Pub Date : 2022-01-01DOI: 10.51694/advweedsci/2022;40:seventy-five010
A. Merotto, D. Gazziero, Maxwel C. Oliveira, J. Scursoni, M. A. Garcia, R. Figueroa, G. Turra
: Background : Agriculture in South America (SA) had a great expansion in the last decades and weed control changed accordingly with region and crop practices. Objective : The objective of this review is to present the history of herbicide use and discuss the main changes in weed management in SA. Methods : Herbicide use quantities were obtained from official institutions and commercial organizations in Argentina, Brazil, Chile, Paraguay and Uruguay. Data were summarized per active ingredient, herbicide mode of action or crop. The evolution of the cultivated area of the main crops in each country, and the crop and weed management associated to it were considered to discuss the importance and the consequences of the main herbicides used. Results : In 2019 the most used herbicides in Brazil were glyphosate, 2,4-D, atrazine, paraquat and diuron representing 62, 15, 7, 5 and 2% of the total amount used. In Argentina, the increasing selection of herbicide resistant populations (4 cases/year), resulted in utilization of older chemistries. Weed control in Uruguay is traditionally benefited from crop/pasture rotations but recently is also facing problems of continuous cropping systems. Agriculture in Chile is more diverse, but similar patterns and problems of herbicide use are present. Conclusions : Intensification of agriculture, no-tillage, glyphosate resistant crops, and herbicide resistant weeds were the most important drivers of herbicide use changes in SA. Integrated weed management is unpostponable to provide sustainable increasing food production in SA.
{"title":"Herbicide use history and perspective in South America","authors":"A. Merotto, D. Gazziero, Maxwel C. Oliveira, J. Scursoni, M. A. Garcia, R. Figueroa, G. Turra","doi":"10.51694/advweedsci/2022;40:seventy-five010","DOIUrl":"https://doi.org/10.51694/advweedsci/2022;40:seventy-five010","url":null,"abstract":": Background : Agriculture in South America (SA) had a great expansion in the last decades and weed control changed accordingly with region and crop practices. Objective : The objective of this review is to present the history of herbicide use and discuss the main changes in weed management in SA. Methods : Herbicide use quantities were obtained from official institutions and commercial organizations in Argentina, Brazil, Chile, Paraguay and Uruguay. Data were summarized per active ingredient, herbicide mode of action or crop. The evolution of the cultivated area of the main crops in each country, and the crop and weed management associated to it were considered to discuss the importance and the consequences of the main herbicides used. Results : In 2019 the most used herbicides in Brazil were glyphosate, 2,4-D, atrazine, paraquat and diuron representing 62, 15, 7, 5 and 2% of the total amount used. In Argentina, the increasing selection of herbicide resistant populations (4 cases/year), resulted in utilization of older chemistries. Weed control in Uruguay is traditionally benefited from crop/pasture rotations but recently is also facing problems of continuous cropping systems. Agriculture in Chile is more diverse, but similar patterns and problems of herbicide use are present. Conclusions : Intensification of agriculture, no-tillage, glyphosate resistant crops, and herbicide resistant weeds were the most important drivers of herbicide use changes in SA. Integrated weed management is unpostponable to provide sustainable increasing food production in SA.","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70675540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-10-19DOI: 10.51694/advweedsci/2021;000015
D. Le, Mauricio A. Morell
Abstract Background: Purple nutsedge is a weed that has a tough profuse underground tuber system, and is predominantly a perennial species in many crops. Objective: To evaluate the influence of different water regimes to the effectiveness of herbicides used for controlling the purple nutsedge. Methods: Experiment was arranged in a Randomized complete block design (RCBD) with a two-factor factorial design and three replications. The net-house tests were conducted with six treatments and two different water regimes of “watered daily” and [...]
{"title":"Influence of water regimes and herbicides for control of purple nutsedge ( Cyperus rotundus )","authors":"D. Le, Mauricio A. Morell","doi":"10.51694/advweedsci/2021;000015","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;000015","url":null,"abstract":"Abstract Background: Purple nutsedge is a weed that has a tough profuse underground tuber system, and is predominantly a perennial species in many crops. Objective: To evaluate the influence of different water regimes to the effectiveness of herbicides used for controlling the purple nutsedge. Methods: Experiment was arranged in a Randomized complete block design (RCBD) with a two-factor factorial design and three replications. The net-house tests were conducted with six treatments and two different water regimes of “watered daily” and [...]","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"38 18","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41246157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-08-03DOI: 10.51694/advweedsci/2021;39:000013
M. A. Butt, M. Zafar, Mushtaq Ahmad, Sadaf-Ilyas Kayani, Saraj Bahadur, F. Ullah, S. Khatoon
Abstract Background Palyno-anatomy of wetland species belonging to 10 families was studied in the present research work through light microscopy (LM) and scanning electron microscopy (SEM), to find valuable taxonomic characters. Objective This study aims to provide baseline information of the micro-morphological characters of 24 wetland species which will be helpful for further identification of wetlands weeds flora. Methods 24 weeds were collected from different wetlands of Azad Kashmir. Taxonomic tools like light microscopic and scanning electron microscopic techniques are [...]
{"title":"The use of taxonomic studies to the identification of wetlands weeds","authors":"M. A. Butt, M. Zafar, Mushtaq Ahmad, Sadaf-Ilyas Kayani, Saraj Bahadur, F. Ullah, S. Khatoon","doi":"10.51694/advweedsci/2021;39:000013","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:000013","url":null,"abstract":"Abstract Background Palyno-anatomy of wetland species belonging to 10 families was studied in the present research work through light microscopy (LM) and scanning electron microscopy (SEM), to find valuable taxonomic characters. Objective This study aims to provide baseline information of the micro-morphological characters of 24 wetland species which will be helpful for further identification of wetlands weeds flora. Methods 24 weeds were collected from different wetlands of Azad Kashmir. Taxonomic tools like light microscopic and scanning electron microscopic techniques are [...]","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41865441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-07-27DOI: 10.51694/advweedsci/2021;39:000012
Renan M. Cantu, L. Albrecht, A. Albrecht, A. F. M. Silva, M. T. Y. Danilussi, J. B. Lorenzetti
Abstract Background In the last two decades, herbicide-resistant biotypes of Conyza bonariensis, Conyza canadensis, and Conyza sumatrensis were identified. Objective: To evaluate herbicide alternatives for the control of C. sumatrensis to replace simplified management at soybean pre-sowing in the no-till system and assess the potential herbicide injury to soybeans. Methods Four experiments were conducted in Palotina, PR, to evaluate alternative managements to the herbicides commonly used in C. sumatrensis , such as synthetic auxins, pre-emergent, and burndown herbicides. All consisted [...]
{"title":"Herbicide alternative for Conyza sumatrensis control in pre-planting in no-till soybeans","authors":"Renan M. Cantu, L. Albrecht, A. Albrecht, A. F. M. Silva, M. T. Y. Danilussi, J. B. Lorenzetti","doi":"10.51694/advweedsci/2021;39:000012","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:000012","url":null,"abstract":"Abstract Background In the last two decades, herbicide-resistant biotypes of Conyza bonariensis, Conyza canadensis, and Conyza sumatrensis were identified. Objective: To evaluate herbicide alternatives for the control of C. sumatrensis to replace simplified management at soybean pre-sowing in the no-till system and assess the potential herbicide injury to soybeans. Methods Four experiments were conducted in Palotina, PR, to evaluate alternative managements to the herbicides commonly used in C. sumatrensis , such as synthetic auxins, pre-emergent, and burndown herbicides. All consisted [...]","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47632663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-01-01DOI: 10.51694/advweedsci/2021;39:00019
Gianmarco J. T. Gallardo, A. L. Bacha, W. C. Carrega, A. R. S. José, P. Alves
Glyphosate is the most widely used herbicide in the world, due to several aspects related to the reduction of labor costs and its mode of action. Thus, as it has a broad spectrum of control and is highly effective, it is the main option for weed control in various agricultural production systems (Duke, Powles, 2008; Velini et al., 2009). However, recent studies have shown that low doses of this herbicide can act stimulating the growth of several plant species (Velini et al., 2008; Cedergreen, Olesen, 2010; Carvalho et al., 2013; Pereira et al., 2013; Carbonari et al., 2014; Nascentes et al., 2018), possibly due to changes in the shikimic acid pathway (Velini et al., 2008), which is responsible for approximately 20% of the carbon assimilated by plants (Haslam, 1993). Such biphasic dose-response effect, in which low doses cause a stimulatory effect, followed by high doses causing a toxic effect, is known as hormesis (Calabrese, Baldwin, 2002). Treating a crop with subdoses of a herbicide for a desirable phenotypic change can be valuable (Duke et al., 2006); for example, when glyphosate is applied in subdoses to stimulate the accumulation of sucrose and prevent flowering in sugar cane (Velini et al., 2009; Araldi, 2010). In a different way, it is also worth mentioning the work of Pereira et al. (2013), that when applying reduced doses (from 3.6 to 36.0 g a.e. ha-1) of glyphosate in eucalyptus seedlings, reported increases of up to 22% in the dry matter of the crop. Doses within this range were also responsible for the increase of up to 20% in the dry matter of non-resistant soybean, compared to the control (Velini et al., 2008). For forage species (Brachiaria brizantha), Nascentes et al. (2015) observed a growth 31.8% greater than plants without application, for the dose of 10.5 g a.e. ha-1. In spite of this, studies that aim to increase the vegetative mass of Panicum maximum for grazing, in response to a hormetic effect, are incipient in the literature. The guinea grass (P. maximum syn. Megathyrsus maximus) is considered an important grass in pasture areas in several regions of Brazil, being one of the first forage species introduced in the country (Souza, 1999). Thus, the knowledge of their physiological and morphological characteristics is essential for the establishment of adequate management (Rodrigues, Reis, 1995). Thus, the study of the hormetic effect caused by low doses of glyphosate can be a viable alternative for the management of this species, aiming to an increase in plant growth and consequently production of green mass. In addition to cultures varying in their responses due to the application of different glyphosate doses, as mentioned above, Belz and Duke (2014) pointed out Abstract: Background: Recent studies have demonstrated an increase in plant growth due to the application of low doses of glyphosate, which is part of the phenomenon known as hormesis. Objective: The present study aimed to evaluate the effects of glyphosate doses
草甘膦是世界上使用最广泛的除草剂，其原因与降低人工成本和作用方式有关。因此，由于它具有广泛的控制范围和高效，它是各种农业生产系统中杂草控制的主要选择(Duke, Powles, 2008;Velini et al.， 2009)。然而，最近的研究表明，低剂量的这种除草剂可以刺激几种植物的生长(Velini等人，2008;Cedergreen, Olesen, 2010;Carvalho et al.， 2013;Pereira et al.， 2013;Carbonari et al.， 2014;Nascentes et al.， 2018)，可能是由于莽草酸途径的变化(Velini et al.， 2008)，该途径负责植物吸收的约20%的碳(Haslam, 1993)。这种低剂量引起刺激作用，高剂量引起毒性作用的双相剂量反应效应被称为激效效应(Calabrese, Baldwin, 2002)。用亚剂量除草剂处理作物以获得理想的表型变化可能是有价值的(Duke et al.， 2006);例如，当以亚剂量施用草甘膦以刺激蔗糖的积累并阻止甘蔗开花时(Velini等人，2009;Araldi, 2010)。同样值得一提的是，Pereira等人(2013)的研究表明，当在桉树幼苗中施用减少剂量(从3.6 g a.e. ha-1降至36.0 g a.e. ha-1)的草甘磷时，该作物的干物质增加了22%。与对照相比，这个范围内的剂量也导致无抗性大豆的干物质增加高达20% (Velini et al.， 2008)。对于饲料物种(Brachiaria brizantha)， Nascentes等(2015)观察到，施用10.5 g a.e. ha-1的剂量比未施用的植物生长高31.8%。尽管如此，为了响应激效效应，旨在通过放牧来最大限度地增加Panicum的营养质量的研究在文献中还处于起步阶段。几内亚草(P. maximum syn. Megathyrsus maximus)被认为是巴西几个地区牧场的重要牧草，是该国最早引进的饲料品种之一(Souza, 1999)。因此，了解它们的生理和形态特征对于建立适当的管理是必不可少的(Rodrigues, Reis, 1995)。因此，研究低剂量草甘膦引起的激效可以成为该物种管理的可行替代方案，旨在增加植物生长，从而产生绿色质量。Belz和Duke(2014)指出，由于施用不同剂量的草甘膦，培养物的反应也会发生变化。摘要:背景:最近的研究表明，由于施用低剂量的草甘膦，植物生长增加，这是一种被称为激效的现象的一部分。目的:研究草甘膦不同剂量对大白菜生理和形态参数的影响。Mombaca。方法:施用草甘膦后，在温室内进行盆栽试验，试验时间为49 d，试验采用完全随机设计，共4个重复。治疗包括10剂草甘膦(0;3.78;8.10;16.64;33.48;67.7;135;270;540和1,080 g (a-1)。进行了生长、气体交换、叶温和植物中毒的评价。数据进行方差分析，当显著性显著时，使用剂量-反应曲线模型进行回归分析。结果:草甘膦亚剂量对大鼠生理参数及生长均有正向影响，且影响值均高于对照组。叶片温度随剂量的增加而逐渐升高。结论:3.78 ~ 270 g a.e. ha-1亚剂量草甘膦对植物生长和生理参数有促进作用。
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Pub Date : 2021-01-01DOI: 10.51694/advweedsci/2021;39:00020
Samane Hasanzadeh, M. Rezvani, R. Abbasi, W. Grichar
Modeling of imazethapyr dose and velvetleaf (abutilon theophrasti density interaction on red bean (phaseolus competition. Abstract: Background: Red bean ( Phaseolus calcaratus L.) is cultivated as an economic crop in the Mazandaran Province, Iran. Velvetleaf ( Abutilon theophrasti Medik.) competes severely with red bean growth and reduces yield. Imazethapyr is a selective herbicide recommended for management of grasses and dicotyledonous weeds in different crops including beans. Objectives : This research was conducted to develop an empirical model of red bean yield that incorporates the dose-responses of imazethapyr and velvetleaf densities. Methods : Modeling of imazethapyr herbicide dose on red bean and velvetleaf competition was conducted using four levels of velvetleaf densities and five dosages of imazethapyr arranged in a factorial design. Results : Velvetleaf competitiveness decreased with the increasing imazethapyr dose represented by the standard dose-response curve. A model was improved to composing the dose-response standard curve with the rectangular hyperbola equation. This model estimated red bean economic yield under velvetleaf-free conditions, weed competitivity with no-herbicide application, and the imazethapyr dosage needed to decrease velvetleaf competitiveness about 50%. Imazethapyr at the 0.66 L ha -1 dose was sufficient to control the highest density (12 plants m -2 ) of velvetleaf. Conclusions : Information gained from this study will be important in evaluating economic and environmental terms.
马泽培剂量与绒叶菌密度相互作用对红豆菜豆竞争的模拟。摘要/ Abstract摘要:背景:红豆(Phaseolus calcaratus L.)是伊朗Mazandaran省的一种经济作物。丝绒叶(Abutilon theophrasti Medik.)对红豆生长造成严重竞争，降低产量。Imazethapyr是一种选择性除草剂，推荐用于包括豆类在内的不同作物的草和双子叶杂草的管理。目的:建立结合咪唑吡韦和丝绒叶浓度的红豆产量的经验模型。方法:采用因子设计，采用4个水平的棉叶密度和5个剂量的马甲醚，建立了马甲醚除草剂对红豆和棉叶竞争的剂量模型。结果:以标准剂量-反应曲线为代表，随着剂量的增加，丝绒叶片的竞争能力下降。改进了用矩形双曲线方程组成剂量-反应标准曲线的模型。该模型估计了无丝绒条件下的红豆经济产量、不施用除草剂时的杂草竞争力以及将丝绒叶片竞争力降低约50%所需的咪唑吡尔用量。以0.66 L / ha -1剂量的吡唑吡韦可有效控制丝绒叶最高密度(12株/ m2 -2)。结论:从这项研究中获得的信息将对经济和环境方面的评估很重要。
{"title":"Modeling of imazethapyr dose and velvetleaf (Abutilon theophrasti medik) density interaction on red bean (Phaseolus calcaratus L.) and velvetleaf competition","authors":"Samane Hasanzadeh, M. Rezvani, R. Abbasi, W. Grichar","doi":"10.51694/advweedsci/2021;39:00020","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:00020","url":null,"abstract":"Modeling of imazethapyr dose and velvetleaf (abutilon theophrasti density interaction on red bean (phaseolus competition. Abstract: Background: Red bean ( Phaseolus calcaratus L.) is cultivated as an economic crop in the Mazandaran Province, Iran. Velvetleaf ( Abutilon theophrasti Medik.) competes severely with red bean growth and reduces yield. Imazethapyr is a selective herbicide recommended for management of grasses and dicotyledonous weeds in different crops including beans. Objectives : This research was conducted to develop an empirical model of red bean yield that incorporates the dose-responses of imazethapyr and velvetleaf densities. Methods : Modeling of imazethapyr herbicide dose on red bean and velvetleaf competition was conducted using four levels of velvetleaf densities and five dosages of imazethapyr arranged in a factorial design. Results : Velvetleaf competitiveness decreased with the increasing imazethapyr dose represented by the standard dose-response curve. A model was improved to composing the dose-response standard curve with the rectangular hyperbola equation. This model estimated red bean economic yield under velvetleaf-free conditions, weed competitivity with no-herbicide application, and the imazethapyr dosage needed to decrease velvetleaf competitiveness about 50%. Imazethapyr at the 0.66 L ha -1 dose was sufficient to control the highest density (12 plants m -2 ) of velvetleaf. Conclusions : Information gained from this study will be important in evaluating economic and environmental terms.","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"15 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70673672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-01-01DOI: 10.51694/advweedsci/2021;39:000014
L. Galon, G. Concenço, L. Agazzi, F. Schreiber, F. Nonemacher, A. Andres
: Background: Weeds compete with crops, demanding efficient control to avoid yield losses. Highly competitive cultivars are a cultural method that can increase weed suppression and reduce the effects of crop-weed competition. Objective: The present study aimed to assess the competitive abilities of barley cultivars (crop) against black oat (weed) and their interference in crop physiology. Methods: A preliminary additive experiment was carried out with increasing densities of barley and black oat to determine the minimal density from where there was no drier mass increasing per area. In the second experiment, a replacement series experiment, five plant proportions (100:0; 75:25; 50:50; 25:75, and 0:100) of the crop were used and the competitor was installed. Fifty days after the emergence, morphophysiological and physiological variables, as well as their respective relative competitiveness indexes, relative clustering coefficient, and species aggressiveness, were all assessed. Results: The variables associated with the photosynthesis were dependent on the cultivar. BRS Cauê was the cultivar that performed better against black oat, with an increase in the overall photosynthetic rate, due to a smaller leaf area loss, as the competition increased. BRS Brau reduced the photosynthesis into smaller proportions for the competitor. The water use was not impacted to the same extent as photosynthesis. Conclusions: BRS Cauê was the most competitive cultivar, suffering the lowest impact of competition with black oat.
{"title":"Morphological and physiological changes in barley cultivars under black oat competition","authors":"L. Galon, G. Concenço, L. Agazzi, F. Schreiber, F. Nonemacher, A. Andres","doi":"10.51694/advweedsci/2021;39:000014","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:000014","url":null,"abstract":": Background: Weeds compete with crops, demanding efficient control to avoid yield losses. Highly competitive cultivars are a cultural method that can increase weed suppression and reduce the effects of crop-weed competition. Objective: The present study aimed to assess the competitive abilities of barley cultivars (crop) against black oat (weed) and their interference in crop physiology. Methods: A preliminary additive experiment was carried out with increasing densities of barley and black oat to determine the minimal density from where there was no drier mass increasing per area. In the second experiment, a replacement series experiment, five plant proportions (100:0; 75:25; 50:50; 25:75, and 0:100) of the crop were used and the competitor was installed. Fifty days after the emergence, morphophysiological and physiological variables, as well as their respective relative competitiveness indexes, relative clustering coefficient, and species aggressiveness, were all assessed. Results: The variables associated with the photosynthesis were dependent on the cultivar. BRS Cauê was the cultivar that performed better against black oat, with an increase in the overall photosynthetic rate, due to a smaller leaf area loss, as the competition increased. BRS Brau reduced the photosynthesis into smaller proportions for the competitor. The water use was not impacted to the same extent as photosynthesis. Conclusions: BRS Cauê was the most competitive cultivar, suffering the lowest impact of competition with black oat.","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70673658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-01-01DOI: 10.51694/advweedsci/2021;39:00016
G. S. F. Souza, R. F. Marques, M. R. R. Pereira, S. R. de Marchi, D. Martins
: Background: Weeds are one of the ecological factors that affect the agricultural economy permanently. Thus, understanding the weed emergence and development is essential in decision making for management strategies. Objective: This study aimed to evaluate the effect of different sowing depths and light intensities on the emergence and development of the weed species Euphorbia heterophylla and Desmodium tortuosum under field conditions. Methods: Each species consisted of an experiment carried out in a completely randomized design with four replications. Treatments were arranged in a 6 × 4 factorial scheme, with six sowing depths (0.5, 1.0, 2.0, 4.0, 8.0, and 12.0 cm) associated with four light intensities (100, 70, 50, and 30% of the solar light intensity) obtained with shading screens. Seedling emergence capacity was evaluated daily to obtain the percentage of emergence and the emergence rate index (ERI). Plant height, time to floral induction, plant dry matter during flowering were also evaluated. Results: Seedlings of E. heterophylla emerged under all solar radiation conditions and sowing up to 12.0 cm deep, while seedlings of D. tortuosum showed no emergence only at 12.0 cm deep with light intensities below 70%. The 100% solar radiation condition provided higher total and daily dry matter accumulation in E. heterophylla plants, while D. tortuosum plants showed higher values for both variables under 70 and 50% incidence of solar radiation. Conclusions: The full sunlight condition provided the best development of E. heterophylla plants. Different levels of lightness and sowing depths interfere the emergence and the development of D. tortuosum plants.
{"title":"Light intensity and sowing depth on the emergence and development of weeds","authors":"G. S. F. Souza, R. F. Marques, M. R. R. Pereira, S. R. de Marchi, D. Martins","doi":"10.51694/advweedsci/2021;39:00016","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:00016","url":null,"abstract":": Background: Weeds are one of the ecological factors that affect the agricultural economy permanently. Thus, understanding the weed emergence and development is essential in decision making for management strategies. Objective: This study aimed to evaluate the effect of different sowing depths and light intensities on the emergence and development of the weed species Euphorbia heterophylla and Desmodium tortuosum under field conditions. Methods: Each species consisted of an experiment carried out in a completely randomized design with four replications. Treatments were arranged in a 6 × 4 factorial scheme, with six sowing depths (0.5, 1.0, 2.0, 4.0, 8.0, and 12.0 cm) associated with four light intensities (100, 70, 50, and 30% of the solar light intensity) obtained with shading screens. Seedling emergence capacity was evaluated daily to obtain the percentage of emergence and the emergence rate index (ERI). Plant height, time to floral induction, plant dry matter during flowering were also evaluated. Results: Seedlings of E. heterophylla emerged under all solar radiation conditions and sowing up to 12.0 cm deep, while seedlings of D. tortuosum showed no emergence only at 12.0 cm deep with light intensities below 70%. The 100% solar radiation condition provided higher total and daily dry matter accumulation in E. heterophylla plants, while D. tortuosum plants showed higher values for both variables under 70 and 50% incidence of solar radiation. Conclusions: The full sunlight condition provided the best development of E. heterophylla plants. Different levels of lightness and sowing depths interfere the emergence and the development of D. tortuosum plants.","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70673188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-01-01DOI: 10.51694/advweedsci/2021;39:00017
R. Thomasi, A. D. Lúcio, T. Amado, L. P. Pott, A. Zanon, I. Werle, M. Macêdo, A. Ulguim
: Background: The evaluation of selective herbicides for weed control in winter cereals is extremely important. Simple methods to evaluate alterations caused by herbicides in the growth and development of winter cereals can be performed with vegetation indices. Objective : Evaluate the potential of different vegetation indices by optical sensors to detect phytotoxicity caused by herbicides in winter cereals. Methods : The experiment was conducted under field conditions, in a randomized block design with four replications. Herbicides were sprayed when the plants were at Z24. The phytotoxicity was evaluated at 7, 14 and 21 days after treatment (DAT) and the normalized difference vegetation index (NDVI) and the normalized difference red edge index (NDRE) at 16, 22 and 37 DAT. Results : The herbicide 2,4-D was less phytotoxic to winter cereals, while metribuzin and saflufenacil caused higher percentages (up to 50%) of visible injuries. The NDRE discriminated more precisely than NDVI the variations in winter cereals, showing alteration in the chlorophyll content due to the phytotoxicity caused by the herbicides. The canonical correlation analysis found an inverse relationship between phytotoxicity and vegetation indices. Conclusions : The winter cereals studied were tolerant to herbicides, enabling the recovery of growth and development. The NDRE index was the most sensitive and showed greater potential in identifying injuries caused by herbicides. The canonical correlation analysis confirmed the inverse relationship between phytotoxicity and the reduction of vegetation indices.
{"title":"Relationship of vegetation indices with herbicide phytotoxicity in winter cereals","authors":"R. Thomasi, A. D. Lúcio, T. Amado, L. P. Pott, A. Zanon, I. Werle, M. Macêdo, A. Ulguim","doi":"10.51694/advweedsci/2021;39:00017","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:00017","url":null,"abstract":": Background: The evaluation of selective herbicides for weed control in winter cereals is extremely important. Simple methods to evaluate alterations caused by herbicides in the growth and development of winter cereals can be performed with vegetation indices. Objective : Evaluate the potential of different vegetation indices by optical sensors to detect phytotoxicity caused by herbicides in winter cereals. Methods : The experiment was conducted under field conditions, in a randomized block design with four replications. Herbicides were sprayed when the plants were at Z24. The phytotoxicity was evaluated at 7, 14 and 21 days after treatment (DAT) and the normalized difference vegetation index (NDVI) and the normalized difference red edge index (NDRE) at 16, 22 and 37 DAT. Results : The herbicide 2,4-D was less phytotoxic to winter cereals, while metribuzin and saflufenacil caused higher percentages (up to 50%) of visible injuries. The NDRE discriminated more precisely than NDVI the variations in winter cereals, showing alteration in the chlorophyll content due to the phytotoxicity caused by the herbicides. The canonical correlation analysis found an inverse relationship between phytotoxicity and vegetation indices. Conclusions : The winter cereals studied were tolerant to herbicides, enabling the recovery of growth and development. The NDRE index was the most sensitive and showed greater potential in identifying injuries caused by herbicides. The canonical correlation analysis confirmed the inverse relationship between phytotoxicity and the reduction of vegetation indices.","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70673442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-01-01DOI: 10.51694/advweedsci/2021;39:00021
R. M. Pedroso, R. Victoria, A. Ulguim, Roberto C Avila, Durval Dourado
: Background: Achieving satisfactory weed control levels in black oat ( Avena strigosa ) fields is often difficult, owing to the limited number of registered herbicide molecules. Objective: To determine novel options for selective, post-emergence chemical weed control in this crop. Methods: Eight herbicide treatments were sprayed in the field onto black oat plants at the tillering stage to evaluate crop safety and control of Conyza spp. and Gamochaeta americana , two major weeds of Brazilian black oats. A separate trial was conducted to further assess herbicide safety in a controlled-environment setting, and mesotrione selectivity was then re-evaluated separately in the greenhouse during the following growing season. Crop phytotoxicity was determined using biomass production both in the field and in greenhouse trials. Results: Mesotrione, bentazon, 2,4-D, and a 2,4-D+bentazon tank-mix produced light symptoms of crop phytotoxicity, from which plants quickly recovered. Conyza spp. control was achieved via applications of mesotrione (192 g a.i. ha -1 ), metsulfuron-methyl (3.9 g a.i. ha -1 ), and a 2,4-D + bentazon tank-mix (502.5 g a.e. ha -1 + 720 g a.i. ha -1 , respectively), whereas proper G. americana control was only achieved via applications of either mesotrione or metsulfuron-methyl. Biomass accumulation by black oat plants in the greenhouse was similar across mesotrione-treated and untreated plants. Conclusions: Mesotrione could become an option for selective, post-emergence weed control in black oat fields, aiding in the fight against multiple herbicide-resistant Conyza spp. populations which are widespread across major black oat-growing areas in Brazil.
背景:由于已登记的除草剂分子数量有限，在黑燕麦田实现令人满意的杂草控制水平通常是困难的。目的:确定新选择的选择性，苗期后化学杂草控制作物。方法:在分蘖期对黑燕麦植株进行田间喷洒8种除草剂，评价巴西黑燕麦两种主要杂草Conyza spp.和Gamochaeta americana的安全性和防治效果。为了进一步评估除草剂在受控环境下的安全性，进行了一项单独的试验，然后在下一个生长季节在温室中单独重新评估了美索三酮的选择性。作物的植物毒性是在田间和温室试验中利用生物质生产来确定的。结果:美索三酮、苯他松、2,4- d和2,4- d +苯他松混合罐对作物产生轻微的植物毒性症状，植物很快恢复。通过施用中三酮(192 g a.i. ha -1)、甲磺隆-甲基(3.9 g a.i. ha -1)和2,4- d +苯达松罐式混合物(分别为502.5 g a.i. ha -1 + 720 g a.i. ha -1)实现了对Conyza的控制，而适当的美洲大蠊控制只能通过施用中三酮或甲磺隆-甲基来实现。温室内黑燕麦植株的生物量积累量在中三酮处理和未处理植株中相似。结论:美索三酮可作为黑燕麦田发生后杂草选择性防治的一种选择，有助于防治在巴西主要黑燕麦种植区广泛存在的多种抗除草剂Conyza种群。
{"title":"Mesotrione use for selective post-emergence control of glyphosate-resistant Conyza spp. in black oats","authors":"R. M. Pedroso, R. Victoria, A. Ulguim, Roberto C Avila, Durval Dourado","doi":"10.51694/advweedsci/2021;39:00021","DOIUrl":"https://doi.org/10.51694/advweedsci/2021;39:00021","url":null,"abstract":": Background: Achieving satisfactory weed control levels in black oat ( Avena strigosa ) fields is often difficult, owing to the limited number of registered herbicide molecules. Objective: To determine novel options for selective, post-emergence chemical weed control in this crop. Methods: Eight herbicide treatments were sprayed in the field onto black oat plants at the tillering stage to evaluate crop safety and control of Conyza spp. and Gamochaeta americana , two major weeds of Brazilian black oats. A separate trial was conducted to further assess herbicide safety in a controlled-environment setting, and mesotrione selectivity was then re-evaluated separately in the greenhouse during the following growing season. Crop phytotoxicity was determined using biomass production both in the field and in greenhouse trials. Results: Mesotrione, bentazon, 2,4-D, and a 2,4-D+bentazon tank-mix produced light symptoms of crop phytotoxicity, from which plants quickly recovered. Conyza spp. control was achieved via applications of mesotrione (192 g a.i. ha -1 ), metsulfuron-methyl (3.9 g a.i. ha -1 ), and a 2,4-D + bentazon tank-mix (502.5 g a.e. ha -1 + 720 g a.i. ha -1 , respectively), whereas proper G. americana control was only achieved via applications of either mesotrione or metsulfuron-methyl. Biomass accumulation by black oat plants in the greenhouse was similar across mesotrione-treated and untreated plants. Conclusions: Mesotrione could become an option for selective, post-emergence weed control in black oat fields, aiding in the fight against multiple herbicide-resistant Conyza spp. populations which are widespread across major black oat-growing areas in Brazil.","PeriodicalId":29845,"journal":{"name":"Advances in Weed Science","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70673555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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