D. Brainard, Erin R. Haramoto, R. León, J. J. Kells, Lee R. Van Wychen, P. Devkota, M. Jugulam, J. Barney
Abstract We conducted an online survey of weed scientists in the United States and Canada to (1) identify research topics perceived to be important for advancing weed science in the next 5 to 10 years and (2) gain insight into potential gaps in current expertise and funding sources needed to address those priorities. Respondents were asked to prioritize nine broad research areas, as well as 5 to 10 subcategories within each of the broad areas. We received 475 responses, with the majority affiliated with academic institutions (55%) and working in cash crop (agronomic or horticultural) study systems (69%). Results from this survey provide valuable discussion points for policy makers, funding agencies, and academic institutions when allocating resources for weed science research. Notably, our survey reveals a strong prioritization of Cultural and Preventative Weed Management (CPWM) as well as the emerging area of Precision Weed Management and Robotics (PWMR). Although Herbicides remain a high-priority research area, continuing challenges necessitating integrated, nonchemical tactics (e.g., herbicide resistance) and emerging opportunities (e.g., robotics) are reflected in our survey results. Despite previous calls for greater understanding and application of weed biology and ecology in weed research, as well as recent calls for greater integration of social science perspectives to address weed management challenges, these areas were ranked considerably lower than those focused more directly on weed management. Our survey also identified a potential mismatch between research priorities and expertise in several areas, including CPWM, PWMR, and Weed Genomics, suggesting that these topics should be prime targets for expanded training and collaboration. Finally, our survey suggests an increasing reliance on private sector funding for research, raising concerns about our discipline's capacity to address important research priority areas that lack clear private sector incentives for investment.
{"title":"A Survey of Weed Research Priorities: Key Findings and Future Directions","authors":"D. Brainard, Erin R. Haramoto, R. León, J. J. Kells, Lee R. Van Wychen, P. Devkota, M. Jugulam, J. Barney","doi":"10.1017/wsc.2023.24","DOIUrl":"https://doi.org/10.1017/wsc.2023.24","url":null,"abstract":"Abstract We conducted an online survey of weed scientists in the United States and Canada to (1) identify research topics perceived to be important for advancing weed science in the next 5 to 10 years and (2) gain insight into potential gaps in current expertise and funding sources needed to address those priorities. Respondents were asked to prioritize nine broad research areas, as well as 5 to 10 subcategories within each of the broad areas. We received 475 responses, with the majority affiliated with academic institutions (55%) and working in cash crop (agronomic or horticultural) study systems (69%). Results from this survey provide valuable discussion points for policy makers, funding agencies, and academic institutions when allocating resources for weed science research. Notably, our survey reveals a strong prioritization of Cultural and Preventative Weed Management (CPWM) as well as the emerging area of Precision Weed Management and Robotics (PWMR). Although Herbicides remain a high-priority research area, continuing challenges necessitating integrated, nonchemical tactics (e.g., herbicide resistance) and emerging opportunities (e.g., robotics) are reflected in our survey results. Despite previous calls for greater understanding and application of weed biology and ecology in weed research, as well as recent calls for greater integration of social science perspectives to address weed management challenges, these areas were ranked considerably lower than those focused more directly on weed management. Our survey also identified a potential mismatch between research priorities and expertise in several areas, including CPWM, PWMR, and Weed Genomics, suggesting that these topics should be prime targets for expanded training and collaboration. Finally, our survey suggests an increasing reliance on private sector funding for research, raising concerns about our discipline's capacity to address important research priority areas that lack clear private sector incentives for investment.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47901811","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}
Carlos Sousa-Ortega, R. León, Nuria Lopez-Martinez, P. Castro-Valdecantos
Abstract North African knapweed (Centaurea diluta Aiton), cornflower (Centaurea cyanus L.), corn marigold [Glebionis segetum (L.) Fourr.], rigid ryegrass (Lolium rigidum Gaudin), and corn poppy (Papaver rhoeas L.) are weeds of economic importance in the Iberian Peninsula, particularly due to limited herbicide options for effective control. For this reason, information about their seedling emergence has become critical to develop effective integrated management strategies and better time control actions. The aims of this study were to evaluate the effect of seed burial depth and soil disturbance on the emergence of these weed species. Two pot experiments were carried out to (1) quantify seedling emergence at three burial depths (2, 5, and 9 cm) and (2) characterize seedling emergence in response to different frequencies and timings of soil disturbance. Burial depth limited the emergence of G. segetum and P. rhoeas at 5 and 9 cm, respectively; while seedling emergence of C. diluta, C. cyanus, and L. rigidum were reduced by 92%, 90%, and 67% at 9 cm compared with 2 cm, respectively. Two or more sequential soil disturbance events increased total seedling emergence of C. diluta, P. rhoeas, and G. segetum compared with single events, while L. rigidum did not respond to repeated soil disturbance. These results suggest that turning the soil to bury weed seeds down to 5 cm or deeper would be a very effective method to control G. segetum and P. rhoeas and moderately effective to control C. cyanus. Also, the use of a stale seedbed would have some efficacy to reduce P. rhoeas and C. diluta weed pressure within the crop. This study illustrates how differences among species in seedling emergence in response to soil depth and disturbance can determine distinct emergence patterns ultimately influencing the selection of weed control tools and timing.
{"title":"Influence of Burial Depth and Soil Disturbance on the Emergence of Common Weed Species in the Iberian Peninsula","authors":"Carlos Sousa-Ortega, R. León, Nuria Lopez-Martinez, P. Castro-Valdecantos","doi":"10.1017/wsc.2023.30","DOIUrl":"https://doi.org/10.1017/wsc.2023.30","url":null,"abstract":"Abstract North African knapweed (Centaurea diluta Aiton), cornflower (Centaurea cyanus L.), corn marigold [Glebionis segetum (L.) Fourr.], rigid ryegrass (Lolium rigidum Gaudin), and corn poppy (Papaver rhoeas L.) are weeds of economic importance in the Iberian Peninsula, particularly due to limited herbicide options for effective control. For this reason, information about their seedling emergence has become critical to develop effective integrated management strategies and better time control actions. The aims of this study were to evaluate the effect of seed burial depth and soil disturbance on the emergence of these weed species. Two pot experiments were carried out to (1) quantify seedling emergence at three burial depths (2, 5, and 9 cm) and (2) characterize seedling emergence in response to different frequencies and timings of soil disturbance. Burial depth limited the emergence of G. segetum and P. rhoeas at 5 and 9 cm, respectively; while seedling emergence of C. diluta, C. cyanus, and L. rigidum were reduced by 92%, 90%, and 67% at 9 cm compared with 2 cm, respectively. Two or more sequential soil disturbance events increased total seedling emergence of C. diluta, P. rhoeas, and G. segetum compared with single events, while L. rigidum did not respond to repeated soil disturbance. These results suggest that turning the soil to bury weed seeds down to 5 cm or deeper would be a very effective method to control G. segetum and P. rhoeas and moderately effective to control C. cyanus. Also, the use of a stale seedbed would have some efficacy to reduce P. rhoeas and C. diluta weed pressure within the crop. This study illustrates how differences among species in seedling emergence in response to soil depth and disturbance can determine distinct emergence patterns ultimately influencing the selection of weed control tools and timing.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41511162","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}
M. Asaduzzaman, E. Koetz, Hanwen Wu, J. Piltz, G. Charles
Abstract Cowvine (Ipomoea lonchophylla J.M. Black) is a native and widely spread summer broadleaf weed in Australia. It contains glycoresins, which are toxic to livestock. However, limited information is available on seed germination ecology and growth phenology of this species. A series of experiments were conducted to determine the response of I. lonchophylla to different environmental conditions. Results showed that the primary dormancy exhibited by I. lonchophylla is due to the physical impediment of the hard seed coat. The seed germination percentage was the highest at the constant temperature of 27 C and alternating temperatures of 35/25 C. Germination of I. lonchophylla was not stimulated by light, suggesting that this species is non-photoblastic. Ipomoea lonchophylla germination was intolerant of a medium to high level of salt stress, and germination was completely inhibited at 250 mM NaCl. The emergence of I. lonchophylla was not restricted by seeding depth up to 8 cm, but only 5% emergence was recorded when seeds were planted at a 16-cm depth. The germination percentage was also drastically reduced by 90% to 100% after exposure to either 3 mo in silage, 48-h digestion in steers, or silage plus digestion treatments. The growth and reproductive phenology of I. lonchophylla was affected by emergence time. Plants that emerged in late spring (November 15) were able to produce more berries per plant than those that emerged in midsummer (January 15) in southern New South Wales. Information gained in our study concerning high soil salinity, ensiling, and digestion will help to develop more sustainable and effective integrated weed management strategies for controlling and reducing the spread of this weed.
豇豆(Ipomoea lonchophylla J.M. Black)是澳大利亚一种广泛分布的本土夏季阔叶杂草。它含有对牲畜有毒的糖树脂。然而，关于该植物种子萌发生态学和生长物候学方面的资料有限。通过一系列的实验，确定了lonchophylla对不同环境条件的响应。结果表明，龙葵的初级休眠是由于硬种皮的物理障碍造成的。27℃恒温和35/25℃交变温度下种子发芽率最高，光照不刺激其萌发，表明该物种为非光敏植物。在250 mM NaCl的胁迫下，长叶榄萌发不耐中高盐胁迫，萌发被完全抑制。埋种深度不超过8 cm，但埋种深度为16 cm时出苗率仅为5%。在青贮3个月、消化48小时或青贮加消化处理后，发芽率也急剧下降了90% ~ 100%。羽化时间对龙葵的生长和繁殖物候有影响。在新南威尔士州南部，晚春(11月15日)出现的植株比仲夏(1月15日)出现的植株每株产出更多的浆果。本研究获得的关于高土壤盐度、青贮和消化的信息将有助于制定更可持续和有效的杂草综合管理策略，以控制和减少这种杂草的传播。
{"title":"Germination Ecology and Growth Phenology of Cowvine (Ipomoea lonchophylla) as Influenced by Environmental Parameters","authors":"M. Asaduzzaman, E. Koetz, Hanwen Wu, J. Piltz, G. Charles","doi":"10.1017/wsc.2023.29","DOIUrl":"https://doi.org/10.1017/wsc.2023.29","url":null,"abstract":"Abstract Cowvine (Ipomoea lonchophylla J.M. Black) is a native and widely spread summer broadleaf weed in Australia. It contains glycoresins, which are toxic to livestock. However, limited information is available on seed germination ecology and growth phenology of this species. A series of experiments were conducted to determine the response of I. lonchophylla to different environmental conditions. Results showed that the primary dormancy exhibited by I. lonchophylla is due to the physical impediment of the hard seed coat. The seed germination percentage was the highest at the constant temperature of 27 C and alternating temperatures of 35/25 C. Germination of I. lonchophylla was not stimulated by light, suggesting that this species is non-photoblastic. Ipomoea lonchophylla germination was intolerant of a medium to high level of salt stress, and germination was completely inhibited at 250 mM NaCl. The emergence of I. lonchophylla was not restricted by seeding depth up to 8 cm, but only 5% emergence was recorded when seeds were planted at a 16-cm depth. The germination percentage was also drastically reduced by 90% to 100% after exposure to either 3 mo in silage, 48-h digestion in steers, or silage plus digestion treatments. The growth and reproductive phenology of I. lonchophylla was affected by emergence time. Plants that emerged in late spring (November 15) were able to produce more berries per plant than those that emerged in midsummer (January 15) in southern New South Wales. Information gained in our study concerning high soil salinity, ensiling, and digestion will help to develop more sustainable and effective integrated weed management strategies for controlling and reducing the spread of this weed.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57585612","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}
M. Esposito, Anna S. Westbrook, A. Maggio, V. Cirillo, A. DiTommaso
Abstract Weeds are a fundamental component of agroecosystems and, if not appropriately managed, can cause severe crop yield losses. New perspectives on weed management are required, because current approaches, such as herbicide application or soil tillage, have significant environmental and agronomic drawbacks. We propose the concept of “neutral weed communities,” which are weed communities that coexist with crops and do not negatively affect crop yield and quality compared with weed-free conditions. Management practices that promote neutral weed communities can enable reduced use of herbicides and soil tillage while enhancing ecosystem services and biodiversity. We report scientific evidence of neutral weed communities and survey ecological explanations for why different weed communities have different effects on crop production. We also propose two weed management approaches for attaining neutral weed communities. The first approach aims to maximize weed biodiversity using traditional approaches such as cropping system diversification and integrated weed management. Higher weed biodiversity is associated with lower dominance of competitive weed species that reduce crop yield. The second approach relies on modern tools such as robots and biotechnology to manipulate the density of specific weed species. This approach can remove highly problematic species and minimize niche overlap between the weeds and crops. Given the complexity of interactions among crops, weeds, and other components of the agroecosystem, we highlight the need for multidisciplinary research to illuminate mechanisms that determine the neutrality of weed communities.
{"title":"Neutral Weed Communities: The Intersection between Crop Productivity, Biodiversity, and Weed Ecosystem services","authors":"M. Esposito, Anna S. Westbrook, A. Maggio, V. Cirillo, A. DiTommaso","doi":"10.1017/wsc.2023.27","DOIUrl":"https://doi.org/10.1017/wsc.2023.27","url":null,"abstract":"Abstract Weeds are a fundamental component of agroecosystems and, if not appropriately managed, can cause severe crop yield losses. New perspectives on weed management are required, because current approaches, such as herbicide application or soil tillage, have significant environmental and agronomic drawbacks. We propose the concept of “neutral weed communities,” which are weed communities that coexist with crops and do not negatively affect crop yield and quality compared with weed-free conditions. Management practices that promote neutral weed communities can enable reduced use of herbicides and soil tillage while enhancing ecosystem services and biodiversity. We report scientific evidence of neutral weed communities and survey ecological explanations for why different weed communities have different effects on crop production. We also propose two weed management approaches for attaining neutral weed communities. The first approach aims to maximize weed biodiversity using traditional approaches such as cropping system diversification and integrated weed management. Higher weed biodiversity is associated with lower dominance of competitive weed species that reduce crop yield. The second approach relies on modern tools such as robots and biotechnology to manipulate the density of specific weed species. This approach can remove highly problematic species and minimize niche overlap between the weeds and crops. Given the complexity of interactions among crops, weeds, and other components of the agroecosystem, we highlight the need for multidisciplinary research to illuminate mechanisms that determine the neutrality of weed communities.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47506836","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}
E. Jones, R. Austin, J. Dunne, R. León, W. Everman
Abstract The current assays to confirm herbicide resistance can be time- and labor-intensive (dose–response) or require a skill set/technical equipment (genetic sequencing). Stakeholders could benefit from a rapid assay to confirm herbicide-resistant weeds to ensure sustainable crop production. Because protoporphyrinogen oxidase (PPO)-inhibiting herbicides rapidly interfere with chlorophyll production/integrity; we propose a new, rapid assay utilizing spectral reflectance to confirm resistance. Leaf disks were excised from two PPO-inhibiting herbicide-resistant (target-site [TSR] and non–target site [NTSR]) and herbicide-susceptible redroot pigweed (Amaranthus retroflexus L.) populations and placed into a 24-well plate containing different concentrations (0 to 10 mM) of fomesafen for 48 h. A multispectral sensor captured images from the red (668 nm), green (560 nm), blue (475 nm), and red edge (717 nm) wavebands after a 48-h incubation period. The green leaf index (GLI) was utilized to determine spectral reflectance ratios of the treated leaf disks. Clear differences of spectral reflectance were observed in the red edge waveband for all populations treated with the 10 mM concentration in the dose–response assays. Differences of spectral reflectance were observed for the NTSR population compared with the TSR and susceptible populations treated with the 10 mM concentration in the green waveband and the GLI in the dose–response assay. Leaf disks from the aforementioned A. retroflexus populations and two additional susceptible populations were subjected to a similar assay with the discriminating concentration (10 mM). Spectral reflectance was different between the PPO-inhibiting herbicide-resistant and herbicide-susceptible populations in the red, blue, and green wavebands. Spectral reflectance was not distinctive between the populations in the red edge waveband and the GLI. The results provide a basis for rapidly (∼48 h) detecting PPO-inhibiting herbicide-resistant A. retroflexus via spectral reflectance. Discrimination between TSR and NTSR populations was possible only in the dose–response assay, but the assay still has utility in distinguishing herbicide-resistant plants from herbicide-susceptible plants.
{"title":"Discrimination between Protoporphyrinogen Oxidase–Inhibiting Herbicide-Resistant and Herbicide-Susceptible Redroot Pigweed (Amaranthus retroflexus) with Spectral Reflectance","authors":"E. Jones, R. Austin, J. Dunne, R. León, W. Everman","doi":"10.1017/wsc.2023.25","DOIUrl":"https://doi.org/10.1017/wsc.2023.25","url":null,"abstract":"Abstract The current assays to confirm herbicide resistance can be time- and labor-intensive (dose–response) or require a skill set/technical equipment (genetic sequencing). Stakeholders could benefit from a rapid assay to confirm herbicide-resistant weeds to ensure sustainable crop production. Because protoporphyrinogen oxidase (PPO)-inhibiting herbicides rapidly interfere with chlorophyll production/integrity; we propose a new, rapid assay utilizing spectral reflectance to confirm resistance. Leaf disks were excised from two PPO-inhibiting herbicide-resistant (target-site [TSR] and non–target site [NTSR]) and herbicide-susceptible redroot pigweed (Amaranthus retroflexus L.) populations and placed into a 24-well plate containing different concentrations (0 to 10 mM) of fomesafen for 48 h. A multispectral sensor captured images from the red (668 nm), green (560 nm), blue (475 nm), and red edge (717 nm) wavebands after a 48-h incubation period. The green leaf index (GLI) was utilized to determine spectral reflectance ratios of the treated leaf disks. Clear differences of spectral reflectance were observed in the red edge waveband for all populations treated with the 10 mM concentration in the dose–response assays. Differences of spectral reflectance were observed for the NTSR population compared with the TSR and susceptible populations treated with the 10 mM concentration in the green waveband and the GLI in the dose–response assay. Leaf disks from the aforementioned A. retroflexus populations and two additional susceptible populations were subjected to a similar assay with the discriminating concentration (10 mM). Spectral reflectance was different between the PPO-inhibiting herbicide-resistant and herbicide-susceptible populations in the red, blue, and green wavebands. Spectral reflectance was not distinctive between the populations in the red edge waveband and the GLI. The results provide a basis for rapidly (∼48 h) detecting PPO-inhibiting herbicide-resistant A. retroflexus via spectral reflectance. Discrimination between TSR and NTSR populations was possible only in the dose–response assay, but the assay still has utility in distinguishing herbicide-resistant plants from herbicide-susceptible plants.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49559465","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}
Eduardo C. Rudell, T. Aarthy, Chandrima Shyam, E. A. Borgato, S. Kaur, M. Jugulam
Abstract Palmer amaranth (Amaranthus palmeri S. Watson) is a troublesome weed in several cropping systems in the United States. The evolution of resistance to multiple herbicides is a challenge for the management of this weed. Recently, we reported metabolic resistance to 2,4-D possibly mediated by cytochrome P450 (P450) activity in a six-way-resistant A. palmeri population (KCTR). Plant growth temperature can influence the herbicide efficacy and level of resistance. The effect of temperature on 2,4-D resistance in A. palmeri is unknown. In the present research, we investigated the response of KCTR and a known susceptible (MSS) A. palmeri response to 2,4-D grown under low-temperature (LT, 24/14 C, day/night [d/n]) or high-temperature (HT, 34/24 C, d/n) regimes. When MSS and KCTR plants were 8- to 10-cm tall, they were treated with 0, 140, 280, 560 (field recommended dose), 1,120, and 2,240 g ai ha–1 of 2,4-D. Further, 8- to 10-cm-tall MSS and KCTR plants grown at LT and HT were also treated with [14C]2,4-D to assess the metabolism of 2,4-D at LT and HT. The results of dose–response experiments suggest that KCTR A. palmeri exhibits 23 times more resistance to 2,4-D at HT than MSS. Nonetheless, at LT, the resistance to 2,4-D in KCTR was only 2-fold higher than in MSS. Importantly, there was enhanced metabolism of 2,4-D in both KCTR and MSS A. palmeri at HT compared with LT. Further, treatment with the P450 inhibitor malathion, followed by 2,4-D increased the susceptibility of KCTR at HT. Overall, rapid metabolism of 2,4-D increased KCTR resistance to 2,4-D at HT compared with LT. Therefore, the application of 2,4-D when temperatures are cooler can improve control of 2,4-D–resistant A. palmeri.
摘要苋菜(Amaranthus palmeri S. Watson)在美国的几个种植系统中是一种麻烦的杂草。对多种除草剂的抗性演变是该杂草管理的一个挑战。最近，我们报道了6路抗性a . palmeri群体(KCTR)对2,4- d的代谢抗性可能是由细胞色素P450 (P450)活性介导的。植物生长温度会影响除草剂的药效和抗性水平。温度对棕榈芽孢杆菌2,4- d抗性的影响尚不清楚。在本研究中，我们研究了KCTR和已知易感(MSS) a . palmeri在低温(LT, 24/14℃，昼/夜[d/n])和高温(HT, 34/24℃，d/n)条件下对2,4- d的反应。当MSS和KCTR植株高8 ~ 10 cm时，分别用0、140、280、560(田间推荐剂量)、1120和2240 g / ha处理2,4- d。此外，在低温和高温下生长的8- 10厘米高的MSS和KCTR植株也处理了[14C]2,4- d，以评估低温和高温下2,4- d的代谢。剂量效应实验结果表明，KCTR A. palmeri在高温下对2,4- d的抗性比MSS高23倍。然而，在LT时，KCTR对2,4- d的抗性仅比MSS高2倍。重要的是，与对照组相比，高温下KCTR和MSS A. palmeri体内2,4- d的代谢增强。此外，用P450抑制剂马拉硫磷治疗后，再用2,4- d治疗，增加了KCTR在高温下的敏感性。总的来说，与低温相比，高温下2,4- d的快速代谢增加了KCTR对2,4- d的抗性。因此，在温度较低时施用2,4- d可以改善对2,4- d抗性的控制。
{"title":"High Temperature Increases 2,4-D Metabolism in Resistant Amaranthus palmeri","authors":"Eduardo C. Rudell, T. Aarthy, Chandrima Shyam, E. A. Borgato, S. Kaur, M. Jugulam","doi":"10.1017/wsc.2023.26","DOIUrl":"https://doi.org/10.1017/wsc.2023.26","url":null,"abstract":"Abstract Palmer amaranth (Amaranthus palmeri S. Watson) is a troublesome weed in several cropping systems in the United States. The evolution of resistance to multiple herbicides is a challenge for the management of this weed. Recently, we reported metabolic resistance to 2,4-D possibly mediated by cytochrome P450 (P450) activity in a six-way-resistant A. palmeri population (KCTR). Plant growth temperature can influence the herbicide efficacy and level of resistance. The effect of temperature on 2,4-D resistance in A. palmeri is unknown. In the present research, we investigated the response of KCTR and a known susceptible (MSS) A. palmeri response to 2,4-D grown under low-temperature (LT, 24/14 C, day/night [d/n]) or high-temperature (HT, 34/24 C, d/n) regimes. When MSS and KCTR plants were 8- to 10-cm tall, they were treated with 0, 140, 280, 560 (field recommended dose), 1,120, and 2,240 g ai ha–1 of 2,4-D. Further, 8- to 10-cm-tall MSS and KCTR plants grown at LT and HT were also treated with [14C]2,4-D to assess the metabolism of 2,4-D at LT and HT. The results of dose–response experiments suggest that KCTR A. palmeri exhibits 23 times more resistance to 2,4-D at HT than MSS. Nonetheless, at LT, the resistance to 2,4-D in KCTR was only 2-fold higher than in MSS. Importantly, there was enhanced metabolism of 2,4-D in both KCTR and MSS A. palmeri at HT compared with LT. Further, treatment with the P450 inhibitor malathion, followed by 2,4-D increased the susceptibility of KCTR at HT. Overall, rapid metabolism of 2,4-D increased KCTR resistance to 2,4-D at HT compared with LT. Therefore, the application of 2,4-D when temperatures are cooler can improve control of 2,4-D–resistant A. palmeri.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48021826","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}
I. Werle, M. Noguera, Srikanth K Karaikal, Pâmela Carvalho-Moore, K. B. Kouamé, Gustavo Henrique Bessa de Lima, T. Roberts, N. Roma‐Burgos
Abstract Field studies were conducted in 2021 in Kibler and Augusta, AR, to determine the effect of winter cover crops and cultivar selection on weed suppression and sweetpotato [Ipomoea batatas (L.) Lam.] yield. The split-split-plot studies evaluated three cover crops [cereal rye (Secale cereale L.) + crimson clover (Trifolium incarnatum L.)], [winter wheat (Triticum aestivum L.) + crimson clover], and fallow; weeding (with or without); and four sweetpotato cultivars (‘Heartogold’, ‘Bayou-Belle-6’, ‘Beauregard-14’, and ‘Orleans’). Heartogold had the tallest canopy, while Beauregard-14 and Bayou Belle-6 had the longest vines at 5 and 8 wk after sweetpotato transplanting. Sweetpotato canopy was about 20% taller in weedy plots compared with the hand-weeded treatment, and vines were shorter under weed interference. Canopy height and vine length of sweetpotato cultivars were not related to weed biomass suppression. However, vine length was positively correlated to all yield grades (r > 0.5). Weed biomass decreased 1-fold in plots with cover crops compared with bare soil at Augusta. Cover crop biomass was positively correlated with jumbo (r = 0.29), no. 1 (r = 0.33), and total sweetpotato yield (r = 0.34). Jumbo yield was affected the most by weed pressure. On average, sweetpotato total yield was reduced by 80% and 60% with weed interference in Augusta and Kibler, respectively. Bayou Belle-6 was the high-yielding cultivar without weed interference in both locations. Bayou Belle-6 and Heartogold were less affected by weed interference than Beauregard-14 and Orleans.
{"title":"Integrating Weed-Suppressive Cultivar and Cover Crops for Weed Management in Organic Sweetpotato Production","authors":"I. Werle, M. Noguera, Srikanth K Karaikal, Pâmela Carvalho-Moore, K. B. Kouamé, Gustavo Henrique Bessa de Lima, T. Roberts, N. Roma‐Burgos","doi":"10.1017/wsc.2023.14","DOIUrl":"https://doi.org/10.1017/wsc.2023.14","url":null,"abstract":"Abstract Field studies were conducted in 2021 in Kibler and Augusta, AR, to determine the effect of winter cover crops and cultivar selection on weed suppression and sweetpotato [Ipomoea batatas (L.) Lam.] yield. The split-split-plot studies evaluated three cover crops [cereal rye (Secale cereale L.) + crimson clover (Trifolium incarnatum L.)], [winter wheat (Triticum aestivum L.) + crimson clover], and fallow; weeding (with or without); and four sweetpotato cultivars (‘Heartogold’, ‘Bayou-Belle-6’, ‘Beauregard-14’, and ‘Orleans’). Heartogold had the tallest canopy, while Beauregard-14 and Bayou Belle-6 had the longest vines at 5 and 8 wk after sweetpotato transplanting. Sweetpotato canopy was about 20% taller in weedy plots compared with the hand-weeded treatment, and vines were shorter under weed interference. Canopy height and vine length of sweetpotato cultivars were not related to weed biomass suppression. However, vine length was positively correlated to all yield grades (r > 0.5). Weed biomass decreased 1-fold in plots with cover crops compared with bare soil at Augusta. Cover crop biomass was positively correlated with jumbo (r = 0.29), no. 1 (r = 0.33), and total sweetpotato yield (r = 0.34). Jumbo yield was affected the most by weed pressure. On average, sweetpotato total yield was reduced by 80% and 60% with weed interference in Augusta and Kibler, respectively. Bayou Belle-6 was the high-yielding cultivar without weed interference in both locations. Bayou Belle-6 and Heartogold were less affected by weed interference than Beauregard-14 and Orleans.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48071248","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}
Martin Ignes, J. McCurdy, J. S. McElroy, E. Castro, J. Ferguson, Ashley N. Meredith, C. A. Rutland, B. Stewart, T. Tseng
Abstract The mitotic-inhibiting herbicide pronamide controls susceptible annual bluegrass (Poa annua L.) pre- and postemergence, but in some resistant populations, postemergence activity is compromised, hypothetically due to a target-site mutation, lack of root uptake, or an unknown resistance mechanism. Three suspected pronamide-resistant (LH-R, SC-R, and SL-R) and two pronamide-susceptible (BS-S and HH-S) populations were collected from Mississippi golf courses. Dose–response experiments were conducted to confirm and quantify pronamide resistance, as well as resistance to flazasulfuron and simazine. Target sites known to confer resistance to mitotic-inhibiting herbicides were sequenced, as were target sites for herbicides inhibiting acetolactate synthase (ALS) and photosystem II (PSII). Pronamide absorption and translocation were investigated following foliar and soil applications. Dose–response experiments confirmed pronamide resistance of LH-R, SC-R, and SL-R populations, as well as instances of multiple resistance to ALS- and PSII-inhibiting herbicides. Sequencing of the α-tubulin gene confirmed the presence of a mutation that substituted isoleucine for threonine at position 239 (Thr-239-Ile) in LH-R, SC-R, SL-R, and BS-S populations. Foliar application experiments failed to identify differences in pronamide absorption and translocation between the five populations, regardless of harvest time. All populations had limited basipetal translocation—only 3% to 13% of the absorbed pronamide—across harvest times. Soil application experiments revealed that pronamide translocation was similar between SC-R, SL-R, and both susceptible populations across harvest times. The LH-R population translocated less soil-applied pronamide than susceptible populations at 24, 72, and 168 h after treatment, suggesting that reduced acropetal translocation may contribute to pronamide resistance. This study reports three new pronamide-resistant populations, two of which are resistant to two modes of action (MOAs), and one of which is resistant to three MOAs. Results suggest that both target site– and translocation-based mechanisms may be associated with pronamide resistance. Further research is needed to confirm the link between pronamide resistance and the Thr-239-Ile mutation of the α-tubulin gene.
{"title":"Target-Site and Non–Target Site Mechanisms of Pronamide Resistance in Annual Bluegrass (Poa annua) Populations from Mississippi Golf Courses","authors":"Martin Ignes, J. McCurdy, J. S. McElroy, E. Castro, J. Ferguson, Ashley N. Meredith, C. A. Rutland, B. Stewart, T. Tseng","doi":"10.1017/wsc.2023.17","DOIUrl":"https://doi.org/10.1017/wsc.2023.17","url":null,"abstract":"Abstract The mitotic-inhibiting herbicide pronamide controls susceptible annual bluegrass (Poa annua L.) pre- and postemergence, but in some resistant populations, postemergence activity is compromised, hypothetically due to a target-site mutation, lack of root uptake, or an unknown resistance mechanism. Three suspected pronamide-resistant (LH-R, SC-R, and SL-R) and two pronamide-susceptible (BS-S and HH-S) populations were collected from Mississippi golf courses. Dose–response experiments were conducted to confirm and quantify pronamide resistance, as well as resistance to flazasulfuron and simazine. Target sites known to confer resistance to mitotic-inhibiting herbicides were sequenced, as were target sites for herbicides inhibiting acetolactate synthase (ALS) and photosystem II (PSII). Pronamide absorption and translocation were investigated following foliar and soil applications. Dose–response experiments confirmed pronamide resistance of LH-R, SC-R, and SL-R populations, as well as instances of multiple resistance to ALS- and PSII-inhibiting herbicides. Sequencing of the α-tubulin gene confirmed the presence of a mutation that substituted isoleucine for threonine at position 239 (Thr-239-Ile) in LH-R, SC-R, SL-R, and BS-S populations. Foliar application experiments failed to identify differences in pronamide absorption and translocation between the five populations, regardless of harvest time. All populations had limited basipetal translocation—only 3% to 13% of the absorbed pronamide—across harvest times. Soil application experiments revealed that pronamide translocation was similar between SC-R, SL-R, and both susceptible populations across harvest times. The LH-R population translocated less soil-applied pronamide than susceptible populations at 24, 72, and 168 h after treatment, suggesting that reduced acropetal translocation may contribute to pronamide resistance. This study reports three new pronamide-resistant populations, two of which are resistant to two modes of action (MOAs), and one of which is resistant to three MOAs. Results suggest that both target site– and translocation-based mechanisms may be associated with pronamide resistance. Further research is needed to confirm the link between pronamide resistance and the Thr-239-Ile mutation of the α-tubulin gene.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44259974","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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