C. Cahoon, D. Jordan, P. Tranel, A. C. York, C. Riggins, R. Seagroves, M. Inman, W. Everman, R. León
Abstract Comparing fitness of herbicide-resistant and herbicide-susceptible weed biotypes is important for managing herbicide resistance. Previous research suggests there is little to no fitness penalty from amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (a mechanism of glyphosate resistance) in Palmer amaranth (Amaranthus palmeri S. Watson) in controlled studies in the greenhouse or growth chamber. A field study was conducted in North Carolina at three locations naturally infested with A. palmeri to determine vegetative, reproductive, and germination fitness of plants with and without EPSPS amplification grown season-long with cotton (Gossypium hirsutum L.). Seed number was not correlated with EPSPS copy number. However, when plants were binned into two groups, those having an EPSPS copy number ≥2 (relative to reference genes) and those having an EPSPS copy number <2, plant fresh weight and seed number were 1.4 and 1.6 times greater, respectively, for plants with fewer than 2 EPSPS copies. Amaranthus palmeri height and seed germination, and yield of cotton, did not differ when comparing the two binned groups. These data suggest that A. palmeri plants with EPSPS amplification are relatively less fit in the absence of glyphosate, but this reduced fitness does not translate into differences in interference with cotton.
摘要比较抗除草剂和敏感除草剂杂草生物型的适合度对管理除草剂抗性具有重要意义。先前的研究表明，在温室或生长室的对照研究中，苋菜(Amaranthus palmeri S. Watson)的5-烯醇丙酮酰紫草酸-3-磷酸合成酶(EPSPS)基因(一种抗草甘膦的机制)的扩增几乎没有适应度损失。在美国北卡罗莱纳州三个自然发生棕毛棉的地点进行了一项野外研究，以确定有无EPSPS扩增的棉花(棉)植物的营养、生殖和发芽适应性。种子数与EPSPS拷贝数不相关。而EPSPS拷贝数≥2(相对内参基因)和EPSPS拷贝数<2的两组，EPSPS拷贝数小于2的植株鲜重和种子数分别是对照组的1.4倍和1.6倍。两组间红苋菜株高、种子发芽率及棉花产量均无显著差异。这些数据表明，在没有草甘膦的情况下，具有EPSPS扩增的棕榈草植株的适合度相对较低，但这种降低的适合度并不转化为对棉花的干扰差异。
{"title":"In-Field Assessment of EPSPS Amplification on Fitness Cost in Mixed Glyphosate-Resistant and Glyphosate-Sensitive Populations of Palmer Amaranth (Amaranthus palmeri)","authors":"C. Cahoon, D. Jordan, P. Tranel, A. C. York, C. Riggins, R. Seagroves, M. Inman, W. Everman, R. León","doi":"10.1017/wsc.2022.60","DOIUrl":"https://doi.org/10.1017/wsc.2022.60","url":null,"abstract":"Abstract Comparing fitness of herbicide-resistant and herbicide-susceptible weed biotypes is important for managing herbicide resistance. Previous research suggests there is little to no fitness penalty from amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (a mechanism of glyphosate resistance) in Palmer amaranth (Amaranthus palmeri S. Watson) in controlled studies in the greenhouse or growth chamber. A field study was conducted in North Carolina at three locations naturally infested with A. palmeri to determine vegetative, reproductive, and germination fitness of plants with and without EPSPS amplification grown season-long with cotton (Gossypium hirsutum L.). Seed number was not correlated with EPSPS copy number. However, when plants were binned into two groups, those having an EPSPS copy number ≥2 (relative to reference genes) and those having an EPSPS copy number <2, plant fresh weight and seed number were 1.4 and 1.6 times greater, respectively, for plants with fewer than 2 EPSPS copies. Amaranthus palmeri height and seed germination, and yield of cotton, did not differ when comparing the two binned groups. These data suggest that A. palmeri plants with EPSPS amplification are relatively less fit in the absence of glyphosate, but this reduced fitness does not translate into differences in interference with cotton.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"663 - 668"},"PeriodicalIF":2.5,"publicationDate":"2022-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47884149","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, R. Thapa, M. Kukal, S. Irmak, S. Mirsky, A. Jhala
Abstract Weeds compete with crops for soil moisture, along with other resources, which can impact the germination, growth, and seed production of weeds; however, this impact has not been systematically recorded and synthesized across diverse studies. To address this knowledge gap, a global meta-analysis was conducted using 1,196 paired observations from 86 published articles assessing the effect of water stress on weed germination, growth characteristics, and seed production. These studies were conducted and published during 1970 through 2020 across four continents (Asia, Australia, Europe, and North America). Imposed water stress was expressed as solution osmotic potential (ψsolution), soil water potential (ψsoil), or soil moisture as percent field capacity. Meta-analysis revealed that water stress inhibits weed germination, growth, and seed production, and the quantitative response intensified with increasing water stress. A ψsolution greater than –0.8 MPa completely inhibits germination of both grass and broadleaf weeds. A ψsolution from –0.09 to –0.32 MPa reduces weed germination by 50% compared with the unstressed condition. Moderate soil water stress, equivalent to 30% to 60% field capacity, inhibits growth characteristics (branches or tillers per plant, leaf area, leaves per plant, plant height, root, and shoot biomass) by 33% and weed seed production by 50%. Severe soil water stress, below 30% field capacity, inhibits weed growth by 51% and seed production by 88%. Although water stress inhibits weed growth, it does not entirely suppress the ability to germinate, grow, and produce seeds, resulting in weed seedbank accumulation. This creates management challenges for producers, because weed seeds can survive in the soil for many years, depending on weed species and environmental conditions. Quantitative information compiled in this meta-analysis can be instrumental to model the weeds' multidimensional responses to water stress and designing integrated weed management strategies for reducing the weed seedbank.
{"title":"Effect of Water Stress on Weed Germination, Growth Characteristics, and Seed Production: A Global Meta-Analysis","authors":"Mandeep Singh, R. Thapa, M. Kukal, S. Irmak, S. Mirsky, A. Jhala","doi":"10.1017/wsc.2022.59","DOIUrl":"https://doi.org/10.1017/wsc.2022.59","url":null,"abstract":"Abstract Weeds compete with crops for soil moisture, along with other resources, which can impact the germination, growth, and seed production of weeds; however, this impact has not been systematically recorded and synthesized across diverse studies. To address this knowledge gap, a global meta-analysis was conducted using 1,196 paired observations from 86 published articles assessing the effect of water stress on weed germination, growth characteristics, and seed production. These studies were conducted and published during 1970 through 2020 across four continents (Asia, Australia, Europe, and North America). Imposed water stress was expressed as solution osmotic potential (ψsolution), soil water potential (ψsoil), or soil moisture as percent field capacity. Meta-analysis revealed that water stress inhibits weed germination, growth, and seed production, and the quantitative response intensified with increasing water stress. A ψsolution greater than –0.8 MPa completely inhibits germination of both grass and broadleaf weeds. A ψsolution from –0.09 to –0.32 MPa reduces weed germination by 50% compared with the unstressed condition. Moderate soil water stress, equivalent to 30% to 60% field capacity, inhibits growth characteristics (branches or tillers per plant, leaf area, leaves per plant, plant height, root, and shoot biomass) by 33% and weed seed production by 50%. Severe soil water stress, below 30% field capacity, inhibits weed growth by 51% and seed production by 88%. Although water stress inhibits weed growth, it does not entirely suppress the ability to germinate, grow, and produce seeds, resulting in weed seedbank accumulation. This creates management challenges for producers, because weed seeds can survive in the soil for many years, depending on weed species and environmental conditions. Quantitative information compiled in this meta-analysis can be instrumental to model the weeds' multidimensional responses to water stress and designing integrated weed management strategies for reducing the weed seedbank.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"621 - 640"},"PeriodicalIF":2.5,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48788381","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}
Sarah Ann Drumm Chu, K. Cassida, M. Singh, E. Burns
Abstract Alfalfa (Medicago sativa L.) hectares in Michigan are declining partly due to reliance on corn (Zea mays L.) silage as a continuous feed source. By interseeding corn and alfalfa, farmers can replace the low alfalfa yield in the establishment year with corn silage while simultaneously establishing alfalfa. A randomized split-block field study was conducted in East Lansing, MI, over 3 yr (2019 to 2021) to determine the critical period of weed control (CPWC) in the interseeded corn and alfalfa system using two corn hybrids with differing leaf architecture (pendulum vs. upright). Whole plots were assigned to corn hybrids interseeded with alfalfa, and subplots were assigned to a surrogate weed, Japanese millet [Echinochloa esculenta (A. Braun) H. Scholz], for the duration of competition treatments. Weed-free and weedy plots were included as controls. At the end of the interseeding year, corn was harvested, while alfalfa was harvested the following year. The CPWC is made up of two components: the critical timing of weed removal (CTWR) and the critical weed-free period (CWFP). Corn hybrid had no impact on the CTWR or CWFP for interseeded corn or alfalfa. Averaged across hybrids, the CTWR was 303 growing degree days (GDD), and CWFP was estimated to be greater than the study duration. The CTWR in the first cutting of alfalfa was estimated to be 369 GDD. The CWFP was estimated to be 394 GDD for a 5% acceptable yield loss for the first alfalfa cutting. Identification of the CPWC in the interseeded system will increase adoption and interest in other interseeded systems that can mitigate potential negative environmental and economic impacts of monoculture agriculture.
摘要:美国密歇根州紫花苜蓿(Medicago sativa L.)种植面积正在减少，部分原因是对玉米(Zea mays L.)青贮饲料的依赖。通过玉米和苜蓿的间种，农民可以在种植苜蓿的同时，用玉米青贮代替立种年的低产苜蓿。在密歇根州东兰辛进行了一项为期3年(2019年至2021年)的随机分块田间研究，以确定玉米和苜蓿杂交系统中杂草控制的关键时期(CPWC)，该研究使用了两种叶片结构不同的玉米杂交种(摆叶与直立叶)。在竞争处理期间，整块地分配给与苜蓿杂交的玉米杂交种，小块地分配给替代杂草谷子[Echinochloa esculenta (a . Braun) H. Scholz]。无杂草样地和杂草样地作为对照。在间播年结束时，收获玉米，而第二年收获苜蓿。CPWC由两部分组成:除草关键时间(CTWR)和无草关键时间(CWFP)。杂交玉米对杂交玉米和苜蓿的CTWR和CWFP无显著影响。杂交组合的平均CTWR为303生长度日(GDD)，估计CWFP大于研究持续时间。首次刈割紫花苜蓿的CTWR估计为369 GDD。CWFP估计为394 GDD，第一次紫花苜蓿切割可接受的产量损失为5%。在杂交系统中确定CPWC将增加对其他杂交系统的采用和兴趣，这些系统可以减轻单一农业对环境和经济的潜在负面影响。
{"title":"Critical Period of Weed Control in an Interseeded System of Corn and Alfalfa","authors":"Sarah Ann Drumm Chu, K. Cassida, M. Singh, E. Burns","doi":"10.1017/wsc.2022.55","DOIUrl":"https://doi.org/10.1017/wsc.2022.55","url":null,"abstract":"Abstract Alfalfa (Medicago sativa L.) hectares in Michigan are declining partly due to reliance on corn (Zea mays L.) silage as a continuous feed source. By interseeding corn and alfalfa, farmers can replace the low alfalfa yield in the establishment year with corn silage while simultaneously establishing alfalfa. A randomized split-block field study was conducted in East Lansing, MI, over 3 yr (2019 to 2021) to determine the critical period of weed control (CPWC) in the interseeded corn and alfalfa system using two corn hybrids with differing leaf architecture (pendulum vs. upright). Whole plots were assigned to corn hybrids interseeded with alfalfa, and subplots were assigned to a surrogate weed, Japanese millet [Echinochloa esculenta (A. Braun) H. Scholz], for the duration of competition treatments. Weed-free and weedy plots were included as controls. At the end of the interseeding year, corn was harvested, while alfalfa was harvested the following year. The CPWC is made up of two components: the critical timing of weed removal (CTWR) and the critical weed-free period (CWFP). Corn hybrid had no impact on the CTWR or CWFP for interseeded corn or alfalfa. Averaged across hybrids, the CTWR was 303 growing degree days (GDD), and CWFP was estimated to be greater than the study duration. The CTWR in the first cutting of alfalfa was estimated to be 369 GDD. The CWFP was estimated to be 394 GDD for a 5% acceptable yield loss for the first alfalfa cutting. Identification of the CPWC in the interseeded system will increase adoption and interest in other interseeded systems that can mitigate potential negative environmental and economic impacts of monoculture agriculture.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"680 - 686"},"PeriodicalIF":2.5,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45953994","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}
April M. Dobbs, Daniel Ginn, S. Skovsen, M. Bagavathiannan, S. Mirsky, C. Reberg-Horton, R. León
Abstract Recent innovations in 3D imaging technology have created unprecedented potential for better understanding weed responses to management tactics. Although traditional 2D imaging methods for mapping weed populations can be limited in the field by factors such as shadows and tissue overlap, 3D imaging mitigates these challenges by using depth data to create accurate plant models. Three-dimensional imaging can be used to generate spatiotemporal maps of weed populations in the field and target weeds for site-specific weed management, including automated precision weed control. This technology will also help growers monitor cover crop performance for weed suppression and detect late-season weed escapes for timely control, thereby reducing seedbank persistence and slowing the evolution of herbicide resistance. In addition to its many applications in weed management, 3D imaging offers weed researchers new tools for understanding spatial and temporal heterogeneity in weed responses to integrated weed management tactics, including weed–crop competition and weed community dynamics. This technology will provide simple and low-cost tools for growers and researchers alike to better understand weed responses in diverse agronomic contexts, which will aid in reducing herbicide use, mitigating herbicide-resistance evolution, and improving environmental health.
{"title":"New Directions in Weed Management and Research Using 3D Imaging","authors":"April M. Dobbs, Daniel Ginn, S. Skovsen, M. Bagavathiannan, S. Mirsky, C. Reberg-Horton, R. León","doi":"10.1017/wsc.2022.56","DOIUrl":"https://doi.org/10.1017/wsc.2022.56","url":null,"abstract":"Abstract Recent innovations in 3D imaging technology have created unprecedented potential for better understanding weed responses to management tactics. Although traditional 2D imaging methods for mapping weed populations can be limited in the field by factors such as shadows and tissue overlap, 3D imaging mitigates these challenges by using depth data to create accurate plant models. Three-dimensional imaging can be used to generate spatiotemporal maps of weed populations in the field and target weeds for site-specific weed management, including automated precision weed control. This technology will also help growers monitor cover crop performance for weed suppression and detect late-season weed escapes for timely control, thereby reducing seedbank persistence and slowing the evolution of herbicide resistance. In addition to its many applications in weed management, 3D imaging offers weed researchers new tools for understanding spatial and temporal heterogeneity in weed responses to integrated weed management tactics, including weed–crop competition and weed community dynamics. This technology will provide simple and low-cost tools for growers and researchers alike to better understand weed responses in diverse agronomic contexts, which will aid in reducing herbicide use, mitigating herbicide-resistance evolution, and improving environmental health.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"641 - 647"},"PeriodicalIF":2.5,"publicationDate":"2022-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49348153","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}
Pub Date : 2022-10-01Epub Date: 2022-04-04DOI: 10.1016/j.cgh.2022.03.030
Andrea Gini, Kevin Selby
{"title":"Fecal Immunochemical Tests: The Right Colorectal Cancer Screening Test for the Average-Risk Population?","authors":"Andrea Gini, Kevin Selby","doi":"10.1016/j.cgh.2022.03.030","DOIUrl":"10.1016/j.cgh.2022.03.030","url":null,"abstract":"","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"47 1","pages":"2216-2217"},"PeriodicalIF":12.6,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79112237","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}
Andrea De Roo, E. Tozzi, D. Benaragama, C. Willenborg
Abstract Two species of cleavers, Galium aparine L. and Galium spurium L., are known to inhabit croplands in western Canada. The latter is the more abundant of the two species. An increased abundance of these species over the most recent decades warrants a more comprehensive understanding of their developmental phenology and the cause of this increase. This study aimed to identify the base temperature and emergence characteristics of Galium spp. across different populations from western Canada. A thermal gradient plate experiment was conducted using five G. spurium populations collected from various Saskatchewan (SK) and Alberta (AB) locations. One known G. aparine reference sample was also included. A common garden experiment was conducted using the six Galium spp. populations to determine emergence characteristics. The base germination temperature identified was 2 C for all populations of G. spurium and 4 C for G. aparine. The median germination temperature for G. aparine was 8.34 C, whereas G. spurium had a similar median germination temperature of 6.5 C. Despite similar germination characteristics, the field emergence study revealed differences between populations' initiation of emergence (150 to 250 growing degree days [GDD]) and time to 50% emergence (275 to 470 GDD) in spring. Highly variable emergence among years and populations within the year (200 to 600 GDD in 2013 and 100 to 200 GDD in 2014) were observed during fall, probably due to differences in moisture availability. Cumulative emergence among populations in fall was very low (1% to 9%) compared with spring emergence (2% to 17%). Overall, this study provides evidence for a low base temperature and differences in emergence periodicity among populations, both of which may be significant factors contributing to the seasonal success of this species.
{"title":"Recruitment Biology of Cleavers (Galium spp.) Populations in Western Canada","authors":"Andrea De Roo, E. Tozzi, D. Benaragama, C. Willenborg","doi":"10.1017/wsc.2022.52","DOIUrl":"https://doi.org/10.1017/wsc.2022.52","url":null,"abstract":"Abstract Two species of cleavers, Galium aparine L. and Galium spurium L., are known to inhabit croplands in western Canada. The latter is the more abundant of the two species. An increased abundance of these species over the most recent decades warrants a more comprehensive understanding of their developmental phenology and the cause of this increase. This study aimed to identify the base temperature and emergence characteristics of Galium spp. across different populations from western Canada. A thermal gradient plate experiment was conducted using five G. spurium populations collected from various Saskatchewan (SK) and Alberta (AB) locations. One known G. aparine reference sample was also included. A common garden experiment was conducted using the six Galium spp. populations to determine emergence characteristics. The base germination temperature identified was 2 C for all populations of G. spurium and 4 C for G. aparine. The median germination temperature for G. aparine was 8.34 C, whereas G. spurium had a similar median germination temperature of 6.5 C. Despite similar germination characteristics, the field emergence study revealed differences between populations' initiation of emergence (150 to 250 growing degree days [GDD]) and time to 50% emergence (275 to 470 GDD) in spring. Highly variable emergence among years and populations within the year (200 to 600 GDD in 2013 and 100 to 200 GDD in 2014) were observed during fall, probably due to differences in moisture availability. Cumulative emergence among populations in fall was very low (1% to 9%) compared with spring emergence (2% to 17%). Overall, this study provides evidence for a low base temperature and differences in emergence periodicity among populations, both of which may be significant factors contributing to the seasonal success of this species.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"669 - 679"},"PeriodicalIF":2.5,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43479224","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}
Jasmine Mausbach, S. Irmak, P. Chahal, D. Sarangi, A. Jhala
Abstract Velvetleaf (Abutilon theophrasti Medik.) is a troublesome broadleaf weed that competes with crops for resources such as soil moisture. Water stress can affect the ability of weed species to grow and produce seeds. The objective of this study was to determine the effect of degree of water stress on the growth and fecundity of A. threophrasti using soil moisture sensors under greenhouse conditions. Abutilon threophrasti seeds collected from a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] field were grown in silty clay loam soil, and plants were maintained at 100%, 75%, 50%, and 25% soil field capacity (FC) corresponding to no, light, moderate, and high water-stress conditions, respectively. Water was added daily to pots based on soil moisture levels detected by a Meter Group 5TM sensor to maintain the desired water-stress level required by treatment. Plants maintained at 100% FC had the maximum number of leaves (28 leaves plant–1), followed by 21 and 15 leaves plant–1 at 75% and 50% FC, respectively. Abutilon threophrasti at 100% and 75% FC achieved maximum plant height (108 to 123 cm) compared with 83 cm at 50% FC. Abutilon threophrasti maintained at 75% FC had the greatest growth index (79,907 cm3) followed by 72,197 cm3 at 100% FC and 64,256 cm3 at 50% FC. Seed production was similar at 100%, 75%, and 50% FC (288 to 453 seeds plant–1) compared with 2 seeds plant–1 at 25% FC. This is because the majority of plants maintained at 25% FC did not survive more than 77 d after transplanting. Seed germination was 96% to 100% at 100%, 75%, and 50% FC compared with 20% germination at 25% FC. Abutilon threophrasti can survive ≥50% FC continuous water-stress conditions, although with reduced leaf number, plant height, and growth index compared with 75% and 100% FC.
{"title":"Effect of Degree of Water Stress on Growth and Fecundity of Velvetleaf (Abutilon theophrasti) Using Soil Moisture Sensors","authors":"Jasmine Mausbach, S. Irmak, P. Chahal, D. Sarangi, A. Jhala","doi":"10.1017/wsc.2022.54","DOIUrl":"https://doi.org/10.1017/wsc.2022.54","url":null,"abstract":"Abstract Velvetleaf (Abutilon theophrasti Medik.) is a troublesome broadleaf weed that competes with crops for resources such as soil moisture. Water stress can affect the ability of weed species to grow and produce seeds. The objective of this study was to determine the effect of degree of water stress on the growth and fecundity of A. threophrasti using soil moisture sensors under greenhouse conditions. Abutilon threophrasti seeds collected from a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] field were grown in silty clay loam soil, and plants were maintained at 100%, 75%, 50%, and 25% soil field capacity (FC) corresponding to no, light, moderate, and high water-stress conditions, respectively. Water was added daily to pots based on soil moisture levels detected by a Meter Group 5TM sensor to maintain the desired water-stress level required by treatment. Plants maintained at 100% FC had the maximum number of leaves (28 leaves plant–1), followed by 21 and 15 leaves plant–1 at 75% and 50% FC, respectively. Abutilon threophrasti at 100% and 75% FC achieved maximum plant height (108 to 123 cm) compared with 83 cm at 50% FC. Abutilon threophrasti maintained at 75% FC had the greatest growth index (79,907 cm3) followed by 72,197 cm3 at 100% FC and 64,256 cm3 at 50% FC. Seed production was similar at 100%, 75%, and 50% FC (288 to 453 seeds plant–1) compared with 2 seeds plant–1 at 25% FC. This is because the majority of plants maintained at 25% FC did not survive more than 77 d after transplanting. Seed germination was 96% to 100% at 100%, 75%, and 50% FC compared with 20% germination at 25% FC. Abutilon threophrasti can survive ≥50% FC continuous water-stress conditions, although with reduced leaf number, plant height, and growth index compared with 75% and 100% FC.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"698 - 705"},"PeriodicalIF":2.5,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42860348","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}
Isaac H. Barnhart, Sarah Lancaster, D. Goodin, Jess J. Spotanski, J. Dille
Abstract Site-specific weed management using open-source object detection algorithms could accurately detect weeds in cropping systems. We investigated the use of object detection algorithms to detect Palmer amaranth (Amaranthus palmeri S. Watson) in soybean [Glycine max (L.) Merr.]. The objectives were to (1) develop an annotated image database of A. palmeri and soybean to fine-tune object detection algorithms, (2) compare effectiveness of multiple open-source algorithms in detecting A. palmeri, and (3) evaluate the relationship between A. palmeri growth features and A. palmeri detection ability. Soybean field sites were established in Manhattan, KS, and Gypsum, KS, with natural populations of A. palmeri. A total of 1,108 and 392 images were taken aerially and at ground level, respectively, between May 27 and July 27, 2021. After image annotation, a total of 4,492 images were selected. Annotated images were used to fine-tune open-source faster regional convolutional (Faster R-CNN) and single-shot detector (SSD) algorithms using a Resnet backbone, as well as the “You Only Look Once” (YOLO) series algorithms. Results demonstrated that YOLO v. 5 achieved the highest mean average precision score of 0.77. For both A. palmeri and soybean detections within this algorithm, the highest F1 score was 0.72 when using a confidence threshold of 0.298. A lower confidence threshold of 0.15 increased the likelihood of species detection, but also increased the likelihood of false-positive detections. The trained YOLOv5 data set was used to identify A. palmeri in a data set paired with measured growth features. Linear regression models predicted that as A. palmeri densities increased and as A. palmeri height increased, precision, recall, and F1 scores of algorithms would decrease. We conclude that open-source algorithms such as YOLOv5 show great potential in detecting A. palmeri in soybean-cropping systems.
基于开源目标检测算法的定点杂草管理可以准确地检测出种植系统中的杂草。本研究利用目标检测算法检测大豆[Glycine max (L.)]中的苋菜(Amaranthus palmeri S. Watson)。稳定)。本研究的目标是:(1)建立棕榈花和大豆的带注释图像数据库，以微调目标检测算法;(2)比较多种开源算法在棕榈花检测中的有效性;(3)评估棕榈花生长特征与棕榈花检测能力之间的关系。在堪萨斯州曼哈顿和堪萨斯州石膏建立了黄豆田基地，并在那里发现了棕榈叶黄豆的天然种群。在2021年5月27日至7月27日期间，在空中和地面分别拍摄了1108和392张图像。经过图像标注后，共选出4492张图像。使用带注释的图像微调开源更快的区域卷积(faster R-CNN)和使用Resnet主干的单镜头检测器(SSD)算法，以及“You Only Look Once”(YOLO)系列算法。结果表明，YOLO v. 5的平均精密度得分最高，为0.77。当置信阈值为0.298时，该算法中棕榈芽孢杆菌和大豆的检测F1得分最高，为0.72。较低的置信阈值为0.15增加了物种检测的可能性，但也增加了假阳性检测的可能性。使用训练好的YOLOv5数据集在与测量的生长特征配对的数据集中识别a . palmeri。线性回归模型预测，随着棕枝密度的增加和棕枝高度的增加，算法的精度、查全率和F1分数均降低。我们认为，YOLOv5等开源算法在大豆种植系统中检测棕榈芽孢杆菌方面具有很大的潜力。
{"title":"Use of Open-Source Object Detection Algorithms to Detect Palmer Amaranth (Amaranthus palmeri) in Soybean","authors":"Isaac H. Barnhart, Sarah Lancaster, D. Goodin, Jess J. Spotanski, J. Dille","doi":"10.1017/wsc.2022.53","DOIUrl":"https://doi.org/10.1017/wsc.2022.53","url":null,"abstract":"Abstract Site-specific weed management using open-source object detection algorithms could accurately detect weeds in cropping systems. We investigated the use of object detection algorithms to detect Palmer amaranth (Amaranthus palmeri S. Watson) in soybean [Glycine max (L.) Merr.]. The objectives were to (1) develop an annotated image database of A. palmeri and soybean to fine-tune object detection algorithms, (2) compare effectiveness of multiple open-source algorithms in detecting A. palmeri, and (3) evaluate the relationship between A. palmeri growth features and A. palmeri detection ability. Soybean field sites were established in Manhattan, KS, and Gypsum, KS, with natural populations of A. palmeri. A total of 1,108 and 392 images were taken aerially and at ground level, respectively, between May 27 and July 27, 2021. After image annotation, a total of 4,492 images were selected. Annotated images were used to fine-tune open-source faster regional convolutional (Faster R-CNN) and single-shot detector (SSD) algorithms using a Resnet backbone, as well as the “You Only Look Once” (YOLO) series algorithms. Results demonstrated that YOLO v. 5 achieved the highest mean average precision score of 0.77. For both A. palmeri and soybean detections within this algorithm, the highest F1 score was 0.72 when using a confidence threshold of 0.298. A lower confidence threshold of 0.15 increased the likelihood of species detection, but also increased the likelihood of false-positive detections. The trained YOLOv5 data set was used to identify A. palmeri in a data set paired with measured growth features. Linear regression models predicted that as A. palmeri densities increased and as A. palmeri height increased, precision, recall, and F1 scores of algorithms would decrease. We conclude that open-source algorithms such as YOLOv5 show great potential in detecting A. palmeri in soybean-cropping systems.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"648 - 662"},"PeriodicalIF":2.5,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48071592","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 Junglerice [Echinochloa colona (L.) Link.] is the most important grass weed species in Australian summer cropping systems. Although it is mainly a spring- and summer-emerging weed species, field observations suggest that E. colona is expanding its seasonality. A common garden experiment was conducted at the University of Queensland farm to examine the effect of planting dates on phenology, growth, and fecundity of eight populations of E. colona. All populations were planted every second month from September to July in 2019 to 2020 and 2020 to 2021. Echinochloa colona took the shortest time (4 to 6 d) to emerge when planted in November or January. However, the November population took the longest number of growing degree days to exhibit panicle emergence. In both years, populations differed in height and leaf, tiller, panicle, and seed production in response to planting times. Plants produced significantly greater biomass for the November planting (123 to 147 g plant–1) followed by the January planting and then the September planting. The March planting produced the lowest biomass. In the first year, the lowest number of seeds (3,500 seeds plant–1) was produced by the March planting; however, in the second year, similar numbers of seeds were produced by the March and July plantings. In the first year, seed production (51,000 seeds plant–1) was greatest for the November planting; however, some populations also produced a similar number of seeds for the January planting. In the second year, significantly greater seed production (111,000 seeds plant–1) was observed for the January planting compared with other planting dates. The aboveground biomass and seed production of E. colona were positively correlated. This study reveals variations among E. colona populations and suggests that although greater emphasis must be placed on controlling spring- and summer-emerging plants, management practices need to be extended throughout the year to control E. colona in southeastern Australia.
{"title":"Phenology, growth, and seed production of junglerice (Echinochloa colona) in response to its emergence time and populations","authors":"B. Chauhan","doi":"10.1017/wsc.2022.51","DOIUrl":"https://doi.org/10.1017/wsc.2022.51","url":null,"abstract":"Abstract Junglerice [Echinochloa colona (L.) Link.] is the most important grass weed species in Australian summer cropping systems. Although it is mainly a spring- and summer-emerging weed species, field observations suggest that E. colona is expanding its seasonality. A common garden experiment was conducted at the University of Queensland farm to examine the effect of planting dates on phenology, growth, and fecundity of eight populations of E. colona. All populations were planted every second month from September to July in 2019 to 2020 and 2020 to 2021. Echinochloa colona took the shortest time (4 to 6 d) to emerge when planted in November or January. However, the November population took the longest number of growing degree days to exhibit panicle emergence. In both years, populations differed in height and leaf, tiller, panicle, and seed production in response to planting times. Plants produced significantly greater biomass for the November planting (123 to 147 g plant–1) followed by the January planting and then the September planting. The March planting produced the lowest biomass. In the first year, the lowest number of seeds (3,500 seeds plant–1) was produced by the March planting; however, in the second year, similar numbers of seeds were produced by the March and July plantings. In the first year, seed production (51,000 seeds plant–1) was greatest for the November planting; however, some populations also produced a similar number of seeds for the January planting. In the second year, significantly greater seed production (111,000 seeds plant–1) was observed for the January planting compared with other planting dates. The aboveground biomass and seed production of E. colona were positively correlated. This study reveals variations among E. colona populations and suggests that although greater emphasis must be placed on controlling spring- and summer-emerging plants, management practices need to be extended throughout the year to control E. colona in southeastern Australia.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"561 - 568"},"PeriodicalIF":2.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41457461","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 Dicamba was labeled in dicamba-resistant cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] in 2017, resulting in a record number of off-target complaints. To address off-target movement via volatilization, experiments were conducted to evaluate the effectiveness of potassium tetraborate tetrahydrate (KBo) as a volatility-reducing agent (VRA) with dicamba. Low-tunnel experiments examined: (1) whether KBo functions as a dicamba VRA, (2) the relationship between KBo concentration and dicamba volatilization, (3) the effectiveness of KBo compared with potassium acetate as a VRA, and (4) the impact of KBo on dicamba volatilization with and without glufosinate. In a large-scale trial (0.4-ha plots), the effectiveness of KBo in reducing dicamba volatilization was quantified relative to a commercial dicamba application labeled for use in 2020. The addition of KBo to dicamba reduced volatility over dicamba alone and a dicamba plus potassium acetate premix. As KBo concentration increased in the dicamba spray solution, volatilization was exponentially reduced. Dicamba volatilization with the addition of KBo at 0.01 M was comparable to dicamba plus potassium acetate at 0.05 M. Potassium tetraborate tetrahydrate was more effective than potassium acetate at reducing volatility of a dicamba plus glufosinate mixture. In large-scale experiments over a 30-h period, the addition of KBo to a diglycolamine plus glyphosate mixture lowered dicamba volatilization 82% to 89% over the herbicide mixture alone. Overall, the addition of KBo to dicamba appears promising as a VRA compared with what is commercially available.
{"title":"Evaluation of Potassium Borate as a Volatility-Reducing Agent for Dicamba","authors":"Mason C. Castner, J. Norsworthy, T. Roberts","doi":"10.1017/wsc.2022.49","DOIUrl":"https://doi.org/10.1017/wsc.2022.49","url":null,"abstract":"Abstract Dicamba was labeled in dicamba-resistant cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] in 2017, resulting in a record number of off-target complaints. To address off-target movement via volatilization, experiments were conducted to evaluate the effectiveness of potassium tetraborate tetrahydrate (KBo) as a volatility-reducing agent (VRA) with dicamba. Low-tunnel experiments examined: (1) whether KBo functions as a dicamba VRA, (2) the relationship between KBo concentration and dicamba volatilization, (3) the effectiveness of KBo compared with potassium acetate as a VRA, and (4) the impact of KBo on dicamba volatilization with and without glufosinate. In a large-scale trial (0.4-ha plots), the effectiveness of KBo in reducing dicamba volatilization was quantified relative to a commercial dicamba application labeled for use in 2020. The addition of KBo to dicamba reduced volatility over dicamba alone and a dicamba plus potassium acetate premix. As KBo concentration increased in the dicamba spray solution, volatilization was exponentially reduced. Dicamba volatilization with the addition of KBo at 0.01 M was comparable to dicamba plus potassium acetate at 0.05 M. Potassium tetraborate tetrahydrate was more effective than potassium acetate at reducing volatility of a dicamba plus glufosinate mixture. In large-scale experiments over a 30-h period, the addition of KBo to a diglycolamine plus glyphosate mixture lowered dicamba volatilization 82% to 89% over the herbicide mixture alone. Overall, the addition of KBo to dicamba appears promising as a VRA compared with what is commercially available.","PeriodicalId":23688,"journal":{"name":"Weed Science","volume":"70 1","pages":"610 - 619"},"PeriodicalIF":2.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46863871","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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