Special Issue "Weed Management & New Approaches"

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Weed Science and Weed Management".

Deadline for manuscript submissions: closed (31 January 2020).

Special Issue Editors

Dr. Ilias Travlos
Website
Guest Editor
Department of Crop Science, Agricultural University of Athens, 75, Iera Odos str., GR11855, Athens, Greece
Interests: weed biology and ecology; herbicide resistance; integrated weed management; agronomy
Special Issues and Collections in MDPI journals
Dr. Nicholas Korres

Guest Editor
Global Change and Photosynthesis Research Unit, USDA-ARS, University of Illinois, 1102 S. Goodwin Ave., Office S-306, Urbana-Champaign, 61801, IL, USA
Interests: weed demographics and population dynamics; weed eco-physiology; weed biology; cropping systems and weed-crop interactions; integrated weed management and herbicide resistance; system dynamics and modelling; big data and data analytics
Dr. Rafael De Prado

Guest Editor
University of Cordoba, Spain
Interests: Herbicide resistance; mechanisms of resistance; weed management
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The core of integrated and sustainable weed management is to use a wide range of tools and methods. To sustain agriculture economically and environmentally and meet future food needs, further research is required to improve weed management and evaluate new approaches. Please share your studies on several topics of weed research in this Special Issue. In particular, submissions on the following topics (but not limited to) are invited: 1) Mechanical weed control with particular emphasis in Robotics; 2) Non-chemical weed control with particular emphasis in allelophathic relationships; 3) Nanotechnology and weed control; 4) Image processing and precision weed control; 5) RNAi technology; 6) Herbicide resistant crops and weeds; 7) Biological weed control; 8) Decision support systems; 9) Integrated weed management; 10) Data knowledge discovery and weed science.

Dr. Ilias Travlos
Dr. Nicholas Korres
Dr. Rafael De Prado
Guest Editors

Manuscript Submission Information

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Keywords

  • Weed management
  • Mechanical weed control
  • Robotics
  • Non-chemical weed control
  • Allelopathy
  • Nanotechnology
  • Image processing
  • Precision weed control
  • RNAi technology
  • Herbicide resistant crops and weeds
  • Biological weed control
  • Decision support systems
  • Integrated weed management
  • Data knowledge discovery

Published Papers (29 papers)

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Open AccessArticle
Allelopathic Potential of Teff Varieties and Effect on Weed Growth
Agronomy 2020, 10(6), 854; https://doi.org/10.3390/agronomy10060854 - 16 Jun 2020
Abstract
Allelopathic potential of 10 teff varieties was assessed in laboratory experimentation (conducted in NIBIO, Norway), and determined with an agar-based bioassay using ryegrass and radish as model weeds. Field experiments were conducted in Tigray, Ethiopia during 2015 and 2016 to identify the most [...] Read more.
Allelopathic potential of 10 teff varieties was assessed in laboratory experimentation (conducted in NIBIO, Norway), and determined with an agar-based bioassay using ryegrass and radish as model weeds. Field experiments were conducted in Tigray, Ethiopia during 2015 and 2016 to identify the most important agronomic traits of teff contributing to its weed competitive ability. A split plot design with three blocks was used considering hand weeding as the main plot and varieties as the subplot. Randomized complete block design (RCBD) with four blocks was used in the laboratory experiment. The highest potential allelopathic activity (PAA) and specific potential allelopathic activity (SPAA) were recorded from a local landrace with an average PAA value of 11.77% and SPAA value of 1.21%/mg respectively, when ryegrass was used as the model weed. ‘Boset’ had the highest average PAA value of 16.25% and an SPAA value of 1.53%/mg, when using radish as the model weed. The lowest PAA and SPAA values were recorded from ‘DZ-Cr-387′ when using ryegrass and radish as model weeds. Days to emergence, height, tiller no./plant, biomass yield, and PAA of the crop significantly contributed to the variance of the weed biomass, cover, and density. Hence, they were the most important agronomic traits enhancing the competitive ability of teff. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Analysis on Efficiency and Influencing Factors of New Soybean Producing Farms
Agronomy 2020, 10(4), 568; https://doi.org/10.3390/agronomy10040568 - 15 Apr 2020
Abstract
The efficiency of new soybean producers is of great importance to the agricultural development of China. Based on the survey data of some counties (cities) in Heilongjiang, Jilin, Liaoning, and Inner Mongolia Autonomous Region, the efficiency of new soybean producers in these regions [...] Read more.
The efficiency of new soybean producers is of great importance to the agricultural development of China. Based on the survey data of some counties (cities) in Heilongjiang, Jilin, Liaoning, and Inner Mongolia Autonomous Region, the efficiency of new soybean producers in these regions is calculated by means of the data envelopment analysis (DEA) model. Then, the Tobit model is used to select relevant explanatory variables to study the factors affecting the production efficiency, and relevant conclusions and suggestions are put forward. The results show that (1) in 2017, the new soybean producers’ average technical efficiency of soybean production in the research samples was 0.618, of which the average pure technical efficiency was 0.680 and the average scale efficiency was 0.872; (2) factors such as the degree of education, the soybean planting area, the degree of mechanization, and the soybean sales channel have positive impacts on the efficiency of new soybean producers, while the ones such as the stability of the soybean price, the difficulty in obtaining soybean market information, and the implementation of the soybean subsidy policy have negative impacts. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
Open AccessArticle
Johnsongrass (Sorghum halepense (L.) Pers.) Interference, Control and Recovery under Different Management Practices and its Effects on the Grain Yield and Quality of Maize Crop
Agronomy 2020, 10(2), 266; https://doi.org/10.3390/agronomy10020266 - 13 Feb 2020
Abstract
Maize is an important crop grown on significant acreage around the world, and a major constraint for its growth is weed interference. Thus, field studies were conducted to examine johnsongrass interference, control, and recovery under different management practices and its effects on maize. [...] Read more.
Maize is an important crop grown on significant acreage around the world, and a major constraint for its growth is weed interference. Thus, field studies were conducted to examine johnsongrass interference, control, and recovery under different management practices and its effects on maize. Our results indicated that the most johnsongrass aboveground biomass was recorded in the nontreated and weed-infested for 55 days after sowing (DAS) treatments, while the lowest values were in nicosulfuron treatments (48 and 60 g a.i./ha). Among the various herbicide treatments, the greatest johnsongrass aboveground biomass was recorded in the isoxaflutole (applied pre-emergence at 99 g a.i./ha) + 1 hoeing treatment. Johnsongrass aboveground biomass at 78–85 DAS was 1.4- to 6.0-fold greater than that at 55 DAS, revealing johnsongrass recovery after nicosulfuron treatments. Johnsongrass competition had a significant impact on maize growth and grain yield. The main crop parameters, such as aboveground biomass, grain yield, and protein content, were lowest in the nontreated and weed-infested for 55 DAS treatments, while the greatest values of these parameters were recorded in the weed-free and nicosulfuron treatments. In conclusion, our results indicated that timely and effective chemical control of johnsongrass is essential for improving grain yield and quality of maize. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Flaming, Glyphosate, Hot Foam and Nonanoic Acid for Weed Control: A Comparison
Agronomy 2020, 10(1), 129; https://doi.org/10.3390/agronomy10010129 - 15 Jan 2020
Cited by 2
Abstract
Synthetic herbicides are commonly used in weed management, however, 70 years of use has led to weed resistance and environmental concerns. These problems have led scientists to consider alternative methods of weed management in order to reduce the inputs and impacts of synthetic [...] Read more.
Synthetic herbicides are commonly used in weed management, however, 70 years of use has led to weed resistance and environmental concerns. These problems have led scientists to consider alternative methods of weed management in order to reduce the inputs and impacts of synthetic herbicides. The aim of this experiment was to test the level of weed control using four weeding methods: glyphosate applied at an ultra-low volume, the organic herbicide nonanoic acid, flaming, and hot foam. The results showed that weed control was effective only when flaming and hot foam were applied (99% and 100% weed control, respectively). Nonanoic acid at a dose of 11 kg a.i. ha−1 diluted in 400 L of water did not control developed plants of Cyperus esculentus (L.), Convolvulus arvensis (L.) and Poa annua (L.). Glyphosate at a dose of 1080 g a.i. ha−1 (pure product) only controlled P. annua (L.), but had no effect on C. esculentus (L.) and C. arvensis (L.). After the aboveground tissues of weeds had died, regrowth began earlier after flaming compared to hot foam. There was no regrowth of P. annua (L.) only after using hot foam and glyphosate. Hot foam was generally better at damaging the meristems of the weeds. In one of the two experiment sites, significantly more time was needed after the hot foam to recover 10% and 50% of the ground compared to flaming. The time needed to recover 90% of the ground was on average 26–27 days for flaming and hot foam, which is the time that is assumed to be required before repeating the application. A total of 29 days after the treatments, weeds were smaller after flaming, glyphosate and hot foam compared to nonanoic acid and the control, where they had more time to grow. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Weed-Competitive Ability of Teff (Eragrostis tef (Zucc.) Trotter) Varieties
Agronomy 2020, 10(1), 108; https://doi.org/10.3390/agronomy10010108 - 11 Jan 2020
Cited by 1
Abstract
Teff is a staple and well adapted crop in Ethiopia. Weed competition and control have major effects on yields and economic returns of the crop in the country. Among the weed management methods, development and use of weed competitive teff varieties remain the [...] Read more.
Teff is a staple and well adapted crop in Ethiopia. Weed competition and control have major effects on yields and economic returns of the crop in the country. Among the weed management methods, development and use of weed competitive teff varieties remain the cheapest and most sustainable weed management option. Ten teff varieties were tested for their weed competitive ability in two locations. Treatments were applied using a split plot design with three blocks at each location for two consecutive seasons. Hand weeding and non-weeded treatments were applied to whole plot treatments with teff varieties assigned as split plots within the whole plot. The main objective was to determine relative competitive ability among teff varieties. Results showed that teff varieties showed significant variation in their weed competitive abilities. The varieties ‘Kora’ and ‘DZ-Cr-387’ significantly reduced weed density, dry weight, and cover more than the other teff varieties. They also had the lowest yield losses with a loss of 6% in biomass yield and 18% in grain yield recorded from ‘Kora’ and a loss of 17% in biomass yield and 21% in grain yield recorded from ‘DZ-Cr-387’. Therefore, they showed the highest weed competitive ability compared to the other varieties. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Harvest Weed Seed Control: Seed Production and Retention of Fallopia convolvulus, Sinapis arvensis, Spergula arvensis and Stellaria media at Spring Oat Maturity
Agronomy 2020, 10(1), 46; https://doi.org/10.3390/agronomy10010046 - 28 Dec 2019
Cited by 1
Abstract
If seeds retained on weeds at crop harvest could be collected and removed by the combine harvester, weed infestation could be reduced in the following years. We estimated the proportion of weed seeds that could be removed at oat harvest. The seed production [...] Read more.
If seeds retained on weeds at crop harvest could be collected and removed by the combine harvester, weed infestation could be reduced in the following years. We estimated the proportion of weed seeds that could be removed at oat harvest. The seed production and shedding pattern of Fallopia convolvulus, Sinapis arvensis, Spergula arvensis and Stellaria media, were assessed in two spring oat fields in Denmark during 2018 and 2019. Ten randomly chosen plants of each species were surrounded by a porous net before flowering. The start time of seed shedding was recorded, and the seeds were collected from the nets and counted weekly until oat harvest. Just before harvest, the retained seeds on the weed plants were counted. The ratio between harvestable seeds and shed seeds during the growing season was determined. On average 260, 195, 411 and 316 seeds plant−1 were produced by F. convolvulus, Sinapis arvensis, Spergula arvensis and S. media, respectively, of which in average 44%, 67%, 45% and 56% of the seeds were retained on the plants at harvest. There was a strong, positive correlation between the weed biomass and the total seed production. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Combination of Herbicide Band Application and Inter-Row Cultivation Provides Sustainable Weed Control in Maize
Agronomy 2020, 10(1), 20; https://doi.org/10.3390/agronomy10010020 - 21 Dec 2019
Cited by 1
Abstract
Herbicides have facilitated weed management but their incorrect use can lead to environmental contamination. Reducing herbicide use by limiting their application to a band along the crop row can decrease their environmental impact. Three field experiments were conducted in North-eastern Italy to evaluate [...] Read more.
Herbicides have facilitated weed management but their incorrect use can lead to environmental contamination. Reducing herbicide use by limiting their application to a band along the crop row can decrease their environmental impact. Three field experiments were conducted in North-eastern Italy to evaluate herbicide band application systems integrated with inter-row hoeing for silage maize. Post-emergence herbicide band application (sprayed area 50% of total field; herbicide dose 50% of that recommended, application with an inter-row cultivator prototype) was compared with pre-emergence band application (sprayed area 33% of total field; herbicide dose 33% of that recommended, application with a seeder) and pre-emergence broadcast application (sprayed area 100% of total field; full recommended herbicide dose, application with a boom sprayer) that is standard management for maize. Weed density and composition were evaluated before and after post-emergence herbicide application and at crop harvest. Crop yield was also recorded. Weed density in untreated areas ranged between 5 and 15 plants m−2 in the different experiments. Optimal weed control and good yields were achieved without significant differences between all treatments. Herbicide band application can provide optimal weed control in silage maize, at the same time allowing a relevant reduction of herbicide input. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Response of Annual Weeds to Glyphosate: Evaluation and Optimization of Application Rate Based on Fecundity-Avoidance Biomass Threshold Criterion
Agronomy 2019, 9(12), 851; https://doi.org/10.3390/agronomy9120851 - 05 Dec 2019
Abstract
The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda [...] Read more.
The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda cristata, Chenopodium album, Digitaria sanguinalis, Eleusine indica and Portulaca oleracea were grown outdoors in pots containing commercial potting medium. An increasing dose of glyphosate was applied to these species at three growth stages. Weed response was evaluated visually compared to the nontreated control and shoot dry weights were recorded. Fecundity was also determined. Based on visual evaluations, the dose of glyphosate required to attain 90% control of the species tested exhibited an application rate margin up to 28.5-fold compared to recommended rate, denoting a potential for rate optimization. Except for A. cristata, the recommended dose of glyphosate could be reduced by 30%–60% and still achieve 90% or greater control. The order of species sensitivity, based on effective dose 50 (ED50 )values, was E. indica > C. album > D. sanguinalis > P. oleracea > A. cristata. The ratio of ED90/ED50 was constant, indicating that increasing the glyphosate dose 8.7-fold would reduce weed biomass 1.8-fold. In most cases, the fecundity-avoidance biomass threshold (i.e., the maximum allowable weed biomass for herbicide application in order to prevent weed seed production and dispersal) for glyphosate was below the ED90 value. Complimentary measures such as fecundity-avoidance biomass threshold will improve herbicide evaluation procedures and preserve the effectiveness of herbicides, including glyphosate, on sensitive species, an important issue particularly when action to reduce herbicide resistance development is highly required. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
First Report of Herbicide-Resistant Echinochloa crus-galli in Uruguayan Rice Fields
Agronomy 2019, 9(12), 790; https://doi.org/10.3390/agronomy9120790 - 22 Nov 2019
Cited by 2
Abstract
Echinochloa crus-galli is the main weed in direct dry-seeded rice systems worldwide and is the target of most herbicide applications. Numerous cases of E. crus-galli biotypes with resistance to herbicides have been reported in different regions of the world; however, to date, no [...] Read more.
Echinochloa crus-galli is the main weed in direct dry-seeded rice systems worldwide and is the target of most herbicide applications. Numerous cases of E. crus-galli biotypes with resistance to herbicides have been reported in different regions of the world; however, to date, no cases have been reported in Uruguay. The purpose of this research is to assess the presence of herbicide-resistant E. crus-galli in the rice fields of Uruguay. More than 40 E. crus-galli biotypes were sampled from eastern to northern regions in different years and assessed following the Herbicide Resistance Action Committee (HRAC) protocols of confirmation, using the herbicides propanil, quinclorac, clomazone, bispyribac–sodium, penoxsulam, imazapyr + imazapic, profoxidim and cyhalofop. Herbicides rates included 0, 0.125, 0.25, 0.50, 1, 2, 4 and 8 times the label rate. Most E. crus-galli biotypes (35) resulted as resistant to quinclorac. Furthermore, resistance was confirmed to propanil in at least seven biotypes, 12 to imazapyr + imazapic, and three to penoxsulam. Five biotypes showed multiple resistance to propanil and quinclorac, and one biotype was resistant to quinclorac, penoxsulam and imazapyr + imazapic. No biotype showed confirmed resistance to clomazone, bispyribac-sodium, cyhalofop or profoxidim—herbicides that ensure satisfactory control. The presence of E. crus-galli herbicide resistant-biotypes reduces herbicide options, threatening rice production in Uruguay. In this context, a redesign of the productive systems would represent an opportunity to complement the chemical control, integrating larger-scale cultural and management practices. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
LPG Flaming—A Safe Post-Emergence Weed Control Tool for Direct Seeded and Bulb Onion
Agronomy 2019, 9(12), 786; https://doi.org/10.3390/agronomy9120786 - 21 Nov 2019
Abstract
The demand for pesticide-free food has increased the need for sustainable organic farming. Onion (Allium cepa L.) is an important vegetable crop cultivated worldwide. The available weed control tools for intra-row weeds following onion emergence are limited. This study aimed to evaluate [...] Read more.
The demand for pesticide-free food has increased the need for sustainable organic farming. Onion (Allium cepa L.) is an important vegetable crop cultivated worldwide. The available weed control tools for intra-row weeds following onion emergence are limited. This study aimed to evaluate the potential use of liquefied petroleum gas (LPG) flaming as a pre- and post-emergence weed control method for both direct-seeded onion seedlings and transplanted onion bulbs. The safety of cross-row, where the flames are targeted to the intra-row area from both sides of the row, and broadcast flaming for bulb onion was compared. Cross-row flaming at twelve days after planting had no effect on onion dry weight, while broadcast flaming-treated plants’ dry weight was reduced by 36% as compared to controls. For the cross-row technique, the tested burners’ angle (45° and 30°) and inter-burner distances (30 and 40 cm) had no impact on weed control efficacy, and similar control levels, between 55% (15 cm) and 45% (10 cm), were observed 15 cm from both sides of the row-center. Direct-seeded onion cultivars were treated at various growth stages. The pre-crop-emergence stage was completely safe for the crop, and the second leaf stage exhibited a wide range of tolerance levels to flaming treatment across the different onion cultivars, with dry weights ranging between 39 and 117% compared to non-treated control in the flaming sensitive and tolerant cultivars, respectively. These results were validated under field conditions using the two most tolerant cultivars (Orlando and Browny); no yield reductions were observed for either cultivar when treated from the third leaf stage. In bulb onion, flaming had no impact on dry weight of shoots or roots when applied from four weeks after planting. This study demonstrates, for the first time, the potential of using flaming as a post-emergence weed control tool for direct-seeded and bulb onion, and at earlier time points than previously shown. Cross-row flaming proved effective for controlling intra-row weeds and can lower weeding costs. Future research should evaluate the safety of sequential applications and test complementary control methods for the initial growth stages. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Spatial and Temporal Distribution of Ecballium elaterium in Almond Orchards
Agronomy 2019, 9(11), 751; https://doi.org/10.3390/agronomy9110751 - 13 Nov 2019
Cited by 1
Abstract
The concept of site-specific weed management is based on the assumption that weeds are aggregated in patches. In this study, we surveyed four plots in four commercial almond orchards for three years and mapped the locations of Ecballium elaterium, a troublesome weed [...] Read more.
The concept of site-specific weed management is based on the assumption that weeds are aggregated in patches. In this study, we surveyed four plots in four commercial almond orchards for three years and mapped the locations of Ecballium elaterium, a troublesome weed in Israeli agriculture, specifically in almond orchards. We analyzed the spatial pattern of the plants’ locations using nearest neighbor analysis and Ripley’s L function. The number of E. elaterium plants increased by more than 70% in the four plots from 2015 to 2016. In addition, the observed mean distance between nearest neighbors increased by more than 10% from 2016 and 2017. We found in all four plots that the spatial pattern of E. elaterium was clustered and that these weed patch locations were consistent over the years although the density within the patches increased. The extent of these clusters ranged between 40 to 70 m and remained similar in size throughout the study. These features make E. elaterium a suitable target for site-specific weed management and for pre-emergence patch spraying. Knowledge of the spatial and temporal pattern of weeds could aid in understanding their ecology and could help target herbicide treatments to specific locations of the field and, thus, reducing the chemical application. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Mulch-Based No-Tillage Effects on Weed Community and Management in an Organic Vegetable System
Agronomy 2019, 9(10), 594; https://doi.org/10.3390/agronomy9100594 - 28 Sep 2019
Cited by 2
Abstract
Weeds can cooperate with the agroecosystem’s functioning by providing ecosystem services. Effective weed management should mitigate negative weed–crop interference, while maintaining a functional and balanced weed community. In a two-year trial, the in-line/roller crimper (RC) was used to terminate an agroecological service crop [...] Read more.
Weeds can cooperate with the agroecosystem’s functioning by providing ecosystem services. Effective weed management should mitigate negative weed–crop interference, while maintaining a functional and balanced weed community. In a two-year trial, the in-line/roller crimper (RC) was used to terminate an agroecological service crop (ASC; here barley, Hordeum vulgare L.) before organic zucchini (Cucurbita pepo, L.) and compared with green manure (GM) ASC and tilled no-ASC with Mater-Bi mulch on the rows (No_ASC). Zucchini yield, soil N availability, weed density/cover, biomass, and community composition were assessed. Analysis of variance, exploratory statistical analysis, and non-parametric inferential approaches were run, respectively, on agronomic data, species-specific weed frequencies, and Shannon diversity. Zucchini yield was the highest in No_ASC, due to soil N immobilization under high C:N barley residues in GM and RC. Multivariate analysis discriminated RC from tilled systems, outlining a specific ensemble of weed species correlated to Shannon diversity. From zucchini fruit set, RC selectively favored Polygonum aviculare L. and Helminthotheca echioides (L.), reasonably because of their oligotrophy and creeping habit. Their dominance finally caused low RC weed control. Results highlight strong weed selective pressure by the mulch-based no-tillage. Understanding the mechanisms underpinning the impact of soil management practices on weed community can drive towards a tailor-made and more effective weed management. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Cost Analysis of Chaff Harvesting Concepts in Germany
Agronomy 2019, 9(10), 579; https://doi.org/10.3390/agronomy9100579 - 25 Sep 2019
Cited by 4
Abstract
This work assesses the costs of exploiting the biomass feedstock chaff. Chaff is a harvest residue generated during the conventional grain harvesting process and usually remains on the field. In this paper, the costs of collecting and supplying chaff to the end user [...] Read more.
This work assesses the costs of exploiting the biomass feedstock chaff. Chaff is a harvest residue generated during the conventional grain harvesting process and usually remains on the field. In this paper, the costs of collecting and supplying chaff to the end user with different harvesting methods and supply chains are analyzed. The costs are estimated for a base case defining a set of general assumptions. The impact of these assumptions is analyzed in a sensitivity analysis by means of tornado diagrams. A full costing method based on the VDI guideline 2067 part 1 is applied for the cost estimation. The cost analysis reveals that ceasing the fractioning of grain, straw and chaff during harvesting and transporting them as a mixture reduces the harvesting costs significantly. The costs are decreased due to a reduction in agricultural operations and processing large amounts of material. The lowest total costs originate from the production of chaff-straw bales. Harvesting chaff as a single fraction leads to the highest costs with the investigated supply chains. Comparing the costs of chaff supply to potential revenues shows that an exploitation of the harvest residue can be economically feasible. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Optimization of Herbicide Use: Study on Spreading and Evaporation Characteristics of Glyphosate-Organic Silicone Mixture Droplets on Weed Leaves
Agronomy 2019, 9(9), 547; https://doi.org/10.3390/agronomy9090547 - 12 Sep 2019
Cited by 2
Abstract
Herbicide deposition rate can be affected by the leaf surface features of weeds and have a significant impact on the overall efficacy. In this paper, an orthogonal experiment was conducted to investigate the differences of droplet evaporation and spreading characteristics corresponding to weed [...] Read more.
Herbicide deposition rate can be affected by the leaf surface features of weeds and have a significant impact on the overall efficacy. In this paper, an orthogonal experiment was conducted to investigate the differences of droplet evaporation and spreading characteristics corresponding to weed leaf surface with hairy, waxy and rough (ridged) structures. Three weed species—Descurainia sophia, Lepidium lotifolium, and Lolium temulentum—were included in the study, representing these three leaf structures respectively. Glyphosate sprays with organic silicone surfactant in different concentrations were composed for the test. Single droplets with two diameters of 0.05 μL and 0.1 μL were deposited on the leaves to evaluate the evaporation and spreading characteristics. A digital camera was used and the evaporation duration and the maximum droplet coverage images could be captured and extracted from the recorded videos. The Image Processing Toolbox in Matlab was applied to segment the images for droplet and leaf background and the binary images’ pixel numbers were counted for coverage area calculation. The results revealed that the evaporation duration was reduced with the increase of the organic silicone concentration, while the spread area was expanded. The droplet spread more widely and evaporated faster on D. sophia leaves than on the leaves with L. lotifolium and L. temulentum surfaces. The spreading area and evaporation duration varied much faster on L. lotifolium leaves than on the leaves of other weed species. The droplet sizes affected spreading more significantly on L. temulentum leaf surface, as the spreading procedure of small size droplets was restrained by the groove structure. The results of this study would benefit the consideration of the farmers when selecting the proper nozzle code and the determining of the surfactant mixture in order to optimize the use of herbicides like glyphosate. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Killing Weed Seeds with Exhaust Gas from a Combine Harvester
Agronomy 2019, 9(9), 544; https://doi.org/10.3390/agronomy9090544 - 12 Sep 2019
Cited by 4
Abstract
We investigated if hot exhaust gas from a combine harvester could be used to reduce germination or kill weed seeds during the harvesting process. During the threshing and cleaning process in the combine, weed seeds and chaff are separated from the crop grains. [...] Read more.
We investigated if hot exhaust gas from a combine harvester could be used to reduce germination or kill weed seeds during the harvesting process. During the threshing and cleaning process in the combine, weed seeds and chaff are separated from the crop grains. After this separation, weed and crop seeds not collected can be exposed to exhaust gas before seeds are returned to the field. Seeds of some common weed species (Alopecurus myosuroides, Centaurea cyanus, Geranium pusillum, Lapsana communis, Lolium perenne, Rumex crispus, Spergula arvensis, and Tripleurospermum inodorum) were treated with exhaust gas at temperatures of 75 °C or 85 °C, 110 °C, and 140 °C for 2, 4, and 6 s, respectively. Afterwards, the seeds were germinated for 16 days. We found that 75 °C and 85 °C were insufficient to significantly reduce germination of the seeds after three durations. Some seeds were still able to germinate after 4 s exposure of 110 °C. An exposure of 140 °C for 4 and 6 s repressed germination of all species. We conclude that there is potential to develop combine harvesters that exploit the exhaust gas to either kill or reduce the ability of weed seeds to germinate before seeds are returned to the field. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Ecological Evidence for the Fitness Trade-Off in Triazine Resistant Chenopodium Album L.: Can We Exploit the Cost of Resistance?
Agronomy 2019, 9(9), 523; https://doi.org/10.3390/agronomy9090523 - 09 Sep 2019
Cited by 2
Abstract
The alleles responsible for herbicide resistance in weeds can result in a fitness cost within affected plants. Over 200 cases of resistance to triazine herbicides have been confirmed in a wide range of weed species globally. In New Zealand, Chenopodium album L. was [...] Read more.
The alleles responsible for herbicide resistance in weeds can result in a fitness cost within affected plants. Over 200 cases of resistance to triazine herbicides have been confirmed in a wide range of weed species globally. In New Zealand, Chenopodium album L. was the first species reported as resistant to triazines. Several studies have already shown that triazine resistance in weeds is associated with fitness costs. Our current study provides further information about fitness penalties caused by triazine resistance during the vegetative growth phase of C. album. Triazine-resistant phenotypes produced less biomass and were shorter than susceptible ones prior to the onset of flowering. At an early stage of growth, triazine-resistant plants had lower photosynthetic efficacy and growth rates than susceptible plants, indicated by lower net assimilation rate (NAR) and relative growth rate (RGR), respectively. However, at a later stage of growth, the resistant plants had greater RGR values than susceptible phenotypes, though there were no significant differences in NAR between triazine-resistant and susceptible plants at this later stage. The triazine-resistant plants had less capacity for vegetative growth than susceptible plants during competition with wheat, indicating less ability to capture resources by triazine-resistant plants under competition. Overall, this study has revealed that the triazine resistance allele caused a substantial fitness cost to C. album only at the early phase of vegetative growth stage; thus, the use of crop competition to try managing triazine-resistant C. album plants should occur during this early phase. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Bastard Cabbage (Rapistrum rugosum L.) Resistance to Tribenuron-Methyl and Iodosulfuron-Methyl-Sodium in Spain and Alternative Herbicides for Its Control
Agronomy 2019, 9(9), 492; https://doi.org/10.3390/agronomy9090492 - 28 Aug 2019
Abstract
Complaints about the lack of control of Rapistrum rugosum with tribenuron-methyl and iodosulfuron-methyl-sodium in winter cereals in Northeastern Spain motivated this study. During 2015–2018, greenhouse trials were conducted to test the responses of two possibly resistant (R1 and R2) and two susceptible populations [...] Read more.
Complaints about the lack of control of Rapistrum rugosum with tribenuron-methyl and iodosulfuron-methyl-sodium in winter cereals in Northeastern Spain motivated this study. During 2015–2018, greenhouse trials were conducted to test the responses of two possibly resistant (R1 and R2) and two susceptible populations to both active ingredients to determine the response of these populations to alternative herbicides. In the first trial that was repeated twice, populations were treated with both active ingredients (three rates, six replicates), and the lack of control confirmed resistance both times. The second trial was conducted on the self-pollinated progeny of the initial populations (13 rates, 6 replicates) to confirm the heritable character of resistance and to determine the resistance factors related to survival and biomass. Resistance factors based on biomass were 188 and 253 for tribenuron-methyl and 42 and 26 for iodosulfuron-methyl-sodium for R1 and R2, respectively, confirming the strong resistance of the progeny. In the third trial, nine active ingredients (a.i.) registered for broadleaved weed control in winter cereals were tested on the four populations (two rates, four replicates). All the alternative herbicides, except florasulam, results in important phytotoxicity to all tested populations, with 100% efficacy for several a.i. This work is the first report of R. rugosum that is resistant to iodosulfuron-methyl-sodium and the first report in Europe of R. rugosum that is resistant to tribenuron-methyl. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
The Use of Different Hot Foam Doses for Weed Control
Agronomy 2019, 9(9), 490; https://doi.org/10.3390/agronomy9090490 - 28 Aug 2019
Cited by 3
Abstract
Thermal weed control technology plays an important role in managing weeds in synthetic herbicide-free systems, particularly in organic agriculture. The use of hot foam represents an evolution of the hot water weed control thermal method, modified by the addition of biodegradable foaming agents. [...] Read more.
Thermal weed control technology plays an important role in managing weeds in synthetic herbicide-free systems, particularly in organic agriculture. The use of hot foam represents an evolution of the hot water weed control thermal method, modified by the addition of biodegradable foaming agents. The aim of this study was to test the weeding effect of different five hot foam doses, in two sites of different weed composition fields [i.e., Festuca arundinacea (Schreb.), Taraxacum officinale (Weber) and Plantago lanceolata (L.)], by evaluating the devitalisation of weeds, their regrowth, the weed dry biomass at the end of the experiment and the temperature of hot foam as affected by different foam doses. The results showed that the effect of the hot foam doses differed with the different infested weed species experiments. In the Festuca arundinacea (Schreb.) infested field, all doses from 3.33 L m−2 to 8.33 L m−2 led to a 100% weed cover devitalisation and a lower weed dry biomass compared to the dose of 1.67 L m−2, whereas the weed regrowth was similar when all doses were applied. In the Taraxacum officinale (Weber) and Plantago lanceolata (L.) infested fields, doses from 5.00 L m−2 to 8.33 L m−2 in site I and from 3.33 L m−2 to 8.33 L m−2 in site II led to 100% of weed cover devitalisation. The highest doses of 6.67 L m−2 and 8.33 L m−2 led to a slower weed regrowth and a lower weed dry biomass compared to the other doses. The time needed for weeds to again cover 50%, after the 100% devitalisation, was, on average, one month when all doses were applied in the Festuca arundinacea (Schreb.) infested field, whereas in the Taraxacum officinale (Weber) and Plantago lanceolata (L.) fields, this delay was estimated only when doses of 6.67 L m−2 and 8.33 L m−2 were used in site I and a dose of 8.33 L m−2 in site II. Thus, in the Festuca arundinacea (Schreb.) field experiments hot foam doses from 3.33 L m−2 to 8.33 L m−2 were effective in controlling weeds, and the use of the lowest dose (i.e., 3.33 L m−2) is recommended. However, for Taraxacum officinale (Weber) and Plantago lanceolata (L.) the highest doses are recommended (i.e., 6.67 L m−2 and 8.33 L m−2), as these led to 100% weed devitalisation, slower regrowth, and lower weed dry biomass than other doses. A delay in the regrowth of weeds by 30 days can lead to the hypothesis that the future application of hot foam as a desiccant in no-till field bands, before the transplant of high-income vegetable crops, will provide a competitive advantage against weeds. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Caffeine: The Allelochemical Responsible for the Plant Growth Inhibitory Activity of Vietnamese Tea (Camellia sinensis L. Kuntze)
Agronomy 2019, 9(7), 396; https://doi.org/10.3390/agronomy9070396 - 18 Jul 2019
Abstract
The present study aimed to examine the phytotoxic potential of seven Vietnamese tea samples based on the specific and total activity of caffeine and tea extracts on test plants. The sandwich method results indicated that the inhibitory effect of tea samples on the [...] Read more.
The present study aimed to examine the phytotoxic potential of seven Vietnamese tea samples based on the specific and total activity of caffeine and tea extracts on test plants. The sandwich method results indicated that the inhibitory effect of tea samples on the radicle and hypocotyl growth of lettuce seedlings was dependent on the concentration and type of tea samples, and also the presence of agar soluble allelochemicals. Among the seven tea samples, the leachates from Vinatea-green tea showed the highest inhibition on the radicle growth of lettuce seedlings with 50% suppression at 0.12 mg dry leaves/mL of agar. Caffeine concentration in tea samples analyzed by high-performance liquid chromatography (HPLC) varied from 20.7 to 38.2 µg/mL of dry leaves. The specific activity (EC50 value) of pure caffeine was 75 µg/mL, and the highest total activity of caffeine estimated in Vinatea-green tea was 0.51 [no unit]. Caffeine from green and oolong tea may be considered as one of the contributors to the inhibitory activity of the crude extract. Moreover, the phytotoxicity of pure caffeine and aqueous tea extracts was highly selective on the growth of different plant species. The concentration of caffeine detected from tea farm soil ranged from 0.137 to 0.145 µg/g soil. The results indicated that caffeine might be considered as a promising allelochemical from Vietnamese tea and can be a good candidate for weed management. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
The First Case of Short-Spiked Canarygrass (Phalaris brachystachys) with Cross-Resistance to ACCase-Inhibiting Herbicides in Iran
Agronomy 2019, 9(7), 377; https://doi.org/10.3390/agronomy9070377 - 14 Jul 2019
Abstract
The weed Phalaris brachystachys Link. severely affects winter cereal production. Acetyle-CoA Carboxylase (ACCase)-inhibiting herbicides are commonly used to control this weed in wheat fields. Thirty-six populations with suspected resistance to ACCase-inhibiting herbicides were collected from wheat fields in the Golestan Province in Iran. [...] Read more.
The weed Phalaris brachystachys Link. severely affects winter cereal production. Acetyle-CoA Carboxylase (ACCase)-inhibiting herbicides are commonly used to control this weed in wheat fields. Thirty-six populations with suspected resistance to ACCase-inhibiting herbicides were collected from wheat fields in the Golestan Province in Iran. A rapid test performed in Petri dishes and whole-plant dose–response experiments were conducted to confirm and investigate the resistance level of P. brachystachys to ACCase-inhibiting herbicides. The seed bioassay results showed that 0.02 mg ai L−1 clodinafop-propargyl (CP) and 1.36 mg ai L−1 of the diclofop-methyl (DM) solution were the optimal amounts for reliably screening resistant and susceptible P. brachystachys populations. In the whole plant bioassay, all populations were found to be resistant to CP, resistance ratios ranging from 2.7 to 11.6, and all of the CP-resistant populations exhibited resistance to DM. Fourteen populations showed low resistance to cycloxydim, and thirteen of these populations were also 2-fold resistant to pinoxaden. The results showed that DM resistance in some P. brachystachys populations is likely due to their enhanced herbicide metabolism, which involves Cytochrome P450 monooxygenases, as demonstrated by the indirect assay. This is the first report confirming the cross-resistance of ACCase-inhibiting herbicides in P. brachystachys in Iran. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Seed Viability of Heracleum mantegazzianum (Apiaceae) Is Quickly Reduced at Temperatures Prevailing in Biogas Plants
Agronomy 2019, 9(6), 332; https://doi.org/10.3390/agronomy9060332 - 21 Jun 2019
Abstract
Heracleum mantegazzianum is an invasive plant species with enormous effect on ecosystems and human health. Mechanical weed management often results in large amounts of biomass. Fermentation in biogas plants can be used for disposal of this biomass contaminated with seeds and for energetic [...] Read more.
Heracleum mantegazzianum is an invasive plant species with enormous effect on ecosystems and human health. Mechanical weed management often results in large amounts of biomass. Fermentation in biogas plants can be used for disposal of this biomass contaminated with seeds and for energetic utilization, if spreading of viable seeds with fermentation residues is prevented. Our aim is to quantify the risk of seed survival in mesophilic biogas plants. Seeds were harvested at three ripening stages in central Germany. They were incubated for 0, 0.5, 1, 2, 4, and 8 days at 35 and 42 °C in water baths. Thereafter, seed viability was assessed by a tetrazolium test. Furthermore, germinative capacity of seeds which had passed an incubation of 48 h at 35 °C were tested. After eight days in water bath none of the 1199 tested seeds were viable anymore. The time until half of the seeds died (ED50) ranged from 9 to 65 h, whereby high temperature accelerated the mortality. Germinative capacity was similar to the seed survival rate. The results suggest that fermentation of H. mantegazzianum biomass poses only a low risk of viable seed spread, if the operating temperature of the biogas plant achieves 42 °C and a high retention time is ensured. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Mulch Treatment Effect on Weed Biomass and Yields of Organic Sweetpotato Cultivars
Agronomy 2019, 9(4), 190; https://doi.org/10.3390/agronomy9040190 - 13 Apr 2019
Cited by 3
Abstract
Weeds are a challenge, particularly in organic agriculture, due to restrictions on the application of synthetic herbicides and chemicals. A preliminary cultivar evaluation trial of organic sweetpotato was conducted in 2015 at Tennessee State University certified organic farm. Three mulches: wheat straw, pine [...] Read more.
Weeds are a challenge, particularly in organic agriculture, due to restrictions on the application of synthetic herbicides and chemicals. A preliminary cultivar evaluation trial of organic sweetpotato was conducted in 2015 at Tennessee State University certified organic farm. Three mulches: wheat straw, pine needle, and black plastic mulch, along with a control (no mulch), were evaluated for their weed management abilities in a sweetpotato field. Four cultivars of sweetpotato were planted in 0.91 m wide mulch beds with 0.3 m row spacing anddrip irrigated with four replications. Data was collected during the growing season on the dry weight of weeds that emerged in a quadrat and yield components at harvest. Results of two-way ANOVA revealed that mulch treatments affected the weed biomass, weed density, and cull yields. Though the use of mulches had no significant effect on other yield components of sweetpotato in this study; it was beneficial for weed management. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Assessment of the Persistence of Avena sterilis L. Patches in Wheat Fields for Site-Specific Sustainable Management
Agronomy 2019, 9(1), 30; https://doi.org/10.3390/agronomy9010030 - 10 Jan 2019
Cited by 1
Abstract
This paper aims to evaluate the spatial persistence of wild oat patches in four wheat fields over time to determine the economic feasibility of using late-season wild oat maps for early site-specific weed management (SSWM) next season. The spatial persistence of wild oat [...] Read more.
This paper aims to evaluate the spatial persistence of wild oat patches in four wheat fields over time to determine the economic feasibility of using late-season wild oat maps for early site-specific weed management (SSWM) next season. The spatial persistence of wild oat patches was analyzed by three tests: land use change detection between years, spatial autocorrelation, and analysis of spreading distance. The temporal trend of wild oat patch distribution showed a clear persistence and a generalized increase in the infested area, with a noticeable level of weed aggregation and a tendency in the new weed patches to emerge close to older ones. To economically evaluate the SSWM, five simulations in four agronomic scenarios, varying wheat yields and losses due to wild oat, were conducted. When yield losses due to wild oat were minimal and for any of the expected wheat yields, some SSWM simulations were more economically profitable than the overall application in most of the fields. Nevertheless, when the yield losses due to wild oat were maximal, all SSWM simulations were less profitable than overall treatment in all the analyzed fields. Although the economic profit variations achieved with SSWM treatments were modest, any of the site-specific treatments tested are preferred to herbicide broadcast over the entire field, in order to reduce herbicide and environmental pollution. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Rigput Brome (Bromus diandrus Roth.) Management in a No-Till Field in Spain
Agronomy 2018, 8(11), 251; https://doi.org/10.3390/agronomy8110251 - 04 Nov 2018
Cited by 2
Abstract
The adoption of no-till (NT) in the semi-arid region of Mediterranean Spain has promoted a weed vegetation change, where rigput brome (Bromus diandrus Roth) represents a main concern. In order to avoid complete reliance on herbicides, the combination of several control methods, [...] Read more.
The adoption of no-till (NT) in the semi-arid region of Mediterranean Spain has promoted a weed vegetation change, where rigput brome (Bromus diandrus Roth) represents a main concern. In order to avoid complete reliance on herbicides, the combination of several control methods, without excluding chemical ones, can contribute to an integrated weed management (IWM) system for this species. In this field study, 12 three-year management programs were chosen, in which alternative non-chemical methods—delay of sowing, crop rotation, sowing density and pattern, stubble removal—are combined with chemical methods to manage B. diandrus in winter cereals under NT. Moreover, their effects on weed control and crop productivity were analyzed from the point of view of the efficiency of the control methods, based on a previously developed emergence model for B. diandrus. All management programs were effective in reducing the weed infestation, despite the different initial weed density between blocks. For high weed density levels (60–500 plants m−2), two years of specific managements resulted in ≥99% reduction of its population. For even higher density levels, three years were needed to assure this reduction level. Both the emergence of the weed and the crop yields are mainly driven by the seasonal climatic conditions in this semi-arid area. For this reason, among the non-chemical methods, only crop rotation and sowing delay contributed to an effective weed population decrease as well as an increase in the economic income of the yield. The other alternative methods did not significantly contribute to controlling the weed. This work demonstrates that mid-term management programs combining chemical with non-chemical methods can effectively keep B. diandrus under control with economic gains compared to traditional field management methods in semi-arid regions. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
Sensitivity Analysis of Alisma plantago-aquatica L., Cyperus difformis L. and Schoenoplectus mucronatus (L.) Palla to Penoxsulam
Agronomy 2018, 8(10), 220; https://doi.org/10.3390/agronomy8100220 - 08 Oct 2018
Cited by 2
Abstract
Determining the intra-specific variability of response to a given herbicide is important for monitoring the possible shifts in the sensitivity of weed populations. This study describes the responses of populations of Alisma plantago-aquatica, Cyperus difformis, and Schoenoplectus mucronatus from Italy, Greece, Portugal, [...] Read more.
Determining the intra-specific variability of response to a given herbicide is important for monitoring the possible shifts in the sensitivity of weed populations. This study describes the responses of populations of Alisma plantago-aquatica, Cyperus difformis, and Schoenoplectus mucronatus from Italy, Greece, Portugal, and Spain to penoxsulam, an acetolactate synthase (ALS) inhibitor widely used in rice. To evaluate previously evolved resistance to ALS inhibitors, sensitivity to azimsulfuron and bensulfuron-methyl was assessed. Dose-response experiments with penoxsulam were performed in a greenhouse simulating paddy rice field conditions. Log-logistic dose-response curves were used to estimate the ED50, ED80, ED90 and GR50, GR80, and GR90. To calculate the average ED and GR and assess the intra-specific variability, an artificial resampling method was performed. Populations ALSPA 0364, 0365, 0469, 0470, 0471; SCPMU 0371, 0475, 0267; CYPDI 0013, 0431, 0432, 0433 appeared to be resistant to sulfonylureas, while a higher sensitivity to penoxsulam was observed, while populations ALSPA 0363, CYPDI 0223 and SCPMU 9719 proved to be cross-resistant. Regardless of species, ED90 of susceptible populations were below penoxsulam label dose (40 g ai ha−1) while they reached values higher than 320 g ai ha−1 for resistant populations. Average GR50 were generally lower than ED50. Sensitivity variability among susceptible populations is relatively low, allowing for discrimination between susceptible and resistant populations, and previously evolved resistance to sulfonylureas can influence sensitivity to penoxsulam. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
First Case of Conyza canadensis from Hungary with Multiple Resistance to Glyphosate and Flazasulfuron
Agronomy 2018, 8(8), 157; https://doi.org/10.3390/agronomy8080157 - 20 Aug 2018
Cited by 5
Abstract
Conyza canadensis is a species invading large areas throughout the world, mainly due to its ability to evolve herbicide resistance. In Hungary, extensive areas have been infested by this species due to the difficulty in controlling it with glyphosate. To determine whether poor [...] Read more.
Conyza canadensis is a species invading large areas throughout the world, mainly due to its ability to evolve herbicide resistance. In Hungary, extensive areas have been infested by this species due to the difficulty in controlling it with glyphosate. To determine whether poor control was a result of misapplication or glyphosate resistance, eight suspected glyphosate-resistant C. canadensis populations from different Hungarian regions were studied. In whole-plant dose-response assays with glyphosate, the LD50 and GR50 values (survival and fresh weight reduction at 50% relative to the untreated control, respectively) indicated that resistance was confirmed in five of the eight populations (H-5 population being the most resistant). Additionally, the shikimic acid accumulation tests corroborated the results observed in the dose–response assays. 11 alternative herbicides from six different modes of action (MOA) were applied at field doses as control alternatives on populations H-5 and H-6 (both in the same regions). The H-5 population showed an unexpected resistance to flazasulfuron (ALS-inhibitor). The ALS enzyme activity studies indicated that the I50 for H-5 with flazasulfuron was 63.3 times higher compared to its correspondent susceptible population (H-6). Therefore, the H-5 population exhibited multiple-resistance to flazasulfuron and glyphosate, being the first case reported in Europe for these two MOA. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Open AccessArticle
First Report of Amaranthus hybridus with Multiple Resistance to 2,4-D, Dicamba, and Glyphosate
Agronomy 2018, 8(8), 140; https://doi.org/10.3390/agronomy8080140 - 06 Aug 2018
Cited by 6
Abstract
In many countries, Amaranthus hybridus is a widespread weed in agricultural systems. The high prolificacy and invasive capacity as well as the resistance of some biotypes to herbicides are among the complications of handling this weed. This paper reports on the first A. [...] Read more.
In many countries, Amaranthus hybridus is a widespread weed in agricultural systems. The high prolificacy and invasive capacity as well as the resistance of some biotypes to herbicides are among the complications of handling this weed. This paper reports on the first A. hybridus biotypes with resistance to auxinic herbicides and multiple resistance to auxinic herbicides and the EPSPs inhibitor, glyphosate. Several dose response assays were carried out to determine and compare sensitivity of six population of A. hybridus to glyphosate, 2,4-D, and dicamba. In addition, shikimic acid accumulation and piperonil butoxide effects on 2,4-D and dicamba metabolism were tested in the same populations. The results showed four populations were resistant to dicamba and three of these were also resistant to 2,4-D, while only one population was resistant to glyphosate. The glyphosate-resistant population also showed multiple resistance to auxinic herbicides. Pretreatment with piperonil butoxide (PBO) followed by 2,4-D or dicamba resulted in the death of all individual weeds independent of herbicide or population. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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Review

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Open AccessReview
Key Aspects on the Biology, Ecology and Impacts of Johnsongrass [Sorghum halepense (L.) Pers] and the Role of Glyphosate and Non-Chemical Alternative Practices for the Management of This Weed in Europe
Agronomy 2019, 9(11), 717; https://doi.org/10.3390/agronomy9110717 - 05 Nov 2019
Cited by 1
Abstract
Sorghum halepense (L.) Pers is a common and noxious worldwide weed of increasing distribution in many European countries. In the present review, information on the biology, ecology, agricultural, economic and environmental impact of johnsongrass is given, and the current status of this weed [...] Read more.
Sorghum halepense (L.) Pers is a common and noxious worldwide weed of increasing distribution in many European countries. In the present review, information on the biology, ecology, agricultural, economic and environmental impact of johnsongrass is given, and the current status of this weed in Europe is discussed. Furthermore, special attention is given to the important role of field trials using glyphosate to control weeds in arable and perennial crops in many European countries. Some of the factors which affect control efficacy and should be taken into account are also discussed. Finally, several non-chemical alternative methods (cultural, mechanical, thermal, biological, etc.) for johnsongrass management are also presented. The adoption of integrated weed management (IWM) techniques such as glyphosate use, crop rotation, and deep tillage is strongly recommended to control plant species that originate from both seed and rhizomes. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
Open AccessReview
Weed Management in New Zealand Pastures
Agronomy 2019, 9(8), 448; https://doi.org/10.3390/agronomy9080448 - 13 Aug 2019
Cited by 6
Abstract
In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in [...] Read more.
In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in New Zealand pastures, and the management strategies being used to control them. There are currently 245 plant species from 40 plant families that are considered to be troublesome weeds in New Zealand pastures. The application of herbicides is an important approach to manage weeds in New Zealand pastures; however, a key to the success of these pastures is the use of clovers in combination with the grasses, so the challenge is to find herbicides that selectively control weeds without damaging these legumes. The use of spot spraying and weed wiping are often required to ensure selective control of some weed species in these pastures. Non-chemical agronomic approaches such as grazing management and using competitive pasture species often play a more important role than herbicides for weed management in many New Zealand pastures. Thus, integrated weed management using a combination of herbicides and good pasture management strategies leads to the most cost-effective and efficient control of pasture weeds in New Zealand. Full article
(This article belongs to the Special Issue Weed Management & New Approaches)
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