuron-methyl (often at reduced rates) has unintentionally selected for ALS-inhibitor-resistant POAAN-R. This is the first report to characterize resistance in P. annua to ALS-mesosulfuron-methyl + iodosulfuron-methyl and pyroxsulam in an arable setting. There is an opportunity to effectively control POAAN-R using herbicides, but this needs a wide-ranging and varied approach, coupled with cultural/non-chemical practices.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135855578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Danica Goggin, Candy Taylor, Roberto Busi, Chad Sayer, Andrew Wells, Mark Slatter, Ken Flower
Abstract Synthetic auxin herbicides were developed and commercialised sixty years before their mode of action was definitively elucidated. Although evolution of resistance to auxinic herbicides proceeded more slowly than for some other herbicide chemistries, it has become a major problem in the dicotyledonous weeds of many cropping areas of the world. With the molecular characterisation of the auxin perception and signalling pathway in the mid-2000s came a greater understanding of how auxinic herbicides work, and how resistance may develop in weeds subjected to repeated selection with these herbicides. In wild radish ( Raphanus raphanistrum L.) populations in southern Australia, resistance to multiple herbicides, including synthetic auxins such as 2,4-D, has reduced the number of chemical control options available. The aim of this study was to determine if compounds involved in auxin biosynthesis, transport and signalling are able to synergise with 2,4-D and increase its ability to control 2,4-D-resistant R. raphanistrum populations. Although some mild synergism was observed with a few compounds (abscisic acid, cyclanilide, tryptamine), the response was not large or consistent enough to warrant further study. Similarly, alternative auxinic herbicides applied pre- or post-emergence were no more effective than 2,4-D. Therefore, whilst use of auxinic herbicides continues to increase due to the adoption of transgenic resistant crops, non-chemical control techniques will become more important and chemical control of 2,4-D-resistant R. raphanistrum should be undertaken with alternative modes of action, using mixtures and good stewardship to delay the development of resistance for as long as possible.
{"title":"Exploring chemical control of 2,4-D-resistant wild radish (<i>Raphanus raphanistrum</i>) with auxin-related compounds","authors":"Danica Goggin, Candy Taylor, Roberto Busi, Chad Sayer, Andrew Wells, Mark Slatter, Ken Flower","doi":"10.1017/wsc.2023.54","DOIUrl":"https://doi.org/10.1017/wsc.2023.54","url":null,"abstract":"Abstract Synthetic auxin herbicides were developed and commercialised sixty years before their mode of action was definitively elucidated. Although evolution of resistance to auxinic herbicides proceeded more slowly than for some other herbicide chemistries, it has become a major problem in the dicotyledonous weeds of many cropping areas of the world. With the molecular characterisation of the auxin perception and signalling pathway in the mid-2000s came a greater understanding of how auxinic herbicides work, and how resistance may develop in weeds subjected to repeated selection with these herbicides. In wild radish ( Raphanus raphanistrum L.) populations in southern Australia, resistance to multiple herbicides, including synthetic auxins such as 2,4-D, has reduced the number of chemical control options available. The aim of this study was to determine if compounds involved in auxin biosynthesis, transport and signalling are able to synergise with 2,4-D and increase its ability to control 2,4-D-resistant R. raphanistrum populations. Although some mild synergism was observed with a few compounds (abscisic acid, cyclanilide, tryptamine), the response was not large or consistent enough to warrant further study. Similarly, alternative auxinic herbicides applied pre- or post-emergence were no more effective than 2,4-D. Therefore, whilst use of auxinic herbicides continues to increase due to the adoption of transgenic resistant crops, non-chemical control techniques will become more important and chemical control of 2,4-D-resistant R. raphanistrum should be undertaken with alternative modes of action, using mixtures and good stewardship to delay the development of resistance for as long as possible.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134976031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ramon G. Leon, Fernando H. Oreja, Steven B. Mirsky, Chris Reberg-Horton
Abstract Replacement series are used by researchers to understand how competition-related variables influence dynamics from the individual to the population and community levels, but this approach has been criticized because of inherent biases associated with plant size differences and density-dependent responses. The use of functional densities instead of demographic densities was proposed to minimize those biases. This work explored three models to determine reference densities for replacement series experiments based on 1) maximum biomass, 2) biomass at onset of diminishing returns (i.e., inflection point), and 3) N uptake equivalency. Replacement series experiments were conducted using redroot pigweed ( Amaranthus hybridus L.):maize ( Zea mays L.) and giant foxtail ( Setaria faberi Herrm.):maize proportions of 1:0, 0.75:0.25, 0.5:0.5, 0.25:0.75, and 0:1. The monoculture density for each species was established according to the three models. Density selection criteria resulted in major differences in competitive interactions between species. The use of functional densities at which the biomass accumulation inflection point for the smaller species allowed both species to exhibit either increases or decreases in biomass production depending on competitive interactions for all inter-specific mixtures. Conversely, the maximum biomass model favored the larger species almost completely inhibiting the growth of the smaller species, which resulted in a poor characterization of competitive responses of the smaller species. The N uptake equivalency model resulted in interactions closer to the predicted neutral competition. The model based on the biomass accumulation inflection point was the most sensitive and informative across all inter-specific mixtures for both species. We propose that to reduce bias associated with species size differences when determining reference densities for replacement series experiments, at least two criteria must be met: 1) the experiment sensitivity allows measuring and quantifying the competitive responses for both species in all mixtures, and 2) the balance between density and carrying capacity of the system minimizes intra-specific competition.
{"title":"Addressing biases in replacement series: the importance of reference density selection for interpretation of competition outcomes","authors":"Ramon G. Leon, Fernando H. Oreja, Steven B. Mirsky, Chris Reberg-Horton","doi":"10.1017/wsc.2023.53","DOIUrl":"https://doi.org/10.1017/wsc.2023.53","url":null,"abstract":"Abstract Replacement series are used by researchers to understand how competition-related variables influence dynamics from the individual to the population and community levels, but this approach has been criticized because of inherent biases associated with plant size differences and density-dependent responses. The use of functional densities instead of demographic densities was proposed to minimize those biases. This work explored three models to determine reference densities for replacement series experiments based on 1) maximum biomass, 2) biomass at onset of diminishing returns (i.e., inflection point), and 3) N uptake equivalency. Replacement series experiments were conducted using redroot pigweed ( Amaranthus hybridus L.):maize ( Zea mays L.) and giant foxtail ( Setaria faberi Herrm.):maize proportions of 1:0, 0.75:0.25, 0.5:0.5, 0.25:0.75, and 0:1. The monoculture density for each species was established according to the three models. Density selection criteria resulted in major differences in competitive interactions between species. The use of functional densities at which the biomass accumulation inflection point for the smaller species allowed both species to exhibit either increases or decreases in biomass production depending on competitive interactions for all inter-specific mixtures. Conversely, the maximum biomass model favored the larger species almost completely inhibiting the growth of the smaller species, which resulted in a poor characterization of competitive responses of the smaller species. The N uptake equivalency model resulted in interactions closer to the predicted neutral competition. The model based on the biomass accumulation inflection point was the most sensitive and informative across all inter-specific mixtures for both species. We propose that to reduce bias associated with species size differences when determining reference densities for replacement series experiments, at least two criteria must be met: 1) the experiment sensitivity allows measuring and quantifying the competitive responses for both species in all mixtures, and 2) the balance between density and carrying capacity of the system minimizes intra-specific competition.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134975883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rishabh Singh, François J. Tardif, Mithila Jugulam
Abstract Phenoxy herbicides (2,4-D and MCPA) are widely used to manage broadleaf weeds including Palmer amaranth ( Amaranthus palmeri S. Watson), one of the most troublesome weeds in the US cropping systems. Previously, we documented resistance to 2,4-D and MCPA in an A. palmeri population (KCTR) from Kansas. Our recent research suggested rapid metabolism of 2,4-D bestows resistance in KCTR A. palmeri ; nonetheless, the mechanism of MCPA resistance in this population is still unknown. The objectives of this research were to 1) evaluate the level of resistance to MCPA in KCTR compared to two known susceptible populations of A. palmeri , MSS and KSS, 2) study the absorption and translocation of [ 14 C]MCPA in KCTR and MSS plants, 3) investigate the metabolic profile of [ 14 C]MCPA in KCTR, MSS, and compare those with MCPA-tolerant wheat ( Triticum aestivum L.) plants, and 4) assess the possible role of cytochrome P450 enzymes (P450s) in MCPA metabolism. Experiments were conducted to assess the level of resistance in KCTR. Using [ 14 C]MCPA, the absorption, translocation, and metabolic profiles were assessed in A. palmeri . Involvement of P450s was confirmed using malathion, a known P450-inhibitor. Regression analyses indicate that KCTR population exhibits a ∼3-fold resistance to MCPA. No difference in absorption of [ 14 C]MCPA was found between MSS or KCTR. However, the KCTR plants translocated less [ 14 C]MCPA at 48 hours after treatment (HAT) and metabolized more MCPA rapidly than MSS plants at 12 and 24 HAT. MCPA resistance in KCTR was reversed upon treatment with malathion indicating the involvement of P450s in metabolism of this herbicide. This is the first report of characterization of MCPA resistance in A. palmeri .
{"title":"Characterization of MCPA Resistance in Palmer amaranth (<i>Amaranthus palmeri</i>)","authors":"Rishabh Singh, François J. Tardif, Mithila Jugulam","doi":"10.1017/wsc.2023.52","DOIUrl":"https://doi.org/10.1017/wsc.2023.52","url":null,"abstract":"Abstract Phenoxy herbicides (2,4-D and MCPA) are widely used to manage broadleaf weeds including Palmer amaranth ( Amaranthus palmeri S. Watson), one of the most troublesome weeds in the US cropping systems. Previously, we documented resistance to 2,4-D and MCPA in an A. palmeri population (KCTR) from Kansas. Our recent research suggested rapid metabolism of 2,4-D bestows resistance in KCTR A. palmeri ; nonetheless, the mechanism of MCPA resistance in this population is still unknown. The objectives of this research were to 1) evaluate the level of resistance to MCPA in KCTR compared to two known susceptible populations of A. palmeri , MSS and KSS, 2) study the absorption and translocation of [ 14 C]MCPA in KCTR and MSS plants, 3) investigate the metabolic profile of [ 14 C]MCPA in KCTR, MSS, and compare those with MCPA-tolerant wheat ( Triticum aestivum L.) plants, and 4) assess the possible role of cytochrome P450 enzymes (P450s) in MCPA metabolism. Experiments were conducted to assess the level of resistance in KCTR. Using [ 14 C]MCPA, the absorption, translocation, and metabolic profiles were assessed in A. palmeri . Involvement of P450s was confirmed using malathion, a known P450-inhibitor. Regression analyses indicate that KCTR population exhibits a ∼3-fold resistance to MCPA. No difference in absorption of [ 14 C]MCPA was found between MSS or KCTR. However, the KCTR plants translocated less [ 14 C]MCPA at 48 hours after treatment (HAT) and metabolized more MCPA rapidly than MSS plants at 12 and 24 HAT. MCPA resistance in KCTR was reversed upon treatment with malathion indicating the involvement of P450s in metabolism of this herbicide. This is the first report of characterization of MCPA resistance in A. palmeri .","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135538982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mandeep Singh, Resham Thapa, Navdeep Singh, Steven B. Mirsky, Bharat S. Acharya, Amit J. Jhala
Abstract Narrow row spacing (<76 cm) could improve crop competitiveness, suppress weeds and might provide yield advantage. Many studies have been conducted to evaluate the impact of narrow row spacing; however, no quantitative synthesis of these studies exists. The objectives of this meta-analysis were to (1) quantify the overall effect of narrow row spacing (<76 cm) on weed density, biomass, control, weed seed production, and yield in corn ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] compared with 76-cm row spacing, and (2) assess the influence of agronomic management decisions (tillage type, weed management, herbicide application frequency and time) on effect of narrow row spacing on weed suppression and corn and soybean yield. We compiled 1,904 pair-wise observations from 35 studies conducted in 12 states in the United States during 1961 to 2018. Averaged across individual observations, narrow row spacing suppressed weed density by 34%, weed biomass by 55%, and weed seed production by 45%, while it improved weed control by 32% and crop yield by 11% compared with 76-cm row spacing. Narrow row spacing in soybean suppressed weed density by 42%, weed biomass by 71%, and increased crop yield by 12% compared with 76-cm row spacing. Although narrow row spacing had a nonsignificant effect on response variables in corn, the number of studies ( n = 1 to 6) and observations ( n = 1 to 59) addressing each response variable were limited. Tillage type (conventional and reduced) did not influence the response of weed density, control, and seed production in narrow row spacing; however, weed biomass and weed seed production were more greatly reduced with the sequential application of herbicides compared with a single application. Thus, narrow row spacing in soybean can be integrated with other options for management of herbicide-resistant weeds.
{"title":"Does narrow row spacing suppress weeds and increase yields in corn and soybean? A meta-analysis","authors":"Mandeep Singh, Resham Thapa, Navdeep Singh, Steven B. Mirsky, Bharat S. Acharya, Amit J. Jhala","doi":"10.1017/wsc.2023.50","DOIUrl":"https://doi.org/10.1017/wsc.2023.50","url":null,"abstract":"Abstract Narrow row spacing (<76 cm) could improve crop competitiveness, suppress weeds and might provide yield advantage. Many studies have been conducted to evaluate the impact of narrow row spacing; however, no quantitative synthesis of these studies exists. The objectives of this meta-analysis were to (1) quantify the overall effect of narrow row spacing (<76 cm) on weed density, biomass, control, weed seed production, and yield in corn ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] compared with 76-cm row spacing, and (2) assess the influence of agronomic management decisions (tillage type, weed management, herbicide application frequency and time) on effect of narrow row spacing on weed suppression and corn and soybean yield. We compiled 1,904 pair-wise observations from 35 studies conducted in 12 states in the United States during 1961 to 2018. Averaged across individual observations, narrow row spacing suppressed weed density by 34%, weed biomass by 55%, and weed seed production by 45%, while it improved weed control by 32% and crop yield by 11% compared with 76-cm row spacing. Narrow row spacing in soybean suppressed weed density by 42%, weed biomass by 71%, and increased crop yield by 12% compared with 76-cm row spacing. Although narrow row spacing had a nonsignificant effect on response variables in corn, the number of studies ( n = 1 to 6) and observations ( n = 1 to 59) addressing each response variable were limited. Tillage type (conventional and reduced) did not influence the response of weed density, control, and seed production in narrow row spacing; however, weed biomass and weed seed production were more greatly reduced with the sequential application of herbicides compared with a single application. Thus, narrow row spacing in soybean can be integrated with other options for management of herbicide-resistant weeds.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136308400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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