Chemical exposure reduction: Factors impacting on South African herbicide sprayers' personal protective equipment compliance and high risk work practices.

Science.gov (United States)

Andrade-Rivas, Federico; Rother, Hanna-Andrea

2015-10-01

The high exposure risks of workers to herbicides in low- and middle-income countries is an important public health concern because of the potential resulting negative impacts on workers' health. This study investigated workers' personal protective equipment (PPE) compliance as a risk mitigation measure; particularly workers who apply herbicides for Working for Water (WfW) - a South African invasive alien vegetation control programme. The study aim was to understand workers' low PPE compliance by analysing their risk perceptions of herbicide use, working conditions and socio-cultural context. Research methods included ethnographic observations, informal interviews, visual media, questionnaires and a focus group. Study results indicated that low PPE compliance persists despite workers' awareness of herbicide exposure risks and as a result of the influence from workers' socio-cultural context (i.e. gender dynamics and social status), herbicide risk perceptions and working conditions (i.e. environmental and logistical). Interestingly, teams comprised of mostly women had the highest compliance rate. These findings highlighted that given the complexity of PPE compliance, especially in countries with several economic and social constraints, exposure reduction interventions should not rely solely on PPE use promotion. Instead, other control strategies requiring less worker input for effectiveness should be implemented, such as elimination and substitution of highly hazardous pesticides, and altering application methods. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Herbicide contamination and the potential impact to seagrass meadows in Hervey Bay, Queensland, Australia.

Science.gov (United States)

McMahon, Kathryn; Bengtson Nash, Susan; Eaglesham, Geoff; Müller, Jochen F; Duke, Norman C; Winderlich, Steve

2005-01-01

Low concentrations of herbicides (up to 70 ng l(-1)), chiefly diuron (up to 50 ng l(-1)) were detected in surface waters associated with inter-tidal seagrass meadows of Zostera muelleri in Hervey Bay, south-east Queensland, Australia. Diuron and atrazine (up to 1.1 ng g(-1) dry weight of sediment) were detected in the sediments of these seagrass meadows. Concentration of the herbicides diuron, simazine and atrazine increased in surface waters associated with seagrass meadows during moderate river flow events indicating herbicides were washed from the catchment to the marine environment. Maximum herbicide concentration (sum of eight herbicides) in the Mary River during a moderate river flow event was 4260 ng l(-1). No photosynthetic stress was detected in seagrass in this study during low river flow. However, with moderate river flow events, nearshore seagrasses are at risk of being exposed to concentrations of herbicides that are known to inhibit photosynthesis.

Uses of thaxtomin and thaxtomin compositions as herbicides

Energy Technology Data Exchange (ETDEWEB)

Koivunen, Marja; Marrone, Pamela

2016-12-27

There is a need for a selective, low-risk herbicide that can be used to control weeds in cereal cultures and turf. The present invention discloses that a bacterial secondary metabolite, thaxtomin and optionally another herbicide is an effective herbicide on broadleaved, sedge and grass weeds. Thaxtomin A and structurally similar compounds can be used as natural herbicides to control the germination and growth of weeds in cereal, turf grass, Timothy grass and pasture grass cultures with no phytotoxicity to these crops. As a natural, non-toxic compound, thaxtomin can be used as a safe alternative for weed control in both conventional and organic farming and gardening systems.

Economics of site-specific and variable-dose herbicide application

DEFF Research Database (Denmark)

Ørum, Jens Erik; Kudsk, Per; Jensen, Peter Kryger

2017-01-01

Site-specific application of pesticides has so far focused mainly on herbicides. The purpose of precision farming technologies in relation to herbicide use is to reduce herbicide cost and environmental impact from spraying, but at the same time to achieve acceptable weed control. Another purpose...... is to increase the spraying capacity, to reduce the number of sprayer refills, and finally to minimize time spent on weed monitoring. In this chapter the relevance and profitability of four precision herbicide application technologies, two weed detection technologies and a low dose decision support system (DSS......) is analysed. With a low dose herbicide, cost can be reduced by 20–50%. It requires, however, proper monitoring of weeds, which can be a time-consuming task that again requires that the farmer is able to identify the dominant weed species. The current development of high-speed camera and software systems can...

Primisulfuron herbicide-resistant tobacco plants: mutant selection in vitro by adventitious shoot formation from cultured leaf discs

International Nuclear Information System (INIS)

Harms, C.T.; DiMaio, J.J.; Jayne, S.M.; Middlesteadt, L.A.; Negrotto, D.V.; Thompson-Taylor, H.; Montoya, A.L.

1991-01-01

A simple procedure has been developed for the rapid and direct selection of herbicide-resistant mutant plants. The procedure uses adventitious shoot formation from suitable explants, such as leaf discs, on a shoot-inducing culture medium containing a toxic herbicide concentration. Resistant green shoots were thus isolated from tobacco (Nicotiana tabacum L.) leaf explants cultured on medium containing 100 μg 1−1 primisulfuron, a new sulfonylurea herbicide. Resistant shoots were recovered from both haploid and diploid explants after UV mutagenesis, as well as without mutagenic treatment. Three mutant plants of separate origin were further analyzed biochemically and genetically. Their acetohydroxyacid synthase (AHAS) enzyme activity was less inhibited by sulfonylurea herbicides than that of unselected, sensitive wild type plants. The extent of inhibition of the AHAS enzyme among the three mutants was different for different sulfonylurea and imidazolinone herbicides suggesting different sites were affected by each mutation. Herbicide tolerance was scored for germinating seedling populations and was found to be inherited as a single dominant nuclear gene. Adventitious shoot formation from cultured leaf discs was used to determine the cross tolerance of mutant plants to various herbicidal AHAS inhibitors. The usefulness of this rapid and direct scheme for mutant selection based on adventitious shoot formation or embryogenesis is discussed. (author)

Comparative environmental impacts of glyphosate and conventional herbicides when used with glyphosate-tolerant and non-tolerant crops

International Nuclear Information System (INIS)

Mamy, Laure; Gabrielle, Benoit; Barriuso, Enrique

2010-01-01

The introduction of glyphosate-tolerant (GT) crops is expected to mitigate the environmental contamination by herbicides because glyphosate is less persistent and toxic than the herbicides used on non-GT crops. Here, we compared the environmental balances of herbicide applications for both crop types in three French field trials. The dynamic of herbicides and their metabolites in soil, groundwater and air was simulated with PRZM model and compared to field measurements. The associated impacts were aggregated with toxicity potentials calculated with the fate and exposure model USES for several environmental endpoints. The impacts of GT systems were lower than those of non-GT systems, but the accumulation in soils of one glyphosate metabolite (aminomethylphosphonic acid) questions the sustainability of GT systems. The magnitude of the impacts depends on the rates and frequency of glyphosate application being highest for GT maize monoculture and lowest for combination of GT oilseed rape and non-GT sugarbeet crops. - The impacts of herbicide applications on glyphosate-tolerant crops could be higher than expected due to the accumulation of a metabolite of glyphosate in soils.

Comparative environmental impacts of glyphosate and conventional herbicides when used with glyphosate-tolerant and non-tolerant crops

Energy Technology Data Exchange (ETDEWEB)

Mamy, Laure, E-mail: laure.mamy@versailles.inra.f [INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France); Gabrielle, Benoit, E-mail: benoit.gabrielle@agroparistech.f [INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France); Barriuso, Enrique, E-mail: barriuso@grignon.inra.f [INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France)

2010-10-15

The introduction of glyphosate-tolerant (GT) crops is expected to mitigate the environmental contamination by herbicides because glyphosate is less persistent and toxic than the herbicides used on non-GT crops. Here, we compared the environmental balances of herbicide applications for both crop types in three French field trials. The dynamic of herbicides and their metabolites in soil, groundwater and air was simulated with PRZM model and compared to field measurements. The associated impacts were aggregated with toxicity potentials calculated with the fate and exposure model USES for several environmental endpoints. The impacts of GT systems were lower than those of non-GT systems, but the accumulation in soils of one glyphosate metabolite (aminomethylphosphonic acid) questions the sustainability of GT systems. The magnitude of the impacts depends on the rates and frequency of glyphosate application being highest for GT maize monoculture and lowest for combination of GT oilseed rape and non-GT sugarbeet crops. - The impacts of herbicide applications on glyphosate-tolerant crops could be higher than expected due to the accumulation of a metabolite of glyphosate in soils.

Selectivity of Some Herbicides to Cocksfoot (Dactylis glomerata L., Grown for Seed Production

Directory of Open Access Journals (Sweden)

Tsvetanka Dimitrova

2012-01-01

Full Text Available The study was conducted to determine selectivity of some herbicides to cocksfoot(Dactylis glomerata L., and their influence on the seed production, during the years 2008-2010. The trial was set on the experimental field of the Institute of Forage Crops – Pleven, onslightly leached chernozem. As a result of the research the following was found: herbicidesArat (500 g/l dicamba + 250 g/l tritosulfuron at the dose of 100 ml/ha, Korida 75 VDG (750g/kg tribenuron-methyl – 15 g/ha and Cambio SL (320 g/l bentazon + 90 g/l dicamba –1250 ml/ha and Grasp 25SK (250 g/l tralkoxyidim + Atplus at rate of 1000 + 1000 ml/ha hadhigh selectivity to cocksfoot, applied at 2-4 leaf stage during establishing year of the stand,and until the stage of the beginning of shooting up in seed production year.Herbicide Topik 080EK (80 g/l clodinofop – propargyl + antidote at rate of 300 ml/ha,showed phytotoxic effect to D. glomerata and caused the reduction of seed and dry biomassproductivity.

Auxin molecular field maps define AUX1 selectivity: many auxin herbicides are not substrates

Czech Academy of Sciences Publication Activity Database

Hoyerová, Klára; Hošek, Petr; Quareshy, M.; Li, J.; Klíma, Petr; Kubeš, Martin; Yemm, A. A.; Neve, P.; Tripathi, A.; Bennett, M.J.; Napier, R. M.

2018-01-01

Roč. 217, č. 4 (2018), s. 1625-1639 ISSN 0028-646X R&D Projects: GA ČR(CZ) GA16-19557S; GA MŠk LD15137 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21519 Institutional support: RVO:61389030 Keywords : auxin transport * cheminformatics * herbicide * herbicide resistance * molecular field maps * pharmacophore * structure–activity relationship * uptake carrier Subject RIV: ED - Physiology OBOR OECD: Cell biology Impact factor: 7.330, year: 2016

Herbicide resistance and biodiversity: agronomic and environmental aspects of genetically modified herbicide-resistant plants.

Science.gov (United States)

Schütte, Gesine; Eckerstorfer, Michael; Rastelli, Valentina; Reichenbecher, Wolfram; Restrepo-Vassalli, Sara; Ruohonen-Lehto, Marja; Saucy, Anne-Gabrielle Wuest; Mertens, Martha

2017-01-01

Farmland biodiversity is an important characteristic when assessing sustainability of agricultural practices and is of major international concern. Scientific data indicate that agricultural intensification and pesticide use are among the main drivers of biodiversity loss. The analysed data and experiences do not support statements that herbicide-resistant crops provide consistently better yields than conventional crops or reduce herbicide amounts. They rather show that the adoption of herbicide-resistant crops impacts agronomy, agricultural practice, and weed management and contributes to biodiversity loss in several ways: (i) many studies show that glyphosate-based herbicides, which were commonly regarded as less harmful, are toxic to a range of aquatic organisms and adversely affect the soil and intestinal microflora and plant disease resistance; the increased use of 2,4-D or dicamba, linked to new herbicide-resistant crops, causes special concerns. (ii) The adoption of herbicide-resistant crops has reduced crop rotation and favoured weed management that is solely based on the use of herbicides. (iii) Continuous herbicide resistance cropping and the intensive use of glyphosate over the last 20 years have led to the appearance of at least 34 glyphosate-resistant weed species worldwide. Although recommended for many years, farmers did not counter resistance development in weeds by integrated weed management, but continued to rely on herbicides as sole measure. Despite occurrence of widespread resistance in weeds to other herbicides, industry rather develops transgenic crops with additional herbicide resistance genes. (iv) Agricultural management based on broad-spectrum herbicides as in herbicide-resistant crops further decreases diversity and abundance of wild plants and impacts arthropod fauna and other farmland animals. Taken together, adverse impacts of herbicide-resistant crops on biodiversity, when widely adopted, should be expected and are indeed very hard

Is hormesis an underestimated factor in the development of herbicide resistance?

Directory of Open Access Journals (Sweden)

Belz, Regina G.

2014-02-01

Full Text Available The growing impact of herbicide resistant weeds increasingly affects weed management and the delay of resistance evolution has become a major task of chemical weed control. Hormesis and, thus, the phenomenon that low doses of herbicides can boost weed growth could be of importance in this regard since the recommended field rate may represent a low dose for weeds that have evolved resistance to the applied herbicide and, thus, a potential hormetic dose. Applying the field rate may thus not only directly select resistant biotypes, it may also indirectly promote the success and spread of resistant biotypes via hormesis. Nevertheless, hormetic effects in resistant weeds are hitherto merely randomly observed and, thus, a clear quantitative basis to judge the significance of hormesis for resistance evolution is lacking. Therefore, this study aimed at quantifying the degree and frequency of herbicide hormesis in sensitive and resistant weed species in order to provide a first indication of whether the phenomenon deserves consideration as a potential factor contributing to the development of herbicide resistance. In germination assays complete dose-response experiments were conducted with sensitive and resistant biotypes of Matricaria inodora (ALS-target-site resistant; treated with iodosulfuron-methyl-sodium/mesosulfuron-methyl, Eleusine indica (glyphosateresistant; treated with glyphosate, and Chenopodium album (triazine/triazinone-target-site resistant; treated with terbuthylazine. After 10 days of cultivation under controlled conditions plant growth was analyzed by measuring shoot/root length and mass. Results indicated that herbicide hormesis occurred on average with a total frequency of 29% in sensitive/resistant biotypes with an average growth increase of 53% occurring typically within a dose zone exceeding 350fold. Hormetic effects occurred, however, very variable and only for specific endpoints and not plant growth in general. If such a

Palmistichus elaeisis (Hymenoptera: Eulophidae as an indicator of toxicity of herbicides registered for corn in Brazil

Directory of Open Access Journals (Sweden)

Claubert W.G de Menezes

2014-09-01

Full Text Available The diversity of plants in agricultural systems benefits natural enemies. Herbicides are used in weed management in corn (Zea mays L. to reduce competition and productivity losses, but they can impact natural enemies and contaminate the environment. The objective was to evaluate toxicity of herbicides on pupae parasitoid Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae. The treatments were represented by the host pupae Tenebrio molitor L., 1785 (Coleoptera: Tenebrionidae and herbicides atrazine, nicosulfuron, paraquat, and tembotrione in commercial doses compared to a control treatment with water. Pupae of T. molitor were immersed in the solution of herbicides and exposed to parasitism by six females of P. elaeisis each. The herbicides atrazine and paraquat were highly toxic and, therefore, not selective to P. elaeisis. Nicosulfuron reduced the sex ratio of P. elaeisis (0.20 ± 0.03, which may affect subsequent generations. Moreover, the herbicide tembotrione was selective to P. elaeisis, showing results comparable to the control. Floristic diversity of weeds can increase food source, habitat, shelter, breeding places and microclimates for insect parasitoids but herbicides formulations can be toxic and these products can affect P. elaeisis or its hosts by direct or indirect contact, showing the importance of selectivity studies for this natural enemy. However, the herbicide tembotrione was selective to P. elaeisis and it can be recommended for programs of sustainable management of weeds in corn crop with this parasitoid.

DNA analysis of herbarium Specimens of the grass weed Alopecurus myosuroides reveals herbicide resistance pre-dated herbicides.

Science.gov (United States)

Délye, Christophe; Deulvot, Chrystel; Chauvel, Bruno

2013-01-01

Acetyl-CoA carboxylase (ACCase) alleles carrying one point mutation that confers resistance to herbicides have been identified in arable grass weed populations where resistance has evolved under the selective pressure of herbicides. In an effort to determine whether herbicide resistance evolves from newly arisen mutations or from standing genetic variation in weed populations, we used herbarium specimens of the grass weed Alopecurus myosuroides to seek mutant ACCase alleles carrying an isoleucine-to-leucine substitution at codon 1781 that endows herbicide resistance. These specimens had been collected between 1788 and 1975, i.e., prior to the commercial release of herbicides inhibiting ACCase. Among the 734 specimens investigated, 685 yielded DNA suitable for PCR. Genotyping the ACCase locus using the derived Cleaved Amplified Polymorphic Sequence (dCAPS) technique identified one heterozygous mutant specimen that had been collected in 1888. Occurrence of a mutant codon encoding a leucine residue at codon 1781 at the heterozygous state was confirmed in this specimen by sequencing, clearly demonstrating that resistance to herbicides can pre-date herbicides in weeds. We conclude that point mutations endowing resistance to herbicides without having associated deleterious pleiotropic effects can be present in weed populations as part of their standing genetic variation, in frequencies higher than the mutation frequency, thereby facilitating their subsequent selection by herbicide applications.

Herbicide Glyphosate Impact to Earthworm (E. fetida

Directory of Open Access Journals (Sweden)

Greta Dajoraitė

2016-10-01

Full Text Available Glyphosate is a broad spectrum weed resistant herbicide. Glyphosate may pose negative impact on land ecosystems because of wide broad usage and hydrofilic characteristic. The aim of this study was to investigate negative effects of glyphosate on soil invertebrate organisms (earthworm Eisenia fetida. The duration of experiment was 8 weeks. The range of the test concentrations of glyphosate were: 0,1, 1, 5, 10, 20 mg/kg. To investigate the glyphosate impact on earthworm Eisenia fetida the following endpoints were measured: survival, reproduction and weight. The exposure to 20 mg/kg glyphosate has led to the 100% mortality of earthworms. Glyphosate has led to decreased E. fetida reproduction, the cocoons were observed only in the lowest concentration (0,1 mg/kg. In general: long-term glyphosate toxicity to earthworms (E. fetida may be significant.

Climate change impacts on risks of groundwater pollution by herbicides: a regional scale assessment

Science.gov (United States)

Steffens, Karin; Moeys, Julien; Lindström, Bodil; Kreuger, Jenny; Lewan, Elisabet; Jarvis, Nick

2014-05-01

Groundwater contributes nearly half of the Swedish drinking water supply, which therefore needs to be protected both under present and future climate conditions. Pesticides are sometimes found in Swedish groundwater in concentrations exceeding the EU-drinking water limit and thus constitute a threat. The aim of this study was to assess the present and future risks of groundwater pollution at the regional scale by currently approved herbicides. We identified representative combinations of major crop types and their specific herbicide usage (product, dose and application timing) based on long-term monitoring data from two agricultural catchments in the South-West of Sweden. All these combinations were simulated with the regional version of the pesticide fate model MACRO (called MACRO-SE) for the periods 1970-1999 and 2070-2099 for a major crop production region in South West Sweden. To represent the uncertainty in future climate data, we applied a five-member ensemble based on different climate model projections downscaled with the RCA3-model (Swedish Meteorological and Hydrological Institute). In addition to the direct impacts of changes in the climate, the risks of herbicide leaching in the future will also be affected by likely changes in weed pressure and land use and management practices (e.g. changes in crop rotations and application timings). To assess the relative importance of such factors we performed a preliminary sensitivity analysis which provided us with a hierarchical structure for constructing future herbicide use scenarios for the regional scale model runs. The regional scale analysis gave average concentrations of herbicides leaching to groundwater for a large number of combinations of soils, crops and compounds. The results showed that future scenarios for herbicide use (more autumn-sown crops, more frequent multiple applications on one crop, and a shift from grassland to arable crops such as maize) imply significantly greater risks of herbicide

Selectable tolerance to herbicides by mutated acetolactate synthase genes integrated into the chloroplast genome of tobacco.

Science.gov (United States)

Shimizu, Masanori; Goto, Maki; Hanai, Moeko; Shimizu, Tsutomu; Izawa, Norihiko; Kanamoto, Hirosuke; Tomizawa, Ken-Ichi; Yokota, Akiho; Kobayashi, Hirokazu

2008-08-01

Strategies employed for the production of genetically modified (GM) crops are premised on (1) the avoidance of gene transfer in the field; (2) the use of genes derived from edible organisms such as plants; (3) preventing the appearance of herbicide-resistant weeds; and (4) maintaining transgenes without obstructing plant cell propagation. To this end, we developed a novel vector system for chloroplast transformation with acetolactate synthase (ALS). ALS catalyzes the first step in the biosynthesis of the branched amino acids, and its enzymatic activity is inhibited by certain classes of herbicides. We generated a series of Arabidopsis (Arabidopsis thaliana) mutated ALS (mALS) genes and introduced constructs with mALS and the aminoglycoside 3'-adenyltransferase gene (aadA) into the tobacco (Nicotiana tabacum) chloroplast genome by particle bombardment. Transplastomic plants were selected using their resistance to spectinomycin. The effects of herbicides on transplastomic mALS activity were examined by a colorimetric assay using the leaves of transplastomic plants. We found that transplastomic G121A, A122V, and P197S plants were specifically tolerant to pyrimidinylcarboxylate, imidazolinon, and sulfonylurea/pyrimidinylcarboxylate herbicides, respectively. Transplastomic plants possessing mALSs were able to grow in the presence of various herbicides, thus affirming the relationship between mALSs and the associated resistance to herbicides. Our results show that mALS genes integrated into the chloroplast genome are useful sustainable markers that function to exclude plants other than those that are GM while maintaining transplastomic crops. This investigation suggests that the resistance management of weeds in the field amid growing GM crops is possible using (1) a series of mALSs that confer specific resistance to herbicides and (2) a strategy that employs herbicide rotation.

Acute and additive toxicity of ten photosystem-II herbicides to seagrass.

Science.gov (United States)

Wilkinson, Adam D; Collier, Catherine J; Flores, Florita; Negri, Andrew P

2015-11-30

Photosystem II herbicides are transported to inshore marine waters, including those of the Great Barrier Reef, and are usually detected in complex mixtures. These herbicides inhibit photosynthesis, which can deplete energy reserves and reduce growth in seagrass, but the toxicity of some of these herbicides to seagrass is unknown and combined effects of multiple herbicides on seagrass has not been tested. Here we assessed the acute phytotoxicity of 10 PSII herbicides to the seagrass Halophila ovalis over 24 and/or 48 h. Individual herbicides exhibited a broad range of toxicities with inhibition of photosynthetic activity (∆F/F(m)') by 50% at concentrations ranging from 3.5 μg l(-1) (ametryn) to 132 μg l(-1) (fluometuron). We assessed potential additivity using the Concentration Addition model of joint action for binary mixtures of diuron and atrazine as well as complex mixtures of all 10 herbicides. The effects of both mixture types were largely additive, validating the application of additive effects models for calculating the risk posed by multiple PSII herbicides to seagrasses. This study extends seagrass ecotoxicological data to ametryn, metribuzin, bromacil, prometryn and fluometuron and demonstrates that low concentrations of PSII herbicide mixtures have the potential to impact ecologically relevant endpoints in seagrass, including ∆F/F(m)'.

Acute and additive toxicity of ten photosystem-II herbicides to seagrass

Science.gov (United States)

Wilkinson, Adam D.; Collier, Catherine J.; Flores, Florita; Negri, Andrew P.

2015-11-01

Photosystem II herbicides are transported to inshore marine waters, including those of the Great Barrier Reef, and are usually detected in complex mixtures. These herbicides inhibit photosynthesis, which can deplete energy reserves and reduce growth in seagrass, but the toxicity of some of these herbicides to seagrass is unknown and combined effects of multiple herbicides on seagrass has not been tested. Here we assessed the acute phytotoxicity of 10 PSII herbicides to the seagrass Halophila ovalis over 24 and/or 48 h. Individual herbicides exhibited a broad range of toxicities with inhibition of photosynthetic activity (∆F/Fm‧) by 50% at concentrations ranging from 3.5 μg l-1 (ametryn) to 132 μg l-1 (fluometuron). We assessed potential additivity using the Concentration Addition model of joint action for binary mixtures of diuron and atrazine as well as complex mixtures of all 10 herbicides. The effects of both mixture types were largely additive, validating the application of additive effects models for calculating the risk posed by multiple PSII herbicides to seagrasses. This study extends seagrass ecotoxicological data to ametryn, metribuzin, bromacil, prometryn and fluometuron and demonstrates that low concentrations of PSII herbicide mixtures have the potential to impact ecologically relevant endpoints in seagrass, including ∆F/Fm‧.

The impact of the herbicide atrazine on growth and photosynthesis of seagrass, Zostera marina (L.), seedlings

International Nuclear Information System (INIS)

Gao Yaping; Fang Jianguang; Zhang Jihong; Ren Lihua; Mao Yuze; Li Bin; Zhang Mingliang; Liu Dinghai; Du Meirong

2011-01-01

Highlights: → Impact of the widely used herbicide atrazine on eelgrass seedlings was studied. → Atrazine presents a threat to eelgrass seedlings growth and photosynthesis. → The impact of atrazine on eelgrass seedlings is much higher than for adult plants. - Abstract: The impact of the widely used herbicide atrazine on seedling growth and photosynthesis of eelgrass was determined. The long-term impact of the herbicide atrazine (1, 10 and 100 μg/L) on growth of eelgrass Zostera marina (L.) seedlings, maintained in outdoor aquaria, was monitored over 4 weeks. Exposure to 10 μg/L atrazine resulted in significantly lower plant fresh weight and total chlorophyll concentration and up to 86.67% mortality at the 100 μg/L concentration. Short-term photosynthetic stress on eelgrass seedlings was determined and compared with adult eelgrass using chlorophyll fluorescence. The effective quantum yield in eelgrass seedlings was significantly depressed at all atrazine concentrations (2, 4, 8, 16, 32 and 64 μg/L) even within 2 h and remained at a lower level than for adult plants for each concentration. These results indicate that atrazine presents a potential threat to seagrass seedling functioning and that the impact is much higher than for adult plants.

Residual herbicide study on selected Hanford Site roadsides

Energy Technology Data Exchange (ETDEWEB)

Smith, J.L.; Kemp, C.J.; Sackschewsky, M.R.

1993-08-01

Westinghouse Hanford Company routinely treats roadsides with herbicides to control undesirable plant growth. An experiment was conducted to test perennial grass germination in soils adjacent to roadways of the Hanford Site. The primary variable was the distance from the roadside. A simple germination test was executed in a controlled-environment chamber to determine the residual effects of these applications. As expected, the greatest herbicide activity was found directly adjacent to the roadway, approximately 0 to 20 ft (0 to 6.3 m) from the roadway.

Herbicide-resistant crops: utilities and limitations for herbicide-resistant weed management.

Science.gov (United States)

Green, Jerry M; Owen, Micheal D K

2011-06-08

Since 1996, genetically modified herbicide-resistant (HR) crops, particularly glyphosate-resistant (GR) crops, have transformed the tactics that corn, soybean, and cotton growers use to manage weeds. The use of GR crops continues to grow, but weeds are adapting to the common practice of using only glyphosate to control weeds. Growers using only a single mode of action to manage weeds need to change to a more diverse array of herbicidal, mechanical, and cultural practices to maintain the effectiveness of glyphosate. Unfortunately, the introduction of GR crops and the high initial efficacy of glyphosate often lead to a decline in the use of other herbicide options and less investment by industry to discover new herbicide active ingredients. With some exceptions, most growers can still manage their weed problems with currently available selective and HR crop-enabled herbicides. However, current crop management systems are in jeopardy given the pace at which weed populations are evolving glyphosate resistance. New HR crop technologies will expand the utility of currently available herbicides and enable new interim solutions for growers to manage HR weeds, but will not replace the long-term need to diversify weed management tactics and discover herbicides with new modes of action. This paper reviews the strengths and weaknesses of anticipated weed management options and the best management practices that growers need to implement in HR crops to maximize the long-term benefits of current technologies and reduce weed shifts to difficult-to-control and HR weeds.

Potential organic herbicides for squash production: Pelargonic acid herbicides AXXE (registered trademark) and Scythe (registered trademark)

Science.gov (United States)

Organic squash (Cucurbita pepo L.) producers need appropriate herbicides that can effectively provide season- long weed control. Research was conducted in southeast Oklahoma (Atoka County, Lane, OK) to determine the impact of potential organic herbicides on weed control efficacy, crop injury, and y...

Weed supression by smother crops and selective herbicides

Directory of Open Access Journals (Sweden)

Severino Francisco José

2004-01-01

Full Text Available Using a smother crop is thought to suppress weed density and to add other beneficial effects in sustainable agricultural systems. Weed suppression ought to be considered an essential component of integrated weed management. However, very little is known about the effects of green manure plants on weeds. This study evaluated the influence of three green manure species on weed suppression and selectivity of herbicides. A field experiment was designed to determine the effect of the green manure species Crotalaria juncea, Arachis pintoi and pigeon pea on the weeds Brachiaria decumbens, guineagrass and hairy beggarticks, and on the natural weed infestation in the inter rows area of an avocado orchard. The weed species were suppressed differently by each green manure species. Soil samples collected from the field experiment presented a residual effect, of at least 30 d, in suppressing weed seed bank recruitment; this residual effect was caused by the residues of the green manure present in the soil. When the green manure was incorporated into the top 5 cm of soil or left on the surface, in a greenhouse experiment, the emergence of weed seeds was significantly inhibited, depending on the species, and on the amount and depth of green manure incorporation. Greenhouse experiments indicate that pre-emergence herbicides cause lower phytotoxicity than post-emergence Arachis pintoi. Smother crops using green manure species, when well established in an area, provide additional weed control to the cropping system and are effective and valuable tools in integrated weed management.

Impacts of agricultural irrigation on nearby freshwater ecosystems: the seasonal influence of triazine herbicides in benthic algal communities.

Science.gov (United States)

Lorente, Carmen; Causapé, Jesús; Glud, Ronnie N; Hancke, Kasper; Merchán, Daniel; Muñiz, Selene; Val, Jonatan; Navarro, Enrique

2015-01-15

A small hydrological basin (Lerma, NE Spain), transformed from its natural state (steppe) to rain-fed agriculture and recently to irrigation agriculture, has been monitored across four seasons of an agricultural year. The goal of this study was to assess how and whether agricultural activities impacted the nearby freshwater ecosystems via runoff. Specifically, we assessed the toxicity of three triazine herbicides, terbuthylazine, atrazine and simazine on the photosynthetic efficiency and structure of algal benthic biofilms (i.e., phototropic periphyton) in the small creek draining the basin. It was expected that the seasonal runoff of the herbicides in the creek affected the sensitivity of the periphyton in accord with the rationale of the Pollution Induced Community Tolerance (PICT): the exposure of the community to pollutants result in the replacement of sensitive species by more tolerant ones. In this way, PICT can serve to establish causal linkages between pollutants and the observed biological impacts. The periphyton presented significantly different sensitivities against terbuthylazine through the year in accord with the seasonal application of this herbicide in the crops nowadays. The sensitivity of already banned herbicides, atrazine and simazine does not display a clear seasonality. The different sensitivities to herbicides were in agreement with the expected exposures scenarios, according to the agricultural calendar, but not with the concentrations measured in water, which altogether indicates that the use of PICT approach may serve for long-term monitoring purposes. That will provide not only causal links between the occurrence of chemicals and their impacts on natural communities, but also information about the occurrence of chemicals that may escape from traditional sampling methods (water analysis). In addition, the EC50 and EC10 of periphyton for terbuthylazine or simazine are the first to be published and can be used for impact assessments

Biotechnology approaches to developing herbicide tolerance ...

African Journals Online (AJOL)

The use of herbicides has revolutionized weed control in many crop production systems. However, with the increasing development of weed resistances to many popular selective herbicides, the need has arisen to rethink the application of chemical weed control. Approaches to maintain the efficiency of chemical weed ...

Hazard and risk of herbicides for marine microalgae

International Nuclear Information System (INIS)

Sjollema, Sascha B.; MartínezGarcía, Gema; Geest, Harm G. van der; Kraak, Michiel H.S.; Booij, Petra; Vethaak, A. Dick; Admiraal, Wim

2014-01-01

Due to their specific effect on photosynthesis, herbicides pose a potential threat to coastal and estuarine microalgae. However, comprehensive understanding of the hazard and risk of these contaminants is currently lacking. Therefore the aim of the present study was to investigate the toxic effects of four ubiquitous herbicides (atrazine, diuron, Irgarol ® 1051 and isoproturon) and herbicide mixtures on marine microalgae. Using a Pulse Amplitude Modulation (PAM) fluorometry based bioassay we demonstrated a clear species and herbicide specific toxicity and showed that the current environmental legislation does not protect algae sufficiently against diuron and isoproturon. Although a low actual risk of herbicides in the field was demonstrated, monitoring data revealed that concentrations occasionally reach potential effect levels. Hence it cannot be excluded that herbicides contribute to observed changes in phytoplankton species composition in coastal waters, but this is likely to occur only occasionally. - Highlights: • The hazard of herbicides for microalgae is compound and species specific. • In general a low risk although occasional potential effect levels are reached. • Current legislation does not protect marine microalgae sufficiently. - The hazard of herbicides in the coastal waters is compound and species specific and although the general risk in the field is low, occasionally potential effect levels are reached

Influence of oligomeric herbicidal ionic liquids with MCPA and Dicamba anions on the community structure of autochthonic bacteria present in agricultural soil

Energy Technology Data Exchange (ETDEWEB)

Ławniczak, Ł., E-mail: lukasz.k.lawniczak@wp.pl [Department of Chemical Technology, Poznan University of Technology, 60-965 Poznan (Poland); Syguda, A., E-mail: Anna.Syguda@put.poznan.pl [Department of Chemical Technology, Poznan University of Technology, 60-965 Poznan (Poland); Borkowski, A., E-mail: a.borkowski@uw.edu.pl [Faculty of Geology, University of Warsaw, 02-089 Warsaw (Poland); Cyplik, P., E-mail: pcyplik@wp.pl [Department of Biotechnology and Food Microbiology, University of Life Sciences in Poznan, 60-627 Poznan (Poland); Marcinkowska, K., E-mail: k.marcinkowska@iorpib.poznan.pl [Institute of Plant Protection - National Research Institute, Poznan 60-318 (Poland); Wolko, Ł., E-mail: wolko@o2.pl [Department of Biochemistry and Biotechnology, Poznań University of Life Sciences in Poznan, 60-632 Poznan (Poland); Praczyk, T., E-mail: t.praczyk@iorpib.poznan.pl [Institute of Plant Protection - National Research Institute, Poznan 60-318 (Poland); Chrzanowski, Ł., E-mail: Lukasz.Chrzanowski@put.poznan.pl [Department of Chemical Technology, Poznan University of Technology, 60-965 Poznan (Poland); Pernak, J., E-mail: Juliusz.Pernak@put.poznan.pl [Department of Chemical Technology, Poznan University of Technology, 60-965 Poznan (Poland)

2016-09-01

The aim of this study was to evaluate the impact of selected herbicidal ionic liquids (HILs), which exhibit high efficacy in terms of weed control and low toxicity, but may be persistent due to limited biodegradability, on the community structure of autochthonic bacteria present in agricultural soil. Four different oligomeric HILs (with two types of cations and different ratio of herbicidal anions) were synthesized and characterized by employing {sup 1}H and {sup 13}C NMR. The results of biodegradation assay indicated that none of the tested HILs could be classified as readily biodegradable (biodegradation rate ranged from 0 to 7%). The conducted field studies confirmed that the herbicidal efficacy of the HILs was higher compared to the reference herbicide mixture by 10 to 30%, depending on the dose and weed species. After termination of field studies, the soil treated with the tested HILs was subjected to next generation sequencing in order to investigate the potential changes in the bacterial community structure. Proteobacteria was the dominant phylum in all studied samples. Treatment with the studied HILs resulted in an increase of Actinobacteria compared to the reference herbicidal mixture. Differenced among the studied HILs were generally associated with a significantly higher abundance of Bacteroidetes in case of 1-HIL-Dicamba 1/3 and Firmicutes in case of 2-HIL-Dicamba 1/3. - Highlights: • Impact of herbicidal ionic liquids on bacterial community structure was studied. • Oligomeric herbicidal ionic liquids were effective but not readily biodegradable. • Next generation sequencing was used to evaluate shifts in bacterial abundance. • Treatment during field trials resulted in changes at class and species level. • Use of herbicidal ionic liquids affects the structure of autochthonic soil bacteria.

Influence of oligomeric herbicidal ionic liquids with MCPA and Dicamba anions on the community structure of autochthonic bacteria present in agricultural soil

International Nuclear Information System (INIS)

Ławniczak, Ł.; Syguda, A.; Borkowski, A.; Cyplik, P.; Marcinkowska, K.; Wolko, Ł.; Praczyk, T.; Chrzanowski, Ł.; Pernak, J.

2016-01-01

The aim of this study was to evaluate the impact of selected herbicidal ionic liquids (HILs), which exhibit high efficacy in terms of weed control and low toxicity, but may be persistent due to limited biodegradability, on the community structure of autochthonic bacteria present in agricultural soil. Four different oligomeric HILs (with two types of cations and different ratio of herbicidal anions) were synthesized and characterized by employing "1H and "1"3C NMR. The results of biodegradation assay indicated that none of the tested HILs could be classified as readily biodegradable (biodegradation rate ranged from 0 to 7%). The conducted field studies confirmed that the herbicidal efficacy of the HILs was higher compared to the reference herbicide mixture by 10 to 30%, depending on the dose and weed species. After termination of field studies, the soil treated with the tested HILs was subjected to next generation sequencing in order to investigate the potential changes in the bacterial community structure. Proteobacteria was the dominant phylum in all studied samples. Treatment with the studied HILs resulted in an increase of Actinobacteria compared to the reference herbicidal mixture. Differenced among the studied HILs were generally associated with a significantly higher abundance of Bacteroidetes in case of 1-HIL-Dicamba 1/3 and Firmicutes in case of 2-HIL-Dicamba 1/3. - Highlights: • Impact of herbicidal ionic liquids on bacterial community structure was studied. • Oligomeric herbicidal ionic liquids were effective but not readily biodegradable. • Next generation sequencing was used to evaluate shifts in bacterial abundance. • Treatment during field trials resulted in changes at class and species level. • Use of herbicidal ionic liquids affects the structure of autochthonic soil bacteria.

Response of soil microbiota to selected herbicide treatments.

Science.gov (United States)

Roslycky, E B

1977-04-01

Recommended concentrations of paraquat alone and its combination with each of linuron, diuron, atrazine, simazine, and simazine plus diuron exerted little effect on total populations of bacteria, actinomycetes, and fungi in Fox sandy loam under laboratory and simulated field conditions in 66 and 77 days, respectively. Respiration of the total microbiota in soil suspension was afeected by the combinations as well as individual herbicides in various concentrations. Yet, the inhibition of the O2 uptake by any of these herbicides, including some extreme concentrations, was not permanent, indicating adaptation, or suppression of specific organisms. Only linuron in concentrations up to 20 microng/ml stimulated respiration of the soil.

Non-target effects of broadleaf herbicide on a native perennial forb: a demographic framework for assessing and minimizing impacts

Science.gov (United States)

Elizabeth E. Crone; Marilyn Marler; Dean E. Pearson

2009-01-01

Invasive species are one of the leading threats to biodiversity worldwide. Therefore, chemical herbicides are increasingly used to control invasive plants in natural and semi-natural areas. Little is known about the non-target impacts of these chemicals on native species. We conducted an experiment to test the demographic effects of the herbicide picloram on a native...

Dicotyledon Weed Quantification Algorithm for Selective Herbicide Application in Maize Crops

DEFF Research Database (Denmark)

Laursen, Morten Stigaard; Nyholm Jørgensen, Rasmus; Midtiby, Henrik Skov

2016-01-01

The stricter legislation within the European Union for the regulation of herbicides that are prone to leaching causes a greater economic burden on the agricultural industry through taxation. Owing to the increased economic burden, research in reducing herbicide usage has been prompted. High-resol...

Bonneville Power Administration Transmission System Vegetation Management Program - Final Environmental Impact Statement

Energy Technology Data Exchange (ETDEWEB)

N/A

2000-06-23

Bonneville is responsible for maintaining a network of 24,000 kilometers (km) or 15,000 miles (mi.) of electric transmission lines and 350 substations in a region of diverse vegetation. This vegetation can interfere with electric power flow, pose safety problems for us and the public, and interfere with our ability to maintain these facilities. We need to (1) keep vegetation away from our electric facilities; (2) increase our program efficiency and consistency; (3) review herbicide use (under increased public scrutiny); and (4) maximize the range of tools we can use while minimizing environmental impact (Integrated Vegetation Management). This Final Environmental Impact Statement (FEIS) establishes Planning Steps for managing vegetation for specific projects (to be tiered to this Environmental Impact Statement (EIS)). In addition to No Action (current practice), alternatives are presented for Rights-of-way, Electric Yards, and Non-electric Facilities (landscaping, work yards). Four vegetation control methods are analyzed manual, mechanical, herbicide, and biological. Also evaluated are 23 herbicide active ingredients and 4 herbicide application techniques (spot, localized, broadcast, and aerial). For rights-of-way, we consider three sets of alternatives: alternative management approaches (time-driven or establishing low-growing plant communities); alternative method packages; and, if herbicides are in a methods package, alternative vegetation selections (noxious weeds, deciduous, or any vegetation). For electric yards, one herbicide-use alternative is considered. For non-electric facilities, two method package alternatives are considered. For rights-of-way, the environmentally preferred alternative(s) would use manual, mechanical, and biological control methods, as well as spot and localized herbicide applications for noxious and deciduous plant species; the BPA-preferred alternative(s) would add broadcast and aerial herbicide applications, and would use herbicides

Using GLEAMS to Select Environmental Windows for Herbicide Application in Forests

Science.gov (United States)

M.C. Smith; J.L. Michael; W.G. Koisel; D.G. Nealy

1994-01-01

Observed herbicide runoff and groundwater data from a pine-release herbicide application study near Gainesville, Florida were used to validate the GLEAMS model hydrology and pesticide component for forest application. The study revealed that model simulations agreed relatively well with the field data for the one-year study. Following validation, a modified version of...

Herbicide Safeners Decrease Sensitivity to Herbicides Inhibiting Acetolactate-Synthase and Likely Activate Non-Target-Site-Based Resistance Pathways in the Major Grass Weed Lolium sp. (Rye-Grass)

OpenAIRE

Duhoux, Arnaud; Pernin, Fanny; Desserre, Diane; D?lye, Christophe

2017-01-01

Herbicides are currently pivotal to control weeds and sustain food security. Herbicides must efficiently kill weeds while being as harmless as possible for crops, even crops taxonomically close to weeds. To increase their selectivity toward crops, some herbicides are sprayed in association with safeners that are bioactive compounds exacerbating herbicide-degrading pathways reputedly specifically in crops. However, exacerbated herbicide metabolism is also a key mechanism underlying evolved non...

Selection of relatively exact reference genes for gene expression studies in goosegrass (Eleusine indica) under herbicide stress.

Science.gov (United States)

Chen, Jingchao; Huang, Zhaofeng; Huang, Hongjuan; Wei, Shouhui; Liu, Yan; Jiang, Cuilan; Zhang, Jie; Zhang, Chaoxian

2017-04-21

Goosegrass (Eleusine indica) is one of the most serious annual grassy weeds worldwide, and its evolved herbicide-resistant populations are more difficult to control. Quantitative real-time PCR (qPCR) is a common technique for investigating the resistance mechanism; however, there is as yet no report on the systematic selection of stable reference genes for goosegrass. This study proposed to test the expression stability of 9 candidate reference genes in goosegrass in different tissues and developmental stages and under stress from three types of herbicide. The results show that for different developmental stages and organs (control), eukaryotic initiation factor 4 A (eIF-4) is the most stable reference gene. Chloroplast acetolactate synthase (ALS) is the most stable reference gene under glyphosate stress. Under glufosinate stress, eIF-4 is the best reference gene. Ubiquitin-conjugating enzyme (UCE) is the most stable reference gene under quizalofop-p-ethyl stress. The gene eIF-4 is the recommended reference gene for goosegrass under the stress of all three herbicides. Moreover, pairwise analysis showed that seven reference genes were sufficient to normalize the gene expression data under three herbicides treatment. This study provides a list of reliable reference genes for transcript normalization in goosegrass, which will facilitate resistance mechanism studies in this weed species.

Herbicide toxicity, selectivity and hormesis of nicosulfuron on 10 Trichogrammatidae (Hymenoptera) species parasitizing Anagasta ( = Ephestia) kuehniella (Lepidoptera: Pyralidae) eggs.

Science.gov (United States)

Leite, Germano L D; de Paulo, Paula D; Zanuncio, José C; Tavares, Wagner De S; Alvarenga, Anarelly C; Dourado, Luan R; Bispo, Edilson P R; Soares, Marcus A

2017-01-02

Selective agrochemicals including herbicides that do not affect non-target organisms such as natural enemies are important in the integrated pest management (IPM) programs. The aim of this study was to evaluate the herbicide toxicity, selectivity and hormesis of nicosulfuron, recommended for the corn Zea mays L. (Poaceae) crop, on 10 Trichogrammatidae (Hymenoptera) species. A female of each Trichogramma spp. or Trichogrammatoidea annulata De Santis, 1972 was individually placed in plastic test tubes (no choice) with a cardboard containing 45 flour moth Anagasta ( = Ephestia) kuehniella Zeller, 1879 (Lepidoptera: Pyralidae) eggs. Parasitism by these natural enemies was allowed for 48 h and the cardboards were sprayed with the herbicide nicosulfuron at 1.50 L.ha -1 , along with the control (only distilled water). Nicosulfuron reduced the emergence rate of Trichogramma bruni Nagaraja, 1983 females, but increased that of Trichogramma pretiosum Riley, 1879, Trichogramma acacioi Brun, Moraes and Smith, 1984 and T. annulata females. Conversely, this herbicide increased the emergence rate of Trichogramma brasiliensis Ashmead, 1904, T. bruni, Trichogramma galloi Zucchi, 1988 and Trichogramma soaresi Nagaraja, 1983 males and decreased those of T. acacioi, Trichogramma atopovilia Oatman and Platner, 1983 and T. pretiosum males. In addition, nicosulfuron reduced the sex ratio of T. galloi, Trichogramma bennetti Nagaraja and Nagarkatti, 1973 and T. pretiosum and increased that of T. acacioi, T. bruni, T. annulata, Trichogramma demoraesi Nagaraja, 1983, T. soaresi and T. brasiliensis. The herbicide nicosulfuron was "harmless" (class 1, <30% reduction) for females and the sex ratio of all Trichogrammatidae species based on the International Organization for Biological Control (IOBC) classification. The possible hormesis effect of nicosulfuron on Trichogrammatidae species and on the bacterium Wolbachia sp. (Rickettsiales: Rickettsiaceae) was also discussed.

Comparative sensitivity of Selenastrum capricornutum and Lemna minor to sixteen herbicides

Science.gov (United States)

Fairchild, J.F.; Ruessler, D.S.; Haverland, P.S.; Carlson, A.R.

1997-01-01

Aquatic plant toxicity tests are frequently conducted in environmental risk assessments to determine the potential impacts of contaminants on primary producers. An examination of published plant toxicity data demonstrates that wide differences in sensitivity can occur across phylogenetic groups of plants. Yet relatively few studies have been conducted with the specific intent to compare the relative sensitivity of various aquatic plant species to contaminants. We compared the relative sensitivity of the algae Selenestrum capricornutum and the floating vascular plant Lemna minor to 16 herbicides (atrazine, metribuzin, simazine, cyanazine, alachlor, metolachlor, chlorsulfuron, metsulfuron, triallate, EPTC, trifluralin, diquat, paraquat, dicamba, bromoxynil, and 2,4-D). The herbicides studied represented nine chemical classes and several modes of action and were chosen to represent major current uses in the United States. Both plant species were generally sensitive to the triazines (atrazine, metribuzin, simazine, and cyanazine), sulfonureas (metsulfuron and chlorsulfuron), pyridines (diquat and paraquat), dinitroaniline (trifluralin), and acetanilide (alachlor and metolachlor) herbicides. Neither plant species was uniformly more sensitive than the other across the broad range of herbicides tested. Lemna was more sensitive to the sulfonureas (metsulfuron and chlorsulfuron) and the pyridines (diquat and parequat) than Selenastrum. However Selenastrum was more sensitive than Lemna to one of two thiocarbamates (triallate) and one of the triazines (cyanazine). Neither species was sensitive to selective broadleaf herbicides including bromoxynil, EPTC, dicamba, or 2,4-D. Results were not always predictable in spite of obvious differences in herbicide modes of action and plant phylogeny. Major departures in sensitivity of Selenastrum occurred between chemicals within individual classes of the triazine, acetanilide, and thiocarbamate herbicides. Results indicate that neither

Are herbicide-resistant crops the answer to controlling Cuscuta?

Science.gov (United States)

Nadler-Hassar, Talia; Shaner, Dale L; Nissen, Scott; Westra, Phill; Rubin, Baruch

2009-07-01

Herbicide-resistant crop technology could provide new management strategies for the control of parasitic plants. Three herbicide-resistant oilseed rape (Brassica napus L.) genotypes were used to examine the response of attached Cuscuta campestris Yuncker to glyphosate, imazamox and glufosinate. Cuscata campestris was allowed to establish on all oilseed rape genotypes before herbicides were applied. Unattached seedlings of C. campestris, C. subinclusa Durand & Hilg. and C. gronovii Willd. were resistant to imazamox and glyphosate and sensitive to glufosinate, indicating that resistance initially discovered in C. campestris is universal to all Cuscuta species. Glufosinate applied to C. campestris attached to glufosinate-resistant oilseed rape had little impact on the parasite, while imazamox completely inhibited C. campestris growth on the imidazolinone-resistant host. The growth of C. campestris on glyphosate-resistant host was initially inhibited by glyphosate, but the parasite recovered and resumed growth within 3-4 weeks. The ability of C. campestris to recover was related to the quality of interaction between the host and parasite and to the resistance mechanism of the host. The parasite was less likely to recover when it had low compatibility with the host, indicating that parasite-resistant crops coupled with herbicide resistance could be highly effective in controlling Cuscuta. (c) 2009 by John Wiley & Sons, Ltd.

Research methods in weed science: herbicide absorption and translocation in plants using radioisotopes

Science.gov (United States)

Herbicide absorption and translocation in plants is a key component in the study of herbicide physiology, mode of action, selectivity, resistance mechanisms, and in the registration process. Radioactive herbicides have been in use for over half-a-century in the research and study of herbicide absorp...

Biomass, Leaf Area, and Resource Availability of Kudzu Dominated Plant Communities Following Herbicide Treatment

Energy Technology Data Exchange (ETDEWEB)

L.T. Rader

2001-10-01

Kudzu is an exotic vine that threatens the forests of the southern U.S. Five herbicides were tested with regard to their efficacy in controlling kudzu, community recover was monitored, and interactions with planted pines were studied. The sites selected were old farm sites dominated by kudzu.These were burned following herbicide treatment. The herbicides included triclopyr, clopyralid, metsulfuron, tebuthiuron, and picloram plus 2,4-D. Pine seedlings were planted the following year. Regression equations were developed for predicting biomass and leaf area. Four distinct plant communities resulted from the treatments. The untreated check continued to be kudzu dominated. Blackberry dominated the clopyradid treatment. Metsulfron, trychlopyr and picloram treated sites resulted in herbaceous dominated communities. The tebuthiuron treatment maintained all vegetation low.

Herbicide Persistence in Seawater Simulation Experiments.

Directory of Open Access Journals (Sweden)

Philip Mercurio

Full Text Available Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR. The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities. Very little degradation was recorded over the standard 60 d period (Experiment 1 so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated

Herbicide Persistence in Seawater Simulation Experiments

Science.gov (United States)

Mercurio, Philip; Mueller, Jochen F.; Eaglesham, Geoff; Flores, Florita; Negri, Andrew P.

2015-01-01

Herbicides are detected year-round in marine waters, including those of the World Heritage listed Great Barrier Reef (GBR). The few previous studies that have investigated herbicide persistence in seawater generally reported half-lives in the order of months, and several studies were too short to detect significant degradation. Here we investigated the persistence of eight herbicides commonly detected in the GBR or its catchments in standard OECD simulation flask experiments, but with the aim to mimic natural conditions similar to those found on the GBR (i.e., relatively low herbicide concentrations, typical temperatures, light and microbial communities). Very little degradation was recorded over the standard 60 d period (Experiment 1) so a second experiment was extended to 365 d. Half-lives of PSII herbicides ametryn, atrazine, diuron, hexazinone and tebuthiuron were consistently greater than a year, indicating high persistence. The detection of atrazine and diuron metabolites and longer persistence in mercuric chloride-treated seawater confirmed that biodegradation contributed to the breakdown of herbicides. The shortest half-life recorded was 88 d for growth-regulating herbicide 2,4-D at 31°C in the dark, while the fatty acid-inhibitor metolachlor exhibited a minimum half-life of 281 d. The presence of moderate light and elevated temperatures affected the persistence of most of the herbicides; however, the scale and direction of the differences were not predictable and were likely due to changes in microbial community composition. The persistence estimates here represent some of the first appropriate data for application in risk assessments for herbicide exposure in tropical marine systems. The long persistence of herbicides identified in the present study helps explain detection of herbicides in nearshore waters of the GBR year round. Little degradation of these herbicides would be expected during the wet season with runoff and associated flood plumes

Dicotyledon Weed Quantification Algorithm for Selective Herbicide Application in Maize Crops.

Science.gov (United States)

Laursen, Morten Stigaard; Jørgensen, Rasmus Nyholm; Midtiby, Henrik Skov; Jensen, Kjeld; Christiansen, Martin Peter; Giselsson, Thomas Mosgaard; Mortensen, Anders Krogh; Jensen, Peter Kryger

2016-11-04

The stricter legislation within the European Union for the regulation of herbicides that are prone to leaching causes a greater economic burden on the agricultural industry through taxation. Owing to the increased economic burden, research in reducing herbicide usage has been prompted. High-resolution images from digital cameras support the studying of plant characteristics. These images can also be utilized to analyze shape and texture characteristics for weed identification. Instead of detecting weed patches, weed density can be estimated at a sub-patch level, through which even the identification of a single plant is possible. The aim of this study is to adapt the monocot and dicot coverage ratio vision (MoDiCoVi) algorithm to estimate dicotyledon leaf cover, perform grid spraying in real time, and present initial results in terms of potential herbicide savings in maize. The authors designed and executed an automated, large-scale field trial supported by the Armadillo autonomous tool carrier robot. The field trial consisted of 299 maize plots. Half of the plots (parcels) were planned with additional seeded weeds; the other half were planned with naturally occurring weeds. The in-situ evaluation showed that, compared to conventional broadcast spraying, the proposed method can reduce herbicide usage by 65% without measurable loss in biological effect.

The impact of the herbicide atrazine on growth and photosynthesis of seagrass, Zostera marina (L.), seedlings.

Science.gov (United States)

Gao, Yaping; Fang, Jianguang; Zhang, Jihong; Ren, Lihua; Mao, Yuze; Li, Bin; Zhang, Mingliang; Liu, Dinghai; Du, Meirong

2011-08-01

The impact of the widely used herbicide atrazine on seedling growth and photosynthesis of eelgrass was determined. The long-term impact of the herbicide atrazine (1, 10 and 100 μg/L) on growth of eelgrass Zostera marina (L.) seedlings, maintained in outdoor aquaria, was monitored over 4 weeks. Exposure to 10 μg/L atrazine resulted in significantly lower plant fresh weight and total chlorophyll concentration and up to 86.67% mortality at the 100 μg/L concentration. Short-term photosynthetic stress on eelgrass seedlings was determined and compared with adult eelgrass using chlorophyll fluorescence. The effective quantum yield in eelgrass seedlings was significantly depressed at all atrazine concentrations (2, 4, 8, 16, 32 and 64 μg/L) even within 2 h and remained at a lower level than for adult plants for each concentration. These results indicate that atrazine presents a potential threat to seagrass seedling functioning and that the impact is much higher than for adult plants. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Effects of a phosphinothricin based herbicide on selected groups of soil microorganisms.

Science.gov (United States)

Pampulha, M E; Ferreira, M A S S; Oliveira, A

2007-08-01

The effects of the herbicide glufosinate-ammonium on soil microbial populations and activity were observed in a laboratory microcosms over a 40 day period. Culturable aerobic bacteria, fungi and actinomycetes, the fundamental groups of heterotrophic microorganisms, were studied. Nitrifiers, considered a very sensitive group to these compounds were also evaluated. Since herbicides have been found to inhibit decomposition of cellulose in the soil, the effects of glufosinate on cellulolytic bacteria and fungi were determined. Dehydrogenase activity as a measure of microbial activity was another parameter considered. Both stimulating and inhibitory effects on microbial populations were observed, depending on concentration of the herbicide and the period of incubation. A severe inhibiting effect of glufosinate on dehydrogenase activity was found. We concluded that the widespread use of this herbicide may have possible injurious effects on soil microorganisms and their activities. The toxicity exerted by glufosinate may lead to a shift in microbial community structure tending toward a significant loss in functional diversity. Dehydrogenase activity was shown to be an important indicator of glufosinate side-effects.

Changes in bacterial community after application of three different herbicides.

Science.gov (United States)

Moretto, Jéssica Aparecida Silva; Altarugio, Lucas Miguel; Andrade, Pedro Avelino; Fachin, Ana Lúcia; Andreote, Fernando Dini; Stehling, Eliana Guedes

2017-07-06

The native soil microbiota is very important to maintain the quality of that environment, but with the intensive use of agrochemicals, changes in microbial biomass and formation of large quantities of toxic waste were observed in soil, groundwater and surface water. Thereby, the goal of this study was to evaluate if the selective pressure exerted by the presence of the herbicides atrazine, diuron and 2,4-D changes the bacterial community structure of an agricultural soil, using denaturing gradient gel electrophoresis technique. According to PERMANOVA analysis, a greater effect of the herbicide persistence time in the soil, the effect of the herbicide class and the effect of interaction between these two factors (persistence time and herbicide class) were observed. In conclusion, the results showed that the selective pressure exerted by the presence of these herbicides altered the composition of the local microbiota, being atrazine and diuron that most significantly affected the bacterial community in soil, and the herbicide 2,4-D was the one that less altered the microbial community and that bacterial community was reestablished first. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Oxidative stress caused by the use of preemergent herbicides in rice crops

Directory of Open Access Journals (Sweden)

Ana Claudia Langaro

Full Text Available ABSTRACT Among the methods of weed control, stands out chemical control. However, even selective, herbicides can trigger the production of reactive species of oxygen and cause oxidative stress. The aim of the study was to evaluate changes in photosynthetic parameters, oxidative damage, antioxidant enzyme activity and altered metabolism of rice plants after applying pre-emergent herbicides. The experiment was conducted in a greenhouse and herbicides used were oxadiazon, pendimethalin and oxyfluorfen, beyond the control without herbicide. There was a reduction of photosynthetic rate and efficiency of carboxylation, compared to the control, when applied herbicides oxyfluorfen and pendimethalin. The major lipid peroxidation and proline accumulation was observed for the herbicide oxyfluorfen. The oxyfluorfen and oxadiazon herbicides also resulted in increased activity of superoxide dismutase, compared to control. When evaluated ascorbate peroxidase activity, there was a higher enzyme activity in plants treated with oxadiazon and pendimethalin. Even selective herbicides registered for weed control in rice crops cause phytotoxicity, reduce height and alter the metabolism of plants, generating reactive oxygen species, which activate enzymatic and non-enzymatic defense systems and result in the degradation of photosynthetic pigments and in reduced protein content.

Phorate can reverse P450 metabolism-based herbicide resistance in Lolium rigidum.

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Busi, Roberto; Gaines, Todd Adam; Powles, Stephen

2017-02-01

Organophosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms, leading to synergistic interactions between the insecticide and the herbicide. In this study we report synergistic versus antagonistic interactions between the organophosphate insecticide phorate and five different herbicides observed in a population of multiple herbicide-resistant Lolium rigidum. Phorate synergised with three different herbicide modes of action, enhancing the activity of the ALS inhibitor chlorsulfuron (60% LD 50 reduction), the VLCFAE inhibitor pyroxasulfone (45% LD 50 reduction) and the mitosis inhibitor trifluralin (70% LD 50 reduction). Conversely, phorate antagonised the two thiocarbamate herbicides prosulfocarb and triallate with a 12-fold LD 50 increase. We report the selective reversal of P450-mediated metabolic multiple resistance to chlorsulfuron and trifluralin in the grass weed L. rigidum by synergistic interaction with the insecticide phorate, and discuss the putative mechanistic basis. This research should encourage diversity in herbicide use patterns for weed control as part of a long-term integrated management effort to reduce the risk of selection of metabolism-based multiple herbicide resistance in L. rigidum. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Screening and selection of most potent diazotrophic cyanobacterial isolate exhibiting natural tolerance to rice field herbicides for exploitation as biofertilizer.

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Singh, Surendra; Datta, Pallavi

2006-01-01

Periodic applications of heavy dosages of herbicides in modern rice-agriculture are a necessary evil for obtaining high crop productivity. Such herbicides are not only detrimental to weeds but biofertilizer strains of diazotrophic cyanobacteria also. It is therefore, essential to screen and select such biofertilizer strains of diazotrophic cyanobacteria exhibiting natural tolerance to common rice-field herbicides that can be further improved by mutational techniques to make biofertilizer technology a viable one. Therefore, efforts have been made to screen five dominant diazotrophic cyanobacterial forms e.g. filamentous heterocystous Nostoc punctiforme , Nostoc calcicola , Anabaena variabilis and unicellular Gloeocapsa sp. and Aphanocapsa sp. along with standard laboratory strain Nostoc muscorum ISU against increasing concentrations (0-100 mg l(-1) of four commercial grade common rice-field herbicides i.e. Arozin, Butachlor, Alachlor and 2,4-D under diazotrophic growth conditions. The lethal and IGC(50) concentrations for all four herbicides tested were found highest for A. variabilis as compared to other test cyanobacteria. The lowest reduction in chlorophyll a content, photosynthetic oxygen evolution, and N(2)-fixation was found in A. variabilis as compared to other rice field isolates and standard laboratory strain N. muscorum ISU. On the basis of prolong survival potential and lowest reductions in vital metabolic activities tested at IGC(50) concentration of four herbicides, it is concluded that A. variabilis is the most potent and promising cyanobacterial isolate as compared with other forms. This could be further improved by mutational techniques for exploitation as most potential and viable biofertilizer strain.

Stress-physiological reactions of the green alga Scenedesmus opoliensis to water pollution with herbicides

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Zsolt Gyula KERESZTES

2009-05-01

Full Text Available The freshwater green alga Scenedesmus opoliensis proves to be a suitable bioindicator of water pollution with different herbicides. One of the best molecular markers of stress condition imposed by herbicides is overproduction of malondialdehyde resulting from lipid peroxidation in the damaged membranes. Methylviologen, a largely used pre-emergence herbicide which generates reactive oxygen species in the illuminated chloroplasts, triggers the accumulation of ascorbic acid and enhances the enzymatic activity of catalase, both of these substances being involved in the antioxidative protection of algal cells. Diuron, a herbicide that inhibits photosynthetic electron transport on the acceptor side of photosystem II, causes a decline in oxygen production and in biomass accumulation of algae. Glufosinate induces accumulation of toxic ammonia and leads to enhanced net oxygen production, associated with a low rate of carbon assimilation. Long-term exposure to micromolar concentrations of herbicides results in significant changes in the rate of cell division, in hotosynthetic parameters and in the intensity of antioxidative defense. A proper bioindication of toxic effects of herbicides on algae requires a selected combination of different physiological and biochemical parameters which reflect the degree of stress exerted on living organisms by water pollution with xenobiotic organic compounds.

Sensitivity to Glufosinate-ammonium herbicide in plants of Glycine max cultivar INCASoy-27

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Jorge Liusvert Pérez Pérez

2014-10-01

Full Text Available This work had as objective to define the minimum concentration of herbicide Glufosinate-ammonium that inhibits the growth of the soybean plants in greenhouse condition. The soybean plants were tried with different concentrations of herbicide (5; 10; 1 5; 20; 25; 30 mg L-1 and a control without herbicide. The increase of the concentrations increased the necrosis of the plants and the use of 20 mgL-1 Glufosinato de amonio herbicide was sufficient to inhibit the plant growth. These results allow using this method of selection in programs of genetic improvement and selection of transgenic soybean plants

Herbicide monitoring in soil, runoff waters and sediments in an olive orchard.

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Calderon, Maria Jesus; De Luna, Elena; Gomez, Jose Alfonso; Hermosin, M Carmen

2016-11-01

Occurrences of surface water contamination by herbicides in areas where olive orchards are established reveal a need to understand soil processes affecting herbicide fate at field scale for this popular Mediterranean crop. A monitoring study with two herbicides (terbuthylazine and oxyfluorfen) in the first 2cm of soil, runoff waters, and sediments, was carried out after under natural rainfall conditions following winter herbicide application. At the end of the 107day field experiment, no residues of the soil applied terbuthylazine were recovered, whereas 42% of the oxyfluorfen applied remained in the top soil. Very low levels of both herbicides were measured in runoff waters; however, concentrations were slightly higher for terbuthylazine (0.53% of applied) than for oxyfluorfen (0.03% of applied), relating to their respective water solubilities. Congruent with soil residue data, 38.15% of the applied oxyfluorfen was found in runoff-sediment, compared to only 0.46% for terbuthylazine. Accordingly, the herbicide soil distribution coefficients measured within runoff field tanks was much greater for oxyfluorfen (Kd=3098) than for terbuthylazine (Kd=1.57). The herbicide oxyfluorfen is co-transported with sediment in runoff, remaining trapped and/or adsorbed to soil particle aggregates, due in part to its low water solubility. In contrast, terbuthylazine soil dissipation may be associated more so with leaching processes, favored by its high water solubility, low sorption, and slow degradation. By comparing these two herbicides, our results reaffirm the importance of herbicide physico-chemical properties in dictating their behavior in soil and also suggest that herbicides with low solubility, as seen in the case oxyfluorfen, remain susceptible to offsite transport associated with sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

Hazard and risk of herbicides for marine microalgae.

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Sjollema, Sascha B; Martínezgarcía, Gema; van der Geest, Harm G; Kraak, Michiel H S; Booij, Petra; Vethaak, A Dick; Admiraal, Wim

2014-04-01

Due to their specific effect on photosynthesis, herbicides pose a potential threat to coastal and estuarine microalgae. However, comprehensive understanding of the hazard and risk of these contaminants is currently lacking. Therefore the aim of the present study was to investigate the toxic effects of four ubiquitous herbicides (atrazine, diuron, Irgarol(®)1051 and isoproturon) and herbicide mixtures on marine microalgae. Using a Pulse Amplitude Modulation (PAM) fluorometry based bioassay we demonstrated a clear species and herbicide specific toxicity and showed that the current environmental legislation does not protect algae sufficiently against diuron and isoproturon. Although a low actual risk of herbicides in the field was demonstrated, monitoring data revealed that concentrations occasionally reach potential effect levels. Hence it cannot be excluded that herbicides contribute to observed changes in phytoplankton species composition in coastal waters, but this is likely to occur only occasionally. Copyright © 2013 Elsevier Ltd. All rights reserved.

Investigation of 10 herbicides in surface waters of a horticultural production catchment in southeastern Australia.

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Allinson, Graeme; Bui, AnhDuyen; Zhang, Pei; Rose, Gavin; Wightwick, Adam M; Allinson, Mayumi; Pettigrove, Vincent

2014-10-01

Herbicides are regularly applied in horticultural production systems and may migrate off-site, potentially posing an ecological risk to surface waterways. However, few studies have investigated the levels and potential ecotoxicological impact of herbicides in horticultural catchments in southern Australia. This study investigated the presence of 10 herbicides at 18 sites during a 5-month period in horticulturally important areas of the Yarra Valley in southeastern Australia. Seven of the 10 herbicides were detected in the streams, in 39 % of spot water samples, in 25 % of surface sediment samples, and in >70 % of the passive sampler systems deployed. Few samples contained residues of ≥2 herbicides. Simazine was the herbicide most frequently detected in water, sediment, and passive sampler samples and had the highest concentrations in water (0.67 μg/L) and sediment (260 μg/kg dry weight). Generally the concentrations of the herbicides detected were several orders of magnitude lower than reported ecotoxicological effect values, including those for aquatic plants and algae, suggesting that concentrations of individual chemicals in the catchment were unlikely to pose an ecological risk. However, little is known about the combined effects of simultaneous, low-level exposure of multiple herbicides of the same mode of action on Australian aquatic organisms nor their contribution when found in mixtures with other pesticides. Further research is required to adequately assess the risk of pesticides in Victorian aquatic environments.

Maize, switchgrass, and ponderosa pine biochar added to soil increased herbicide sorption and decreased herbicide efficacy.

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Clay, Sharon A; Krack, Kaitlynn K; Bruggeman, Stephanie A; Papiernik, Sharon; Schumacher, Thomas E

2016-08-02

Biochar, a by-product of pyrolysis made from a wide array of plant biomass when producing biofuels, is a proposed soil amendment to improve soil health. This study measured herbicide sorption and efficacy when soils were treated with low (1% w/w) or high (10% w/w) amounts of biochar manufactured from different feedstocks [maize (Zea mays) stover, switchgrass (Panicum vigatum), and ponderosa pine (Pinus ponderosa)], and treated with different post-processing techniques. Twenty-four hour batch equilibration measured sorption of (14)C-labelled atrazine or 2,4-D to two soil types with and without biochar amendments. Herbicide efficacy was measured with and without biochar using speed of seed germination tests of sensitive species. Biochar amended soils sorbed more herbicide than untreated soils, with major differences due to biochar application rate but minor differences due to biochar type or post-process handling technique. Biochar presence increased the speed of seed germination compared with herbicide alone addition. These data indicate that biochar addition to soil can increase herbicide sorption and reduce efficacy. Evaluation for site-specific biochar applications may be warranted to obtain maximal benefits without compromising other agronomic practices.

Forward selection for multiple resistance across the non-selective glyphosate, glufosinate and oxyfluorfen herbicides in Lolium weed species.

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Fernández, Pablo; Alcántara, Ricardo; Osuna, María D; Vila-Aiub, Martin M; Prado, Rafael De

2017-05-01

In the Mediterranean area, Lolium species have evolved resistance to glyphosate after decades of continual use without other alternative chemicals in perennial crops (olive, citrus and vineyards). In recent years, oxyfluorfen alone or mixed with glyphosate and glufosinate has been introduced as a chemical option to control dicot and grass weeds. Dose-response studies confirmed that three glyphosate-resistant Lolium weed species (L. rigidum, L. perenne, L. multiflorum) collected from perennial crops in the Iberian Peninsula have also evolved resistance to glufosinate and oxyfluorfen herbicides, despite their recent introduction. Based on the LD 50 resistance parameter, the resistance factor was similar among Lolium species and ranged from 14- to 21-fold and from ten- to 12-fold for oxyfluorfen and glufosinate respectively. Similarly, about 14-fold resistance to both oxyfluorfen and glufosinate was estimated on average for the three Lolium species when growth reduction (GR 50 ) was assessed. This study identified oxyfluorfen resistance in a grass species for the first time. A major threat to sustainability of perennial crops in the Iberian Peninsula is evident, as multiple resistance to non-selective glyphosate, glufosinate and oxyfluorfen herbicides has evolved in L. rigidum, L. perenne and L. multiflorum weeds. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

economics of herbicide weed management in wheat in ethiopia ...

African Journals Online (AJOL)

ACSS

Effective use of herbicides for the control of annual grass and broadleaf weeds in wheat (Triticum aestivum L.) was not a reality in Ethiopia, until in recent years. This study aimed at evaluating different post-emergence herbicides against annual grasses and broadleaf weeds in wheat for selection and incorporation into an ...

Relationship between weed dormancy and herbicide rotations: implications in resistance evolution.

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Darmency, Henri; Colbach, Nathalie; Le Corre, Valérie

2017-10-01

It is suggested that selection for late germinating seed cohorts is significantly associated with herbicide resistance in some cropping systems. In turn, it is conceivable that rotating herbicide modes of action selects for populations with mutations for increased secondary dormancy, thus partially overcoming the delaying effect of rotation on resistance evolution. Modified seed dormancy could affect management strategies - like herbicide rotation - that are used to prevent or control herbicide resistance. Here, we review the literature for data on seed dormancy and germination dynamics of herbicide-resistant versus susceptible plants. Few studies use plant material with similar genetic backgrounds, so there are few really comparative data. Increased dormancy and delayed germination may co-occur with resistance to ACCase inhibitors, but there is no clear-cut link with resistance to other herbicide classes. Population shifts are due in part to pleiotropic effects of the resistance genes, but interaction with the cropping system is also possible. We provide an example of a model simulation that accounts for genetic diversity in the dormancy trait, and subsequent consequences for various cropping systems. We strongly recommend adding more accurate and detailed mechanistic modelling to the current tools used today to predict the efficiency of prevention and management of herbicide resistance. These models should be validated through long-term experimental designs including mono-herbicide versus chemical rotation in the field. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Photodegradation of the herbicide azimsulfuron using nanocrystalline titania films as photocatalyst and low intensity Black Light radiation or simulated solar radiation as excitation source

International Nuclear Information System (INIS)

Pelentridou, Katerina; Stathatos, Elias; Karasali, Helen; Lianos, Panagiotis

2009-01-01

Aqueous solutions of the herbicide azimsulfuron have been treated by a photocatalytic process employing titania nanocrystalline films as photocatalyst. Results showed that solutions of this herbicide at maximum possible concentration can be photodegraded in a time of a few hours by using low intensity UVA radiation comparable with that of the UVA of solar noon. Similar results have also been obtained with simulated solar radiation. Thus heterogeneous photocatalysis can be employed for the treatment of waters polluted by this herbicide

[Determination of acetanilide herbicide residues in tea by gas chromatography-mass spectrometry with two different ionization techniques].

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Shen, Weijian; Xu, Jinzhong; Yang, Wenquan; Shen, Chongyu; Zhao, Zengyun; Ding, Tao; Wu, Bin

2007-09-01

An analytical method of solid phase extraction-gas chromatography-mass spectrometry with two different ionization techniques was established for simultaneous determination of 12 acetanilide herbicide residues in tea-leaves. Herbicides were extracted from tea-leaf samples with ethyl acetate. The extract was cleaned-up on an active carbon SPE column connected to a Florisil SPE column. Analytical screening was determined by the technique of gas chromatography (GC)-mass spectrometry (MS) in the selected ion monitoring (SIM) mode with either electron impact ionization (EI) or negative chemical ionization (NCI). It is reliable and stable that the recoveries of all herbicides were in the range from 50% to 110% at three spiked levels, 10 microg/kg, 20 microg/kg and 40 microg/kg, and the relative standard deviations (RSDs) were no more than 10.9%. The two different ionization techniques are complementary as more ion fragmentation information can be obtained from the EI mode while more molecular ion information from the NCI mode. By comparison of the two techniques, the selectivity of NCI-SIM was much better than that of EI-SIM method. The sensitivities of the both techniques were high, the limit of quantitative (LOQ) for each herbicide was no more than 2.0 microg/kg, and the limit of detection (LOD) with NCI-SIM technique was much lower than that of EI-SIM when analyzing herbicides with several halogen atoms in the molecule.

Impact of herbicides on some agronomic and chemical characteristics of flue-cured virginia (FCV tobacco (Nicotiana tabacum L.

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Muhammad Azim Khan

2006-09-01

Full Text Available A field experiment was carried out at Tobacco Research Station Khan Ghari, Mardan, (NWFP- Pakistan during spring 2003 to study the impact of herbicides on some agronomic and chemical characteristics of flue-cured virginia (FCV tobacco (Nicotiana tabacum L.. The experiment was laid out in RCB design, replicated four times with ten treatments, comprising hand weeding, weedy check, pre-transplanting herbicides; S-metalocholar @ 1.92, pendimethalin (EC @ 1.00, pendimethalin (CS @ 1.00, and butralin @ 1.44 kg a.i ha-1 and the post-transplanting herbicides include; clodinafop @ 0.04, fenoxaprop-p-ethyl @ 1.00, acetochlor @ 0.125 and glyphosate @ 0.95 kg a.i ha-1. None of the herbicides except S-metalocholar had a phytotoxic effect on tobacco. All the parameters except the number of leaves plant-1 were significantly affected by different treatments. The highest (228.3 weeds density m-2 was observed in weedy check while minimum (69 was recorded in pendimethalin (EC treatment. The maximum grade index of 74.60% was recorded in acetochlor and minimum grade index of 53.88% was recorded in S-metalocholar treatments. Nicotine (% was higher in pendimethalin (EC treated plots with 2.362%; however it was comparable to all other treatments. The maximum percent reducing sugar of 18.22% was recorded in pendimethalin (CS treatment, while minimum of 12.42% reducing sugar was recorded in weedy check. Similarly maximum yield of 2465 kg ha-1 was recorded in pendimethalin (EC treatment and minimum yield of 1703 kg ha-1 was recorded in weedy check (control treatment. Thus it can be concluded from the experiment that herbicides proved effective against weeds and their growth and promoted tobacco quality and yield. Hence the use of herbicides not only increases the net income of the farmers but also will make the weed seed bank poorer.

Multi-residues analysis of pre-emergence herbicides in fluvial sediments: application to the mid-Garonne River.

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Devault, Damien A; Merlina, Georges; Lim, Puy; Probst, Jean-Luc; Pinelli, Eric

2007-09-01

Contamination of man and ecosystems by pesticides has become a major environmental concern. Whereas many studies exist on contamination from agriculture, the effects of urban sources are usually omitted. Fluvial sediment is a complex matrix of pollutants but little is known of its recent herbicide content. This study proposes a method for a fast and reliable analysis of herbicides by employing the accelerated solvent extractor (ASE). The aim of the study is to show the impact of a major town (Toulouse) on the herbicide content in the river. In this study, three herbicide families (i.e.s-triazine, substituted ureas and anilides) were analysed in fluvial sediment fractions at 11 sampling sites along the mid-Garonne River and its tributaries. River water contamination by herbicides is minor, except for at three sites located in urban areas. Among the herbicidal families studied, urban and suburban areas are distinguished from rural areas and were found to be the most contaminated sites during the study period, a winter low-water event. The herbicide content of the coarse sediment fractions is about one third of that found in the fine fractions and usually ignored. The distribution of pesticide concentrations across the whole range of particle sizes was investigated to clarify the role of plant remains on the significant accumulation in the coarse fractions.

Selective isolation and screening of fungi with herbicidal potential ...

African Journals Online (AJOL)

The respective fungal isolates were cultivated in modified Fries media under standard condition. The mycelia and the filtrate were extracted with ethyl acetate and the concentrated extract was evaluated for the herbicidal activity adopting leaf necrosis assay. Among the different isolates, extract prepared from A. alternata and ...

Seletividade de herbicidas pós-emergentes na cultura da mandioca Selectivity of post-emergent herbicides for cassava crop

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D.V. Silva

2012-12-01

Full Text Available A resposta da mandioca à aplicação de herbicidas varia desde a total seletividade até o completo comprometimento da produção devido à intoxicação provocada. Desse modo, objetivou-se neste trabalho avaliar a seletividade de herbicidas aplicados em pós-emergência na mandioca. Para isso, foi conduzido experimento em casa de vegetação, em blocos casualizados com 23 tratamentos (22 herbicidas + testemunha, em quatro repetições. Os herbicidas foram aplicados 60 dias após a brotação da mandioca, quando as plantas apresentavam cerca de 15 folhas completamente expandidas. Avaliou-se semanalmente a toxicidade das plantas e, aos 35 dias após a aplicação, elas foram coletadas para determinação da matéria seca. Os sintomas mais visíveis de intoxicação da mandioca ocorreram 21 dias depois da aplicação, para a maioria dos produtos testados. Ao final do período de avaliação, a mandioca apresentava sinais de recuperação dos danos visuais provocados pelos herbicidas tóxicos à cultura. Ametryn, ametryn + trifloxysulfuron-sodium, atrazine, diuron + hexazinone e sulfentrazone provocaram as maiores reduções de matéria seca e causaram os maiores danos visíveis; de modo contrário, bentazon, fluazifop-p-butil, mesotrione e tembotrione foram os menos tóxicos à cultura. Constataram-se diferentes níveis de seletividade dos herbicidas à cultura, sendo bentazon, fluazifop-p-butil, mesotrione e tembotrione os herbicidas considerados seletivos para uso em programas de manejo de plantas daninhas.The cassava response to herbicide application varies from complete selectivity to full production loss due to the poisoning caused. Thus, the objective of this work was to evaluate the selectivity of herbicides applied at post-emergence in cassava. An experiment was arranged in a randomized block design, under greenhouse conditions, including 23 treatments (22 herbicides + control and four replications. The herbicides were applied 60 days

Phytotoxicity of Four Photosystem II Herbicides to Tropical Seagrasses

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Flores, Florita; Collier, Catherine J.; Mercurio, Philip; Negri, Andrew P.

2013-01-01

Coastal waters of the Great Barrier Reef (GBR) are contaminated with agricultural pesticides, including the photosystem II (PSII) herbicides which are the most frequently detected at the highest concentrations. Designed to control weeds, these herbicides are equally potent towards non-target marine species, and the close proximity of seagrass meadows to flood plumes has raised concerns that seagrasses may be the species most threatened by herbicides from runoff. While previous work has identified effects of PSII herbicides on the photophysiology, growth and mortality in seagrass, there is little comparative quantitative toxicity data for seagrass. Here we applied standard ecotoxicology protocols to quantify the concentrations of four priority PSII herbicides that inhibit photochemistry by 10, 20 and 50% (IC10, IC20 and IC50) over 72 h in two common seagrass species from the GBR lagoon. The photosystems of seagrasses Zostera muelleri and Halodule uninervis were shown to be generally more sensitive to the PSII herbicides Diuron, Atrazine, Hexazinone and Tebuthiuron than corals and tropical microalgae. The herbicides caused rapid inhibition of effective quantum yield (∆F/F m ′), indicating reduced photosynthesis and maximum effective yields (Fv/Fm) corresponding to chronic damage to PSII. The PSII herbicide concentrations which affected photosynthesis have been exceeded in the GBR lagoon and all of the herbicides inhibited photosynthesis at concentrations lower than current marine park guidelines. There is a strong likelihood that the impacts of light limitation from flood plumes and reduced photosynthesis from PSII herbicides exported in the same waters would combine to affect seagrass productivity. Given that PSII herbicides have been demonstrated to affect seagrass at environmental concentrations, we suggest that revision of environmental guidelines and further efforts to reduce PSII herbicide concentrations in floodwaters may both help protect seagrass meadows

Phytotoxicity of four photosystem II herbicides to tropical seagrasses.

Science.gov (United States)

Flores, Florita; Collier, Catherine J; Mercurio, Philip; Negri, Andrew P

2013-01-01

Coastal waters of the Great Barrier Reef (GBR) are contaminated with agricultural pesticides, including the photosystem II (PSII) herbicides which are the most frequently detected at the highest concentrations. Designed to control weeds, these herbicides are equally potent towards non-target marine species, and the close proximity of seagrass meadows to flood plumes has raised concerns that seagrasses may be the species most threatened by herbicides from runoff. While previous work has identified effects of PSII herbicides on the photophysiology, growth and mortality in seagrass, there is little comparative quantitative toxicity data for seagrass. Here we applied standard ecotoxicology protocols to quantify the concentrations of four priority PSII herbicides that inhibit photochemistry by 10, 20 and 50% (IC10, IC20 and IC50) over 72 h in two common seagrass species from the GBR lagoon. The photosystems of seagrasses Zosteramuelleri and Haloduleuninervis were shown to be generally more sensitive to the PSII herbicides Diuron, Atrazine, Hexazinone and Tebuthiuron than corals and tropical microalgae. The herbicides caused rapid inhibition of effective quantum yield (∆F/F m '), indicating reduced photosynthesis and maximum effective yields (Fv/Fm ) corresponding to chronic damage to PSII. The PSII herbicide concentrations which affected photosynthesis have been exceeded in the GBR lagoon and all of the herbicides inhibited photosynthesis at concentrations lower than current marine park guidelines. There is a strong likelihood that the impacts of light limitation from flood plumes and reduced photosynthesis from PSII herbicides exported in the same waters would combine to affect seagrass productivity. Given that PSII herbicides have been demonstrated to affect seagrass at environmental concentrations, we suggest that revision of environmental guidelines and further efforts to reduce PSII herbicide concentrations in floodwaters may both help protect seagrass meadows of

Phytotoxicity of four photosystem II herbicides to tropical seagrasses.

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Florita Flores

Full Text Available Coastal waters of the Great Barrier Reef (GBR are contaminated with agricultural pesticides, including the photosystem II (PSII herbicides which are the most frequently detected at the highest concentrations. Designed to control weeds, these herbicides are equally potent towards non-target marine species, and the close proximity of seagrass meadows to flood plumes has raised concerns that seagrasses may be the species most threatened by herbicides from runoff. While previous work has identified effects of PSII herbicides on the photophysiology, growth and mortality in seagrass, there is little comparative quantitative toxicity data for seagrass. Here we applied standard ecotoxicology protocols to quantify the concentrations of four priority PSII herbicides that inhibit photochemistry by 10, 20 and 50% (IC10, IC20 and IC50 over 72 h in two common seagrass species from the GBR lagoon. The photosystems of seagrasses Zosteramuelleri and Haloduleuninervis were shown to be generally more sensitive to the PSII herbicides Diuron, Atrazine, Hexazinone and Tebuthiuron than corals and tropical microalgae. The herbicides caused rapid inhibition of effective quantum yield (∆F/F m ', indicating reduced photosynthesis and maximum effective yields (Fv/Fm corresponding to chronic damage to PSII. The PSII herbicide concentrations which affected photosynthesis have been exceeded in the GBR lagoon and all of the herbicides inhibited photosynthesis at concentrations lower than current marine park guidelines. There is a strong likelihood that the impacts of light limitation from flood plumes and reduced photosynthesis from PSII herbicides exported in the same waters would combine to affect seagrass productivity. Given that PSII herbicides have been demonstrated to affect seagrass at environmental concentrations, we suggest that revision of environmental guidelines and further efforts to reduce PSII herbicide concentrations in floodwaters may both help protect

Fate of 2,4-D herbicide in soil-plant ecosystems

International Nuclear Information System (INIS)

Onal, G.

1983-01-01

Herbicide was applied to wheat, barley and oat plants grown under laboratory, greenhouse and field conditions and the fate of the herbicide was investigated using carbon 14 radioisotope. Results of the investigation indicate that (1) under laboratory condition degradation of the herbicide was faster in the soil, rich in organic matter and was not influenced by humidity; (2) the absorption of the herbicide by the plants was low under greenhouse conditions and (3) the uptake of the chemical by the plants grown in the field was higher in the presence of fertilizer (diammonium phosphate)

Testing Transgenic Aspen Plants with bar Gene for Herbicide Resistance under Semi-natural Conditions.

Science.gov (United States)

Lebedev, V G; Faskhiev, V N; Kovalenko, N P; Shestibratov, K A; Miroshnikov, A I

2016-01-01

Obtaining herbicide resistant plants is an important task in the genetic engineering of forest trees. Transgenic European aspen plants (Populus tremula L.) expressing the bar gene for phosphinothricin resistance have been produced using Agrobacterium tumefaciens-mediated transformation. Successful genetic transformation was confirmed by PCR analysis for thirteen lines derived from two elite genotypes. In 2014-2015, six lines were evaluated for resistance to herbicide treatment under semi-natural conditions. All selected transgenic lines were resistant to the herbicide Basta at doses equivalent to 10 l/ha (twofold normal field dosage) whereas the control plants died at 2.5 l/ha. Foliar NH4-N concentrations in transgenic plants did not change after treatment. Extremely low temperatures in the third ten-day period of October 2014 revealed differences in freeze tolerance between the lines obtained from Pt of f2 aspen genotypes. Stable expression of the bar gene after overwintering outdoors was confirmed by RT-PCR. On the basis of the tests, four transgenic aspen lines were selected. The bar gene could be used for retransformation of transgenic forest trees expressing valuable traits, such as increased productivity.

A comparison of the herbicide tolerances of rare and common plants in an agricultural landscape.

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Egan, J Franklin; Graham, Ian M; Mortensen, David A

2014-03-01

Declining plant biodiversity in agroecosystems has often been attributed to escalating use of chemical herbicides, but other changes in farming systems, including the clearing of seminatural habitat fragments, confound the influence of herbicides. The present study introduces a new approach to evaluate the impacts of herbicide pollution on plant communities at landscape or regional scales. If herbicides are in fact a key factor shaping agricultural plant diversity, one would expect to see the signal of past herbicide impacts in the current plant community composition of an intensively farmed region, with common, successful species more tolerant to widely used herbicides than rare or declining species. Data from an extensive field survey of plant diversity in Lancaster County, Pennsylvania, USA, were compared with herbicide bioassay experiments in a greenhouse to test the hypothesis that common species possess higher herbicide tolerances than rare species. Five congeneric pairs of rare and common species were treated with 3 commonly used herbicide modes of action in bioassay experiments, and few significant differences were found in the tolerances of rare species relative to common species. These preliminary results suggest that other factors beyond herbicide exposure may be more important in shaping the distribution and abundance of plant species diversity across an agricultural landscape. © 2014 SETAC.

Transmission System Vegetation Management Program. Draft Environmental Impact Statement

International Nuclear Information System (INIS)

1999-01-01

Bonneville is responsible for maintaining a network of 24,000 kilometers (km) or 15,000 miles (mi.) of electric transmission lines and 350 substations in a region of diverse vegetation. This vegetation can interfere with electric power flow, pose safety problems for Bonneville and the public, and interfere with their ability to maintain these facilities. They need to (1) keep vegetation away from the electric facilities; (2) increase their program efficiency and consistency; (3) review herbicide use (under increased public scrutiny); and (4) maximize the range of tools they can use while minimizing environmental impact (Integrated Vegetation Management). This DEIS establishes Planning Steps for managing vegetation for specific projects (to be tiered to this EIS). In addition to No Action (current practice), alternatives are presented for Rights-of-way, Electric Yards, and Non-electric Facilities (landscaping, work yards). Four vegetation control methods are analyzed: manual, mechanical, herbicide, and biological. Also evaluated are 24 herbicide active ingredients and 4 herbicide application techniques (spot, localized, broadcast, and aerial). For rights-of-way, they consider three sets of alternatives: alternative management approaches (time-driven or establishing low-growing plant communities); alternative method packages; and, if herbicides are in a methods package, alternative vegetation selections (noxious weeds, deciduous, or any vegetation). For electric yards, one herbicide-use alternative is considered. For non-electric facilities, two method package alternatives are considered. For rights-of-way, the environmentally preferred alternative(s) would use manual, mechanical, and biological control methods, as well as spot and localized herbicide applications for noxious and deciduous plant species; the BPA-preferred alternative(s) would add broadcast and aerial herbicide applications, and would use herbicides on any vegetation. Both would favor a management

Plant reproduction is altered by simulated herbicide drift to constructed plant communities

Science.gov (United States)

Herbicide drift may have unintended impacts on native vegetation, adversely affecting structure and function of plant communities. However, these potential effects have been rarely studied or quantified. To determine potential ecological effects of herbicide drift, we construct...

Plant breeding by using radiation mutation - Selection of herbicide-resistant cell lines by using {gamma}-rays

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyo Yeon [Sunchun University, Sunchun (Korea); Seo, Yong Weon [Korea University, Seoul (Korea)

2000-04-01

In order to develop the herbicide resistant cell lines, micro calli derived from rice anther culture and mature seed of wheat cultivars were irradiated with gamma rays. 1) The callus was dedifferentiated by 7 or 21 day pretreatment at 7 deg. C in two rice cultivars, Ilpumbyeo ad Dongjinbyeo. 2) To check the optimum concentration of herbicide, three herbicides were tested with micro calli. 3) The optimum dose of gamma ray to seeds of wheat seemed to be from 100 to 150 Gy. 4) AFLP and RAPD technique were established to develope herbicide resistant molecular marker in rice. 34 refs., 10 figs., 5 tabs. (Author)

Efficacy of selected herbicide formulations on sugarcane field weeds ...

African Journals Online (AJOL)

In continuation for the search of appropriate weed control strategy for sugarcane field weeds at the Unilorin Sugar Research Institute (USRI), Ilorin located at 8o 030' N; 4o 32' E , Nigeria. Field trials were laid out in a randomized complete block design during 2012 and 2013 growing seasons to evaluate four herbicide ...

Effects of selected herbicides and fungicides on growth, sporulation and conidial germination of entomopathogenic fungus Beauveria bassiana.

Science.gov (United States)

Celar, Franci A; Kos, Katarina

2016-11-01

The in vitro fungicidal effects of six commonly used fungicides, namely fluazinam, propineb, copper(II) hydroxide, metiram, chlorothalonil and mancozeb, and herbicides, namely isoxaflutole, fluazifop-P-butyl, flurochloridone, foramsulfuron, pendimethalin and prosulfocarb, on mycelial growth, sporulation and conidial germination of entomopathogenic fungus Beauveria bassiana (ATCC 74040) were investigated. Mycelial growth rates and sporulation at 15 and 25 °C were evaluated on PDA plates containing 100, 75, 50, 25, 12.5, 6.25 and 0% of the recommended application rate of each pesticide. The tested pesticides were classified in four scoring categories based on reduction in mycelial growth and sporulation. All pesticides, herbicides and fungicides tested had fungistatic effects of varying intensity, depending on their rate in the medium, on B. bassiana. The most inhibitory herbicides were flurochloridone and prosulfocarb, and fluazinam and copper(II) hydroxide were most inhibitory among the fungicides, while the least inhibitory were isoxaflutole and chlorothalonil. Sporulation and conidial germination of B. bassiana were significantly inhibited by all tested pesticides compared with the control treatment. Flurochloridone, foramsulfuron, prosulfocarb and copper(II) hydroxide inhibited sporulation entirely at 100% rate (99-100% inhibition), and the lowest inhibition was shown by fluazifop-P-butyl (22%) and metiram (33%). At 100% dosage, all herbicides in the test showed a high inhibitory effect on conidial germination. Conidial germination inhibition ranged from 82% with isoxaflutole to 100% with fluorochloridone, pendimethalin and prosulfocarb. At 200% dosage, inhibition rates even increased (96-100%). All 12 pesticides tested had a fungistatic effect on B. bassiana of varying intensity, depending on the pesticide and its concentration. B. bassiana is highly affected by some herbicides and fungicides even at very low rates. Flurochloridone, foramsulfuron

Perspectives on transgenic, herbicide-resistant crops in the United States almost 20 years after introduction.

Science.gov (United States)

Duke, Stephen O

2015-05-01

Herbicide-resistant crops have had a profound impact on weed management. Most of the impact has been by glyphosate-resistant maize, cotton, soybean and canola. Significant economic savings, yield increases and more efficacious and simplified weed management have resulted in widespread adoption of the technology. Initially, glyphosate-resistant crops enabled significantly reduced tillage and reduced the environmental impact of weed management. Continuous use of glyphosate with glyphosate-resistant crops over broad areas facilitated the evolution of glyphosate-resistant weeds, which have resulted in increases in the use of tillage and other herbicides with glyphosate, reducing some of the initial environmental benefits of glyphosate-resistant crops. Transgenic crops with resistance to auxinic herbicides, as well as to herbicides that inhibit acetolactate synthase, acetyl-CoA carboxylase and hydroxyphenylpyruvate dioxygenase, stacked with glyphosate and/or glufosinate resistance, will become available in the next few years. These technologies will provide additional weed management options for farmers, but will not have all of the positive effects (reduced cost, simplified weed management, lowered environmental impact and reduced tillage) that glyphosate-resistant crops had initially. In the more distant future, other herbicide-resistant crops (including non-transgenic ones), herbicides with new modes of action and technologies that are currently in their infancy (e.g. bioherbicides, sprayable herbicidal RNAi and/or robotic weeding) may affect the role of transgenic, herbicide-resistant crops in weed management. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Effects of the herbicide imazapyr on juvenile Oregon spotted frogs

Science.gov (United States)

Yahnke, Amy E.; Grue, Christian E.; Hayes, Marc P.; Troiano, Alexandra T.

2013-01-01

Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5 L/ha) and high-volume (7.0 L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs.

Herbicide Safeners Decrease Sensitivity to Herbicides Inhibiting Acetolactate-Synthase and Likely Activate Non-Target-Site-Based Resistance Pathways in the Major Grass Weed Lolium sp. (Rye-Grass

Directory of Open Access Journals (Sweden)

Arnaud Duhoux

2017-08-01

Full Text Available Herbicides are currently pivotal to control weeds and sustain food security. Herbicides must efficiently kill weeds while being as harmless as possible for crops, even crops taxonomically close to weeds. To increase their selectivity toward crops, some herbicides are sprayed in association with safeners that are bioactive compounds exacerbating herbicide-degrading pathways reputedly specifically in crops. However, exacerbated herbicide metabolism is also a key mechanism underlying evolved non-target-site-based resistance to herbicides (NTSR in weeds. This raised the issue of a possible role of safeners on NTSR evolution in weeds. We investigated a possible effect of the respective field rates of the two broadly used safeners cloquintocet-mexyl and mefenpyr-diethyl on the sensitivity of the troublesome global weed Lolium sp. (rye-grass to the major herbicides inhibiting acetolactate-synthase (ALS pyroxsulam and iodosulfuron + mesosulfuron, respectively. Three Lolium sp. populations were studied in three series of experiments. The first experiment series compared the frequencies of plants surviving application of each herbicide alone or in association with its safener. Safener co-application caused a net increase ranging from 5.0 to 46.5% in the frequency of plants surviving the field rate of their associated herbicide. In a second series of experiments, safener effect was assessed on individual plant sensitivity using vegetative propagation. A reduction in sensitivity to pyroxsulam and to iodosulfuron + mesosulfuron was observed for 44.4 and 11.1% of the plants in co-treatment with cloquintocet-mexyl and mefenpyr-diethyl, respectively. A third series of experiments investigated safener effect on the expression level of 19 Lolium sp. NTSR marker genes. Safeners showed an enhancing effect on the expression level of 10 genes. Overall, we demonstrated that cloquintocet-mexyl and mefenpyr-diethyl both reduced the sensitivity of Lolium sp. to their

Herbicide Safeners Decrease Sensitivity to Herbicides Inhibiting Acetolactate-Synthase and Likely Activate Non-Target-Site-Based Resistance Pathways in the Major Grass Weed Lolium sp. (Rye-Grass).

Science.gov (United States)

Duhoux, Arnaud; Pernin, Fanny; Desserre, Diane; Délye, Christophe

2017-01-01

Herbicides are currently pivotal to control weeds and sustain food security. Herbicides must efficiently kill weeds while being as harmless as possible for crops, even crops taxonomically close to weeds. To increase their selectivity toward crops, some herbicides are sprayed in association with safeners that are bioactive compounds exacerbating herbicide-degrading pathways reputedly specifically in crops. However, exacerbated herbicide metabolism is also a key mechanism underlying evolved non-target-site-based resistance to herbicides (NTSR) in weeds. This raised the issue of a possible role of safeners on NTSR evolution in weeds. We investigated a possible effect of the respective field rates of the two broadly used safeners cloquintocet-mexyl and mefenpyr-diethyl on the sensitivity of the troublesome global weed Lolium sp. (rye-grass) to the major herbicides inhibiting acetolactate-synthase (ALS) pyroxsulam and iodosulfuron + mesosulfuron, respectively. Three Lolium sp. populations were studied in three series of experiments. The first experiment series compared the frequencies of plants surviving application of each herbicide alone or in association with its safener. Safener co-application caused a net increase ranging from 5.0 to 46.5% in the frequency of plants surviving the field rate of their associated herbicide. In a second series of experiments, safener effect was assessed on individual plant sensitivity using vegetative propagation. A reduction in sensitivity to pyroxsulam and to iodosulfuron + mesosulfuron was observed for 44.4 and 11.1% of the plants in co-treatment with cloquintocet-mexyl and mefenpyr-diethyl, respectively. A third series of experiments investigated safener effect on the expression level of 19 Lolium sp. NTSR marker genes. Safeners showed an enhancing effect on the expression level of 10 genes. Overall, we demonstrated that cloquintocet-mexyl and mefenpyr-diethyl both reduced the sensitivity of Lolium sp. to their associated ALS

Herbicides: A new threat to the Great Barrier Reef

International Nuclear Information System (INIS)

Lewis, Stephen E.; Brodie, Jon E.; Bainbridge, Zoe T.; Rohde, Ken W.; Davis, Aaron M.; Masters, Bronwyn L.; Maughan, Mirjam; Devlin, Michelle J.; Mueller, Jochen F.; Schaffelke, Britta

2009-01-01

The runoff of pesticides (insecticides, herbicides and fungicides) from agricultural lands is a key concern for the health of the iconic Great Barrier Reef, Australia. Relatively low levels of herbicide residues can reduce the productivity of marine plants and corals. However, the risk of these residues to Great Barrier Reef ecosystems has been poorly quantified due to a lack of large-scale datasets. Here we present results of a study tracing pesticide residues from rivers and creeks in three catchment regions to the adjacent marine environment. Several pesticides (mainly herbicides) were detected in both freshwater and coastal marine waters and were attributed to specific land uses in the catchment. Elevated herbicide concentrations were particularly associated with sugar cane cultivation in the adjacent catchment. We demonstrate that herbicides reach the Great Barrier Reef lagoon and may disturb sensitive marine ecosystems already affected by other pressures such as climate change. - Herbicide residues have been detected in Great Barrier Reef catchment waterways and river water plumes which may affect marine ecosystems.

DSSHerbicide: Herbicide field trials in winter wheat. How to come to a decision

Directory of Open Access Journals (Sweden)

Sefzat, David

2014-02-01

Full Text Available Herbicide decision support systems can calculate efficient, economically optimized herbicide mixtures with reduced dosages, if field specific weed data are given. Thus, they can be a sensible tool for integrated weed control. However, advises of decision support systems have to be tested before introducing them into practical farming. In Mecklenburg-Vorpommern two herbicide field trials were installed with four different prototypes of decision support systems. An untreated plot and three expert advices, private advisors, official advisory service and a farmer decision, were included as additional test variables. Herbicide efficacies in autumn, weed dry matter after spring applications, herbicide costs and wheat yield were measured to evaluate the decision support system prototypes. In one field trial with low weed density before treatments efficacies were at least 85%. In two prototypes efficacies were lower than in the expert plots. No significant differences between decision variables were found regarding weed dry matter after spraying in spring. On this site, herbicide costs were higher when expert advises were used compared to decision support system advises. No significant differences were detected in yield. Even yield in “untreated” was not significantly different. The second field trial carried higher weed densities. Here herbicide efficacies were lower in all treatments. Poa annua and Matricaria recutita were significantly affected by the treatments resulting from the decision tools. However, these differences did not result in statistically different weed dry matter or wheat yield. Three of the prototypes advised solutions with very low herbicide costs in autumn, but high costs in spring. As a result, total weed costs in these plots were higher than in the plots advised by experts. It is concluded from the field trials, that different prototypes of decision support systems are giving sensible herbicide advice. In fields with low

Seletividade do herbicida fluazifop-p-butil para cucurbitáceas Selectivity of the herbicide fluazifop-p-buthyl for cucurbitaceae

Directory of Open Access Journals (Sweden)

R.A. Vidal

2000-01-01

Full Text Available Experimentos foram conduzidos em condições de casa de vegetação, com o objetivo de avaliar a seletividade do herbicida fluazifop-p-butil nas doses de 0, 94, 188, 376 e 752 g i.a. ha-1 para cinco espécies de cucurbitáceas (abobrinha, melancia, melão, moranga e pepino. Foi determinada a fitotoxicidade aos 14 dias após a aplicação dos tratamentos (DAT. Aos 20 DAT foram avaliadas a estatura, área foliar e matéria seca. O melão e o pepino mostraram sensibilidade ao fluazifop-p-butil na maior dose estudada, com maior intensidade no melão. Os resultados demonstraram que existe resposta a estes herbicidas mesmo dentro da classe Dicotiledoneae. Especula-se que essas respostas possam auxiliar no entendimento do completo mecanismo de ação desse herbicida.Experiments were conducted under greenhouse conditions to evaluate the selectivity of the herbicide fluazifop-p-buthyl at rates of 0, 94, 188 and 752 g a.i. ha-1 for five cucurbitaceous species (summer squash, watermelon, melon, pumpkin and cucumber. Plant injury at 14 days after treatments (DAT and plant size, leaf area and dry weight at 20 DAT were determined. Melon and cucumber were susceptible to fluazifop-p-buthyl at the highest rate with highest herbicide effect being observed on melon. These results indicated that responses to these herbicides occur, even in the Dicotiledonae class. These responses are thought to help understand the overall mechanism of action of this herbicide.

Transcript markers of herbicide stress in Arabidopsis and their cross-species extrapolation to Brassica

Science.gov (United States)

Low concentrations and short environmental persistence times of some herbicides make it difficult to develop analytical methods to detect herbicide residues in plants or soils. In contrast, genomics may provide tools to identify herbicide exposure to plants in field settings. Usi...

Histopathological study on the effect of rice herbicides on grass carp ...

African Journals Online (AJOL)

user

2011-02-14

Feb 14, 2011 ... observe the impact of herbicides on the histopathology of the fish, the fingerlings were collected from the field trenches ... is almost non-existent in India; the reasons being that increasing ... intensive rice-cum-fish culture offered the opportunity for ..... Toxicity of herbicides to Malaysian rice field fish. In: Proc.

Effects of herbicides on fish

DEFF Research Database (Denmark)

Solomon, Keith R.; Dalhoff, Kristoffer; Volz, David

2013-01-01

Herbicides are used to control weeds and are usually targeted to processes and target sites that are specific to plants. As a result, most herbicides are not acutely toxic to fish. Exceptions to this general rule are uncouplers of oxidative phosphorylation and some herbicides that interfere...... with cell division. Chronic and sublethal effects have been studied for some herbicides, but fewer data are available for these effects than for acute effects. The sublethal effects of herbicides that have been studied include reproduction, stress, olfaction, and behavior. Although some of these responses......, and reproduction. As with all pesticides, herbicides may have indirect effects in fish. These effects are mediated by herbicide-induced changes in food webs or in the physical environment. Indirect effects can only occur if direct effects occur first and would be mediated by the killing of plants by herbicides...

Subcritical water extraction combined with molecular imprinting technology for sample preparation in the detection of triazine herbicides.

Science.gov (United States)

Zhao, Fengnian; Wang, Shanshan; She, Yongxin; Zhang, Chao; Zheng, Lufei; Jin, Maojun; Shao, Hua; Jin, Fen; Du, Xinwei; Wang, Jing

2017-09-15

A selective, environmentally friendly, and cost-effective sample extraction method based on a combination of subcritical water extraction (SWE) and molecularly imprinted solid-phase extraction (MISPE) was developed for the determination of eight triazine herbicides in soil samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In SWE, the highest extraction yields of triazine herbicides were obtained under 150°C for 15min using 20% ethanol as the organic modifier. Addition of MIP during SWE increased the extraction efficiency, and using MIP as a selective SPE sorbent improved the enrichment capability. Soil samples were treated with the optimized extraction MIP/SWE-MISPE method and analyzed by LC-MS/MS. The novel technique was then applied to soil samples for the determination of triazine herbicides, and better recoveries (78.9%-101%) were obtained compared with using SWE-MISPE (30%-67%). Moreover, this newly developed method displayed good linearity (R 2 >0.99) and precision (2.7-9.8%), and low enough detection limits (0.4-3.3μgkg -1 ). This combination of SWE and MIP technology is a simple, effective and promising method to selectively extract class-specific compounds in complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Histopathological study on the effect of rice herbicides on grass carp ...

African Journals Online (AJOL)

Grass carp (Ctenopharyngodan idella) fingerlings were exposed to rice herbicides butachlor 1.5 kg ha-1, oxyfluorfen 0.25 kg ha-1 and thiobencarb 1.5 kg ha-1, 12 days after their application in the respective fields. To observe the impact of herbicides on the histopathology of the fish, the fingerlings were collected from the ...

Weed control changes and genetically modified herbicide tolerant crops in the USA 1996-2012.

Science.gov (United States)

Brookes, Graham

2014-01-01

Crops that have been genetically modified (GM) to be tolerant to herbicides have been widely grown in the USA since 1996. The rapid and widespread adoption of this technology reflects the important economic and environmental benefits that farmers have derived from its use (equal to $21.7 billion additional farm income and a 225 million kg reduction in herbicide active ingredient use 1996-2012). During this time, weed control practices in these crops relative to the 'conventional alternative' have evolved to reflect experience of using the technology, the challenges that have arisen and the increasing focus in recent years on developing sustainable production systems. This paper examines the evidence on the changing nature of herbicides used with these crops and in particular how farmers addressed the challenge of weed resistance. The evidence shows that use of the technology has resulted in a net reduction in both the amount of herbicide used and the associated environmental impact, as measured by the EIQ indicator when compared to what can reasonably be expected if the area planted to GM HT crops reverted to conventional production methods. It also facilitated many farmers being able to derive the economic and environmental benefits associated with switching from a plough-based to a no tillage or conservation tillage production system. In terms of herbicide use, the technology has also contributed to a change the profile of herbicides used. A broad range of, mostly selective herbicides has been replaced by one or 2 broad-spectrum herbicides (mostly glyphosate) used in conjunction with one or 2 other (complementary) herbicides. Since the mid-2000s, the average amount of herbicide applied and the associated environmental load, as measured by the EIQ indicator, have increased on both GM HT and conventional crops. A primary reason for these changes has been increasing incidence of weed species developing populations resistant to herbicides and increased awareness of

Lethal and sub-lethal chronic effects of the herbicide diuron on seagrass

Energy Technology Data Exchange (ETDEWEB)

Negri, Andrew P., E-mail: a.negri@aims.gov.au [Australian Institute of Marine Science, Townsville, Queensland 4810 (Australia); Flores, Florita [Australian Institute of Marine Science, Townsville, Queensland 4810 (Australia); Mercurio, Phil [Australian Institute of Marine Science, Townsville, Queensland 4810 (Australia); University of Queensland and National Research Centre for Environmental Toxicology, Coopers Plains, Queensland 4108 (Australia); Mueller, Jochen F. [University of Queensland and National Research Centre for Environmental Toxicology, Coopers Plains, Queensland 4108 (Australia); Collier, Catherine J. [Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER), James Cook University, Cairns, Queensland 4870 (Australia)

2015-08-15

Highlights: • We performed chronic exposures of two seagrass species to the herbicide diuron. • Diuron affected photosystem II (PSII) at 0.3 μg l{sup −1} and growth at 7.2 μg l{sup −1}. • Biomarkers indicated that carbon-assimilation from photosynthesis dropped following 0.6 μg l{sup −1} diuron exposure. • Energetic reserves in the seagrass were halved at 1.7 μg l{sup −1} after 11 weeks. • Chronic exposure to diuron is likely to enhance the impacts of low light stress during flood plumes - Abstract: Photosystem II herbicides from agricultural sources have been detected throughout nearshore tropical habitats including seagrass meadows. While PSII herbicides have been shown to inhibit growth in microalgae at low concentrations, the potential impacts of chronic low concentration exposures to seagrass health and growth have not been investigated. Here we exposed two tropical seagrass species Halodule uninervis and Zostera muelleri to elevated diuron concentrations (from 0.3 to 7.2 μg l{sup −1}) over a 79-day period followed by a 2-week recovery period in uncontaminated seawater. PAM fluorometry demonstrated rapid effect of diuron on photosystem II (PSII) in both seagrass species at 0.3 μg l{sup −1}. This effect included significant inhibition of photosynthetic efficiency (ΔF/F{sub m}′) and inactivation of PSII (F{sub v}/F{sub m}) over the 11 week exposure period. Significant mortality and reductions in growth was only observed at the highest exposure concentration of 7.2 μg l{sup −1} diuron. However, biochemical indicators demonstrated that the health of seagrass after this prolonged exposure was significantly compromised at lower concentrations. For example, the drop in C:N ratios (0.6 μg l{sup −1}) and reduced δ{sup 13}C (1.7 μg l{sup −1}) in seagrass leaves indicated reduced C-assimilation from photosynthesis. Critically, the energetic reserves of the plants (as measured by starch content in the root-rhizome complex) were

Lethal and sub-lethal chronic effects of the herbicide diuron on seagrass

International Nuclear Information System (INIS)

Negri, Andrew P.; Flores, Florita; Mercurio, Phil; Mueller, Jochen F.; Collier, Catherine J.

2015-01-01

Highlights: • We performed chronic exposures of two seagrass species to the herbicide diuron. • Diuron affected photosystem II (PSII) at 0.3 μg l −1 and growth at 7.2 μg l −1 . • Biomarkers indicated that carbon-assimilation from photosynthesis dropped following 0.6 μg l −1 diuron exposure. • Energetic reserves in the seagrass were halved at 1.7 μg l −1 after 11 weeks. • Chronic exposure to diuron is likely to enhance the impacts of low light stress during flood plumes - Abstract: Photosystem II herbicides from agricultural sources have been detected throughout nearshore tropical habitats including seagrass meadows. While PSII herbicides have been shown to inhibit growth in microalgae at low concentrations, the potential impacts of chronic low concentration exposures to seagrass health and growth have not been investigated. Here we exposed two tropical seagrass species Halodule uninervis and Zostera muelleri to elevated diuron concentrations (from 0.3 to 7.2 μg l −1 ) over a 79-day period followed by a 2-week recovery period in uncontaminated seawater. PAM fluorometry demonstrated rapid effect of diuron on photosystem II (PSII) in both seagrass species at 0.3 μg l −1 . This effect included significant inhibition of photosynthetic efficiency (ΔF/F m ′) and inactivation of PSII (F v /F m ) over the 11 week exposure period. Significant mortality and reductions in growth was only observed at the highest exposure concentration of 7.2 μg l −1 diuron. However, biochemical indicators demonstrated that the health of seagrass after this prolonged exposure was significantly compromised at lower concentrations. For example, the drop in C:N ratios (0.6 μg l −1 ) and reduced δ 13 C (1.7 μg l −1 ) in seagrass leaves indicated reduced C-assimilation from photosynthesis. Critically, the energetic reserves of the plants (as measured by starch content in the root-rhizome complex) were approximately halved following diuron exposure at and above

Effect of sugarcane cropping systems on herbicide losses in surface runoff.

Science.gov (United States)

Nachimuthu, Gunasekhar; Halpin, Neil V; Bell, Michael J

2016-07-01

Herbicide runoff from cropping fields has been identified as a threat to the Great Barrier Reef ecosystem. A field investigation was carried out to monitor the changes in runoff water quality resulting from four different sugarcane cropping systems that included different herbicides and contrasting tillage and trash management practices. These include (i) Conventional - Tillage (beds and inter-rows) with residual herbicides used; (ii) Improved - only the beds were tilled (zonal) with reduced residual herbicides used; (iii) Aspirational - minimum tillage (one pass of a single tine ripper before planting) with trash mulch, no residual herbicides and a legume intercrop after cane establishment; and (iv) New Farming System (NFS) - minimum tillage as in Aspirational practice with a grain legume rotation and a combination of residual and knockdown herbicides. Results suggest soil and trash management had a larger effect on the herbicide losses in runoff than the physico-chemical properties of herbicides. Improved practices with 30% lower atrazine application rates than used in conventional systems produced reduced runoff volumes by 40% and atrazine loss by 62%. There were a 2-fold variation in atrazine and >10-fold variation in metribuzin loads in runoff water between reduced tillage systems differing in soil disturbance and surface residue cover from the previous rotation crops, despite the same herbicide application rates. The elevated risk of offsite losses from herbicides was illustrated by the high concentrations of diuron (14μgL(-1)) recorded in runoff that occurred >2.5months after herbicide application in a 1(st) ratoon crop. A cropping system employing less persistent non-selective herbicides and an inter-row soybean mulch resulted in no residual herbicide contamination in runoff water, but recorded 12.3% lower yield compared to Conventional practice. These findings reveal a trade-off between achieving good water quality with minimal herbicide contamination and

Discharge of landfill leachate to streambed sediments impacts the mineralization potential of phenoxy acid herbicides depending on the initial abundance of tfdA gene classes

DEFF Research Database (Denmark)

Pazarbasi, Meric Batioglu; Milosevic, Nemanja; Malaguerra, Flavio

2013-01-01

discharge to SM3, and lower herbicide mass discharges to SM1 and SM2 were determined due to groundwater discharge rates and herbicide concentrations. SM1-sediment with the lowest abundance of tfdA gene classes had the slowest mineralization, whereas SM2- and SM3-sediments with more abundant tfdA genes had......To understand the role of abundance of tfdA gene classes belonging to β- and γ-proteobacteria on phenoxy acid herbicide degradation, streambed sediments were sampled around three seepage meters (SMs) installed in a landfill-impacted groundwater–surface water interface. Highest herbicide mass...... faster mineralization. The observed difference in mineralization rates between discharge zones was simulated by a Monod-based kinetic model, which confirmed the role of abundance of tfdA gene classes. This study suggests presence of specific degraders adapted to slow growth rate and high yield strategy...

In situ impact of multiple pulses of metal and herbicide on the seagrass, Zostera capricorni.

Science.gov (United States)

Macinnis-Ng, Catriona M O; Ralph, Peter J

2004-04-28

Tides and freshwater inflow which influence water movement in estuarine areas govern the exposure-regime of pollutants. In this experiment, we examined the in situ impact of double pulses of copper and the herbicide Irgarol 1051 on the photosynthesis of the seagrass, Zostera capricorni. Despite a 4-day recovery period between the two 10h pulses of toxicant, the effective quantum yield of photosystem II (DeltaF/Fm') and total chlorophyll concentrations indicated that multiple-pulses had a greater impact than a single pulse. During the first exposure period, samples exposed to Irgarol 1051 had DeltaF/Fm' values as low as zero while controls remained around 0.6 relative units. After the second exposure period, treated samples recovered to only 0.4 relative units. Samples exposed to copper had DeltaF/Fm' values around 0.3 relative units during the first exposure period and while these samples recovered before the second dose, they remained below 0.2 relative units after the second exposure period. Alternate samples were also exposed to one toxicant, allowed to recover and then exposed to the other toxicant. DeltaF/Fm' values indicated that copper exposure followed by Irgarol 1051 exposure was more toxic than Irgarol 1051 exposure followed by copper exposure.

In situ impact of multiple pulses of metal and herbicide on the seagrass, Zostera capricorni

International Nuclear Information System (INIS)

Macinnis-Ng, Catriona M.O.; Ralph, Peter J.

2004-01-01

Tides and freshwater inflow which influence water movement in estuarine areas govern the exposure-regime of pollutants. In this experiment, we examined the in situ impact of double pulses of copper and the herbicide Irgarol 1051 on the photosynthesis of the seagrass, Zostera capricorni. Despite a 4-day recovery period between the two 10 h pulses of toxicant, the effective quantum yield of photosystem II (ΔF/Fm') and total chlorophyll concentrations indicated that multiple-pulses had a greater impact than a single pulse. During the first exposure period, samples exposed to Irgarol 1051 had ΔF/Fm' values as low as zero while controls remained around 0.6 relative units. After the second exposure period, treated samples recovered to only 0.4 relative units. Samples exposed to copper had ΔF/Fm' values around 0.3 relative units during the first exposure period and while these samples recovered before the second dose, they remained below 0.2 relative units after the second exposure period. Alternate samples were also exposed to one toxicant, allowed to recover and then exposed to the other toxicant. ΔF/Fm' values indicated that copper exposure followed by Irgarol 1051 exposure was more toxic than Irgarol 1051 exposure followed by copper exposure

In situ impact of multiple pulses of metal and herbicide on the seagrass, Zostera capricorni

Energy Technology Data Exchange (ETDEWEB)

Macinnis-Ng, Catriona M.O.; Ralph, Peter J

2004-04-28

Tides and freshwater inflow which influence water movement in estuarine areas govern the exposure-regime of pollutants. In this experiment, we examined the in situ impact of double pulses of copper and the herbicide Irgarol 1051 on the photosynthesis of the seagrass, Zostera capricorni. Despite a 4-day recovery period between the two 10 h pulses of toxicant, the effective quantum yield of photosystem II ({delta}F/Fm') and total chlorophyll concentrations indicated that multiple-pulses had a greater impact than a single pulse. During the first exposure period, samples exposed to Irgarol 1051 had {delta}F/Fm' values as low as zero while controls remained around 0.6 relative units. After the second exposure period, treated samples recovered to only 0.4 relative units. Samples exposed to copper had {delta}F/Fm' values around 0.3 relative units during the first exposure period and while these samples recovered before the second dose, they remained below 0.2 relative units after the second exposure period. Alternate samples were also exposed to one toxicant, allowed to recover and then exposed to the other toxicant. {delta}F/Fm' values indicated that copper exposure followed by Irgarol 1051 exposure was more toxic than Irgarol 1051 exposure followed by copper exposure.

Selectivity and weed control efficacy of some herbicides applied to sprinkler irrigated rice (Oryza sativa L.)

Energy Technology Data Exchange (ETDEWEB)

Cavero, J; Zaragoza, C; Cirujeda, A; Anzalone, A; Faci, J M; Blanco, O

2011-07-01

Sprinkler irrigation can reduce the irrigation water needed to grow rice. However, most available information on weed control with herbicides is related to flood irrigated rice because this is the main growing method. Field experiments were conducted at Zaragoza (Spain) during two years to study weed control and tolerance of sprinkler irrigated rice to several herbicides. The main weeds were Atriplex prostrata Boucher ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. and Sonchus oleraceus L. Rice cv Guadiamar was tolerant to preemergence (PRE) application of clomazone at 0.36 kg ha{sup -}1 and oxadiazon at 0.5 kg ha{sup -}1. PRE application of pendimethalin at 1.32 kg ha{sup -}1 combined with clomazone at 0.36 kg ha{sup -}1 decreased rice yield. Postemergence (POST) application of bentazon at 1.6 kg ha{sup -}1 + MCPA at 0.25 kg ha{sup -}1 did not injure rice but POST application of azimsulfuron at 0.025 kg ha{sup -}1 produced visual crop injury. Only treatments that controlled grassy weeds since rice was planted and by more than 80% at harvest time lead to acceptable rice yield (> 5,000 kg ha{sup -}1). Clomazone applied PRE at 0.36 kg ha{sup -}1 provided good control of grassy weeds (> 80%) and the highest rice yield, so it is recommended as a selective and efficacious PRE treatment for weed control of annual weeds in sprinkler irrigated rice. The perennial purple nutsedge was difficult to control at high plant densities (> 150 plants m{sup -}2) and the recommended herbicide is azimsulfuron applied at POST at 0.02 kg ha{sup -}1. (Author) 37 refs.

Sensitivity of Phaseolus vulgaris cv. `CIAP 7247F' plants to Glufosinate ammonium herbicide in greenhouse

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Idalmis Bermúdez-Caraballoso

2014-01-01

Full Text Available Genetic breeding in Phaseolus by genetic transformation requires an efficient selection system. The present investigation was aimed to determine the minimum lethal concentration of glufosinate-ammonium (Finale ® in beans plants cv. `CIAP 7247F' grown in greenhouse. Different concentrations of the herbicide were applied to the foliage of plants in acclimatization phase (20, 30 y 40 mg l-1 and the control. Results showed that the minimum lethal concentration in plants in acclimatization phase was 30 mg l-1. Results also demonstrated that is possible the use of the herbicide as a selective agent of beans transformants cv. `CIAP 7247F' carrying the bar gene. Keywords: genetic transformation, herbicide, selective agent, tissue culture

Controlled Release Formulations of Auxinic Herbicides

Science.gov (United States)

Kowalski, Witold J.; Siłowiecki, Andrzej.; Romanowska, Iwona; Glazek, Mariola; Bajor, Justyna; Cieciwa, Katarzyna; Rychter, Piotr

2013-04-01

Controlled release formulations are applied extensively for the release of active ingredients such as plant protection agents and fertilizers in response to growing concern for ecological problems associated with increased use of plant protection chemicals required for intensive agricultural practices [1]. We synthesized oligomeric mixtures of (R,S)-3-hydroxy butyric acid chemically bonded with 2,4-D, Dicamba and MCPA herbicides (HBA) respectively, and determined their molecular structure and molecular weight dispersion by the size exclusion chromatography, proton magnetic resonance spectrometry and electro-spray ionization mass spectrometry. Further we carried out bioassays of herbicidal effectiveness of the HBA herbicides vs. series of dicotyledonous weeds and crop injury tests [2, 3, 4]. Field bioassays were accomplished according to the EPPO standards [5]. Groups of representative weeds (the development stages in the BCCH scale: 10 - 30) were selected as targets. Statistical variabilities were assessed by the Fisher LSD test for plants treated with the studied herbicides in form of HBA oligomers, the reference herbicides in form of dimethyl ammonium salts (DMA), and untreated plants. No statistically significant differences in the crop injuries caused by the HBA vs. the DMA reference formulation were observed. The effectiveness of the HBA herbicides was lower through the initial period (ca. 2 weeks) relative to the DMA salts, but a significant increase in the effectiveness of the HBA systems followed during the remaining fraction of each assay. After 6 weeks all observed efficiencies approached 100%. The death of weeds treated with the HBA herbicides was delayed when compared with the DMA reference herbicides. The delayed uptake observed for the HBA oligomers relative to the DMA salts was due to controlled release phenomena. In case of the DMA salts the total amount of active ingredients was available at the target site. By contrast, the amount of an active

The influence of selected spraying parameters on two formulation of sulfonylurea herbicides effect

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Renata KIELOCH

2013-03-01

Full Text Available The objective of this study was the evaluation of spray volume and nozzle type effect on different formulation (water dispersible granules - WG and oil dispersion - OD of two sulfonylurea herbicides: the mixture iodosulfuron methyl sodium + amidosulfuron and iodosulfuron methyl sodium + mesosulfuron methyl efficacy. There were investigated three levels of spray volume (125 l*ha-1, 250 l*ha-1 and 350 l*ha-1 and two types of nozzle (extended range flat nozzle TeeJet XR 11003-VS and drift guard flat nozzle TeeJet DG 11003-VS. Each herbicide was used at recommended dose and reduced by half. Spray volume and nozzle type did not affect activity of the mixture iodosulfuron methyl sodium + amidosulfuron, but differentiated the efficacy of OD formulation of iodosulfuron methyl sodium + mesosulfuron methyl, when it was applied at lowered dose. As spray volume rose, herbicide efficacy decreased. Nozzle type influenced OD formulation of the mixture iodosulfuron methyl sodium + mesosulfuron methyl, independently on dose. Significantly weaker efficacy was obtained when drift guard nozzle was used.

Limited fitness costs of herbicide-resistance traits in Amaranthus tuberculatus facilitate resistance evolution

Science.gov (United States)

The fitness cost of herbicide resistance (HR) in the absence of herbicide selection plays a key role in HR evolution. Quantifying the fitness cost of resistance, however, is challenging, and there exists a knowledge gap in this area. A synthetic Amaranthus tuberculatus population segregating for fiv...

Predictive value of species sensitivity distributions for effects of herbicides in freshwater ecosystems

NARCIS (Netherlands)

Brink, van den P.J.; Blake, N.; Brock, T.C.M.; Maltby, L.

2006-01-01

In this article we present a review of the laboratory and field toxicity of herbicides to aquatic ecosystems. Single-species acute toxicity data and ( micro) mesocosm data were collated for nine herbicides. These data were used to investigate the importance of test species selection in constructing

Mechanism of sulfonylurea herbicide resistance in the broadleaf weed, Kochia scoparia

International Nuclear Information System (INIS)

Saari, L.L.; Cotterman, J.C.; Primiani, M.M.

1990-01-01

Selection of kochia (Kochia scoparia) biotypes resistant to the sulfonylurea herbicide chlorsulfuron has occurred through the continued use of this herbicide in monoculture cereal-growing areas in the United States. The apparent sulfonylurea resistance observed in kochia was confirmed in greenhouse tests. Fresh and dry weight accumulation in the resistance kochia was 2- to >350-fold higher in the presence of four sulfonylurea herbicides as compared to the susceptible biotype. Acetolactate synthase (ALS) activity isolated from sulfonylurea-resistant kochia was less sensitive to inhibition by three classes of ALS-inhibiting herbicides, sulfonylureas, imidazolinones, and sulfonanilides. The decrease in ALS sensitivity to inhibition (as measured by the ratio of resistant I 50 to susceptible I 50 ) was 5- to 28-fold, 2- to 6-fold, and 20-fold for sulfonylurea herbicides, imidazolinone herbicides, and a sulfonanilide herbicide, respectively. No differences were observed in the ALS-specific activities or the rates of [ 14 C]chlorsulfuron uptake, translocation, and metabolism between susceptible and resistant kochia biotypes. The K m values for pyruvate using ALS from susceptible and resistant kochia were 2.13 and 1.74 mM, respectively. Based on these results, the mechanism of sulfonylurea resistance in this kochia biotype is due solely to a less sulfonylurea-sensitive ALS enzyme

Herbicide and fertilizers promote analogous phylogenetic responses but opposite functional responses in plant communities

International Nuclear Information System (INIS)

Pellissier, Loïc; Wisz, Mary S; Strandberg, Beate; Damgaard, Christian

2014-01-01

Throughout the world, herbicides and fertilizers change species composition in agricultural communities, but how do the cumulative effects of these chemicals impact the functional and phylogenetic structure of non-targeted communities when they drift into adjacent semi-natural habitats? Based on long-term experiment we show that fertilizer and herbicides (glyphosate) have contrasting effects on functional structure, but can increase phylogenetic diversity in semi-natural plant communities. We found that an increase in nitrogen promoted an increase in the average specific leaf area and canopy height at the community level, but an increase in glyphosate promoted a decrease in those traits. Phylogenetic diversity of plant communities increased when herbicide and fertilizer were applied together, likely because functional traits facilitating plant success in those conditions were not phylogenetically conserved. Species richness also decreased with increasing levels of nitrogen and glyphosate. Our results suggest that predicting the cumulative effects of agrochemicals is more complex than anticipated due to their distinct selection of traits that may or may not be conserved phylogenetically. Precautionary efforts to mitigate drift of agricultural chemicals into semi-natural habitats are warranted to prevent unforeseeable biodiversity shifts. (paper)

Impact of weed control strategies on resistance evolution in Alopecurus myosuroides – a long-term field trial

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Ulber, Lena

2016-02-01

Full Text Available The impact of various herbicide strategies on populations of Alopecurus myosuroides is investigated in a longterm field trial situated in Wendhausen (Germany since 2009. In the initial years of the field experiment, resistant populations were selected by means of repeated application of the same herbicide active ingredients. For the selection of different resistance profiles, herbicides with actives from different HRAC groups were used. The herbicide actives flupyrsulfuron, isoproturon und fenoxaprop-P were applied for two years on large plots. In a succeeding field trial starting in 2011, it was investigated if the now existing resistant field populations could be controlled by various herbicide strategies. Eight different strategies consisting of various herbicide combinations were tested. Resistance evolution was investigated by means of plant counts and molecular genetic analysis.

Natural compounds as next-generation herbicides.

Science.gov (United States)

Dayan, Franck E; Duke, Stephen O

2014-11-01

Herbicides with new modes of action (MOAs) are badly needed due to the rapidly evolving resistance to commercial herbicides, but a new MOA has not been introduced in over 20 years. The greatest pest management challenge for organic agriculture is the lack of effective natural product herbicides. The structural diversity and evolved biological activity of natural phytotoxins offer opportunities for the development of both directly used natural compounds and synthetic herbicides with new target sites based on the structures of natural phytotoxins. Natural phytotoxins are also a source for the discovery of new herbicide target sites that can serve as the focus of traditional herbicide discovery efforts. There are many examples of strong natural phytotoxins with MOAs other than those used by commercial herbicides, which indicates that there are molecular targets of herbicides that can be added to the current repertoire of commercial herbicide MOAs. © 2014 American Society of Plant Biologists. All Rights Reserved.

[Effects of herbicide on grape leaf photosynthesis and nutrient storage].

Science.gov (United States)

Tan, Wei; Wang, Hui; Zhai, Heng

2011-09-01

Selecting three adjacent vineyards as test objects, this paper studied the effects of applying herbicide in growth season on the leaf photosynthetic apparatus and branch nutrient storage of grape Kyoho (Vitis vinfrraxVitis labrusca). In the vineyards T1 and T2 where herbicide was applied in 2009, the net photosynthesis rate (Pa) of grape leaves had a significant decrease, as compared with that in vineyard CK where artificial weeding was implemented. The leaves at the fourth node in vineyard T1 and those at the sixth node in vineyard T2 had the largest decrement of Pn (40.5% and 32.1%, respectively). Herbicide had slight effects on the leaf stomatal conductance (Gs). In T1 where herbicide application was kept on with in 2010, the Pn, was still significantly lower than that in CK; while in T2 where artificial weeding was implemented in 2010, the Pn and Gs of top- and middle node leaves were slightly higher than those in T1, but the Pn was still lower than that in CK, showing the aftereffects of herbicide residual. The herbicide application in 2009 decreased the leaf maximum photochemical efficiency of PS II (Fv/Fm) and performance index (P1) while increased the relative variable fluorescence in the J step and K step, indicating the damage of electron transportation of PS II center and oxygen-evolving complex. Herbicide application decreased the pigment content of middle-node leaves in a dose-manner. Applying herbicide enhanced the leaf catalase and peroxidase activities significantly, increased the superoxide dismutase (SOD) activity of middle-node leaves, but decreased the SOD activity of top- and bottom node leaves. After treated with herbicide, the ascorbate peroxidase (APX) activity of middle- and bottom node leaves increased, but that of top-node leaves decreased. Herbicide treatment aggravated leaf lipid peroxidation, and reduced the soluble sugar, starch, free amino acids, and soluble protein storage in branches.

Evaluation of three herbicide resistance genes for use in genetic transformations and for potential crop protection in algae production.

Science.gov (United States)

Brueggeman, Andrew J; Kuehler, Daniel; Weeks, Donald P

2014-09-01

Genes conferring resistance to the herbicides glyphosate, oxyfluorfen and norflurazon were developed and tested for use as dominant selectable markers in genetic transformation of Chlamydomonas reinhardtii and as potential tools for the protection of commercial-scale algal production facilities against contamination by organisms sensitive to these broad-spectrum herbicides. A synthetic glyphosate acetyltransferase (GAT) gene, when fitted with a strong Chlamydomonas promoter, conferred a 2.7×-fold increase in tolerance to the EPSPS inhibitor, glyphosate, in transgenic cells compared with progenitor WT cells. A mutant Chlamydomonas protoporphyrinogen oxidase (protox, PPO) gene previously shown to produce an enzyme insensitive to PPO-inhibiting herbicides, when genetically engineered, generated transgenic cells able to tolerate up to 136× higher levels of the PPO inhibitor, oxyfluorfen, than nontransformed cells. Genetic modification of the Chlamydomonas phytoene desaturase (PDS) gene-based gene sequences found in various norflurazon-resistant organisms allowed production of transgenic cells tolerant to 40× higher levels of norflurazon than nontransgenic cells. The high efficiency of all three herbicide resistance genes in producing transgenic cells demonstrated their suitability as dominant selectable markers for genetic transformation of Chlamydomonas and, potentially, other eukaryotic algae. However, the requirement for high concentrations of glyphosate and its associated negative effects on cell growth rates preclude its consideration for use in large-scale production facilities. In contrast, only low doses of norflurazon and oxyfluorfen (~1.5 μm and ~0.1 μm, respectively) are required for inhibition of cell growth, suggesting that these two herbicides may prove effective in large-scale algal production facilities in suppressing growth of organisms sensitive to these herbicides. © 2014 Society for Experimental Biology, Association of Applied Biologists and

Weed control in distress – can all weeds still be controlled with herbicides in future?

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Drobny, Hans G.

2016-02-01

Full Text Available The introduction and availability of highly active and selective herbicides in all important field crops, in the last decades, enabled the simplification and money saving in crop rotations and agronomic measures. This resulted in respective specialized and adapted weed populations, and consequently an increasing selection of resistant populations. Since the introduction of the ALS-inhibitors (starting 1985 and the 4-HPPD-inhibitors (2001, no new MoA-Classes were registered, and there are none in the registration process. Several established herbicides were not registered or re-registered in the EU, or were severely restricted in their application. The cost and the risk to develop and register a new selective herbicide in the EU are hardly justified, in relation to their market potential. The only solution on problem fields, with resistant populations, is to change the agronomic practices, like crop rotation, soil tillage, seeding time, etc., as a precautionary principle also on still „normal“ fields. The different advising institutions have to integrate these aspects into their recommendations, besides the proper herbicide management.

Selectivity and stability of new herbicides and herbicide combinations for the seed yields of some field crops II. Effect at milk thistle (Silybum Marianum Gaertn.)

OpenAIRE

G. Delchev

2016-01-01

Abstract. During 2013 – 2015 on pellic vertisol soil type was conducted a field experiment. Under investigation was Bulgarian milk thistle cultivar Silmar (Silybum marianum Gaertn.). Factor A included the years of investigation. Factor B included no treated check, 6 soil-applied herbicides – Tendar EC, Sharpen 33 EC, Merlin flex 480 SC, Smerch 24 ЕC, Raft 400 SC, Eagle 75 DF and 5 foliar-applied herbicides – Kalin flo, Eclipse 70 DWG, Sultan 500 SC, Granstar super 50 SG, Starane 250 ...

Chromatographic determination of herbicide residues in various matrices

Czech Academy of Sciences Publication Activity Database

Cserháti, T.; Forgács, E.; Deyl, Zdeněk; Mikšík, Ivan; Eckhardt, Adam

2004-01-01

Roč. 18, č. 6 (2004), s. 350-359 ISSN 0269-3879 Institutional research plan: CEZ:AV0Z5011922 Keywords : herbicide residues * extraction methods * HPLC Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.069, year: 2004

Improvements in the use of aquatic herbicides and establishment of future research directions

Science.gov (United States)

Getsinger, K.D.; Netherland, M.D.; Grue, C.E.; Koschnick, T.J.

2008-01-01

Peer-reviewed literature over the past 20 years identifies significant changes and improvements in chemical control strategies used to manage nuisance submersed vegetation. The invasive exotic plants hydrilla (Hydrilla verticillata L.f. Royle) and Eurasian watermilfoil (Myriophyllum spicatum L.) continue to spread and remain the plant species of greatest concern for aquatic resource managers at the national scale. Emerging exotic weeds of regional concern such as egeria (Egeria densa Planch.), curlyleaf pondweed (Potamogeton crispus L.), and hygrophila (Hygrophila polysperma (Roxb.) T. Anders), as well as native plants such as variable watermilfoil (Myriophyllum heterophyllum Michx), and cabomba (Cabomba caroliniana Gray) are invasive outside their home ranges. In addition, there is always the threat of new plant introductions such as African elodea (Lagarosiphon major (Ridley) Moss) or narrow-leaf anacharis (Egeria najas Planchon). The registration of the bleaching herbicide fluridone in the mid 1980s for whole-lake and large-scale management stimulated numerous lines of research involving reduction of use rates, plant selectivity, residue monitoring, and impacts on fisheries. In addition to numerous advances, the specificity of fluridone for a single plant enzyme led to the first documented case of herbicide resistance in aquatic plant management. The resistance of hydrilla to fluridone has stimulated a renewed interest by industry and others in the registration of alternative modes of action for aquatic use. These newer chemistries tend to be enzyme-specific compounds with favorable non-target toxicity profiles. Registration efforts have been facilitated by increased cooperation between key federal government agencies that have aquatic weed control and research responsibilities, and regulators within the U.S. Environmental Protection Agency (USEPA). We reviewed past and current research efforts to identify areas in need of further investigation and to establish

A herbicide structure-activity analysis of the antimalarial lead compound MMV007978 against Arabidopsis thaliana.

Science.gov (United States)

Corral, Maxime G; Leroux, Julie; Tresch, Stefan; Newton, Trevor; Stubbs, Keith A; Mylne, Joshua S

2018-07-01

To fight herbicide-resistant weeds, new herbicides are needed; particularly ones with new modes of action. Building on the revelation that many antimalarial drugs are herbicidal, here we focus on the Medicines for Malaria Venture antimalarial lead compound MMV007978 that has herbicidal activity against the model plant Arabidopsis thaliana. Twenty-two variations of the lead compound thiophenyl motif revealed that change was tolerated provided ring size and charge were retained. MMV007978 was active against select monocot and dicot weeds, and physiological profiling indicated that its mode of action is related to germination and cell division. Of interest is the fact that the compound has a profile that is currently not found among known herbicides. We demonstrate that the antimalarial compound MMV007978 is also herbicidal and that exploiting lead compounds that are often understudied could lead to the identification of interesting herbicidal scaffolds. Further structural investigation of MMV007978 could provide improved herbicidal chemistries with a potential new mode of action. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Seletividade de herbicidas aplicados em pré-emergência em gramíneas forrageiras Selectivity of pre-emergence herbicides applied on forage grasses

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A.C.P Rodrigues-Costa

2011-09-01

Full Text Available O presente trabalho teve o objetivo de avaliar a seletividade de herbicidas aplicados em pré-emergência sobre a produção e a qualidade de sementes de Brachiaria brizantha cv. Marandu e Brachiaria decumbens cv. Basilisk. Os herbicidas avaliados foram: diuron (800 e 1.600 g ha-1, ametryn (625 e 1.250 g ha-1, imazaquin (75 e 150 g ha-1, imazethapyr (50 e 100 g ha-1 e flumetsulam (70 e 140 g ha-1, além de uma testemunha sem aplicação de herbicidas. As espécies foram avaliadas separadamente no campo. Os experimentos foram instalados no delineamento em blocos casualizados com quatro repetições. Os herbicidas ametryn (625 g ha-1, imazaquin (75 e 150 g ha-1, imazethapyr (50 e 100 g ha-1 e flumetsulam (70 e 140 g ha-1 foram os que proporcionaram maior seletividade às plantas de B. brizantha, enquanto para B. decumbens o diuron (800 e 1.600 g ha-1, o ametryn (625 e 1.250 g ha-1 e o imazethapyr (50 e 100 g ha-1 foram mais seletivos, destacando-se o diuron na menor dose. Contudo, os herbicidas avaliados não alteram a produção e a qualidade das sementes das forrageiras estudadas.This study aimed to evaluate the selectivity of pre-emergence herbicides on yield and seed quality of Brachiaria brizantha cv. Brizantha and Brachiaria decumbens cv. Basilisk. The herbicides evaluated were: diuron (800 and 1.600 g ha-1, ametryn (625 and 1.250 g ha-1, imazaquin (75 and 150 g ha-1, imazethapyr (50 and 100 g ha-1 and flumetsulam (70 and 140 g ha-1, plus a control without herbicide application. The species were evaluated separately in the field. The experiments were arranged in a randomized block design with four replications. The herbicides ametryn (625 g ha-1, imazaquin (75 and 150 g ha-1, imazethapyr (50 and 100 g ha-1, and flumetsulam (70 and 140 g ha-1 provided the highest selectivity to B. brizantha plants, while for B. decumbens, diuron (800 and 1.600 g ha-1, ametryn (625 and 1.250 g ha-1, and imazethapyr (50 and 100 g ha-1 were more selective

Effects Of Spring Herbicide Treatments On Winter Wheat Growth And Grain Yield*

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Hamouz P.

2015-03-01

Full Text Available Herbicides provide a low-cost solution for protecting crops from significant yield losses. If weed infestations are below damage thresholds, however, then herbicide application is unnecessary and can even lead to yield loss. A small-plot field trial was conducted to examine the effect of herbicides on winter wheat yields. Weeds were removed manually from the trial area before herbicide application. Twenty-four treatments were tested in four replications. Treatment 1 consisted of an untreated weed-free control, whereas the other treatments comprised applications of the following herbicides and their combinations: metsulfuron-methyl + tribenuron-methyl (4.95 + 9.99 g ha−1, pinoxaden (30 g ha−1, fluroxypyr (175 g ha−1, and clopyralid (120 g ha−1. Water (250 l ha−1 or a urea-ammonium nitrate fertilizer solution (UAN, 120.5 l ha−1 was used as the herbicide carrier. Crop injury 30 days after treatment and yield loss were recorded. Results showed minor crop injury by herbicides and their combinations when applied without UAN and moderate injury caused by UAN in combination with herbicides. Yield losses reached 5.3% and 4.3% in those treatments where all of the tested herbicides were applied with and without UAN, respectively. The effect of all treatments on crop yield was, however, statistically insignificant (P = 0.934.

Impact of some herbicides on the biomass activity in biological treatment plants and biodegradability enhancement by a photo-Fenton process.

Science.gov (United States)

Benzaquén, T B; Benzzo, M T; Isla, M A; Alfano, O M

2013-01-01

In recent years, the use of agrochemicals has increased because they are essential for profitable agricultural production. Herbicides are heavily demanded compounds and among these, the most marketed are 2,4-D, atrazine and acetochlor. They have characteristics that can cause problems to humans and the environment. Therefore, it is necessary to design systems that can reduce these compounds to harmless molecules. This work aims at evaluating the possibility of incorporating these herbicides into degradable effluents in a biological treatment system, without reducing its efficiency. For this purpose, studies of organic matter degradability in the presence of these agrochemicals were performed. A synthetic effluent based on glucose and mineral salts was inoculated with microorganisms. Glucose consumption and biomass concentration were assessed. Subsequently, preliminary studies were performed to test the viability of degradation of the most harmful compound with an advanced oxidation process (AOP). The results showed that the incorporation of these herbicides into degradable effluents in a biological treatment system has a negative impact on microorganisms. Therefore, the application of an AOP, such as the Fenton or photo-Fenton processes, prior to a biological treatment was found to degrade these substances to simpler and less toxic molecules.

Herbicides interfere with antigrazer defenses in Scenedesmus obliquus.

Science.gov (United States)

Zhu, Xuexia; Sun, Yunfei; Zhang, Xingxing; Heng, Hailu; Nan, Haihong; Zhang, Lu; Huang, Yuan; Yang, Zhou

2016-11-01

The extensive application of herbicides has led to a serious threat of herbicide contamination to aquatic ecosystem. Herbicide exposure affects aquatic communities not only by exerting toxicity on single species but also by changing interspecific interactions. This study investigated the antigrazer defenses of the common green alga Scenedesmus obliquus against different herbicides [glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), and atrazine] at various concentrations (0-2.0 mg L(-1)). In the presence of grazer (Daphnia)-derived cues, S. obliquus populations without herbicides formed high proportions of multicelled (e.g., four- and eight-celled) colonies. This result confirms that S. obliquus exhibits a morphological defense against grazing risk. At the low concentration range of 0.002-0.02 mg L(-1), the three herbicides exerted no influence on the growth and photosynthetic efficiency of S. obliquus, and multicelled colonies showed constant proportions. At the high concentration range of 0.20-2.0 mg L(-1), atrazine significantly inhibited the algal growth and photosynthesis whereas glyphosate or 2,4-D did not. Nonetheless, these levels of glyphosate or 2,4-D remarkably decreased the proportion of multicelled colonies, with reduced numbers of cells per particle in Daphnia filtrate-treated population. No eight-celled colony was formed after treatment with atrazine at 0.20-2.0 mg L(-1) despite the addition of Daphnia filtrate. These results suggest that herbicide exposure impairs antigrazer colonial morphs in phytoplankton although it is not sufficient to hamper algal growth. This phenomenon can increase the risk of predation by herbivores, thereby disrupting the inducible phytoplankton community. Furthermore, the predator-prey interactions between herbivores and phytoplankton can be potentially changed more seriously than previously considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

Leaching of the S-metolachlor herbicide associated with paraquat or glyphosate in a no-tillage system

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Anderson Luis Nunes

2016-09-01

Full Text Available The combined use of desiccant and residual herbicides is a common management practice under no-tillage systems. However, the effect of desiccant herbicides and mulch on the leaching of residual herbicide is unknown. This study aimed at assessing the leaching of the S-metolachlor herbicide applied to ryegrass sequentially or in association with paraquat or glyphosate. A randomized blocks design was used, with four repetitions and treatments distributed over split-plots. The desiccant herbicides paraquat (600 g ha-1 or glyphosate (720 g ha-1 were used in the main plot, while S-metolachlor (2,800 g ha-1 was applied sequentially or in association with the desiccant herbicides in the subplots. There was also a control containing only desiccant herbicide, with no application of residual herbicide. The type of desiccant did not affect the leaching of the residual herbicide. In addition, the chosen method to apply the residual herbicide, sequentially or in association with the desiccant, did not impact the S-metolachlor behavior in the soil. The bioavailable concentration in the soil, 25 days after the application, was 90 g a.i. ha-1, at a depth of 18 cm.

Discovery of Putative Herbicide Resistance Genes and Its Regulatory Network in Chickpea Using Transcriptome Sequencing

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Mir A. Iquebal

2017-06-01

Full Text Available Background: Chickpea (Cicer arietinum L. contributes 75% of total pulse production. Being cheaper than animal protein, makes it important in dietary requirement of developing countries. Weed not only competes with chickpea resulting into drastic yield reduction but also creates problem of harboring fungi, bacterial diseases and insect pests. Chemical approach having new herbicide discovery has constraint of limited lead molecule options, statutory regulations and environmental clearance. Through genetic approach, transgenic herbicide tolerant crop has given successful result but led to serious concern over ecological safety thus non-transgenic approach like marker assisted selection is desirable. Since large variability in tolerance limit of herbicide already exists in chickpea varieties, thus the genes offering herbicide tolerance can be introgressed in variety improvement programme. Transcriptome studies can discover such associated key genes with herbicide tolerance in chickpea.Results: This is first transcriptomic studies of chickpea or even any legume crop using two herbicide susceptible and tolerant genotypes exposed to imidazoline (Imazethapyr. Approximately 90 million paired-end reads generated from four samples were processed and assembled into 30,803 contigs using reference based assembly. We report 6,310 differentially expressed genes (DEGs, of which 3,037 were regulated by 980 miRNAs, 1,528 transcription factors associated with 897 DEGs, 47 Hub proteins, 3,540 putative Simple Sequence Repeat-Functional Domain Marker (SSR-FDM, 13,778 genic Single Nucleotide Polymorphism (SNP putative markers and 1,174 Indels. Randomly selected 20 DEGs were validated using qPCR. Pathway analysis suggested that xenobiotic degradation related gene, glutathione S-transferase (GST were only up-regulated in presence of herbicide. Down-regulation of DNA replication genes and up-regulation of abscisic acid pathway genes were observed. Study further reveals

Endocrine disruption of sexual selection by an estrogenic herbicide in the mealworm beetle (Tenebrio molitor).

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McCallum, Malcolm L; Matlock, Makensey; Treas, Justin; Safi, Barroq; Sanson, Wendy; McCallum, Jamie L

2013-12-01

The role that endocrine disruption could play in sexual selection remains relatively untested, and although estrogens occur in insects, little information exists about their biological role in insect reproduction. Atrazine is a commonly applied herbicide that mimics estrogen in vertebrates. Tenebrio molitor were raised from egg to adult under a gradation of environmentally relevant atrazine exposures and a non-treated control. Atrazine was delivered in the drinking water ad libitum. Female T. molitor were provided with a choice between unrelated males raised under three levels of atrazine exposures. Female preference for males demonstrated a non-monotonic inverted U-shaped response to atrazine exposure. There was no significant difference between the control and the high exposure to atrazine. Excluding the control, female preference increased as exposure concentration increased. These results have important repercussions for nonlethal effects of endocrine disruption on populations, their capacity to interfere with sexual selection, and the role of estrogen in pheromone communication among insects.

Laboratory study on leachability of five herbicides in South Australian soils.

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Ying, G G; Williams, B

2000-03-01

Norflurazon, oxadiazon, oxyfluorfen, trifluralin and simazine are herbicides widely used in the vineyards of the Barossa Valley, South Australia. The leaching behaviour of norflurazon, oxadiazon, oxyfluorfen and trifluralin was investigated on four key soils in the Barossa Valley. Leaching potential on packed soil columns and actual mobility using intact soil columns were investigated. On the packed soil columns, norflurazon was the most leachable herbicide. More of the herbicides were detected in the leachates from the sandy soils (Mountadam and Nuriootpa) than from the clayey soils (Lyndoch and Tanunda). Organic matter is generally low in soils in the Barossa region. Porosity and saturated conductivity significantly affect herbicide movement and in the sandy Mountadam and Nuriootpa soils, the water flux is greater than for the higher clay content Lyndoch and Tanunda soils. Increasing the time interval between herbicide application and the incidence of "rainfall" reduced the amounts of herbicides found in the leachates. The use of intact soil columns and including simazine for comparison showed that both norflurazon and simazine were present in the leachates. Simazine was the first herbicide to appear in leachates. Sectioning of the intact soil columns after leaching clearly demonstrated that norflurazon and simazine reached the bottom of the soil columns for all soils studied. Greater amounts of norflurazon were retained in the soil columns compared with simazine. The other herbicides were mostly retained in the initial sections of the soil columns.

Toxicity of herbicides used in the sugarcane crop to diazotrophic bacterium Herbaspirillum seropedicae

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Sergio de Oliveira Procópio

2014-10-01

Full Text Available The objective of this work was to identify herbicides used in the sugarcane crop that affects neither the growth, the development, of nor the process of biological nitrogen fixation (BNF by the diazotrophic bacterium Herbaspirillum seropedicae. Eighteen herbicides (paraquat, ametryne, tebuthiuron, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron sodium + ametryne], glyphosate, MSMA e 2,4-D were tested in their respective commercial doses regarding their impact on the growth of the bacteria in liquid medium DIGs. For this, we determined the duration of lag phase, generation time and maximum cell density of H. seropedicae, calculated from optical density data obtained at regular intervals during the incubation of cultures for 33 h at 32oC. We also evaluated the impact of herbicides on nitrogenase activity of H. seropedicae grown in semi-solid N-free JNFb medium. The effects of herbicides on the growth variables and the ARA were compared with the untreated control by Dunnett test. A completely randomized design was used. The herbicides paraquat, imazapyr, ametryne, glyphosate and oxyfluorfen inhibited the growth of H. seropedicae in vitro. Ametryne, oxyfluorfen and glyphosate caused a small reduction in the duration of the lag phase of diazotrophic bacteria H. seropedicae. Oxyfluorfen, ametryne and imazapyr resulted in increased the generation time by H. seropedicae. Glyphosate promoted drastic reduction in biological nitrogen fixation in vitro by H. seropedicae. The other tested herbicides did not affect the growth or the same BNF by H. seropedicae.

The direct and indirect effects of a glyphosate-based herbicide and nutrients on Chironomidae (Diptera) emerging from small wetlands.

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Baker, Leanne F; Mudge, Joseph F; Houlahan, Jeff E; Thompson, Dean G; Kidd, Karen A

2014-09-01

Laboratory and mesocosm experiments have demonstrated that some glyphosate-based herbicides can have negative effects on benthic invertebrate species. Although these herbicides are among the most widely used in agriculture, there have been few multiple-stressor, natural system-based investigations of the impacts of glyphosate-based herbicides in combination with fertilizers on the emergence patterns of chironomids from wetlands. Using a replicated, split-wetland experiment, the authors examined the effects of 2 nominal concentrations (2.88 mg acid equivalents/L and 0.21 mg acid equivalents/L) of the glyphosate herbicide Roundup WeatherMax, alone or in combination with nutrient additions, on the emergence of Chironomidae (Diptera) before and after herbicide-induced damage to macrophytes. There were no direct effects of treatment on the structure of the Chironomidae community or on the overall emergence rates. However, after macrophyte cover declined as a result of herbicide application, there were statistically significant increases in emergence in all but the highest herbicide treatment, which had also received no nutrients. There was a negative relationship between chironomid abundance and macrophyte cover on the treated sides of wetlands. Fertilizer application did not appear to compound the effects of the herbicide treatments. Although direct toxicity of Roundup WeatherMax was not apparent, the authors observed longer-term impacts, suggesting that the indirect effects of this herbicide deserve more consideration when assessing the ecological risk of using herbicides in proximity to wetlands. © 2014 SETAC.

Lethal and sub-lethal chronic effects of the herbicide diuron on seagrass.

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Negri, Andrew P; Flores, Florita; Mercurio, Phil; Mueller, Jochen F; Collier, Catherine J

2015-08-01

Photosystem II herbicides from agricultural sources have been detected throughout nearshore tropical habitats including seagrass meadows. While PSII herbicides have been shown to inhibit growth in microalgae at low concentrations, the potential impacts of chronic low concentration exposures to seagrass health and growth have not been investigated. Here we exposed two tropical seagrass species Halodule uninervis and Zostera muelleri to elevated diuron concentrations (from 0.3 to 7.2μgl(-1)) over a 79-day period followed by a 2-week recovery period in uncontaminated seawater. PAM fluorometry demonstrated rapid effect of diuron on photosystem II (PSII) in both seagrass species at 0.3μgl(-1). This effect included significant inhibition of photosynthetic efficiency (ΔF/Fm') and inactivation of PSII (Fv/Fm) over the 11 week exposure period. Significant mortality and reductions in growth was only observed at the highest exposure concentration of 7.2μgl(-1) diuron. However, biochemical indicators demonstrated that the health of seagrass after this prolonged exposure was significantly compromised at lower concentrations. For example, the drop in C:N ratios (0.6μgl(-1)) and reduced δ(13)C (1.7μgl(-1)) in seagrass leaves indicated reduced C-assimilation from photosynthesis. Critically, the energetic reserves of the plants (as measured by starch content in the root-rhizome complex) were approximately halved following diuron exposure at and above 1.7μgl(-1). During the 2-week recovery period, the photosynthetic capacity of the seagrass improved with only plants from the highest diuron treatment still exhibiting chronic damage to PSII. This study shows that, although seagrass may survive prolonged herbicide exposures, concentrations ≥0.6μgl(-1) diuron equivalents cause measureable impacts on energetic status that may leave the plants vulnerable to other simultaneous stressors. For example, tropical seagrasses have been heavily impacted by reduced light from coastal

CADDIS Volume 2. Sources, Stressors and Responses: Herbicides

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Introduction to the herbicides module, when to list herbicides as a candidate cause, ways to measure herbicides, simple and detailed conceptual diagrams for herbicides, herbicides module references and literature reviews.

Herbicide residues in grapes and wine.

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Ying, G G; Williams, B

1999-05-01

The persistence of several common herbicides from grapes to wine has been studied. Shiraz, Tarrango and Doradillo grapes were separately sprayed with either norflurazon, oxyfluorfen, oxadiazon or trifluralin-persistent herbicides commonly used for weed control in vineyards. The dissipation of the herbicides from the grapes was followed for 28 days following treatment. Results showed that norflurazon was the most persist herbicide although there were detectable residues of all the herbicides on both red and white grapes at the end of the study period. The penetration of herbicides into the flesh of the grapes was found to be significantly greater for white grapes than for red grapes. Small-lot winemaking experiments showed that norflurazon persisted at levels close to the initial concentration through vinification and into the finished wine. The other herbicides degraded, essentially via first-order kinetics, within the period of "first fermentation" and had largely disappeared after 28 days. The use of charcoal together with filter pads, or with diatomaceous earth was shown to be very effective in removing herbicide residues from the wine. A 5% charcoal filter removed more than 96% of the norflurazon persisting in the treated wine.

Seletividade de herbicidas para cebola em semeadura direta Selectivity of herbicides for onions in direct sowing

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Lino R. Ferreira

1999-04-01

Full Text Available As plantas de cebola provenientes da semeadura direta, têm-se mostrado muito sensíveis aos herbicidas recomendados para a cultura transplantada, principalmente aqueles com ação sobre plantas daninhas dicotiledôneas. Os efeitos do fracionamento da dose dos herbicidas oxyfluorfen, ioxynil-octanoato, fluazifop-p-butil e sethoxydim foram avaliados em dois cultivares (Granex Ouro e Granex 33, no sistema de semeadura direta. A tolerância dos dois cultivares ao oxyfluorfen e ao ioxynil-octanoato aumentou com a idade das plantas e com o parcelamento das doses, aplicando-se doses menores no estádio de duas folhas. Sethoxydim e fluazifop-p-butil foram seletivos para a cultura, independente da dose inicial aplicada e do cultivar avaliado.The plants of onions, from direct sowing, have shown to be quite sensitive toward herbicides recommended for transplanted culture, especially those acting on dycotiledoneous weeds. The effects of dose fractionating of herbicides oxyfluorfen, ioxynil-octanoato, fluazifop-p-butil and sethoxydim were evaluated in two cultivars (Granex Ouro and Granex 33, in the direct sowing system. The tolerance of the two cultivars toward oxyfluorfen and ioxynyl-octanoato increased with the plants age and with the parceling of the doses, applying smaller doses in the two leaves stage. Sethoxydim and fluazifop-p-butyl were selective for the culture, regardless of the applied initial doses and the evaluated cultivar.

Spot Spraying Reduces Herbicide Concentrations in Runoff.

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Melland, Alice R; Silburn, D Mark; McHugh, Allen D; Fillols, Emilie; Rojas-Ponce, Samuel; Baillie, Craig; Lewis, Stephen

2016-05-25

Rainfall simulator trials were conducted on sugar cane paddocks across dry-tropical and subtropical Queensland, Australia, to examine the potential for spot spraying to reduce herbicide losses in runoff. Recommended rates of the herbicides glyphosate, 2,4-D, fluoroxypyr, atrazine, and diuron were sprayed onto 0, 20, 40, 50, 70, or 100% of the area of runoff plots. Simulated rainfall was applied 2 days after spraying to induce runoff at one plant cane and three ratoon crop sites. Over 50% of all herbicides were transported in the dissolved phase of runoff, regardless of the herbicide's sediment-water partition coefficient. For most sites and herbicides, runoff herbicide concentrations decreased with decreasing spray coverage and with decreasing herbicide load in the soil and cane residues. Importantly, sites with higher infiltration prior to runoff and lower total runoff had lower runoff herbicide concentrations.

Photochemical oxidation processes for the elimination of phenyl-urea herbicides in waters

International Nuclear Information System (INIS)

Benitez, F. Javier; Real, Francisco J.; Acero, Juan L.; Garcia, Carolina

2006-01-01

Four phenyl-urea herbicides (linuron, chlorotoluron, diuron, and isoproturon) were individually photooxidized by monochromatic UV radiation in ultra-pure aqueous solutions. The influence of pH and temperature on the photodegradation process was established, and the first-order rate constants and quantum yields were evaluated. The sequence of photodecomposition rates was: linuron > chlorotoluron > diuron > isoproturon. The simultaneous photooxidation of mixtures of the selected herbicides in several types of waters was then performed by means of UV radiation alone, and by UV radiation combined with hydrogen peroxide. The types of waters used were: ultra-pure water, a commercial mineral water, a groundwater, and a lake water. The influence of the independent variables in these processes - the presence or absence of tert-butyl alcohol, types of herbicide and waters, and concentration of hydrogen peroxide - were established and discussed. A kinetic study was performed using a competitive kinetic model that allowed various rate constants to be evaluated for each herbicide. This kinetic model allows one to predict the elimination of these phenyl-urea herbicides in contaminated waters by the oxidation systems used (UV alone and combined UV/H 2 O 2 ). The herbicide concentrations predicted by this model agree well with the experimental results that were obtained

Photochemical oxidation processes for the elimination of phenyl-urea herbicides in waters

Energy Technology Data Exchange (ETDEWEB)

Benitez, F. Javier [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)]. E-mail: javben@unex.es; Real, Francisco J. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain); Acero, Juan L. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain); Garcia, Carolina [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)

2006-11-16

Four phenyl-urea herbicides (linuron, chlorotoluron, diuron, and isoproturon) were individually photooxidized by monochromatic UV radiation in ultra-pure aqueous solutions. The influence of pH and temperature on the photodegradation process was established, and the first-order rate constants and quantum yields were evaluated. The sequence of photodecomposition rates was: linuron > chlorotoluron > diuron > isoproturon. The simultaneous photooxidation of mixtures of the selected herbicides in several types of waters was then performed by means of UV radiation alone, and by UV radiation combined with hydrogen peroxide. The types of waters used were: ultra-pure water, a commercial mineral water, a groundwater, and a lake water. The influence of the independent variables in these processes - the presence or absence of tert-butyl alcohol, types of herbicide and waters, and concentration of hydrogen peroxide - were established and discussed. A kinetic study was performed using a competitive kinetic model that allowed various rate constants to be evaluated for each herbicide. This kinetic model allows one to predict the elimination of these phenyl-urea herbicides in contaminated waters by the oxidation systems used (UV alone and combined UV/H{sub 2}O{sub 2}). The herbicide concentrations predicted by this model agree well with the experimental results that were obtained.

Herbicide options for hardwood management

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Andrew W. Ezell; A. Brady Self

2016-01-01

The use of herbicides in hardwood management presents special problems in that many of the most effective herbicides are either designed to control hardwoods or the product is not labeled for such applications. Numerous studies involving herbicide application in hardwoods have been completed at Mississippi State University. This paper is a compilation of results from...

Photosensitized herbicidal action

Energy Technology Data Exchange (ETDEWEB)

Zweig, A; Nachtigall, G W [American Cyanamid Co., Stamford, Conn.

1975-12-01

The herbicidal action produced by the colorless hydrocarbon fluoranthene sprayed on the leaves of growing plants did not occur when uv radiation was removed from the light to which the plants are exposed. If the uv component of the light under which the plants were grown was augmented, the herbicidal effect of fluoranthene was increased. The mechanism of this photodynamic action is discussed.

Glufosinate herbicide intoxication causing unconsciousness, convulsion, and 6th cranial nerve palsy.

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Park, Jae-seok; Kwak, Soo-Jung; Gil, Hyo-wook; Kim, So-Young; Hong, Sae-yong

2013-11-01

Although glufosinate ammonium herbicides are considered safe when used properly, ingestion of the undiluted form can cause grave outcomes. Recently, we treated a 34-yr-old man who ingested glufosinate ammonium herbicide. In the course of treatment, the patient developed apnea, mental deterioration, and sixth cranial nerve palsy; he has since been discharged with full recovery after intensive care. This case report describes the clinical features of glufosinate intoxication with a focus on sixth cranial nerve palsy. Our observation suggests that neurologic manifestations after ingestion of a "low-grade toxicity herbicide" are variable and more complex than that was previously considered.

Sensor-based assessment of herbicide effects

DEFF Research Database (Denmark)

Streibig, Jens Carl; Rasmussen, Jesper; Andújar, D.

2014-01-01

Non-destructive assessment of herbicide effects may be able to support integrated weed management. To test whether effects of herbicides on canopy variables could be detected by sensors, two crops were used as models and treated with herbicides at BBCH 20 using a logarithmic sprayer. Twelve days...... after spraying at BBCH 25 and 42 days after sowing, nine sensor systems scanned a spring barley and an oilseed rape field experiment sown at different densities and sprayed with increasing field rates of glyphosate and tribenuron-methyl. The objective was to compare ED50s for crops and weeds derived...... by the different sensors in relation to crop density and herbicides. Although sensors were not directly developed to detect herbicide symptoms, they all detected changes in canopy colours or height and crop density. Generally ED50s showed the same pattern in response to crop density within herbicide...

Microevolution of ALS inhibitor herbicide resistance in loose silky bentgrass (Apera spica-venti)

DEFF Research Database (Denmark)

Babineau, Marielle

, the ALS resistant biotypes have a fitness advantage over the susceptible biotype in time to germination and time to flowering and seed production growth stages. This study increased the understanding of the spatial, phenotypic, genetic and ecological processes and consequences in ALS herbicide resistance......-neighborhood experiments were conducted with ALS resistant and susceptible populations with a randomized genetic background, vegetative and reproductive growth stages were compared. The results show a large variation in the response of neighboring populations to ALS herbicide. Multiple resistance is observed between ALS...... from known metabolic herbicide resistance pathways, such as cytochrome P450s, ABC-transporters, UDP-glycosyltransferase and glutathione S-transferase, are identified and quantified. Different gene families are up-regulated at different times after herbicide treatment. In low competition conditions...

Herbicide-tolerant Transgenic Soybean over 15 Years of Cultivation: Pesticide Use, Weed Resistance, and Some Economic Issues. The Case of the USA

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Sylvie Bonny

2011-08-01

Full Text Available Genetically modified (GM herbicide-tolerant (HT crops have been largely adopted where they have been authorized. Nevertheless, they are fiercely criticized by some, notably because of the herbicide use associated with them. However, how much herbicide is applied to GMHT crops compared to conventional crops, and what impacts does the use of herbicide have? The paper first presents some factors explaining the predominance of GMHT crops. Then, trends in the use of herbicide for GM crops are studied in the case of the most widespread HT crop: HT soybean in the USA. The trends in the toxicity of herbicides applied to HT soybean are also addressed, as well as the appearance of glyphosate-resistant (GR weeds. Lastly, the paper examines the spread of GR weeds and its impact. How are farmers, weed scientists, and the industry coping with this development, and what are the prospects of glyphosate-tolerant crops given weed resistance? In conclusion, some issues of sustainability and innovation governance raised by genetically modified herbicide-tolerant crops are discussed.

Cross-resistance to herbicides in annual ryegrass (lolium rigidum)

International Nuclear Information System (INIS)

Christopher, J.T.; Powles, S.B.; Liljegren, D.R.; Holtum, J.A.M.

1991-01-01

Lolium rigidum Gaud. biotype SLR31 is resistant to the herbicide diclofop-methyl and cross-resistant to several sulfonylurea herbicides. Wheat and the cross-resistant ryegrass exhibit similar patterns of resistance to sulfonylurea herbicides, suggesting that the mechanism of resistance may be similar. Cross-resistant ryegrass is also resistant to the wheat-selective imidazolinone herbicide imazamethabenz. The cross-resistant biotype SLR31 metabolized [phenyl-U- 14 C]chlorsulfuron at a faster rate than a biotype which is susceptible to both diclofop-methyl and chlorsulfuron. A third biotype which is resistant to diclofop-methyl but not to chlorsulfuron metabolized chlorsulfuron at the same rate as the susceptible biotype. The increased metabolism of chlorsulfuron observed in the cross-resistant biotype is, therefore, correlated with the patterns of resistance observed in these L. rigidum biotypes. During high performance liquid chromatography analysis the major metabolite of chlorsulfuron in both susceptible and cross-resistant ryegrass coeluted with the major metabolite produced in wheat. The major product is clearly different from the major product in the tolerant dicot species, flax (Linium usitatissimum). The elution pattern of metabolites of chlorsulfuron was the same for both the susceptible and cross-resistant ryegrass but the cross-resistant ryegrass metabolized chlorsulfuron more rapidly. The investigation of the dose response to sulfonylurea herbicides at the whole plant level and the study of the metabolism of chlorsulfuron provide two independent sets of data which both suggest that the resistance to chlorsulfuron in cross-resistant ryegrass biotype SLR31 involves a wheat-like detoxification system

Changes in the persistence of two phenylurea herbicides in two Mediterranean soils under irrigation with low- and high-quality water: A laboratory approach.

Science.gov (United States)

ElGouzi, Siham; Draoui, Khalid; Chtoun, E H; Dolores Mingorance, M; Peña, Aránzazu

2015-12-15

The disappearance of two phenylurea herbicides, chlorotoluron (CHL) and isoproturon (IPU), in two Mediterranean soils, an agricultural calcareous soil (S5) and an organic forest soil (S2), was assessed under irrigation with high- and low-quality water. Irrigation with wastewater, as opposed to irrigation with high-quality water, increased the degradation rate of both herbicides in both soils. For each soil, the decay rate of IPU was always higher than that of CHL, and both pesticides disappeared more rapidly from S5 with lower clay and organic carbon content than from S2. The degradation rate was inversely related with pesticide sorption on soil, because increased sorption would reduce pesticide bioavailability for decomposition. In most cases the residual concentration in soil of both phenylurea herbicides was better fitted to a bi-exponential decay model than to first-order or first-order with plateau models. Dehydrogenase activity, used as an indication of microbial activity, was very high in S2 in comparison with S5, but was not related to pesticide disappearance. Copyright © 2015 Elsevier B.V. All rights reserved.

Downy Brome (Bromus tectorum L. and Broadleaf Weed Control in Winter Wheat with Acetolactate Synthase-Inhibiting Herbicides

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Patrick W. Geier

2013-04-01

Full Text Available A study was conducted for three seasons in northwest Kansas, USA to evaluate acetolactate synthase (ALS-inhibiting herbicides for downy brome (Bromus tectorum L. and winter annual broadleaf weed control in winter wheat. Herbicides included pyroxsulam at 18.4 g ai ha−1, propoxycarbazone-Na at 44 g ai ha−1, premixed propoxycarbazone-Na & mesosulfuron-methyl at 27 g ai ha−1, and sulfosulfuron at 35 g ai ha−1. The herbicides were applied postemergence in fall and spring seasons. Averaged over time of application, no herbicide controlled downy brome more than 78% in any year. When downy brome densities were high, control was less than 60%. Pyroxsulam controlled downy brome greater than or similar to other herbicides tested. Flixweed (Descurainia sophia L., blue mustard [Chorispora tenella (Pallas DC.], and henbit (Lamium amplexicaule L. control did not differ among herbicide treatments. All herbicides tested controlled flixweed and blue mustard at least 87% and 94%, respectively. However, none of the herbicides controlled henbit more than 73%. Fall herbicide applications improved weed control compared to early spring applications; improvement ranged from 3% to 31% depending on the weed species. Henbit control was greatly decreased by delaying herbicide applications until spring compared to fall applications (49% vs. 80% control. Herbicide injury was observed in only two instances. The injury was ≤13% with no difference between herbicides and the injury did not impact final plant height or grain yield.

Effect of selectivity of herbicides and plant growth regulators used in sugarcane crops on immature stages of Trichogramma galloi (Hymenoptera: Trichogrammatidae).

OpenAIRE

OLIVEIRA, H. N. de; ANTIGO, M. R.; CARVALHO, G. A.; GLAESER, D. F.

2014-01-01

Herbicides and plant growth regulators are often used in sugarcane management. However, the use of non-selective pesticides can cause adverse effects on the efficiency of beneficial insects in integrated pest management. Within this context, this study aimed to evaluate the effect of such products on the immature stages of the parasitoid Trichogramma galloi. Eggs of Diatraea saccharalis containing the parasitoid at the egg-larva stage and at the prepupal and pupal stages were immersed in test...

Effect of selectivity of herbicides and plant growth regulators used in sugarcane crops on immature stages of Trichogramma galloi (Hymenoptera: Trichogrammatidae)

OpenAIRE

Oliveira, H.N.; Antigo, M.R.; Carvalho, G.A.; Glaeser, D.F.

2014-01-01

Herbicides and plant growth regulators are often used in sugarcane management. However, the use of non-selective pesticides can cause adverse effects on the efficiency of beneficial insects in integrated pest management. Within this context, this study aimed to evaluate the effect of such products on the immature stages of the parasitoid Trichogramma galloi. Eggs of Diatraea saccharalis containing the parasitoid at the egg-larva stage and at the prepupal and pupal stages were immersed in test...

Impact of Grassland Reseeding, Herbicide spraying and Ploughing on Diversity and Abundance of Soil Arthropods.

OpenAIRE

Wei Liu; Wei Liu; Wei Liu; Junling Zhang; Stuart L Norris; Phil Murray

2016-01-01

In order to determine the interactive effect of reseeding, herbicide spraying and ploughing on soil fauna communities, we conducted a grassland reseeding experiment combined with pre-reseed management to examine how with the whole reseeding process affects soil faunal composition. Sampling occasions and exact treatments were as follows: 1) before chemical herbicide spray; 2) after spray but before ploughing; 3) after ploughing but before reseeding; and 4) after one year of recovery. Our resul...

Combined thermal and herbicide stress in functionally diverse coral symbionts

International Nuclear Information System (INIS)

Dam, J.W. van; Uthicke, S.; Beltran, V.H.; Mueller, J.F.; Negri, A.P.

2015-01-01

Most reef building corals rely on symbiotic microalgae (genus Symbiodinium) to supply a substantial proportion of their energy requirements. Functional diversity of different Symbiodinium genotypes, endorsing the host with physiological advantages, has been widely reported. Yet, the influence of genotypic specificity on the symbiont's susceptibility to contaminants or cumulative stressors is unknown. Cultured Symbiodinium of presumed thermal-tolerant clade D tested especially vulnerable to the widespread herbicide diuron, suggesting important free-living populations may be at risk in areas subjected to terrestrial runoff. Co-exposure experiments where cultured Symbiodinium were exposed to diuron over a thermal stress gradient demonstrated how fast-growing clade C1 better maintained photosynthetic capability than clade D. The mixture toxicity model of Independent Action, considering combined thermal stress and herbicide contamination, revealed response additivity for inhibition of photosynthetic yield in both tested cultures, emphasizing the need to account for cumulative stressor impacts in ecological risk assessment and resource management. - Highlights: • Water quality influences thermal stress thresholds in different Symbiodinium types. • Photosystem of clade D tested more sensitive than C1 to a common herbicide. • Increased thermal tolerance quickly countered in presence of herbicide. • Mixture toxicity approach demonstrated response additivity for combined stressors. • Symbiotic partnership may be compromised in areas subjected to terrestrial runoff. - Thermal-tolerant Symbiodinium type D tested especially vulnerable to a common herbicide, emphasizing the significance of cumulative stressors in ecological risk management

Early Identification of Herbicide Stress in Soybean (Glycine max (L.) Merr.) Using Chlorophyll Fluorescence Imaging Technology.

Science.gov (United States)

Li, Hui; Wang, Pei; Weber, Jonas Felix; Gerhards, Roland

2017-12-22

Herbicides may damage soybean in conventional production systems. Chlorophyll fluorescence imaging technology has been applied to identify herbicide stress in weed species a few days after application. In this study, greenhouse experiments followed by field experiments at five sites were conducted to investigate if the chlorophyll fluorescence imaging is capable of identifying herbicide stress in soybean shortly after application. Measurements were carried out from emergence until the three-to-four-leaf stage of the soybean plants. Results showed that maximal photosystem II (PS II) quantum yield and shoot dry biomass was significantly reduced in soybean by herbicides compared to the untreated control plants. The stress of PS II inhibiting herbicides occurred on the cotyledons of soybean and plants recovered after one week. The stress induced by DOXP synthase-, microtubule assembly-, or cell division-inhibitors was measured from the two-leaf stage until four-leaf stage of soybean. We could demonstrate that the chlorophyll fluorescence imaging technology is capable for detecting herbicide stress in soybean. The system can be applied under both greenhouse and field conditions. This helps farmers to select weed control strategies with less phytotoxicity in soybean and avoid yield losses due to herbicide stress.

Epigenetic regulation – contribution to herbicide resistance in weeds?

Czech Academy of Sciences Publication Activity Database

Markus, C.; Pečinka, Aleš; Karan, R.; Barney, J. N.; Merotto, A.

2018-01-01

Roč. 74, č. 2 (2018), s. 275-281 ISSN 1526-498X Institutional support: RVO:61389030 Keywords : DNA methylation * epigenetic s * gene expression * gene regulation * herbicide detoxification * plant stress response Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 3.253, year: 2016

Avaliação de herbicidas para dois cultivares de mandioca Selectivity of herbicide alternatives for two cassava cultivars

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D.F Biffe

2010-12-01

Full Text Available É importante avaliar a tolerância de variedade de mandioca a novas alternativas de controle químico, com o intuito de ampliar as opções disponíveis. Este trabalho teve como objetivo avaliar a seletividade de herbicidas aplicados em pré-emergência, para duas importantes variedades de mandioca cultivadas no Estado do Paraná. Os herbicidas e respectivas doses (g i.a. ha-1 avaliadas foram: diuron (400 e 800, metribuzin (360 e 720, isoxaflutole (60, atrazine (720, S-metolachlor (1.920 e as misturas ametryn + clomazone (1.350+1.900, ametryn+trifluralin (1.500+1.350, isoxaflutole+metribuzin (60+320, isoxaflutole+diuron (60+400, combinados com uso de uma testemunha dupla adjacente a cada tratamento. Os cultivares utilizados neste trabalho foram Fécula Branca e Fibra. Apenas o herbicida S-metolachlor, para ambos os cultivares, e metribuzin (360 g i.a. ha-1, para o cultivar Fibra, não provocaram injúrias. Atrazine provocou redução de estande para o cultivar Fécula Branca aos 60 DAP, mas não foi detectada redução na altura de plantas. Tanto atrazine (para os dois cultivares quanto diuron na dose de 800 g i.a. ha-1 (para o cultivar Fécula Branca afetaram a produtividade de raízes. Dessa forma, atrazine foi considerado não seletivo para ambos os cultivares, e a maior dose de diuron foi também considerada não seletiva para o cultivar Fécula Branca. Há diferenças de tolerância entre os cultivares, sendo o Fibra, de modo geral, mais tolerante aos herbicidas avaliados.It is important to evaluate the tolerance of cassava varieties under new weed chemical control alternatives. Thus, this study aimed to evaluate the selectivity of herbicides, applied at pre-emergence, for two important cassava varieties grown in the state of Paraná, Brazil. The herbicides and respective doses (g a.i. ha-1 were: diuron (400 and 800, metribuzin (360 and 720, isoxaflutole (60, atrazine (720, S-metolachlor (1,920 and mixtures ametryn+clomazone (1

Ecological review of black-grass (Alopecurus myosuroides Huds. propagation abilities in relationship with herbicide resistance

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Maréchal, PY.

2012-01-01

Full Text Available Alopecurus myosuroides Huds. (black-grass has always been a major concern for cereal growers, and the development of herbicide resistance does not improve the situation. This review article summarizes the different traits involved in the dispersal pattern of herbicide resistant black-grass individuals within a susceptible field population. Therefore, the whole life cycle of black-grass is depicted from the seed to the seed. From the early vegetative development to the seed falling, every stage is described, taking into account how herbicide resistance can influence or exert a different impact compared to susceptible plants.

Formulants of glyphosate-based herbicides have more deleterious impact than glyphosate on TM4 Sertoli cells.

Science.gov (United States)

Vanlaeys, Alison; Dubuisson, Florine; Seralini, Gilles-Eric; Travert, Carine

2018-05-15

Roundup and Glyphogan are glyphosate-based herbicides containing the same concentration of glyphosate and confidential formulants. Formulants are declared as inert diluents but some are more toxic than glyphosate, such as the family of polyethoxylated alkylamines (POEA). We tested glyphosate alone, glyphosate-based herbicide formulations and POEA on the immature mouse Sertoli cell line (TM4), at concentrations ranging from environmental to agricultural-use levels. Our results show that formulations of glyphosate-based herbicides induce TM4 mitochondrial dysfunction (like glyphosate, but to a lesser extent), disruption of cell detoxification systems, lipid droplet accumulation and mortality at sub-agricultural doses. Formulants, especially those present in Glyphogan, are more deleterious than glyphosate and thus should be considered as active principles of these pesticides. Lipid droplet accumulation after acute exposure to POEA suggests the rapid penetration and accumulation of formulants, leading to mortality after 24 h. As Sertoli cells are essential for testicular development and normal onset of spermatogenesis, disturbance of their function by glyphosate-based herbicides could contribute to disruption of reproductive function demonstrated in mammals exposed to these pesticides at a prepubertal stage of development. Copyright © 2017. Published by Elsevier Ltd.

Oxidative stress induced by glyphosate-based herbicide on freshwater turtles.

Science.gov (United States)

Héritier, Laurent; Duval, David; Galinier, Richard; Meistertzheim, Anne-Leila; Verneau, Olivier

2017-12-01

Freshwater ecosystems face very strong anthropogenic pressures, among which overexploitation, habitat degradation, flow modification, species invasion, and water pollution lead to growing threats on biodiversity. Urbanization through wastewater treatment, industry through the release of inorganic and organic chemicals, and agriculture through the use of pesticides and herbicides are the main factors involved in water pollution. In France, more precisely in the Pyrénées-Orientales department, the poor quality of the watercourses is attributable overall to the use of glyphosate-based herbicides in agricultural activities. Because these chemicals can impact individuals, populations, and biodiversity, we investigated, under experimental conditions, the physiological response of animals facing abiotic contaminants. We selected as a model, juveniles of the freshwater turtle Trachemys scripta elegans. We measured the gene expression and activity of the catalase and superoxide dismutase enzymes as well as the levels of lipid peroxidation, which are all oxidative stress biomarkers, in turtles challenged with high concentrations of glyphosate-based herbicides, on the one hand, and with degraded waters collected from a local watercourse, on the other. We also measured the acetylcholinesterase activity across the same animals. We showed through variations in gene expression and enzyme activity that a glyphosate commercial formulation induced a stress in turtles. A similar outcome was obtained when turtles faced degraded waters. The results indicated that the poor quality of regional waters could be a real threat for animal health. Because turtles are globally less sensitive to contaminants than amphibians, which are lacking in the degraded waters of the Pyrénées-Orientales department, they could constitute an excellent model to follow the evolution of water quality through the study of oxidative stress biomarkers. Environ Toxicol Chem 2017;36:3343-3350. © 2017 SETAC. �

Seletividade de herbicidas sobre Myracrodruon urundeuva (Aroeira Selectivity of herbicides upon Myracrodruon urundeuva (Aroeira

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N.F. Duarte

2006-06-01

Full Text Available O objetivo deste trabalho foi verificar a seletividade de herbicidas utilizados em áreas de eucalipto sobreo crescimento de Myracrodruon urundeuva. O experimento foi conduzido em casa de vegetação em duas épocas diferentes (2002 e 2003, em delineamento inteiramente casualizado, arranjado em esquema fatorial (5x4, sendo cinco herbicidas em quatro doses, com seis repetições. Os tratamentos, com as doses, foram: haloxyfop-methyl (0,00, 120, 240 e 480 g ha-1, sulfentrazone (0,00, 300, 600 e 1.200 g ha-1, isoxaflutole (0,00, 150, 300 e 600 g ha-1, oxyfluorfen (0,00, 720, 1.440 e 2.880 g ha-1; e glyphosate (0,00, 720, 1.440 e 2.880 g ha-1. Em ambos os experimentos foram avaliados: efeitos fitotóxicos do produto, número de folíolos, altura de plantas; no segundo, foi feita ainda a análise de clorofila a e b e de carotenóides. O herbicida que apresentou maior fitoxicidade e que comprometeu o desenvolvimento da aroeira foi o glyphosate, sendo, portanto, não recomendado para o controle de invasoras em áreas de plantio de aroeira. Os outros herbicidas não comprometeram o desenvolvimento desta planta, apresentando, por isso, potencial para uso no manejo de plantas daninhas no cultivo desta espécie.The objective of this work was to verify the selectivity of herbicides applied in eucalyptus areas upon the growth of Myracrodruon urundeuva.. The experiment was carried out under greenhouse conditions during two seasons (2002 and 2003, in a completely randomized experimental design with five herbicides in four doses arranged in a factorial design 5x4, and six replicates. The treatments were: haloxyfop-methyl at the doses (0.00, 120, 240 and 480 g ha-1; sulfentrazone (0.00, 300, 600 and 1.200 g ha-1, isoxaflutole (0.00, 150, 300 and 600 g ha-1; oxyfluoren (0.00, 720, 1.440 and 2.880 g ha-1 and glyphosate (0.00, 720, 1.440 and 2.880 g ha-1 plant toxicity effects, number of leaflets and plant height were evaluated in both experiments and analyses of

Effect of herbicides on microbiological properties of soil

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Milošević Nada A.

2002-01-01

Full Text Available Microorganisms decompose herbicides and they may serve as bioindicators of soil changes following herbicide application. Certain microbial species may be used as bioherbicides. This study has shown that Azotobacter is most sensitive to herbicide application; it is, therefore, a reliable indicator of the biological value of soil. The numbers of this group of nitrogen-fixing bacteria decrease considerably in the period of 7-14 days after herbicide application. Simultaneously, the numbers of Actinomycetes and less so of fungi increase, indicating that these microorganisms use herbicides as sources of biogenous elements. Rate of herbicidal decomposition depends on the properties of the preparation applied herbicide dose as well as on the physical and chemical soil properties, soil moisture and temperature, ground cover, agrotechnical measures applied and the resident microbial population.

GLOBAL EXPRESSION PROFILING AS A TOOL TO DEVELOP MOLECULAR MARKERS LINKED TO HERBICIDE STRESS IN ARABIDOPSIS

Science.gov (United States)

Herbicide drift (unintentional physical movement from target to off-target plants) is a cause of crop loss in US. Low-dose, high-potency herbicides that have short environmental persistence times constrain efforts to develop or identify metabolite or biochemical markers of exposu...

Adsorption of chloroacetanilide herbicides on soil and its components. III. Influence of clay acidity, humic acid coating and herbicide structure on acetanilide herbicide adsorption on homoionic clays.

Science.gov (United States)

Liu, Wei-ping; Fang, Zhuo; Liu, Hui-jun; Yang, Wei-chun

2002-04-01

Adsorption of chloroacetanilide herbicides on homoionic montmorillonite, soil humic acid, and their mixtures was studied by coupling batch equilibration and FT-IR analysis. Adsorption isotherms of acetochlor, alachlor, metolachlor and propachlor on Ca(2+)-, Mg(2+)-, Al(3+)- and Fe(3+)-saturated clays were well described by the Freundlich equation. Regardless of the type of exchange cations, Kf decreased in the order of metolachlor > acetolachlor > alachlor > propachlor on the same clay. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in binding, probably via H-bond with water molecules in the clay interlayer. The type and position of substitutions around the carbonyl group may have affected the electronegativity of oxygen, thus influencing the relative adsorption of these herbicides. For the same herbicide, adsorption on clay increased in the order of Mg2+ < Ca2+ < Al3+ < or = Fe3+ which coincided with the increasing acidity of homoionic clays. Acidity of cations may have affected the protonation of water, and thus the strength of H-bond between the clay water and herbicide. Complexation of clay and humic acid resulted in less adsorption than that expected from independent adsorption by the individual constituents. The effect varied with herbicides, but the greatest decrease in adsorption occurred at a 60:40 clay-to-humic acid ratio for all the herbicides. Causes for the decreased adsorption need to be characterized to better understand adsorption mechanisms and predict adsorption from soil compositions.

Effect of Temperature and Chemical Additives on the Efficacy of the Herbicides Glufosinate and Glyphosate in Weed Management of Liberty-Link and Roundup-Ready Soybeans

OpenAIRE

Pline, Wendy Ann

1999-01-01

The introduction of herbicide resistant crops offers producers many more options for weed control systems. These crops allow environmentally safe, non-selective herbicides to be used as selective herbicides, broadening the spectrum of weeds controlled, while not harming the crop. As these crops are very new on the market, investigation of their performance under various environmental conditions as well as in various weed control programs is needed. Liberty-link ® soybeans are resistant t...

The impact of herbicide-resistant rice technology on phenotypic diversity and population structure of United States weedy rice.

Science.gov (United States)

Burgos, Nilda Roma; Singh, Vijay; Tseng, Te Ming; Black, Howard; Young, Nelson D; Huang, Zhongyun; Hyma, Katie E; Gealy, David R; Caicedo, Ana L

2014-11-01

The use of herbicide-resistant (HR) Clearfield rice (Oryza sativa) to control weedy rice has increased in the past 12 years to constitute about 60% of rice acreage in Arkansas, where most U.S. rice is grown. To assess the impact of HR cultivated rice on the herbicide resistance and population structure of weedy rice, weedy samples were collected from commercial fields with a history of Clearfield rice. Panicles from each weedy type were harvested and tested for resistance to imazethapyr. The majority of plants sampled had at least 20% resistant offspring. These resistant weeds were 97 to 199 cm tall and initiated flowering from 78 to 128 d, generally later than recorded for accessions collected prior to the widespread use of Clearfield rice (i.e. historical accessions). Whereas the majority (70%) of historical accessions had straw-colored hulls, only 30% of contemporary HR weedy rice had straw-colored hulls. Analysis of genotyping-by-sequencing data showed that HR weeds were not genetically structured according to hull color, whereas historical weedy rice was separated into straw-hull and black-hull populations. A significant portion of the local rice crop genome was introgressed into HR weedy rice, which was rare in historical weedy accessions. Admixture analyses showed that HR weeds tend to possess crop haplotypes in the portion of chromosome 2 containing the ACETOLACTATE SYNTHASE gene, which confers herbicide resistance to Clearfield rice. Thus, U.S. HR weedy rice is a distinct population relative to historical weedy rice and shows modifications in morphology and phenology that are relevant to weed management. © 2014 American Society of Plant Biologists. All Rights Reserved.

New Technologies for Insect-Resistant and Herbicide-Tolerant Plants.

Science.gov (United States)

Lombardo, Luca; Coppola, Gerardo; Zelasco, Samanta

2016-01-01

The advent of modern molecular biology and recombinant DNA technology has resulted in a dramatic increase in the number of insect-resistant (IR) and herbicide-tolerant (HT) plant varieties, with great economic benefits for farmers. Nevertheless, the high selection pressure generated by control strategies for weed and insect populations has led to the evolution of herbicide and pesticide resistance. In the short term, the development of new techniques or the improvement of existing ones will provide further instruments to counter the appearance of resistant weeds and insects and to reduce the use of agrochemicals. In this review, we examine some of the most promising new technologies for developing IR and HT plants, such as genome editing and antisense technologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Herbicide injury induces DNA methylome alterations in Arabidopsis

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Gunjune Kim

2017-07-01

Full Text Available The emergence of herbicide-resistant weeds is a major threat facing modern agriculture. Over 470 weedy-plant populations have developed resistance to herbicides. Traditional evolutionary mechanisms are not always sufficient to explain the rapidity with which certain weed populations adapt in response to herbicide exposure. Stress-induced epigenetic changes, such as alterations in DNA methylation, are potential additional adaptive mechanisms for herbicide resistance. We performed methylC sequencing of Arabidopsis thaliana leaves that developed after either mock treatment or two different sub-lethal doses of the herbicide glyphosate, the most-used herbicide in the history of agriculture. The herbicide injury resulted in 9,205 differentially methylated regions (DMRs across the genome. In total, 5,914 of these DMRs were induced in a dose-dependent manner, wherein the methylation levels were positively correlated to the severity of the herbicide injury, suggesting that plants can modulate the magnitude of methylation changes based on the severity of the stress. Of the 3,680 genes associated with glyphosate-induced DMRs, only 7% were also implicated in methylation changes following biotic or salinity stress. These results demonstrate that plants respond to herbicide stress through changes in methylation patterns that are, in general, dose-sensitive and, at least partially, stress-specific.

Weed spectrum and selectivity of tembotrione under varying environmental conditions

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Gatzweiler, Elmar

2012-03-01

Full Text Available Tembotrione is a novel HPPD maize herbicide effective against a wide range of broadleaf and grass weeds. Some characteristics of this compound are described in this paper linking weed and crop responses following tembotrione applications to environmental parameters or use conditions. The activity of HPPD herbicides is very much dependant on the availability of light. Increasing illumination intensities following application augmented the activity levels of several comparable HPPD compounds in a growth chamber experiment. Tembotrione was shown to be more efficacious at low and high illumination intensities compared to standard herbicides applied at the same rate. At the high intensity, tembotrione retained its high efficacy from two up to four weeks after application showing a rapid and strong herbicidal activity. The activity following post-emergent treatments of tembotrione against broadleaf weeds was influenced by soil characteristics such as soil texture and organic matter content in a glasshouse test. The level of weed suppression clearly declined stronger on heavier soils than on lighter soils at a rather low application rate of 12.5 g a.i./ha and lower. This is a clear indication of residual efficacy of tembotrione. The selectivity of tembotrione was tested on numerous maize varieties following post-emergent treatment with tembotrione alone or in mixture with the safener isoxadifen-ethyl under field conditions in Germany in comparison to a standard herbicide. The level of crop phytotoxicity tended to increase in the following order: Tembotrione plus safener, standard herbicide to tembotrione alone. Only the mixture of tembotrione with safener did not cause significant adverse effects on maize. Another field experiment in the USA examined crop phytotoxicity using one maize variety in a situation of infurrow soil insecticide treatment followed by a post-emergent application of tembotrione (plus/minus isoxadifen-ethyl and standard herbicides

Sorption behaviour of herbicides in soils

International Nuclear Information System (INIS)

Luchini, L.C.; Wiendl, F.M.; Ruegg, E.F.; Instituto Biologico, Sao Paulo

1988-01-01

Environmental contamination by herbicides is related with the sorption phenomenon of these compounds in the soils. The behaviour of paraquat, 2,4-D and diuron was studied in soils with different physico-chemical properties, through the Freundlich adsorption and desorption isotherms, using 14 C-radiolabeled herbicides. Results of the range of the adsorption-desorption of each herbicide was related mainly with the chemical characteristics of these compounds. (author) [pt

Assessing the extent and effects of herbicide drift into Danish hedgerows

DEFF Research Database (Denmark)

Pedersen, Marianne Bruus; Andersen, H. V.; Strandberg, M. T.

Very low dosages of herbicides are known to cause effects on bird cherry (Prunus avium) and hawthorn (Crataegus monogyna). It is not yet known whether other hedgerow trees and shrubs are equally sensitive to herbicide drift, to which extent spray drift into hedges and other habitats close to fiel...... were assessed. Metsulfuron methyl effects on Sambucus nigra (elder) and Sorbus intermedia were studied in separate experiments and will include second year effects. Methods and preliminary results are presented and discussed in relation to pesticide regulation....

In-field frequencies and characteristics of oilseed rape with double herbicide resistance.

Science.gov (United States)

Dietz-Pfeilstetter, Antje; Zwerger, Peter

2009-01-01

When growing different transgenic herbicide-resistant oilseed rape cultivars side by side, seeds with multiple herbicide resistance can arise, possibly causing problems for the management of volunteer plants. Large-scale field experiments were performed in the years 1999/2000 and 2000/2001 in order to investigate the frequencies and the consequences of the transfer of herbicide resistance genes from transgenic oilseed rape to cultivars grown on neighboring agricultural fields. Transgenic oilseed rape with resistance to glufosinate-ammonium (LibertyLink, LL) and with glyphosate resistance (RoundupReady, RR), respectively, was sown in adjacent 0.5 ha plots, surrounded by about 8 ha non-transgenic oilseed rape. The plots and the field were either in direct contact (0.5 m gap width) or they were separated by 10 m of fallow land. Seed samples taken during harvest in the transgenic plots at different distances were investigated for progeny with resistance to the respective other herbicide. It was found that outcrossing frequencies were reduced to different extents by a 10 m isolation distance. In addition to pollen-mediated transgene flow as a result of outcrossing, we found considerable seed-mediated gene flow by adventitious dispersal of transgenic seeds through the harvesting machine. Volunteer plants with double herbicide resistance emerging in the transgenic plots after harvest were selected by suitable applications of the complementary herbicides Basta and Roundup Ultra. In both years, double-resistant volunteers were largely restricted to the inner edges of the plots. Expression analysis under controlled laboratory conditions of double-resistant plants generated by manual crosses revealed stability of transgene expression even at elevated temperatures. Greenhouse tests with double-resistant oilseed rape plants gave no indication that the sensitivity to a range of different herbicides is changed as compared to non-transgenic oilseed rape.

Sorption, desorption and leaching potential of sulfonylurea herbicides in Argentinean soils.

Science.gov (United States)

Azcarate, Mariela P; Montoya, Jorgelina C; Koskinen, William C

2015-01-01

The sulfonylurea (SUs) herbicides are used to control broadleaf weeds and some grasses in a variety of crops. They have become popular because of their low application rates, low mammalian toxicity and an outstanding herbicidal activity. Sorption is a major process influencing the fate of pesticides in soil. The objective of this study was to characterize sorption-desorption of four sulfonylurea herbicides: metsulfuron-methyl (methyl 2-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoylsulfamoyl)]benzoate), sulfometuron-methyl (methyl 2-[(4,6-dimethylpyrimidin-2-yl)carbamoylsulfamoyl]benzoate), rimsulfuron (1-(4,6-dimethoxypyrimidin-2-yl)-3-(3-ethylsulfonyl-2-pyridylsulfonyl)urea) and nicosulfuron (2-[(4,6-dimethoxypyrimidin-2-yl)carbamoylsulfamoyl]-N,N-dimethylnicotinamide) from different soil horizons of different landscape positions. Sorption was studied in the laboratory by batch equilibration method. Sorption coefficients (K(d-SE)) showed that rimsulfuron (K(d-SE) = 1.18 to 2.08 L kg(-1)) and nicosulfuron (K(d-SE) = 0.02 to 0.47 L kg(-1)) were more highly sorbed than metsulfuron-methyl (K(d-SE) = 0.00 to 0.05 L kg(-1)) and sulfometuron-methyl (K(d-SE) = 0.00 to 0.05 L kg(-1)). Sorption coefficients (K(d-SE)) were correlated with pH and organic carbon content. All four herbicides exhibited desorption hysteresis where the desorption coefficients (K(d-D)) > K(d-SE). To estimate the leaching potential, K(oc) and ground-water ubiquity score (GUS) were used to calculate the half-life (t1/2) required to be classified as "leacher" or "nonleacher". According to the results, rimsulfuron and nicosulfuron herbicides would be classified as leachers, but factors such as landscape position, soil depth and the rate of decomposition in surface and subsurface soils could change the classification. In contrast, these factors do not affect classification of sulfometuron-methyl and metsulfuron-methyl; they would rank as leachers.

Evaluating the impact of synthetic herbicides on soil dwelling macrobes and the physical state of soil in an agro-ecosystem.

Science.gov (United States)

Frimpong, J O; Ofori, E S K; Yeboah, S; Marri, D; Offei, B K; Apaatah, F; Sintim, J O; Ofori-Ayeh, E; Osae, M

2018-07-30

This study evaluated three herbicides active ingredients: Paraquat, Glyphosate and 2,4-D Amine in commercial formulations as Frankoquat, Roundup and Agriherb respectively under field conditions to determine their influence on soil dwelling macrobes and the physical state of soil. Herbicides were serially diluted to three treatment concentrations for each plus three controls. Herbicide concentrations were applied to the demarcated field on three consecutive occasions in splits. Macrobes extraction from soil was done under a stereo microscope at 20 × magnification. The Simpson's diversity index was used to calculate the soil macrobes diversity. Soil water content, bulk density and total porosity of sampled soils were determined. The study revealed that both herbicides and non-herbicides treatment had no statistical significance (p > 0.05) on the soil dwelling macrobes. Also, a Simpson's index of diversity, estimated as 53.46%, showed how the experimental area is lowly diverse in the specific soil dwelling macrobes identified. Significant correlations existed between the soil water content, bulk density, total porosity and number of soil macrobes at p dwelling macrobes decreased with increasing soil physical conditions. Thus, the dynamics in soil physical properties affected macrobes abundance in soil, with the slightest influence coming from the herbicides concentrations used in the experiment. The study recommended that Frankoquat and Roundup herbicides could be used to control weeds on farmer's field because, their influence were slightly felt on the soil macrobes and also, quite a number soil dwelling macrobes recovered after application. Copyright © 2018 Elsevier Inc. All rights reserved.

Drazepinone, a trisubstituted tetrahydronaphthofuroazepinone with herbicidal activity produced by Drechslera siccans.

Science.gov (United States)

Evidente, Antonio; Andolfi, Anna; Vurro, Maurizio; Fracchiolla, Mariano; Zonno, Maria Chiara; Motta, Andrea

2005-03-01

When grown in a minimal-defined medium, a strain of Drechslera siccans, a pathogenic fungus isolated from seeds of Lolium perenne, produced phytotoxic metabolites. This strain is one of the best toxin producers among several grass pathogenic fungal strains collected and tested to find phytotoxins to be used as natural herbicides of monocot weeds. From the culture filtrates of D. siccans, we isolated a new phytotoxic trisubstituted naphthofuroazepinone, named drazepinone, and characterised it as a 3,5,12a-trimethyl-2,5,5a,12a-tetrahydro-1H-naphtho[2',3':4,5]furo[2,3-b]azepin-2-one. Assayed at 2 microg microl(-1) solution the novel metabolite proved to have broad-spectrum herbicidal properties, without antibacterial and antifungal activities, and low zootoxic activity. Its original chemical structure and the interesting biological properties make drazepinone a potential natural herbicide.

Herbicide and fertilizers promote analogous phylogenetic responses but opposite functional responses in plant communities

DEFF Research Database (Denmark)

Pellissier, Loïc; Wisz, Mary S.; Strandberg, Beate

2014-01-01

on long-term experiment we show that fertilizer and herbicides (glyphosate) have contrasting effects on functional structure, but can increase phylogenetic diversity in semi-natural plant communities. We found that an increase in nitrogen promoted an increase in the average specific leaf area and canopy...... height at the community level, but an increase in glyphosate promoted a decrease in those traits. Phylogenetic diversity of plant communities increased when herbicide and fertilizer were applied together, likely because functional traits facilitating plant success in those conditions were......Throughout the world, herbicides and fertilizers change species composition in agricultural communities, but how do the cumulative effects of these chemicals impact the functional and phylogenetic structure of non-targeted communities when they drift into adjacent semi-natural habitats? Based...

Response of Transplanted Aman Rice Varieties to Herbicides in Strip-Tilled Non-Puddled Soil

Directory of Open Access Journals (Sweden)

Taslima Zahan1

2017-12-01

Full Text Available BACKGROUND: Sensitivity of crop cultivars may vary to commonly used herbicides resulting in potential yield loss and reduce farm profit. Transplanting of rice seedlings in strip-tilled non-puddled field is a new practice for which herbicide tolerant varieties need to select. Therefore, a study was executed at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh during 2013 to evaluate the response of some popular transplanted aman rice varieties to different herbicides at their recommended rate and to select most tolerant aman rice variety or varieties for strip-tilled non-puddled transplanting. METHODOLOGY: Twelve aman rice varieties (BR11, BRRI dhan33, BRRI dhan39, BRRI dhan44, BRRI dhan46, BRRI dhan49, BRRI dhan51, BRRI dhan52, BRRI dhan56, BRRI dhan57, BRRI hybrid dhan-4 and BINA dhan7 were examined in the study against six herbicides (2 pre-emergence: pyrazosulfuron-ethyl and butachlor; 1 early post-emergence: orthosulfamuron and 3 late post-emergence: acetochlor + bensulfuron methyl, butachlor + propanil and 2,4-D amine along with one untreated manually weed-free control. KEY FINDINGS: The study revealed that aman rice varieties responded differentially to different herbicides. All rice varieties performed better in pyrazosulfuron-ethyl treated plots relative to the other herbicide treated plots and even than the control plots. Pyrazosulfuron-ethyl increased grain yield of all aman rice varieties by 0.6-32.6% over control and butachlor + propanil provided increased grain yield in all rice varieties by 2.0-25.5% except BRRI hybrid dhan-4. The study also disclosed that BRRI dhan57 and BRRI hybrid dhan-4 gone through the yield loss by application of 2,4-D amine and BRRI dhan56 by application of butachlor and orthosulfamuron. Moreover, acetochlor + bensulfuron methyl produced shorter plants and caused yield loss by 7.8-27.1% in all aman rice varieties compared to the control and BRRI dhan39 was the most susceptible

Estimation of herbicide bioconcentration in sugarcane (Saccharum officinarum L.

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Antonio Luiz Cerdeira

2015-04-01

Full Text Available Sugarcane is an important crop for sugar and biofuel production in Brazil. Growers depend greatly on herbicides to produce it. This experiment used herbicide physical-chemical and sugarcane plant physiological properties to simulate herbicide uptake and estimate the bioconcentration factor (BCF. The (BCF was calculated for the steady state chemical equilibrium between the plant herbicide concentration and soil solution. Plant-water partition coefficient (sugarcane bagasse-water partition coefficient, herbicide dilution rate, metabolism and dissipation in the soil-plant system, as well as total plant biomass factors were used. In addition, we added Tebuthiuron at rate of 5.0kg a.i. ha-1 to physically test the model. In conclusion, the model showed the following ranking of herbicide uptake: sulfentrazone > picloram >tebuthiuron > hexazinone > metribuzin > simazine > ametryn > diuron > clomazone > acetochlor. Furthermore, the highest BCF herbicides showed higher Groundwater Ubiquity Score (GUS index indicating high leaching potential. We did not find tebuthiuron in plants after three months of herbicide application

Adsorption of sugar beet herbicides to Finnish soils.

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Autio, Sari; Siimes, Katri; Laitinen, Pirkko; Rämö, Sari; Oinonen, Seija; Eronen, Liisa

2004-04-01

Three sugar beet herbicides, ethofumesate, phenmedipham and metamitron, are currently used on conventional sugar beet cultivation, while new varieties of herbicide resistant (HR) sugar beet, tolerant of glyphosate or glufosinate-ammonium, are under field testing in Finland. Little knowledge has so far been available on the adsorption of these herbicides to Finnish soils. The adsorption of these five herbicides was studied using the batch equilibrium method in 21 soil samples collected from different depths. Soil properties like organic carbon content, texture, pH and partly the phosphorus and oxide content of the soils were tested against the adsorption coefficients of the herbicides. In general, the herbicides studied could be arranged according to their adsorption coefficients as follows: glyphosate>phenmedipham>ethofumesate approximately glufosinate-ammonium>metamitron, metamitron meaning the highest risk of leaching. None of the measured soil parameters could alone explain the adsorption mechanism of these five herbicides. The results can be used in model assessments of risk for leaching to ground water resulting from weed control of sugar beet in Finland.

Valerian (Valeriana officinalis L. tolerance to some post-emergence herbicides

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Monjezi Nadia

2015-12-01

Full Text Available Valerian (Valeriana officinalis L. is a medicinal plant, but its cultivation is restricted by weed competition. Therefore, three rates (0.75X, 1X, and 1.25X, where X is equal to the recommended dose of haloxyfop-R (methyl ester, sethoxydim, oxadiargyl, bentazon, oxadiazon, and oxyfluorfen were applied at the 3-4 leaf stages to valerian plants. This application was done to select the herbicide type and rate for post-controlling broadleaf and grasses weeds in this species. Herbicide injury, Soil-Plant Analyses Development (SPAD reading, number of leaves per plant, stem diameter, and fresh and dry weights were determined 10, 20, and 30 days after herbicide application. Oxyfluorfen application caused the most herbicide injury followed by bentazon. Injury increased as the rate and the days after application increased. Oxadiazon only caused significant damage 30 days after application under all three rates. Other treatments showed no marked injuries under any rate or date after application, as compared with the control. Effects on other measured traits depended on the trait, herbicide, and herbicide rate. The highest SPAD, leaf number, shoot diameter, fresh weight and dry weight, was recorded under application of 30 mg a.i. ∙ kg-1 soil oxadiargyl and 90 mg a.i. ∙ kg-1 soil oxadiazon, 81 mg a.i. ∙ kg-1 soil haloxyfop-R, 37.5 mg a.i. ∙ kg-1 soil oxadiargyl, 22.5 mg a.i. ∙ kg-1 soil oxadiargyl, 81 mg a.i. ∙ kg-1 soil haloxyfop-R, and 81 mg a.i. ∙ kg-1 soil haloxyfop-R, respectively. To sum up, the results showed that sethoxydim, oxadiargyl, and haloxyfop-R produced no significant symptoms of phytotoxicity or reduction of measured traits. This means that oxadiargyl, haloxyfop-R, and sethoxydim may be used safely for weed control of valerian at the rates used in this experiment under similar conditions.

CADDIS Volume 2. Sources, Stressors and Responses: Herbicides - Detailed Conceptual Diagram

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Introduction to the herbicides module, when to list herbicides as a candidate cause, ways to measure herbicides, simple and detailed conceptual diagrams for herbicides, herbicides module references and literature reviews.

CADDIS Volume 2. Sources, Stressors and Responses: Herbicides - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the herbicides module, when to list herbicides as a candidate cause, ways to measure herbicides, simple and detailed conceptual diagrams for herbicides, herbicides module references and literature reviews.

Linking fluorescence induction curve and biomass in herbicide screening.

Science.gov (United States)

Christensen, Martin G; Teicher, Harald B; Streibig, Jens C

2003-12-01

A suite of dose-response bioassays with white mustard (Sinapis alba L) and sugar beet (Beta vulgaris L) in the greenhouse and with three herbicides was used to analyse how the fluorescence induction curves (Kautsky curves) were affected by the herbicides. Bentazone, a photosystem II (PSII) inhibitor, completely blocked the normal fluorescence decay after the P-step. In contrast, fluorescence decay was still obvious for flurochloridone, a PDS inhibitor, and glyphosate, an EPSP inhibitor, which indicated that PSII inhibition was incomplete. From the numerous parameters that can be derived from OJIP-steps of the Kautsky curve the relative changes at the J-step [Fvj = (Fm - Fj)/Fm] was selected to be a common response parameter for the herbicides and yielded consistent dose-response relationships. Four hours after treatment, the response Fvj on the doses of bentazone and flurochloridone could be measured. For glyphosate, the changes of the Kautsky curve could similarly be detected 4 h after treatment in sugar beet, but only after 24 hs in S alba. The best prediction of biomass in relation to Fvj was found for bentazone. The experiments were conducted between May and August 2002 and showed that the ambient temperature and solar radiation in the greenhouse could affect dose-response relationships. If the Kautsky curve parameters should be used to predict the outcome of herbicide screening experiments in the greenhouse, where ambient radiation and temperature can only partly be controlled, it is imperative that the chosen fluorescence parameters can be used to predict accurately the resulting biomass used in classical bioassays.

Transgenic and herbicide resistant pearl millet (Pennisetum glaucum L.) R.Br. via microprojectile bombardment of scutellar tissue

CSIR Research Space (South Africa)

Girgi, M

2002-01-01

Full Text Available systems in cereals. In the early 1990?s genetic transformation using immature embryos as explants was successful in rice (Christou et al. 1991), sorghum (Casas et al. 1993) and wheat (Vasil et al. 1992). Yet, the genetic transformation of pearl millet...). The de- velopment of a low-cost method will form the basis for future genetic enhancement of this crop for the benefit of India and Sub-Saharan Africa. Five geneti- cally independent transgenic plants were identified by selection with the herbicide Basta...

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

International Nuclear Information System (INIS)

Gonzalez-Barreiro, O.; Rioboo, C.; Herrero, C.; Cid, A.

2006-01-01

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Barreiro, O. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Rioboo, C. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Herrero, C. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Cid, A. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain)]. E-mail: cid@udc.es

2006-11-15

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides.

Studies on maize inbred lines susceptibility to herbicides

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Stefanović Lidija

2010-01-01

Full Text Available This paper presents the analysis of results obtained during long- term studies on the response of maize inbred lines to herbicides. Under the agroecological conditions of Zemun Polje the response (reaction of maize inbred lines to herbicides of different classes was investigated. Biological tests were performed and some agronomic, morphological, physiological and biochemical parameters were determined when the response of maize inbred lines to herbicides was estimated. The use of active ingredients of herbicides from triazine, acetanilide, thiocarbamate to new chemical groups (sulfonylurea etc., have been resulted in changes in weed suppression and susceptibility of inbred lines. Obtained results show that effects of herbicides on susceptible maize genotypes can be different: they can slowdown the growth and development and affect the plant height; they can also affect the stages of the tassel and ear development and at the end they can reduced grain yield of the tested inbreds. Numerous studies confirmed the existence of differences in susceptibility level of maize genotypes in relation to herbicides. According to gained results the recommendations for growers are made on the possibility of the application of new herbicides in the hybrid seed production.

Impact of Grassland Reseeding, Herbicide Spraying and Ploughing on Diversity and Abundance of Soil Arthropods.

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Liu, Wei; Zhang, Junling; Norris, Stuart L; Murray, Philip J

2016-01-01

In order to determine the interactive effect of reseeding, herbicide spraying and ploughing on soil fauna communities, we conducted a grassland reseeding experiment combined with pre-reseed management to examine how with the whole reseeding process affects soil faunal composition. Sampling occasions and exact treatments were as follows: (1) before chemical herbicide spray; (2) after spray but before ploughing; (3) after ploughing but before reseeding; and (4) after 1 year of recovery. Our results demonstrate that, Acari and Collembola were the two soil fauna taxa with the highest abundance and accounted for around 96% of the relative total abundance among the various managements. Herbicide application tended to increase soil invertebrate abundance. Conversely, subsequent ploughing significantly reduced soil invertebrate abundance and had an obvious negative effect on soil primary and secondary decomposers, which were mainly due to the variations of Acari (especially Oribatida) and Coleoptera group abundance. Moreover, reseeding also reduced the individual number of the groups mentioned above, and favored those predators with a larger body size and individual weight. After 1 year recovery, Collembola abundance recovered to the pre-treatment levels, while with Arthropod and Acari groups were still fluctuating.

Impact of Grassland Reseeding, Herbicide spraying and Ploughing on Diversity and Abundance of Soil Arthropods.

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Wei Liu

2016-08-01

Full Text Available In order to determine the interactive effect of reseeding, herbicide spraying and ploughing on soil fauna communities, we conducted a grassland reseeding experiment combined with pre-reseed management to examine how with the whole reseeding process affects soil faunal composition. Sampling occasions and exact treatments were as follows: 1 before chemical herbicide spray; 2 after spray but before ploughing; 3 after ploughing but before reseeding; and 4 after one year of recovery. Our results demonstrate that, Acari and Collembola were the two soil fauna taxa with the highest abundance and accounted for around 96% of the relative total abundance among the various managements. Herbicide application tended to increase soil invertebrate abundance. Conversely, subsequent ploughing significantly reduced soil invertebrate abundance and had an obvious negative effect on soil primary and secondary decomposers, which were mainly due to the variations of Acari (especially Oribatida and Coleoptera group abundance. Moreover, reseeding also reduced the individual number of the groups mentioned above, and favoured those predators with a larger body size and individual weight. After one year recovery, Collembola abundance recovered to the pre-treatment levels, while with Arthropod and Acari groups were still fluctuating.

Impact of Grassland Reseeding, Herbicide Spraying and Ploughing on Diversity and Abundance of Soil Arthropods

Science.gov (United States)

Liu, Wei; Zhang, Junling; Norris, Stuart L.; Murray, Philip J.

2016-01-01

In order to determine the interactive effect of reseeding, herbicide spraying and ploughing on soil fauna communities, we conducted a grassland reseeding experiment combined with pre-reseed management to examine how with the whole reseeding process affects soil faunal composition. Sampling occasions and exact treatments were as follows: (1) before chemical herbicide spray; (2) after spray but before ploughing; (3) after ploughing but before reseeding; and (4) after 1 year of recovery. Our results demonstrate that, Acari and Collembola were the two soil fauna taxa with the highest abundance and accounted for around 96% of the relative total abundance among the various managements. Herbicide application tended to increase soil invertebrate abundance. Conversely, subsequent ploughing significantly reduced soil invertebrate abundance and had an obvious negative effect on soil primary and secondary decomposers, which were mainly due to the variations of Acari (especially Oribatida) and Coleoptera group abundance. Moreover, reseeding also reduced the individual number of the groups mentioned above, and favored those predators with a larger body size and individual weight. After 1 year recovery, Collembola abundance recovered to the pre-treatment levels, while with Arthropod and Acari groups were still fluctuating. PMID:27555863

Analysis and detection of the herbicides dimethenamid and flufenacet and their sulfonic and oxanilic acid degradates in natural water

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Zimmerman, L.R.; Schneider, R.J.; Thurman, E.M.

2002-01-01

Dimethenamid [2-chloro-N-(2,4-dimethyl-3-thienyl)-N-(2-methoxy-1-methylethyl)acetamide] and flufenacet [N-(4-fluorophenyl)-N-(1-methylethyl)-2-(5-(trifluoromethyl)-1,3,4- thiadiazol-2-yl)oxy] were isolated by C-18 solid-phase extraction and separated from their ethanesulfonic acid (ESA) and oxanilic acid (OXA) degradates during their elution using ethyl acetate for the parent compound, followed by methanol for the polar degradates. The parent compounds were detected using gas chromatography-mass spectrometry in selected-ion mode. The ESA and OXA degradates were detected using high-performance liquid chromatography-electrospray mass spectrometry (HPLC-ESPMS) in negative-ion mode. The method detection limits for a 123-mL sample ranged from 0.01 to 0.07 μg/L. These methods are compatible with existing methods and thus allow for analysis of 17 commonly used herbicides and 18 of their degradation compounds with one extraction. In a study of herbicide transport near the mouth of the Mississippi River during 1999 and 2000, dimethenamid and its ESA and OXA degradates were detected in surface water samples during the annual spring flushes. For flufenacet, the only detections at the study site were for the ESA degradates in samples collected at the peak of the herbicide spring flush in 2000. The low frequency of detections in surface water likely is due to dimethenamid and flufenacet being relatively new herbicides. In addition, detectable amounts of the stable degradates have not been detected in ground water.

Biochar soil additions impacts herbicide fate: Importance of application timing and feedstock species

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BACKGROUND: Biochar (BC), solid biomass subjected to pyrolysis, can alter the fate of pesticides in soil. We investigated the effect of soil amendment with several biochars on the sorption, persistence, leaching and bioefficacy of the herbicides clomazone (CMZ) and bispyribac sodium (BYP). RESULTS:...

Seletividade de herbicidas aplicados nas gramas Santo Agostinho e Esmeralda Selectivity of herbicides applied on St. Augustinegrass and Emerald turfs

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N.V. Costa

2010-01-01

Full Text Available Objetivou-se neste trabalho avaliar a seletividade de herbicidas aplicados nas gramas Santo Agostinho (Stenotaphrum secundatum e Esmeralda (Zoysia japonica em condições de campo. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições. As gramas foram cortadas a 3 cm de altura e, em seguida, foram feitas as aplicações dos herbicidas. Os tratamentos utilizados foram: testemunha sem aplicação, fluazifop-p-butil (125 g ha-1, sethoxydim+óleo mineral (276 g ha-1 + 0,5% v v-1 de Assist, bispyribac-sodium (25 g ha-1, chlorimuron-ethyl (15 g ha-1, ethoxysulfuron (150 g ha-1, halosulfuron (112,5 g ha-1, iodosulfuron-methyl (10 g ha-1, metsulfuron-methyl (2,4 g ha-1, nicosulfuron (125 g ha-1, pyrithiobac-sodium (140 g ha-1, trifloxysulfuron-sodium (22,5 g ha-1, 2,4-D (720 g ha-1, quinclorac (375 g ha-1, atrazina (1.250 g ha-1, bentazon (600 g ha-1, linuron (1.350 g ha-1, fomesafen (187,5 g ha-1, lactofen (120 g ha-1, oxadiazon (600 g ha-1 e oxyfluorfen (720 g ha-1. Os herbicidas que apresentaram potencial de seletividade para o gramado de S. secundatum foram: os inibidores da ALS chlorimuron-ethyl, ethoxysulfuron, halosulfuron, iodosulfuron-methyl e metsulfuron-methyl, o mimetizador de auxina 2,4-D, os inibidores do fotossistema II atrazina e bentazon, bem como os inibidores da Protox fomesafen, lactofen e o oxadiazon. Para o gramado de Z. japonica, os herbicidas que apresentaram potencial de seletividade foram: os inibidores da ALS chlorimuron-ethyl, ethoxysulfuron, halosulfuron, metsulfuron-methyl e nicosulfuron, os mimetizadores de auxina 2,4-D e quinclorac, os inibidores do fotossistema II atrazina e bentazon, além dos inibidores da Protox fomesafen, lactofen e o oxadiazon.The objective of this study was to evaluate the selectivity of herbicides applied on turfgrasses St. Augustinegrass (Stenotaphrum secundatum and Emerald (Zoysia japonica under field conditions. The experimental design was randomized blocks

Comparative effects of herbicides on photosynthesis and growth of tropical estuarine microalgae

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Magnusson, Marie [AIMS at JCU, Australian Institute of Marine Science, School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811 (Australia); School of Marine and Tropical Biology, James Cook University, Douglas Campus, Townsville 4811 (Australia); Heimann, Kirsten [School of Marine and Tropical Biology, James Cook University, Douglas Campus, Townsville 4811 (Australia)], E-mail: Kirsten.Heimann@jcu.edu.au; Negri, Andrew P. [Australian Institute of Marine Science, PMB 3 Townsville MC, QLD 4810 (Australia)

2008-09-15

Pulse amplitude modulation (PAM) fluorometry is ideally suited to measure the sub-lethal impacts of photosystem II (PSII)-inhibiting herbicides on microalgae, but key relationships between effective quantum yield [Y(II)] and the traditional endpoints growth rate ({mu}) and biomass increase are unknown. The effects of three PSII-inhibiting herbicides; diuron, hexazinone and atrazine, were examined on two tropical benthic microalgae; Navicula sp. (Heterokontophyta) and Nephroselmis pyriformis (Chlorophyta). The relationships between Y(II), {mu} and biomass increase were consistent (r{sup 2} {>=} 0.90) and linear (1:1), validating the utility of PAM fluorometry as a rapid and reliable technique to measure sub-lethal toxicity thresholds of PSII-inhibiting herbicides in these microalgae. The order of toxicity (EC{sub 50} range) was: diuron (16-33 nM) > hexazinone (25-110 nM) > atrazine (130-620 nm) for both algal species. Growth rate and photosynthesis were affected at diuron concentrations that have been detected in coastal areas of the Great Barrier Reef.

Comparative effects of herbicides on photosynthesis and growth of tropical estuarine microalgae

International Nuclear Information System (INIS)

Magnusson, Marie; Heimann, Kirsten; Negri, Andrew P.

2008-01-01

Pulse amplitude modulation (PAM) fluorometry is ideally suited to measure the sub-lethal impacts of photosystem II (PSII)-inhibiting herbicides on microalgae, but key relationships between effective quantum yield [Y(II)] and the traditional endpoints growth rate (μ) and biomass increase are unknown. The effects of three PSII-inhibiting herbicides; diuron, hexazinone and atrazine, were examined on two tropical benthic microalgae; Navicula sp. (Heterokontophyta) and Nephroselmis pyriformis (Chlorophyta). The relationships between Y(II), μ and biomass increase were consistent (r 2 ≥ 0.90) and linear (1:1), validating the utility of PAM fluorometry as a rapid and reliable technique to measure sub-lethal toxicity thresholds of PSII-inhibiting herbicides in these microalgae. The order of toxicity (EC 50 range) was: diuron (16-33 nM) > hexazinone (25-110 nM) > atrazine (130-620 nm) for both algal species. Growth rate and photosynthesis were affected at diuron concentrations that have been detected in coastal areas of the Great Barrier Reef

Methods for Rapid Screening in Woody Plant Herbicide Development

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William Stanley

2014-07-01

Full Text Available Methods for woody plant herbicide screening were assayed with the goal of reducing resources and time required to conduct preliminary screenings for new products. Rapid screening methods tested included greenhouse seedling screening, germinal screening, and seed screening. Triclopyr and eight experimental herbicides from Dow AgroSciences (DAS 313, 402, 534, 548, 602, 729, 779, and 896 were tested on black locust, loblolly pine, red maple, sweetgum, and water oak. Screening results detected differences in herbicide and species in all experiments in much less time (days to weeks than traditional field screenings and consumed significantly less resources (<500 mg acid equivalent per herbicide per screening. Using regression analysis, various rapid screening methods were linked into a system capable of rapidly and inexpensively assessing herbicide efficacy and spectrum of activity. Implementation of such a system could streamline early-stage herbicide development leading to field trials, potentially freeing resources for use in development of beneficial new herbicide products.

A Rapid and Simple Bioassay Method for Herbicide Detection

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Xiu-Qing Li

2008-01-01

Full Text Available Chlamydomonas reinhardtii, a unicellular green alga, has been used in bioassay detection of a variety of toxic compounds such as pesticides and toxic metals, but mainly using liquid culture systems. In this study, an algal lawn--agar system for semi-quantitative bioassay of herbicidal activities has been developed. Sixteen different herbicides belonging to 11 different categories were applied to paper disks and placed on green alga lawns in Petri dishes. Presence of herbicide activities was indicated by clearing zones around the paper disks on the lawn 2-3 days after application. The different groups of herbicides induced clearing zones of variable size that depended on the amount, mode of action, and chemical properties of the herbicides applied to the paper disks. This simple, paper-disk-algal system may be used to detect the presence of herbicides in water samples and act as a quick and inexpensive semi-quantitative screening for assessing herbicide contamination.

FLAMMABILITY OF HERBICIDE-TREATED GUAVA FOLIAGE

Science.gov (United States)

Guava leaves treated with herbicide were found to be less flammable than untreated green leaves or dead leaves . Differences in flammability were...determined by small-scale laboratory fires, differential thermal analysis, and thermogravimetric analysis. The herbicide-treated leaves had a higher ash

Seletividade de herbicidas a genótipos de cana-de-açúcar Herbicide selectivity to sugarcane genotypes

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L Galon

2009-12-01

Full Text Available A cultura da cana-de-açúcar, por ter desenvolvimento inicial lento até 60 dias após a emergência, apresenta pouca capacidade competitiva com as plantas daninhas. Por isso, o uso de herbicidas nesse período é prática comum no canavial. No entanto, há variação entre genótipos de cana-de-açúcar na tolerância a herbicidas. Os genótipos pouco tolerantes podem ser intoxicados e, em alguns casos, ocorre redução da produtividade da cana-deaçúcar. Neste trabalho, avaliou-se a tolerância de três genótipos aos herbicidas ametryn, trifloxysulfuron-sodium e à mistura comercial desses, em 0,0, 0,5, 1,0 e 3,0 vezes a dose comercial recomendada. O experimento foi realizado em ambiente protegido. Foi empregado o delineamento experimental inteiramente casualizado, com quatro repetições. Os tratamentos constaram dos genótipos SP80-1816, RB855113 e RB867515, combinados aos herbicidas ametryn, trifloxysulfuron-sodium e ametryn + trifloxysulfuron-sodium, nas doses de 0, 0,5, 1,0 e 3,0 vezes a dose comercial recomendada pelo fabricante. A intoxicação das plantas (% foi avaliada aos 14, 28 e 42 dias após a aplicação dos herbicidas (DAT. As outras variáveis aferidas aos 80 dias após a brotação das gemas foram: área foliar e massa da matéria seca da parte aérea. Em geral, os genótipos SP80-1816 e RB85513 foram menos tolerantes aos herbicidas ametryn, trifloxysulfuron-sodium e à mistura formulada de ametryn + trifloxysulfuron-sodium do que o RB867515 em todas as doses. Eles apresentaram elevados índices de intoxicação aos 14, 28 e 42 dias após a aplicação dos herbicidas. Concluiu-se que o genótipo RB855113 foi o mais sensível aos herbicidas, seguido pelo SP80-1816, sendo o RB867515 o mais tolerante.Due to a slow initial development up to 60 days after emergence, sugarcane shows little competitive capacity over weeds. Thus, the use of herbicides during this period is a common practice in the sugarcane crop. However, there is

Sample clean-up, enrichment and determination of s-triazine herbicides from southern ethiopian lakes supported using liquid membrane extraction

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Jan Åke Jönsson

2000-06-01

Full Text Available The liquid membrane extraction method has been employed for selectively extracting trace quantities of s-triazine herbicides in environmental waters collected from lakes Awassa, Chamo and Abbya, located in close proximity to the agricultural farms in Southern Ethiopia. In liquid membrane extraction, the uncharged triazine compounds from the flowing donor solution diffuse through a porous poly(tetrafluoroethylene (PTFE membrane, containing a water immiscible organic solvent. The s-triazine molecules are then irreversibly trapped in the stagnant acidic acceptor phase since they become protonated. Using both di-n-hexylether and n-undecane membrane solvents, s-traizine herbicides were extracted and low detection limits of about 1 ng/L have been obtained by extraction of three liters of sample solution spiked with 0.1 g/L of each triazine. Residues of atrazine and terbutryn ranging in concentration from 0.02 to 0.05 g/L have been successfully determined.

Effects of the herbicide glyphosate on non-target plant native species from Chaco forest (Argentina).

Science.gov (United States)

Florencia, Ferreira María; Carolina, Torres; Enzo, Bracamonte; Leonardo, Galetto

2017-10-01

Agriculture based on transgenic crops has expanded in Argentina into areas formerly occupied by Chaco forest. Even though glyphosate is the herbicide most widely used in the world, increasing evidence indicates severe ecotoxicological effects on non-target organisms as native plants. The aim of this work is to determine glyphosate effects on 23 native species present in the remaining Chaco forests immersed in agricultural matrices. This is a laboratory/greenhouse approach studying acute effects on seedlings after 21 days. A gradient of glyphosate rates (525, 1050, 2100, 4200, and 8400g ai/Ha; recommended field application rate (RFAR) = 2100g ai/Ha) was applied on four-week seedlings cultivated in a greenhouse and response variables (phytotoxicity, growth reduction, and sensitivity to the herbicide) were measured. This gradient of herbicide rates covers realistic rates of glyphosate applications in the crop field and also those that can reach vegetation of forest relicts by off-target drift and overspray. Testing was performed following guidelines for vegetative vigour (post-germination spray). All species showed lethal or sublethal effects after the application of the 25% of RFAR (50% of species showed severe phytotoxicity or death and 70% of species showed growth reduction). The results showed a gradient of sensitivity to glyphosate by which some of the studied species are very sensitive to glyphosate and seedlings died with 25% of RFAR while other species can be classified as herbicide-tolerant. Thus, the vegetation present in the forest relicts could be strongly affected by glyphosate application on crops. Lethal and sublethal effects of glyphosate on non-target plants could promote both the loss of biodiversity in native forest relicts immersed in the agroecosystems and the selection of new crop weeds considering that some biotypes are continuously exposed to low doses of glyphosate. Copyright © 2017 Elsevier Inc. All rights reserved.

Efficacy evaluation of selected herbicides on weed control and productivity evaluation of Bt cotton in Punjab.

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Singh, Kulvir; Rathore, Pankaj

2015-07-01

Field experiments were conducted during Kharif 2012 and 2013 to evaluate the efficacy of different herbicides for weed management in cotton. Highest seed cotton yield (3537.3 kg ha(-1)) was recorded in weed free plots followed by pendimethalin @1.0 kg a.i ha(-1) as Pre.em.+quizalofopethyl @50 g a.i ha(-1) post-em at 2-4 weed leaf stage + one hoeing (3318.9 kg ha") owing to improved number of bolls per plant and boll weight. Statistically least yield was recorded underweedy check (1435.4 kg ha(-1)). Application of pyrithiobac sodium could not express any visible toxic effect on crop indicating its selectivity for cotton, although none of the tested new chemicals i.e., pyrithiobac sodium@ 62.5g a.i ha(-1) and quizalofopethyl @50g a.i ha(-1) when applied alone could not outperform the existing recommended chemicals for weed management. Yield losses to the extent of 6.2-59.4% were recorded due to weed competition. Weed control efficiency (WCE) was highest under weed free check (86.8%) followed by pendimethalin @1.0 kg a.i ha(-1) as Pre. em.+quizalofopethyl @50g a.i ha(-1), at 2-4 weed leaf stage + one hoeing (73.7%), whereas minimum values were for weedy check (24.7%). Though net returns (r94660 ha(-1)) were highest for weed free check but higher B:C ratio (2:11) was observed for pendimethalin @1.0 kg a.i ha(-1) as Pre em.+quizalofopethyl @50 g a.i ha(-1) post-em at 2-4 weed leaf stage+one hoeing. Therefore, for reasons such as labor shortage besides their timely availability, using these herbicides in combination with cultural practices could be the practical solution foreconomically efficient and effective weed management.

Preemergence herbicides on weed control in elephant grass pasture

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Alexandre Magno Brighenti

Full Text Available ABSTRACT Elephant grass (Pennisetum purpureum Schum. is an important forage crop that has been proposed as a potential feedstock for bioenergy production. However, weed interference is a major factor limiting elephant grass production. Field experiments were conducted in 2014 and 2015 to evaluate preemergence herbicides for selective weed control in an elephant grass pasture. Herbicide treatments included atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, diuron + hexazinone, sulfentrazone, imazethapyr, and atrazine at label use rates. Weedy and weed-free treatments were included. Atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine did not cause phytotoxicity on elephantgrass 35 days after treatment (DAT. However, diuron + hexazinone and imazethapyr were the most phytotoxic on elephantgrass, resulting in 81 and 70% phytotoxicity in 2014, and 7 and 6% phytotoxicity in 2015 respectively 35 DAT. All treatments provided effective weed control (>81% with the exception of ethoxysulfuron (0 and 11% in 2014 and 2015, respectively, and atrazine (59% in 2014. These results show that atrazine + S-metolachlor, atrazine + simazine, ametryn, ethoxysulfuron, S-metolachlor, sulfentrazone, and atrazine were selectives when applied in preemergence in elephant grass pasture.

The benefits of herbicide-resistant crops.

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Green, Jerry M

2012-10-01

Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture. Copyright © 2012 Society of Chemical Industry.

Vertical migration of some herbicides through undisturbed and homogenized soil columns

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Md. Wasim Aktar

2009-01-01

Full Text Available A laboratory experiment was conducted by using three herbicides, two from dinitroaniline group and one from thiocarbamate group to know their degree of downward movement (leachability through soil columns and their contribution in ground water contamination. Soil columns were loaded with Pendimethalin, Benthiocarb and Oryzalin @ 10.0, 10.0 and 7.7 kg a.i. ha-1, respectively. After 30 days soil samples were analyzed from each segments (i.e. 0-6, 6-12, 12-18, and 18-24 and 24-30 cm for Benthiocarb and Pendimethalin by GLC equipped with Ni63 electron capture detector (ECD and for Oryzalin by HPLC coupled with UV-VIS detector. The results obtained in the present study reveal that the residues of the three herbicides under investigation were predominantly confined to the upper soil layer (0-6 cm. Comparatively, low mobility of these herbicides in soils could be due to strong adsorption of these chemical to soil colloids.

Vertical migration of some herbicides through undisturbed and homogenized soil columns

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Aktar, Md. Wasim; Sengupta, Dwaipayan; Purkait, Swarnali; Chowdhury, Ashim

2008-01-01

A laboratory experiment was conducted by using three herbicides, two from dinitroaniline group and one from thiocarbamate group to know their degree of downward movement (leachability) through soil columns and their contribution in ground water contamination. Soil columns were loaded with Pendimethalin, Benthiocarb and Oryzalin at doses of 10.0, 10.0 and 7.7 kg/ha, respectively. After 30 days soil samples were analyzed from each segments (i.e. 0–6, 6–12, 12–18, 18–24 and 24–30 cm) for Benthiocarb and Pendimethalin by GLC equipped with Ni63 electron capture detector (ECD) and for Oryzalin by HPLC coupled with UV-VIS detector. The results obtained in the present study reveal that the residues of the three herbicides under investigation were predominantly confined to the upper soil layer (0–6 cm). Comparatively, low mobility of these herbicides in soils could be due to strong adsorption of these chemical to soil colloids. PMID:21218121

Vertical migration of some herbicides through undisturbed and homogenized soil columns

Directory of Open Access Journals (Sweden)

Md. Wasim Aktar

2008-12-01

Full Text Available A laboratory experiment was conducted by using three herbicides, two from dinitroaniline group and one from thiocarbamate group to know their degree of downward movement (leachability through soil columns and their contribution in ground water contamination. Soil columns were loaded with Pendimethalin, Benthiocarb and Oryzalin @ 10.0, 10.0 and 7.7 kg a.i. ha-1, respectively. After 30 days soil samples were analyzed from each segments (i.e. 0-6, 6-12, 12-18, and 18-24 and 24-30 cm for Benthiocarb and Pendimethalin by GLC equipped with Ni63 electron capture detector (ECD and for Oryzalin by HPLC coupled with UV-VIS detector. The results obtained in the present study reveal that the residues of the three herbicides under investigation were predominantly confined to the upper soil layer (0-6 cm. Comparatively, low mobility of these herbicides in soils could be due to strong adsorption of these chemical to soil colloids.

The Impact of Herbicide-Resistant Rice Technology on Phenotypic Diversity and Population Structure of United States Weedy Rice1[W][OPEN

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Burgos, Nilda Roma; Singh, Vijay; Tseng, Te Ming; Black, Howard; Young, Nelson D.; Huang, Zhongyun; Hyma, Katie E.; Gealy, David R.; Caicedo, Ana L.

2014-01-01

The use of herbicide-resistant (HR) Clearfield rice (Oryza sativa) to control weedy rice has increased in the past 12 years to constitute about 60% of rice acreage in Arkansas, where most U.S. rice is grown. To assess the impact of HR cultivated rice on the herbicide resistance and population structure of weedy rice, weedy samples were collected from commercial fields with a history of Clearfield rice. Panicles from each weedy type were harvested and tested for resistance to imazethapyr. The majority of plants sampled had at least 20% resistant offspring. These resistant weeds were 97 to 199 cm tall and initiated flowering from 78 to 128 d, generally later than recorded for accessions collected prior to the widespread use of Clearfield rice (i.e. historical accessions). Whereas the majority (70%) of historical accessions had straw-colored hulls, only 30% of contemporary HR weedy rice had straw-colored hulls. Analysis of genotyping-by-sequencing data showed that HR weeds were not genetically structured according to hull color, whereas historical weedy rice was separated into straw-hull and black-hull populations. A significant portion of the local rice crop genome was introgressed into HR weedy rice, which was rare in historical weedy accessions. Admixture analyses showed that HR weeds tend to possess crop haplotypes in the portion of chromosome 2 containing the ACETOLACTATE SYNTHASE gene, which confers herbicide resistance to Clearfield rice. Thus, U.S. HR weedy rice is a distinct population relative to historical weedy rice and shows modifications in morphology and phenology that are relevant to weed management. PMID:25122473

Weed management through herbicide application in direct-seeded rice and yield modeling by artificial neural network

Energy Technology Data Exchange (ETDEWEB)

Ghosh, D.; Singh, U.P.; Ray, K.; Das, A.

2016-11-01

In direct seeded rice (DSR) cultivation, weed is the major constraint mainly due to absence of puddling in field. The yield loss due to weed interference is huge, may be up to 100%. In this perspective, the present experiment was conducted to study the efficacy of selected herbicides, and to predict the rice yield using artificial neural network (ANN) models. The dry weight and density of weeds were recorded at different growth stages and consequently herbicidal efficacy was evaluated. Experimental results revealed that pre-emergence (PRE) herbicide effectively controlled the germination of grassy weeds. Application bispyribac-sodium as post-emergence (POST) following PRE herbicides (clomazone or pendimethalin) or as tank-mixture with clomazone effectively reduced the density and biomass accumulation of diverse weed flora in DSR. Herbicidal treatments improved the plant height, yield attributes and grain yield (2.7 to 5.5 times) over weedy check. The sensitivity of the best ANN model clearly depicts that the weed control index (WCI) of herbicides was most important than their weed control efficiency (WCE). Besides, the early control of weeds is a better prescription to improve rice yield. Differences in sensitivity values of WCI and WCE across the crop growth stages also suggest that at 15, 30 and 60 days after sowing, herbicides most effectively controlled sedges, broad leaves and grasses, respectively. Based on the grain yield and herbicidal WCE, it can be concluded that the combined application of pendimethalin or clomazone as PRE followed by bispyribac-sodium as POST or tank-mixture of clomazone + bispyribac sodium can effectively control different weed flushes throughout the crop growth period in DSR. (Author)

Metabolism of nitrodiphenyl ether herbicides by dioxin-degrading bacterium Sphingomonas wittichii RW1.

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Keum, Young Soo; Lee, Young Ju; Kim, Jeong-Han

2008-10-08

Nitrodiphenyl ether herbicides, including chlomethoxyfen, nitrofen, and oxyfluorfen are potent herbicides. Some metabolites and parent compounds are considered as possible mutagens and endocrine disruptors. Both properties pose serious hygienic and environmental risks. Sphingomonas wittichii RW1 is a well-known degrader of polychlorinated dibenzo- p-dioxins, dibenzofurans, and diphenyl ethers. However, no detailed research of its metabolic activity has been performed against pesticides with a diphenyl ether scaffold. In this study, we report S. wittichii RW1 as a very potent diphenyl ether herbicide-metabolizing bacterium with broad substrate specificity. The structures of metabolites were determined by instrumental analysis and synthetic standards. Most pesticides were rapidly removed from the culture medium in the order of nitrofen > oxyfluorfen > chlomethoxyfen. In general, herbicides were degraded through the initial reduction and N-acetylation of nitro groups, followed by ether bond cleavage. Relatively low concentrations of phenolic and catecholic metabolites throughout the study suggested that these metabolites were rapidly metabolized and incorporated into primary metabolism. These results indicate that strain RW1 has very versatile metabolic activities over a wide range of environmental contaminants.

Getting More Ecologically Relevant Information from Laboratory Tests: Recovery of Lemna minor After Exposure to Herbicides and Their Mixtures.

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Knežević, Varja; Tunić, Tanja; Gajić, Pero; Marjan, Patricija; Savić, Danko; Tenji, Dina; Teodorović, Ivana

2016-11-01

Recovery after exposure to herbicides-atrazine, isoproturon, and trifluralin-their binary and ternary mixtures, was studied under laboratory conditions using a slightly adapted standard protocol for Lemna minor. The objectives of the present study were (1) to compare empirical to predicted toxicity of selected herbicide mixtures; (2) to assess L. minor recovery potential after exposure to selected individual herbicides and their mixtures; and (3) to suggest an appropriate recovery potential assessment approach and endpoint in a modified laboratory growth inhibition test. The deviation of empirical from predicted toxicity was highest in binary mixtures of dissimilarly acting herbicides. The concentration addition model slightly underestimated mixture effects, indicating potential synergistic interactions between photosynthetic inhibitors (atrazine and isoproturon) and a cell mitosis inhibitor (trifluralin). Recovery after exposure to the binary mixture of atrazine and isoproturon was fast and concentration-independent: no significant differences between relative growth rates (RGRs) in any of the mixtures (IC10 Mix , 25 Mix , and 50 Mix ) versus control level were recorded in the last interval of the recovery phase. The recovery of the plants exposed to binary and ternary mixtures of dissimilarly acting herbicides was strictly concentration-dependent. Only plants exposed to IC10 Mix , regardless of the herbicides, recovered RGRs close to control level in the last interval of the recovery phase. The inhibition of the RGRs in the last interval of the recovery phase compared with the control level is a proposed endpoint that could inform on reversibility of the effects and indicate possible mixture effects on plant population recovery potential.

Using fluorescent dyes as proxies to study herbicide removal by sorption in buffer zones.

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Dollinger, Jeanne; Dagès, Cécile; Voltz, Marc

2017-04-01

The performance of buffer zones for removing pesticides from runoff water varies greatly according to landscape settings, hydraulic regime, and system design. Evaluating the performance of buffers for a range of pesticides and environmental conditions can be very expensive. Recent studies suggested that the fluorescent dyes uranine and sulforhodamine B could be used as cost-effective surrogates of herbicides to evaluate buffer performance. However, while transformation mechanisms in buffers have been extensively documented, sorption processes of both dyes have rarely been investigated. In this study, we measured the adsorption, desorption, and kinetic sorption coefficients of uranine and sulforhodamine B for a diverse range of buffer zone materials (soils, litters, plants) and compared the adsorption coefficients (Kd) to those of selected herbicides. We also compared the global sorption capacity of 6 ditches, characterized by varying proportions of the aforementioned materials, between both dyes and a set of four herbicides using the sorption-induced pesticide retention indicator (SPRI). We found that both the individual Kd of uranine for the diverse buffer materials and the global sorption capacity of the ditches are equivalent to those of the herbicides diuron, isoproturon, and metolachlor. The Kd of sulforhodamine B on plants and soils are equivalent to those of glyphosate, and the global sorption capacities of the ditches are equivalent for both molecules. Hence, we demonstrate for the first time that uranine can be used as a proxy of moderately hydrophobic herbicides to evaluate the performance of buffer systems, whereas sulforhodamine B can serve as a proxy for more strongly sorbing herbicides.

Environmental and health effects of the herbicide glyphosate.

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Van Bruggen, A H C; He, M M; Shin, K; Mai, V; Jeong, K C; Finckh, M R; Morris, J G

2018-03-01

The herbicide glyphosate, N-(phosphonomethyl) glycine, has been used extensively in the past 40years, under the assumption that side effects were minimal. However, in recent years, concerns have increased worldwide about the potential wide ranging direct and indirect health effects of the large scale use of glyphosate. In 2015, the World Health Organization reclassified glyphosate as probably carcinogenic to humans. A detailed overview is given of the scientific literature on the movement and residues of glyphosate and its breakdown product aminomethyl phosphonic acid (AMPA) in soil and water, their toxicity to macro- and microorganisms, their effects on microbial compositions and potential indirect effects on plant, animal and human health. Although the acute toxic effects of glyphosate and AMPA on mammals are low, there are animal data raising the possibility of health effects associated with chronic, ultra-low doses related to accumulation of these compounds in the environment. Intensive glyphosate use has led to the selection of glyphosate-resistant weeds and microorganisms. Shifts in microbial compositions due to selective pressure by glyphosate may have contributed to the proliferation of plant and animal pathogens. Research on a link between glyphosate and antibiotic resistance is still scarce but we hypothesize that the selection pressure for glyphosate-resistance in bacteria could lead to shifts in microbiome composition and increases in antibiotic resistance to clinically important antimicrobial agents. We recommend interdisciplinary research on the associations between low level chronic glyphosate exposure, distortions in microbial communities, expansion of antibiotic resistance and the emergence of animal, human and plant diseases. Independent research is needed to revisit the tolerance thresholds for glyphosate residues in water, food and animal feed taking all possible health risks into account. Copyright © 2017 Elsevier B.V. All rights reserved.

EVALUATION DE L’IMPACT ENVIRONNEMENTAL : Evaluation des impacts du flux de transgènes de tolérance à différents herbicides à large spectre

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Astoin Marie-Florence

2000-07-01

Full Text Available Ce texte est tiré du rapport « Introduction de variétés génétiquement modifiées de colza tolérantes à différents herbicides : évaluation des impacts agro-environnementaux et propositions de scénarios de gestion » établi par le Cetiom dans le cadre du moratoire sur les variétés génétiquement modifiées de colza. Les auteurs se réservent la possibilité d’ici publication définitive du rapport d’apporter des modifications à ce texte.

Seletividade de herbicidas aplicados em pós-emergência para a cultura da mandioquinha-salsa Peruvian carrot tolerance to post-emergence herbicides

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R.S. Freitas

2004-03-01

and high] with 39 treatments distributed in randomized blocks, with three repetitions. The herbicide doses (g ha-1 were: bentazon (600, 720, and 960, clethodim (84, 96, and 108, fenoxaprop-p-ethyl (68, 90, and 110, flazasulfuron (50, 75, and 100, fluazifop-p-butyl (94, 187, and 250, halosulfuron (75, 112, and 150, imazamox (28, 35, and 42, linuron (900, 1,350, and 1,800, oxadiazon (500, 750, and 1,000, propaquizafop (100, 125, and 150, sethoxydin (184, 230, and 276, and ammonium-glufosinate (200, 300, and 400. The plants were harvested at 49 days after treatment application (DAA. The herbicides halosulfuron, flazasulfuron, imazamox and bentazon caused high toxicity and damage to the crop, being non-selective for Peruvian carrot. Low and medium doses of linuron and oxadiazon, and low dose of ammonium-glufosinate caused toxicity just after spraying, but the crop showed good recovery from 28 DAA. Fluazifop-p-butyl was selective in low doses. Clethodim, fenoxaprop-p-ethyl, propaquizafop, and sethoxydin were the most selective to Peruvian carrot.

A 3D-Printed, Portable, Optical-Sensing Platform for Smartphones Capable of Detecting the Herbicide 2,4-Dichlorophenoxyacetic Acid

Energy Technology Data Exchange (ETDEWEB)

Wang, Yijia [School; College; Zeinhom, Mohamed M. A. [School; Food; Yang, Mingming [School; Sun, Rongrong [School; Wang, Shengfu [College; Smith, Jordan N. [Health; amp, Exposure Science, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Timchalk, Charles [Health; amp, Exposure Science, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Li, Lei [School; Lin, Yuehe [School; Du, Dan [School

2017-08-14

Onsite rapid detection of herbicide and herbicide residuals in environmental and biological specimens is important for agriculture, environment, food safety, and health care. Traditional method for herbicide detection requires expensive laboratory equipment and a long turn-round time. In this work, we developed a single-stripe microliter plate smartphone colorimetric device for rapid and low-cost in-field test. This portable smartphone platform is capable of screening 8 samples in a microplate single-stripe. The device combined the advantages of small size (50×100×160 mm3) and low cost ($10). The platform was calibrated by using two different dye solutions, i.e. methyl blue (MB) and Rhodamine B, for green and red channels. The results showed good correlation with results attained from a traditional laboratory reader. We demonstrated the application of this platform for an herbicide, 2,4-Dichlorophenoxyacetic acid detection in the range of 1 ppb to 80 ppb. Spiked samples of tap water, rat serum, plasma and human serum were tested by our device. Recoveries obtained varied from 95.6% to 105.2% for all spiked samples using the microplate reader and from 93.7% to 106.9% using the smartphone device. This work validated that the smartphone optical sensing platform is comparable to the commercial microplate reader, it is eligible for onsite rapid and low-cost detection of herbicide for environmental evaluation and biological monitoring.

Structural and functional effects of herbicides on non-target organisms in aquatic ecosystems with an emphasis on atrazine

Science.gov (United States)

Fairchild, James; Kortekamp, Andreas

2011-01-01

Herbicide use has increased dramatically around the world over the past 6 decades (Gianessi and Reigner, 2007). Few herbicides were in use in the 1950s. However, by 2001 approximately 1.14 billion kilograms of herbicides were applied globally for the control of undesireable vegetation in agricultural, silvicultural, lawncare, aquacultural, and irrigation/recreational water management activities (Kiely et al., 2004). Twenty-eight percent of the total mass of herbicides is applied in the United States, with the remaining 72 percent being applied elsewhere around the globe (Kiely et al., 2004). Herbicides represent 36% of global pesticide use, followed by insecticides (25%), fungicides (10%) and other chemical classes (Kiely et al., 2004). Agricultural production accounts for approximately 90% of herbicide use in the U.S. (Kiely et al., 2004). Gianessi and Reigner (2007) indicated that herbicides are routinely used on more than 90% of the area designated for large commercial crops including corn, soybeans, cotton, sugar beets, peanuts, and rice. Increased farm mechanization, technological advancements in production of inexpensive sources of inorganic nitrogen fertilizer (e.g., anhydrous ammonia), and conversion of forest, grassland, and wetland habitats to cropland has led to a tremendous increase in global food production over the past half-century. Herbicides have augmented advances in large-scale agricultural systems and have largely replaced mechanical and hand-weeding control mechanisms (Gianessi and Reigner, 2007). The wide-spread use of herbicides in agriculture has resulted in frequent chemical detections in surface and groundwaters (Gilliom, 2007). The majority of herbicides used are highly water soluble and are therefore prone to runoff from terrestrial environments. In additon, spray drift and atmospheric deposition can contribute to herbicide contamination of aquatic environments. Lastly, selected herbicides are deliberately applied to aquatic environments

Routine determination of sulfonylurea, imidazolinone, and sulfonamide herbicides at nanogram-per-liter concentrations by solid-phase extraction and liquid chromatography/mass spectrometry

Science.gov (United States)

Furlong, E.T.; Burkhardt, M.R.; Gates, Paul M.; Werner, S.L.; Battaglin, W.A.

2000-01-01

Sulfonylurea (SU), imidazolinone (IMI), and sulfonamide (SA) herbicides are new classes of low-application-rate herbicides increasingly used by farmers. Some of these herbicides affect both weed and crop species at low dosages and must be carefully used. Less is known about the effect of these compounds on non-crop plant species, but a concentration of 100 ng/l in water has been proposed as the threshold for possible plant toxicity for most of these herbicides. Hence, analytical methods must be capable of detecting SUs, IMIs, and SAs at concentrations less than 100 ng/l in ambient water samples. The authors developed a two-cartridge, solid-phase extraction method for isolating 12 SU, 3 IMI, and 1 SA herbicides by using high-performance liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS) to identify and quantify these herbicides to 10 ng/l. This method was used to analyze 196 surface- and ground-water samples collected from May to August 1998 throughout the Midwestern United States, and more than 100 quality-assurance and quality-control samples. During the 16 weeks of the study, the HPLC/ESI-MS maintained excellent calibration linearity across the calibration range from 5 to 500 ng/l, with correlation coefficients of 0.9975 or greater. Continuing calibration verification standards at 100-ng/l concentration were analyzed throughout the study, and the average measured concentrations for individual herbicides ranged from 93 to 100 ng/l. Recovery of herbicides from 27 reagent-water samples spiked at 50 and 100 ng/l ranged from 39 to 92%, and averaged 73%. The standard deviation of recoveries ranged from 14 to 26%, and averaged 20%. This variability reflects multiple instruments, operators, and the use of automated and manual sample preparation. Spiked environmental water samples had similar recoveries, although for some herbicides, the sample matrix enhanced recoveries by as much as 200% greater than the spiked concentration. This matrix

Influence of herbicide structure, clay acidity, and humic acid coating on acetanilide herbicide adsorption on homoionic clays.

Science.gov (United States)

Liu, Weiping; Gan, Jianying; Yates, Scott R

2002-07-03

Adsorption of chloroacetanilide herbicides on homoionic montmorillonite was studied by coupling batch equilibration and FT-IR analysis. Adsorption decreased in the order metolachlor > acetochlor > alachlor > propachlor on Ca(2+)- or Mg(2+)-saturated clays and in the order metolachlor > alachlor > acetachlor > propachlor on Al(3+)- or Fe(3+)-saturated clays. FT-IR spectra showed that the carbonyl group of the herbicide molecule was involved in bonding. For the same herbicide, adsorption of alachlor, acetachlor, and metolachlor on clay followed the order Ca(2+) approximately Mg(2+) < Al(3+) < or = Fe(3+), which coincided with the increasing acidity of homoionic clays. Adsorption of propachlor, however, showed an opposite dependence, suggesting a different governing interaction. In clay and humic acid mixtures, herbicide adsorption was less than that expected from independent additive adsorption by the individual constituents, and the deviation was dependent on the clay-to-humic acid ratio, with the greatest deviation consistently occurring at a 60:40 clay-to-humic acid ratio.

Seletividade de herbicidas aplicados em pré-emergência na cultura de cana-de-açúcar tratada com nematicidas Selectivity of pre-emergence herbicides to sugarcane treated with nematicides

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E. Negrisoli

2004-12-01

Full Text Available O objetivo do trabalho foi estudar a seletividade de herbicidas para a cultura da cana-de-açúcar quando aplicado em culturas tratadas com nematicidas. O experimento foi instalado em área pertencente à Usina São José, município de Borebi-SP, ano agrícola de 2000/01. A variedade de cana-de-açúcar utilizada foi a RB855113. Utilizou-se o delineamento experimental de blocos ao acaso em parcelas subdivididas, com quatro repetições. Cada parcela correspondeu a 27 linhas de 10,0 m, espaçadas em 1,0 m, sendo dividida em três subparcelas. As parcelas corresponderam aos tratamentos com os herbicidas, e as subparcelas, à aplicação ou não dos nematicidas carbofuran (2,10 kg ha-1 e terbufós 2,25 kg ha��. Os herbicidas testados foram: tebuthiuron (1,12 kg ha-1, ametryne (1,75 kg ha¹, sulfentrazone (0,8 kg ha-1, metribuzin (1,92 kg ha-1, isoxaflutole (0,0525 kg ha¹, clomazone (1,25 kg ha¹, oxyfluorfen (0,36 kg ha-1 e azafenidin+hexazinone (0,1575 + 0,2025 kg ha-1, sendo todos aplicados em pré-emergência, além de uma parcela como testemunha. Os resultados obtidos evidenciaram que os herbicidas oxyfluorfen e azafenidin+hexazinone causaram os maiores níveis de fitotoxicidade na cana-de-açúcar, independentemente do uso dos nematicidas carbofuran e terbufós. Os herbicidas tebuthiuron, ametryne, sulfentrazone, metribuzin, isoxaflutole, clomazone, oxyfluorfen e azafenidin+hexazinone, aplicados em doses representativas das comercialmente utilizadas, mostraram-se seletivos à cana-de-açúcar, não afetando seu crescimento, sua produtividade e suas características tecnológicas. Os nematicidas não interferiram nos níveis de intoxicação provocados pelos herbicidas utilizados na cultura.The objective of this work was to study the selectivity of herbicides to sugarcane when applied in crops treated with nematicides. The experiment was carried out in Borebi, São Paulo-Brazil, during the growing season 2000/2001. The sugar cane variety

Using Bioassays and Species Sensitivity Distributions to Assess Herbicide Toxicity towards Benthic Diatoms

Science.gov (United States)

Larras, Floriane; Bouchez, Agnès; Rimet, Frédéric; Montuelle, Bernard

2012-01-01

Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD) could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC5) and the Effective Concentration 50 (EC50) for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC5) and 50 (HC50). Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII) herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and “motile” guild species were more tolerant of PSII inhibitors, while N-autotroph and “low profile” guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron. PMID:22952981

Using bioassays and species sensitivity distributions to assess herbicide toxicity towards benthic diatoms.

Directory of Open Access Journals (Sweden)

Floriane Larras

Full Text Available Although benthic diatoms are widely used in ecological studies of aquatic systems, there is still a dearth of data concerning species sensitivities towards several contaminants. Within the same community, different species may respond differently depending on their physiological and ecological characteristics. This lack of knowledge makes specific appropriate risk assessment impossible. To find out whether species sensitivity distribution (SSD could be used to estimate the risk of herbicide toxicity for diatoms, we need to know whether their sensitivity depends on their physiological and ecological characteristics. We carried out single-species bioassays on 11 diatom species exposed to 8 herbicides. Dose-responses relationships were used to extrapolate the Effective Concentration 5 (EC(5 and the Effective Concentration 50 (EC(50 for each exposure. These data were used to fit a SSD curve for each herbicide, and to determine the Hazardous concentration 5 (HC(5 and 50 (HC(50. Our results revealed a high level of variability of the sensitivity in the set of species tested. For photosystem-II inhibitor (PSII herbicides, diatoms species displayed a typical grouping of sensitivity levels consistent with their trophic mode and their ecological guild. N-heterotroph and "motile" guild species were more tolerant of PSII inhibitors, while N-autotroph and "low profile" guild species were more sensitive. Comprehensive SSD curves were obtained for 5 herbicides, but not for sulfonylurea herbicides or for dimetachlor, which had toxicity levels that were below the range of concentration tested. The SSD curves provided the following ranking of toxicity: diuron> terbutryn> isoproturon> atrazine> metolachlor. The HC that affected 5% of the species revealed that, even at the usual environmental concentrations of herbicides, diatom assemblages could be affected, especially by isoproturon, terbutryn, and diuron.

Manual herbicide application methods for managing vegetation in Appalachian hardwood forests

Science.gov (United States)

Jeffrey D. Kochenderfer; James N. Kochenderfer; Gary W. Miller

2012-01-01

Four manual herbicide application methods are described for use in Appalachian hardwood forests. Stem injection, basal spray, cut-stump, and foliar spray techniques can be used to control interfering vegetation and promote the development of desirable reproduction and valuable crop trees in hardwood forests. Guidelines are presented to help the user select the...

Antioxidant activity of rice plants sprayed with herbicides

Directory of Open Access Journals (Sweden)

Marcos André Nohatto

2016-03-01

Full Text Available Understanding the physiological defense behavior of plants subjected to herbicide application may help to identify products with higher or lower capacity to cause oxidative stress in crops. This study aimed at evaluating the effect of herbicides in the antioxidant activity of rice plants. The experimental design was completely randomized, with six replications. Treatments consisted of the herbicides bentazon (photosystem II inhibitor; 960 g ha-1, penoxsulam (acetolactate synthase inhibitor; 60 g ha-1, cyhalofop-butyl (acetyl coenzyme-A carboxylase inhibitor; 315 g ha-1 and a control. After the herbicides application, samples of rice shoots were collected at 12, 24, 48 and 96 hours after application (HAA. The components evaluated were hydrogen peroxide (H2O2, lipid peroxidation and activity of the antioxidant enzymes superoxide dismutase (SOD and catalase (CAT. Bentazon (up to 24 HAA and penoxsulam (48 and 96 HAA reduced the CAT activity. Moreover, these herbicides increased the levels of H2O2, lipid peroxidation and SOD activity, indicating a condition of oxidative stress in rice plants. The cyhalofop-butyl herbicide did not alter the antioxidant activity, showing that it causes less stress to the crop.

Prediction of climate impacts on pesticide leaching to the aquatic environments

Energy Technology Data Exchange (ETDEWEB)

Henriksen, Hans Joergen; Rosenbom, A.; van der Keur, P.; Kjaer, J.; Sonnenborg, T. [GEUS Danmark, Copenhagen (Denmark); Olesen, J.E. [Aarhus Univ., Tjele (Denmark); Nistrup Joergensen, L. [Aarhus Unv., Slagelse (Denmark); Boessing Christensen, O. [Danmarks Meteorologiske Institut (DMI), Copenhagen (Denmark)

2013-10-01

The report evaluates direct (precipitation, actual evapotranspiration and temperature) and indirect (crop rotations, crop management, and pesticide use) climatic change effects on pesticide-leaching to groundwater and the aquatic environment by use of MACRO and MIKE SHE model. The analysis is based on five model pesticides: low-dose herbicides, ordinary herbicides, strongly sorbing herbicides, fungicides and insecticides, and selected farm types (arable and dairy) for the variable saturated sandy soil (Jyndevad) and loamy soil (Faardrup). The evaluation has the aim at describing the implications of future climatic factors on pesticide leaching to groundwater as realistic as possible, based on realistic doses and parameters from MACRO setups from the Danish Pesticide Leaching Assessment Programme. (Author)

Assessment of the levels of N- (Phosphonomethyl) glycine glyphosate in selected glyphosate-based herbicides on the Ghanaian market

International Nuclear Information System (INIS)

Iddrisu, Adisatu

2016-07-01

Sixty one (61) samples of Glyphosate based herbicides were collected from the central commercial hub of Kumasi (Kejetia) and ware houses of importers in Ashanti and Greater Accra regions of Ghana and analyzed using high performance liquid chromatography (HPLC). Information about the efficacy of the numerous Glyphosate herbicides on the market was also collected by way of questionnaire. Results of the analysis indicated that only ten (16.4 %) out of the sixty one samples met the Environmental Protection Agency’s requirement of ±5 % of the stated active ingredient concentration and 51 samples representing 83.6 % were all out of the acceptable range. Active ingredient was either understated or overstated. About 21.6 % of the samples that failed to meet requirements were overstated and 78.4 % were understated. Apart from a few of the samples that had concentrations higher than stated label claims with 69 g/L (19.2 %) highest, most samples were generally lower than stated label claims. Some (G09, G18 and G44) samples contained virtually no active ingredient with shortfalls as high as 98.6%. Some of these shortfalls explained findings from the field investigations where some respondents complained of Glyphosate not being efficacious. Farmers may follow the application and safety instructions but this only holds true as long as the herbicides provide efficient control of weed. This can only be achieved with products of consistently high quality. This study also discovered that, there was no possibility of adulteration of the herbicide along the value chain as results for products picked from ware houses of importers did not differ much from those picked from the open market. Results from the other method employed in Glyphosate determination was UV/VIV spectroscopy, this method is simpler and faster and readily available in most laboratories in Ghana. Results from UV/VIS were comparable to that of the HPLC with generally lower values for UV/VIS readings. It is therefore

Herbicides and their transformation products in source-water aquifers tapped by public-supply wells in Illinois, 2001-02

Science.gov (United States)

Mills, Patrick C.; McMillan, William D.

2004-01-01

During 2001-02, ground-water samples were collected from 117 public-supply wells distributed throughout Illinois to evaluate the occurrence of herbicides and their transformation products in the State?s source-water aquifers. Wells were selected using a stratified-random method to ensure representation of the major types of source-water aquifers in the State. Samples were analyzed for 18 herbicides and 18 transformation products, including 3 triazine and 14 chloroacetanilide products. Herbicide compounds (field-applied parent herbicides and their transformation products) were detected in 34 percent of samples. A subset of samples was collected unfiltered to determine if analytical results for herbicides in unfiltered samples are similar to those in paired filtered samples and, thus, can be considered equally representative of herbicide concentrations in ground water supplied to the public. The study by the U.S. Geological Survey was done in cooperation with the Illinois Environmental Protection Agency. Parent herbicides were detected in only 4 percent of all samples. The six most frequently detected herbicide compounds (from 5 to 28 percent of samples) were chloroacetanilide transformation products. The frequent occurrence of transformation products and their higher concentrations relative to those of most parent herbicides confirm the importance of obtaining information on transformation products to understand the mobility and fate of herbicides in ground-water systems. No sample concentrations determined during this study exceeded current (2003) Federal or State drinking-water standards; however, standards are established for only seven parent herbicides. Factors related to the occurrence of herbicide compounds in the State?s source-water aquifers include unconsolidated and unconfined conditions, various hydrogeologic characteristics and well-construction aspects at shallow depths, and proximity to streams. Generally, the closer an aquifer (or well location) is

Weed infestation of a winter wheat canopy under the conditions of application of different herbicide doses and foliar fertilization

Directory of Open Access Journals (Sweden)

Piotr Kraska

2012-12-01

Full Text Available The present study was carried out in the years 2006-2008 in the Bezek Experimental Farm (University of Life Sciences in Lublin. A two-factor field experiment was set up according to a randomized block design, in three replications. The experimental field was situated on medium heavy mixed rendzina developed from chalk rock with medium dusty loam granulometric composition. The soil was characterised by neutral pH, a very high content of P (342.1 and K (278.9 along with a very low level of magnesium (16.0 mg × kg-1 of soil and organic carbon (over 3.5%. The aim of this research was to compare the effect of three herbicide doses and two foliar fertilizers applied in a winter wheat canopy on weed infestation. The herbicides Mustang 306 SE 0.4 l × ha-1 and Attribut 70 WG 60 g × ha-1 were applied at full recommended doses as well as at doses reduced to 75% and 50%. Foliar fertilizers Insol 3 (1 1 × ha-1 and FoliCare (20 kg × ha-1 were applied at full recommended doses twice in the growing season BBCH* development stage 23-25* and 33-35*. The control was not treated with the herbicides and foliar fertilizers. The weed infestation level was determined by means of the quantitative gravimetric method at two dates: the first one 6 weeks after herbicide application and the second one - before harvest. The number of weed individuals was counted; species composition and air-dry biomass of aboveground parts were estimated from randomly selected areas of 1 m × 0.25 m at four sites on each plot. Galium aparine and Apera spica-venti plants were sampled for molecular analysis 6 weeks after herbicide application (the treatments with the full herbicide dose, a 50% dose and the control without herbicides. The density of weeds and weed air-dry weight were statistically analysed by means of variance analysis, and the mean values were estimated with Tukey's confidence intervals (p=0.05. It was found that the number of weeds and air-dry weight of weeds in the

Occurrence of phosphorus, other nutrients, and triazine herbicides in water from the Hillsdale Lake basin, Northeast Kansas, May 1994 through May 1995

Science.gov (United States)

Putnam, J.E.

1997-01-01

An investigation of the occurrence of phosporus, other nutrients, and triazine herbicides in water samples from the Hillsdale Lake Basin in northeast Kansas was conducted from May 1994 through May 1995. Point-source and nonpoint-source contributions of these water-quality constituents were estimated by conducting synoptic sampling at 48 sites in the basin during five periods of low- flow conditions. Samples were collected for the determination of nutrients, including total phosphorus as phosphorus, dissolved orthophosphate as phosphorus, total nitrite plus nitrate as nitrogen, and total ammonia plus organic nitrogen as nitrogen, and for selected triazine herbicides. On the basis of criteria developed by the Kansas Department of Health and Environment, the Hillsdale Water-Quality Protection Project established a goal to maintain water quality in the tributaries of the Hillsdale Lake Basin at a mean annual low-flow total phosphorus concentration of 0.05 mg/L (milligrams per liter). The mean low- flow total phosphorus concentration of water samples collected in the Big Bull Creek (which includes drainage from Martin Creek), Rock Creek, Little Bull Creek, Wade Branch, and Smith Branch subbasins during low-flow conditions ranged from 0.05 to 4.9 mg/L during this study. Of the 44 sites sampled during low flow, 95 percent had low-flow total phosphorus concentrations larger than the 0.05-mg/L criterion. Discharges from wastewater- treatment plants located in Big Bull Creek and Martin Creek subbasins and the Little Bull Creek subbasin affected nutrient concentrations. Nutrient concentrations in water samples collected from the subbasins not affected by point-source discharges generally were smaller than those in the Big Bull Creek and Little Bull Creek subbasins. Estimated annual low-flow phosphorus loads computed at sampling sites located at the outlet of the subbasins show that the Big Bull Creeksubbasin, which includes drainage from the Martin Creek subbasin, had the

Bio stimulation for the Enhanced Degradation of Herbicides in Soil

International Nuclear Information System (INIS)

Kanissery, R.G; Sims, G.K

2011-01-01

Cleanup of herbicide-contaminated soils has been a dire environmental concern since the advent of industrial era. Although microorganisms are excellent degraders of herbicide compounds in the soil, some reparation may need to be brought about, in order to stimulate them to degrade the herbicide at a faster rate in a confined time frame. Bio stimulation through the appropriate utilization of organic amendments and nutrients can accelerate the degradation of herbicides in the soil. However, effective use of bio stimulants requires thorough comprehension of the global redox cycle during the microbial degradation of the herbicide molecules in the soil. In this paper, we present the prospects of using bio stimulation as a powerful remediation strategy for the rapid cleanup of herbicide-polluted soils.

Effect of soil herbicides on the antioxidant system of maize vegetative organs during ontogenesis

Directory of Open Access Journals (Sweden)

I.P. Grigoryuk

2016-06-01

Full Text Available The impact of soil herbicides Harnes, Frontier and Merlin on the activity of enzymes superoxid dismutase (SOD, EC 1.15.1.1, catalase (CAT, EC 1.11.1.6, and benzidine peroxidase (POD, EC 1.11.1.7 in maize (Zea mays L.; cultivar Kadr 267 MV roots and leaves was studied in the field experiment. It was established that the adaptation of maize plants to the herbicides treatment was accompanied by significant activation of antioxidant enzymes both in roots (39%, 57%, and 67% above control level and leaves (50%, 64%, and 77% above control, respectively during different vegetation stages (shoots emergence; 3–5 leaves phase; florescence. The herbicides-induced changes of enzymes activity high correlated with ontogenetic dynamics of control plants activity: r = 0.98 for SOD; r = 0.96 for POD; r = 0.98 for CAT.

Annual Herbicide Loadings

Data.gov (United States)

U.S. Environmental Protection Agency — Pesticides, Herbicides, Fungicides...etc, are used for a variety of purposes, including control of household, lawn, and garden pests; for control of mosquitoes and...

Agricultural herbicide transport in a first-order intermittent stream, Nebraska, USA

Science.gov (United States)

Vogel, J.R.; Linard, J.I.

2011-01-01

The behavior of herbicides in surface waters is a function of many variables, including scale of the watershed, physical and chemical properties of the herbicide, physical and chemical properties of the soil, rainfall intensity, and time of year. In this study, the transport of 6 herbicides and 12 herbicide degradates was examined during the 2004 growing season in an intermediate-scale agricultural watershed (146 ha) that is drained by a first-order intermittent stream, and the mass load for each herbicide in the stream was estimated. The herbicide load during the first week of storm events after application ranged from 17% of annual load for trifluralin to 84% of annual load for acetochlor. The maximum weekly herbicide load in the stream was generally within the first 3 weeks after application for those compounds that were applied within the watershed during 2004, and later for herbicides not applied within the watershed during 2004 but still detected in the stream. The apparent dominant mode of herbicide transport in the stream-determined by analysis amongst herbicide and conservative ion concentrations at different points in the hydrograph and in base flow samples-was either overland runoff or shallow subsurface flow, depending on the elapsed time after application and type of herbicide. The load as a percentage of use (LAPU) for the parent compounds in this study was similar to literature values for those compounds applied by the farmer within the watershed, but smaller for those herbicides that had rainfall as their only source within the watershed.

Occurrence of dichloroacetamide herbicide safeners and co-applied herbicides in midwestern U.S. streams

Science.gov (United States)

Woodward, Emily; Hladik, Michelle; Kolpin, Dana W.

2018-01-01

Dichloroacetamide safeners (e.g., AD-67, benoxacor, dichlormid, and furilazole) are co-applied with chloroacetanilide herbicides to protect crops from herbicide toxicity. While such safeners have been used since the early 1970s, there are minimal data about safener usage, occurrence in streams, or potential ecological effects. This study focused on one of these research gaps, occurrence in streams. Seven Midwestern U.S. streams (five in Iowa and two in Illinois), with extensive row-crop agriculture, were sampled at varying frequencies from spring 2016 through summer 2017. All four safeners were detected at least once; furilazole was the most frequently detected (31%), followed by benoxacor (29%), dichlormid (15%), and AD-67 (2%). The maximum concentrations ranged from 42 to 190 ng/L. Stream detections and concentrations of safeners appear to be driven by a combination of timing of application (spring following herbicide application) and precipitation events. Detected concentrations were below known toxicity levels for aquatic organisms.

BELVEDERE® Extra – a new high performance- herbicide in beets

Directory of Open Access Journals (Sweden)

Donati, Alexandra

2014-03-01

Full Text Available Common lambsquarters, cleavers, ladysthumb and wild buckwheat, chamomile, mercury, foolsparsleey and volunteer rapes are only some of the most important weeds in fooder and sugar beets. For the control of classical weed societies farmers can fall back on a limited number of active ingredients. Generally, Phenmedipham (PMP, Desmedipham (DMP and Ethofumesate are the basis of a spray sequence. They are complemented with other active ingredients depending on the specific weed situation. The newly formulated BELVEDERE® Extra combines the three mentioned active ingredients in an optimal ratio. Hence, the herbicide covers a very broad weed spectrum with an excellent efficacy on Common lambsquarters, cleavers, ladysthumb and wild buckwheat. BELVEDERE® EXTRA is a liquid, selective, and systemic herbicide. It is formulated as suspoemulsion so that a high efficacy is achieved while preserving a very good selectivity. The product allows for flexible control of leaf activity as an additive (e.g. OLEO FC is appended. Ethofumesate, which is mainly effective via the roots of the plant, belongs to a different HRAC group than Phenmedipham and Desmedipham. The high concentration of 200 g/L Ethofumesate leads to an effective resistance management especially regarding Fathen and other important weeds. Since 23rd of September 2013 BELVEDERE® extra is registered for post emergence splitting application (3 applications against annual dicotyledonous weeds. The maximum application rate per treatment is 1,3 L/ha. In combination with GOLTIX® TITAN® (Metamitron + Quinmerac or Goltix® Gold (Metamitron the weed spectrum is broadened. Basically, a timely application whose application rates are adapted to the location is essential for a good efficacy of beet herbicides.

Control of Butterfly Bush with Postemergence Herbicides

Science.gov (United States)

Butterfly bush (Buddleja davidii) is classified as invasive in several parts of the United States. Two experiments were conducted to evaluate the effectiveness of four herbicides and two application methods on postemergence butterfly bush control. The four herbicides included: Roundup (glyphosate)...

ACETANILIDE HERBICIDE DEGRADATION PRODUCTS BY LC/MS

Science.gov (United States)

Acetanilide herbicides are frequently applied in the U.S. on crops (corn, soybeans, popcorn, etc.) to control broadleaf and annual weeds. The acetanilide and acetamide herbicides currently registered for use in the U.S. are alachlor, acetochlor, metolachlor, propachlor, flufen...

Acute and additive toxicity of ten photosystem-II herbicides to seagrass

OpenAIRE

Adam D. Wilkinson; Catherine J. Collier; Florita Flores; Andrew P. Negri

2015-01-01

Photosystem II herbicides are transported to inshore marine waters, including those of the Great Barrier Reef, and are usually detected in complex mixtures. These herbicides inhibit photosynthesis, which can deplete energy reserves and reduce growth in seagrass, but the toxicity of some of these herbicides to seagrass is unknown and combined effects of multiple herbicides on seagrass has not been tested. Here we assessed the acute phytotoxicity of 10 PSII herbicides to the seagrass Halophila ...

A 3D-Printed, Portable, Optical-Sensing Platform for Smartphones Capable of Detecting the Herbicide 2,4-Dichlorophenoxyacetic Acid.

Science.gov (United States)

Wang, Yijia; Zeinhom, Mohamed M A; Yang, Mingming; Sun, Rongrong; Wang, Shengfu; Smith, Jordan N; Timchalk, Charles; Li, Lei; Lin, Yuehe; Du, Dan

2017-09-05

Onsite rapid detection of herbicides and herbicide residuals in environmental and biological specimens are important for agriculture, environmental concerns, food safety, and health care. The traditional method for herbicide detection requires expensive laboratory equipment and a long turnaround time. In this work, we developed a single-stripe microliter plate smartphone-based colorimetric device for rapid and low-cost in-field tests. This portable smartphone platform is capable of screening eight samples in a single-stripe microplate. The device combined the advantages of small size (50 × 100 × 160 mm 3 ) and low cost ($10). The platform was calibrated by using two different dye solutions, i.e. methyl blue (MB) and rhodamine B, for the red and green channels. The results showed good correlation with results attained from a traditional laboratory reader. We demonstrated the application of this platform for detection of the herbicide 2,4-dichlorophenoxyacetic acid in the range of 1 to 80 ppb. Spiked samples of tap water, rat serum, plasma, and human serum were tested by our device. Recoveries obtained varied from 95.6% to 105.2% for all of the spiked samples using the microplate reader and from 93.7% to 106.9% for all of the samples using the smartphone device. This work validated that the smartphone optical-sensing platform is comparable to the commercial microplate reader; it is eligible for onsite, rapid, and low-cost detection of herbicides for environmental evaluation and biological monitoring.

Herbicidal treatments for control of Papaver somniferum L.

Science.gov (United States)

Horowitz, M

1980-01-01

Fifty-five commercially available herbicides were evaluated for possible use to destroy illicit opium poppy crops (Papaver somniferum). In the first stage, herbicides were sprayed on poppy plants grown in containers. The following compounds killed poppy plants: (a) herbicides with typical foliar activity--amitrole, bromoxynil, 2,4-D, glyphosate, ioxynil and paraquat; and (b) herbicides with root and foliar activity--the triazines ametryn, atrazine, metribuzin, prometryn, simazine and terbutryn; the substituted ureas benzthiazuron, chloroxuron, diuron, fluometuron, linuron, methabenzthiazuron, neburon and phenobenzuron; and the miscellaneous compounds karbutilate, methazole, oxadiazon and pyrazon. Severe but sublethal injury was caused by cycloate, EPTC, molinate, pobulate, cacodylate + MSMA, ethofumesate, perfluidone and phenmedipham. Abnormal development of vegetative or reproductive parts of the plant was induced by benefin, butralin, dinitramine, pendimethalin, trifluralin, diphenamid, napropamide, dalapon and propham. Efficient herbicides with negligible persistence in soil at the doses applied were evaluated on poppy plants in the field at various stages of growth. Small plants were severely injured by 2,4-D, killed rapidly by bromoxynil, ioxynil, paraquat (in mixture + diquat), and more slowly by glyphosate and metribuzin. The resistance to herbicides increased with the age of the poppy plant. Severe damage with partial kill of developed plants was obtained with bromoxynil, ioxynil, glyphosate, and paraquat + diquat; the last treatment produced the fastest effect.

Environmental determinants of the urinary concentrations of herbicides during pregnancy: the PELAGIE mother-child cohort (France).

Science.gov (United States)

Chevrier, Cécile; Serrano, Tania; Lecerf, Rémi; Limon, Gwendolina; Petit, Claire; Monfort, Christine; Hubert-Moy, Laurence; Durand, Gaël; Cordier, Sylvaine

2014-02-01

Herbicides are generally the most extensively used of the pesticides applied to agricultural crops. However, the literature contains little evidence useful in assessing the potential sources of the general population's exposure to herbicides, including by residential proximity to crops. The objective of this study was to take advantage of data from the PELAGIE mother-child cohort to identify the main determinants of the body burden of exposure to the chloroacetanilide and triazine herbicides commonly used on corn crops in Brittany, France, before 2006. Urine samples from a randomly selected subcohort of women in the first trimester of pregnancy (n=579) were assayed for herbicide metabolites. The residential exposure resulting from proximity to corn crops was assessed with satellite-image-based scores combined with meteorological data. Data on diet, drinking tap water (from the public water supply), occupations, and household herbicide use were collected by questionnaires. Herbicides were quantified in 5.3% to 39.7% of urine samples. Alachlor and acetochlor were found most frequently in the urine of women living in rural areas. The presence of dealkylated triazine metabolites in urine samples was positively associated with residential proximity to corn crops (OR=1.38, 95% CI: 1.05-1.80). Urinary metabolites of both atrazine and dealkylated triazine were correlated with tap water consumption (OR=2.94, 1.09-7.90, and OR=1.82, 1.10-3.03, respectively); hydroxylated triazine metabolites were correlated with fish intake (OR=1.48, 1.09-1.99). This study reinforces previous results that suggest that environmental contamination resulting from agricultural activities may contribute to the general population's exposure to herbicides. © 2013.

Delivery of calibration workshops covering herbicide application equipment : final report.

Science.gov (United States)

2014-03-31

Proper herbicide sprayer set-up and calibration are critical to the success of the Oklahoma Department of Transportation (ODOT) herbicide program. Sprayer system set-up and calibration training is provided in annual continuing education herbicide wor...

Herbicide-resistant crop biotechnology: potential and pitfalls

Science.gov (United States)

Herbicide-resistant crops are an important agricultural biotechnology that can enable farmers to effectively control weeds without harming their crops. Glyphosate-resistant (i.e. Roundup Ready) crops have been the most commercially successful varieties of herbicide-resistant crops and have been plan...

Assessing the extent and effects of herbicide drift into Danish hedgerows

DEFF Research Database (Denmark)

Bruus, M.; Strandberg, M. T.; Andersen, H. V.

Very low dosages of herbicides are known to cause effects on bird cherry (Prunus avium) and hawthorn (Crataegus monogyna). With the purpose of studying whether this is a general phenomenon two other common hedgerow species, Sambucus nigra (elder) and Sorbus intermedia (Swedish whitebeam), were...

Bacillus megaterium strains derived from water and soil exhibit differential responses to the herbicide mesotrione.

Science.gov (United States)

Dobrzanski, Tatiane; Gravina, Fernanda; Steckling, Bruna; Olchanheski, Luiz R; Sprenger, Ricardo F; Espírito Santo, Bruno C; Galvão, Carolina W; Reche, Péricles M; Prestes, Rosilene A; Pileggi, Sônia A V; Campos, Francinete R; Azevedo, Ricardo A; Sadowsky, Michael J; Beltrame, Flávio L; Pileggi, Marcos

2018-01-01

The intense use of herbicides for weed control in agriculture causes selection pressure on soil microbiota and water ecosystems, possibly resulting in changes to microbial processes, such as biogeochemical cycles. These xenobiotics may increase the production of reactive oxygen species and consequently affect the survival of microorganisms, which need to develop strategies to adapt to these conditions and maintain their ecological functionality. This study analyzed the adaptive responses of bacterial isolates belonging to the same species, originating from two different environments (water and soil), and subjected to selection pressure by herbicides. The effects of herbicide Callisto and its active ingredient, mesotrione, induced different adaptation strategies on the cellular, enzymatic, and structural systems of two Bacillus megaterium isolates obtained from these environments. The lipid saturation patterns observed may have affected membrane permeability in response to this herbicide. Moreover, this may have led to different levels of responses involving superoxide dismutase and catalase activities, and enzyme polymorphisms. Due to these response systems, the strain isolated from water exhibited higher growth rates than did the soil strain, in evaluations made in oligotrophic culture media, which would be more like that found in semi-pristine aquatic environments. The influence of the intracellular oxidizing environments, which changed the mode of degradation of mesotrione in our experimental model and produced different metabolites, can also be observed in soil and water at sites related to agriculture. Since the different metabolites may present different levels of toxicity, we suggest that this fact should be considered in studies on the fate of agrochemicals in different environments.

Removal of glyphosate herbicide from water using biopolymer membranes.

Science.gov (United States)

Carneiro, Rafael T A; Taketa, Thiago B; Gomes Neto, Reginaldo J; Oliveira, Jhones L; Campos, Estefânia V R; de Moraes, Mariana A; da Silva, Camila M G; Beppu, Marisa M; Fraceto, Leonardo F

2015-03-15

Enormous amounts of pesticides are manufactured and used worldwide, some of which reach soils and aquatic systems. Glyphosate is a non-selective herbicide that is effective against all types of weeds and has been used for many years. It can therefore be found as a contaminant in water, and procedures are required for its removal. This work investigates the use of biopolymeric membranes prepared with chitosan (CS), alginate (AG), and a chitosan/alginate combination (CS/AG) for the adsorption of glyphosate present in water samples. The adsorption of glyphosate by the different membranes was investigated using the pseudo-first order and pseudo-second order kinetic models, as well as the Langmuir and Freundlich isotherm models. The membranes were characterized regarding membrane solubility, swelling, mechanical, chemical and morphological properties. The results of kinetics experiments showed that adsorption equilibrium was reached within 4 h and that the CS membrane presented the best adsorption (10.88 mg of glyphosate/g of membrane), followed by the CS/AG bilayer (8.70 mg of glyphosate/g of membrane). The AG membrane did not show any adsorption capacity for this herbicide. The pseudo-second order model provided good fits to the glyphosate adsorption data on CS and CS/AG membranes, with high correlation coefficient values. Glyphosate adsorption by the membranes could be fitted by the Freundlich isotherm model. There was a high affinity between glyphosate and the CS membrane and moderate affinity in the case of the CS/AG membrane. Physico-chemical characterization of the membranes showed low values of solubility in water, indicating that the membranes are stable and not soluble in water. The SEM and AFM analysis showed evidence of the presence of glyphosate on CS membranes and on chitosan face on CS/AG membranes. The results showed that the glyphosate herbicide can be adsorbed by chitosan membranes and the proposed membrane-based methodology was successfully used to

Biotransformation of benzonitrile herbicides via the nitrile hydratase-amidase pathway in rhodococci

Czech Academy of Sciences Publication Activity Database

Veselá, Alicja Barbara; Pelantová, Helena; Šulc, Miroslav; Macková, M.; Lovecká, P.; Thimová, P.; Pasquarelli, F.; Pičmanová, Martina; Pátek, Miroslav; Bhalla, T. C.; Martínková, Ludmila

2012-01-01

Roč. 39, č. 12 (2012), s. 1811-1819 ISSN 1367-5435 R&D Projects: GA MŠk OC09046; GA ČR(CZ) GAP504/11/0394; GA ČR GD305/09/H008 Keywords : Nitrile hydratase * Amidase * Benzonitrile herbicides Subject RIV: EE - Microbiology, Virology Impact factor: 2.321, year: 2012

Seletividade de herbicidas, aplicados em pós-emergência, às plantas de alfafa Selectivity of applied port-emergence herbicides in the alfafa plants

Directory of Open Access Journals (Sweden)

Gláucia de Mello

2000-08-01

Full Text Available Foram conduzidos doi experimentos na UNESP/Jaboticabal, em casa-de-vegetação, com o objetivo de avaliar-se a toxicidade de diferentes herbicidas, aplicados em pós-emergênica, às plantas de alfafa. No primeiro, utilizou-se de um delineamento experimental com parcelas inteiramente casualizadas para avaliar-se os efeitos fitotóxicos dos seguintes herbicidas: MSMA, clethodim + óleo mineral, lactofen, fluazifop-pbutil, fomesafen + óleo mineral haloxyfop-methyl + óleo mineral, fenoxaprop-ethyl, chlorimuronethyl, halosulfuron + óleo mineral, nicosulfuron, acifluorfen, imazethapyr, bentazon + óleo mineral e cyanazine + simazine, todos em só dose. Foram feitas avaliações da fitotoxicidade por meio de notas, atribuídas visualmente, em função dos sintomas constatados nas plantas. A altura das plantas e o peso da matéria seca da parte área foram avaliadas no período de desenvolvimento inicial e após a primeira rebrota. No segundo experimento foi seguido mesmo esquema de instalação e condução do anterior, após escolherse os herbicidas e doses, sendo eles, o MSMA, chlorimuron-ethyl, imazethapyr, bentazon + óleo mineral, clethodim, clethodim + óleo mineral e bentazon + MSMA. Os herbicidas mais seletivos às plantas de alfafa foram haloxyfop-methyl, fluazifop-p-butil, fenoxaprop-ethyl, MSMA, imazethapyr, bentazon e clethodim isolado e adicionado de óleo mineral.Two experiments were carried out in a greenhouse, belonging to the Departamento de Defesa Fitissanitária da Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal/UNESP, with the purpose of evaluating the selectivity of different used post-emergence herbicides on alfafa plants. The experimental design was completely randomized to evaluate the phytotoxical effects of following herbicides: MSMA, clethodim plus mineral oil, lactofen, fluazifop-p-butil, fomesafen plus mineral oil, haloxyfop-methyl plus mineral oil, chlorimuron-ethyl, halosulfuron plus mineral oil

Approaches to early detection of herbicide resistance in Apera spica-venti regarding intra- and inter-field situations

DEFF Research Database (Denmark)

Schulz, Andrea; Mathiassen, Solvejg K; de Mol, Friederike

2014-01-01

at answering the questions: (1) Can the intra-field distribution of an Apera spica-venti population be used to indicate the first steps in the evolution of resistance? Is the selection of field populations based on casual observations of farmers an approach to get a reasonable overview on the resistance status...... differences in the susceptibility of samples collected within the same field. Herbicide efficacy was not plant density-dependent, but it was related to spatial plant distribution depending on the processing direction in the field. The inter-field situation survey confirmed resistance to at least one herbicide......, resistance was only confirmed in 56% of the fields in which farmers suspected resistance indicating that poor herbicide performance can be caused by other reasons as for example poor environmental conditions....

Discovery of new herbicide modes of action with natural phytotoxins

Science.gov (United States)

About 20 modes of action (MOAs) are utilized by commercial herbicides, and almost 30 years have passed since the last new MOA was introduced. Rapidly increasing evolution of resistance to herbicides with these MOAs has greatly increased the need for herbicides with new MOAs. Combinatorial chemistry ...

Imazapyr (herbicide) seed dressing increases yield, suppresses ...

African Journals Online (AJOL)

from damage. In 1998/99 season, a trial was initiated at Chitedze Research Station under artificial infection, to evaluate the effects of seed dressing with imazapyr (an acetolactate synthase {ALS} inhibiting herbicide) using three seed treatment methods (coating, priming or drenching) and three herbicide rates (15, 30 and 45 ...

Herbicide on Weed Composition, Diversity and Density in Silage Corn (cv. Sc 704

Directory of Open Access Journals (Sweden)

M. Zafarian

2012-07-01

Full Text Available In order to study the effect of plant density, planting pattern and herbicide dosage of nicosulfuron, a field experiment was arranged in a factorial split plot treatments based on RCBD with three replications in Chenaran, Khorasan Razavi, in 2010. The experimental treatments consisted of a factorial plant density (100000, 120000 and 140000 plants ha-1 in the planting pattern (single and double row as main plot and herbicide dosage of nicousulforon in four levels (0, 1, 1/5 and 2, l.ha-1 as sub-plot. Samplings were made at in five stages (37days after the emergence of corn and it was repeated once per 20 days. The results indicated reducing the weed density and dry matter of weeds in the first stage after the herbicide treatment. Moreover, it was observed a significant interaction effect between plant density with planting pattern and between planting pattern with herbicides dosages during growth season on reducing weed density and dry matter. Also results indicated that in between of this experiment's treatments, nicosulfuron herbicide reduced weed density at the beginning of growth season and double row planting pattern suppressed weed density during growing season, and resulted in lowest Jacard similarity index (Sj of weed species. Results also indicated that with increasing of plant density and herbicide dosage especially in composition of double row planting pattern, according to Shannon- Wiener index, sensitive population such as common purslane (Portulaca oleracea L., buckhorn plantain (Plantago lanceolata L., prostrate knotweed (Polygonum aviculareL., black nightshade (Solanum nigrum L. and Johnson grass (Sorghum halepens L. was reduced in during growing season. Simpson dominance index, showed that some low populated weeds such as redroot pigweed (Amaranthus retroflexus L., common lambsquarters (Chenopodium album L., field bindweed (Convolvulus arvensis L. and Canada thistle (Circum arvensis L. persisted their growth up to the end of

Detection of photosynthetic herbicides: Algal growth inhibition test vs. electrochemical photosystem II biosensor

Czech Academy of Sciences Publication Activity Database

Masojídek, Jiří; Souček, Pavel; Máchová, J.; Frolík, Jan; Klem, Karel; Malý, J.

2011-01-01

Roč. 74, č. 1 (2011), s. 117-122 ISSN 0147-6513 R&D Projects: GA MPO FT-TA/089 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z60870520 Keywords : PSII-biosensor * Biotest * Herbicide Subject RIV: EE - Microbiology, Virology Impact factor: 2.294, year: 2011

Raw or incubated olive-mill wastes and its biotransformed products as agricultural soil amendments-effect on sorption-desorption of triazine herbicides.

Science.gov (United States)

Delgado-Moreno, Laura; Almendros, Gonzalo; Peña, Aránzazu

2007-02-07

Raw olive-mill waste and soil amendments obtained from their traditional composting or vermicomposting were added, at rates equivalent to 200 Mg ha-1, to a calcareous silty clay loam soil in a laboratory test, in order to improve its fertility and physicochemical characteristics. In particular, the effects on the sorption-desorption processes of four triazine herbicides have been examined. We found that comparatively hydrophobic herbicides terbuthylazine and prometryn increased their retention on amended soil whereas the more polar herbicides simazine and cyanazine were less affected. Soil application of olive cake, without transformation, resulted in the highest herbicide retention. Its relatively high content in aliphatic fractions and lipids could explain the increased herbicide retention through hydrophobic bonding and herbicide diffusion favored by poorly condensed macromolecular structures. On the other hand, the condensed aromatic structure of the compost and vermicompost from olive cake could hinder diffusion processes, resulting in lower herbicide sorption. In fact, the progressive humification in soil of olive-mill solid waste led to a decrease of sorption capacity, which suggested important changes in organic matter quality and interactions during the mineralization process. When soil amended with vermicompost was incubated for different periods of time, the enhanced herbicide sorption capacity persisted for 2 months. Pesticide desorption was reduced by the addition of fresh amendments but was enhanced during the transformation process of amendments in soil. Our results indicate the potential of soil amendments based on olive-mill wastes in the controlled, selective release of triazine herbicides, which varies depending on the maturity achieved by their biological transformation.

Fourier transform of delayed fluorescence as an indicator of herbicide concentration.

Science.gov (United States)

Guo, Ya; Tan, Jinglu

2014-12-21

It is well known that delayed fluorescence (DF) from Photosystem II (PSII) of plant leaves can be potentially used to sense herbicide pollution and evaluate the effect of herbicides on plant leaves. The research of using DF as a measure of herbicides in the literature was mainly conducted in time domain and qualitative correlation was often obtained. Fourier transform is often used to analyze signals. Viewing DF signal in frequency domain through Fourier transform may allow separation of signal components and provide a quantitative method for sensing herbicides. However, there is a lack of an attempt to use Fourier transform of DF as an indicator of herbicide. In this work, the relationship between the Fourier transform of DF and herbicide concentration was theoretically modelled and analyzed, which immediately yielded a quantitative method to measure herbicide concentration in frequency domain. Experiments were performed to validate the developed method. Copyright © 2014 Elsevier Ltd. All rights reserved.

Avaliação da eficiência de herbicidas no controle de plantas daninhas em alfafa Decreasing of weed plants using herbicides and herbicides mix in alfalfa crop

Directory of Open Access Journals (Sweden)

Wilson da Silva

2004-08-01

Full Text Available Objetivou-se neste trabalho avaliar a seletividade e a eficiência de herbicidas no controle de plantas daninhas na cultura da alfafa. Foram desenvolvidos dois experimentos em Anápolis, GO. No primeiro, avaliaram-se oito herbicidas (imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl, imazamox aplicados em pós-emergência da alfafa, e no segundo, seis misturas de herbicidas [(diuron + MSMA, (diuron + MSMA, (diuron + paraquat, (diuron + paraquat] aplicados um dia após o corte da alfafa. Em ambos os experimentos, foram incluídas duas testemunhas (capinada e sem capina, sendo os tratamentos distribuídos em blocos ao acaso com quatro repetições. Os herbicidas como imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl e imazamox foram seletivos à cultura da alfafa e eficientes no controle de plantas daninhas. As misturas dos herbicidas (diuron + MSMA e (diuron + paraquat aplicados logo após o corte da alfafa causaram danos às folhas e aos caules remanescentes. As brotações, todavia, surgiram isentas de toxicidade, apresentando crescimento e desenvolvimento normais. Essas misturas promoveram eficiente controle de plantas daninhas, e não afetaram o acúmulo de biomassa seca e altura de plantas em relação à testemunha capinada. O não-controle das plantas daninhas reduziu a produção de biomassa seca e a altura das plantas de alfafa em 74,5% e 42,8%, respectivamente.The objectives of this study were to evaluate the efficiency and selectivity of herbicides on the weed plants control at the alfalfa crop. Two experiments were carried out at the Experimental Station of Agenciarural, located in Anápolis, GO. In the first experiment it was evaluated eight herbicides (imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl and imazamox post emergency and in the second experiment six different mixed of herbicides [(diuron + MSMA, (diuron + MSMA, (diuron + paraquat, (diuron + paraquat] applied one day after the alfalfa harvesting

Hydrolysis of benzonitrile herbicides by soil actinobacteria and metabolite toxicity

Czech Academy of Sciences Publication Activity Database

Veselá, Alicja Barbara; Franc, M.; Pelantová, Helena; Kubáč, David; Vejvoda, Vojtěch; Šulc, Miroslav; Bhalla, T. C.; Macková, M.; Lovecká, P.; Janů, P.; Demnerová, K.; Martínková, Ludmila

2011-01-01

Roč. 22, č. 6 (2011), s. 761-770 ISSN 0923-9820 R&D Projects: GA MPO FT-TA5/043; GA MŠk OC09046; GA MŠk(CZ) LC06010; GA AV ČR IAA500200708; GA ČR GD305/09/H008 Institutional research plan: CEZ:AV0Z50200510 Keywords : nitrilase * benzonitrile herbicides * chloroxynil Subject RIV: CE - Biochemistry Impact factor: 2.017, year: 2011

Hydrolysis of benzonitrile herbicides by soil actinobacteria and metabolite toxicity

Czech Academy of Sciences Publication Activity Database

Veselá, Alicja Barbara; Franc, M.; Pelantová, Helena; Kubáč, David; Vejvoda, Vojtěch; Šulc, Miroslav; Bhalla, T. C.; Macková, M.; Lovecká, P.; Janů, P.; Demnerová, K.; Martínková, Ludmila

2010-01-01

Roč. 21, č. 5 (2010), s. 761-770 ISSN 0923-9820 R&D Projects: GA MPO FT-TA5/043; GA MŠk OC09046; GA MŠk(CZ) LC06010; GA AV ČR IAA500200708; GA ČR GD305/09/H008 Institutional research plan: CEZ:AV0Z50200510 Keywords : Benzonitrile herbicides * nitrilase * Chloroxynil Subject RIV: EE - Microbiology, Virology Impact factor: 2.012, year: 2010

Rationale for a natural products approach to herbicide discovery.

Science.gov (United States)

Dayan, Franck E; Owens, Daniel K; Duke, Stephen O

2012-04-01

Weeds continue to evolve resistance to all the known modes of herbicidal action, but no herbicide with a new target site has been commercialized in nearly 20 years. The so-called 'new chemistries' are simply molecules belonging to new chemical classes that have the same mechanisms of action as older herbicides (e.g. the protoporphyrinogen-oxidase-inhibiting pyrimidinedione saflufenacil or the very-long-chain fatty acid elongase targeting sulfonylisoxazoline herbicide pyroxasulfone). Therefore, the number of tools to manage weeds, and in particular those that can control herbicide-resistant weeds, is diminishing rapidly. There is an imminent need for truly innovative classes of herbicides that explore chemical spaces and interact with target sites not previously exploited by older active ingredients. This review proposes a rationale for a natural-products-centered approach to herbicide discovery that capitalizes on the structural diversity and ingenuity afforded by these biologically active compounds. The natural process of extended-throughput screening (high number of compounds tested on many potential target sites over long periods of times) that has shaped the evolution of natural products tends to generate molecules tailored to interact with specific target sites. As this review shows, there is generally little overlap between the mode of action of natural and synthetic phytotoxins, and more emphasis should be placed on applying methods that have proved beneficial to the pharmaceutical industry to solve problems in the agrochemical industry. Published 2012 by John Wiley & Sons, Ltd.

Winter Annual Weed Response to Nitrogen Sources and Application Timings prior to a Burndown Corn Herbicide

Directory of Open Access Journals (Sweden)

Kelly A. Nelson

2015-01-01

Full Text Available Autumn and early preplant N applications, sources, and placement may affect winter annual weed growth. Field research evaluated (1 the effect of different nitrogen sources in autumn and early preplant on total winter annual weed growth (2006–2010, and (2 strip-till and broadcast no-till N applied in autumn and early preplant on henbit (Lamium amplexicaule L. growth (2008–2010 prior to a burndown herbicide application. Total winter annual weed biomass was greater than the nontreated control when applying certain N sources in autumn or early preplant for no-till corn. Anhydrous ammonia had the lowest average weed density (95 weeds m−2, though results were inconsistent over the years. Winter annual weed biomass was lowest (43 g m−2 when applying 32% urea ammonium nitrate in autumn and was similar to applying anhydrous ammonia in autumn or early preplant and the nontreated control. Henbit biomass was 28% greater when applying N in the autumn compared to an early preplant application timing. Nitrogen placement along with associated tillage with strip-till placement was important in reducing henbit biomass. Nitrogen source selection, application timing, and placement affected the impact of N on winter annual weed growth and should be considered when recommending a burndown herbicide application timing.

Efficacité de quelques herbicides des céréales dans une culture du blé tendre conduite en semis direct

Directory of Open Access Journals (Sweden)

Badr HAJJAJ

2016-12-01

Full Text Available In order to evaluate the efficacy of 11 cereal herbicides on no till soft wheat, two trials were conducted in Chaouia region during 2014-2015 growing season. Dominant species of weed flora in Sidi El Aidi site were: Bromus rigidus, Lolium rigidum and Avena sterilis. Dominant species of weed flora in Ouled Said site were: Avena sterilis, Centaurea diluta and Papaver rhoeas. The obtained results showed that “Pyroxsulam” and “Mesosulfuron Sodium + Iodosulfuron sodium” gavethe best efficacy on rip gut brome. Prosulfocarb provided excellent control of ryegrass but no effect on ripgut brome or wild oat. Broadleaf herbicides provided moderate to good control. “Mesosulfuron Sodium +Iodosulfuron sodium” need to be completed with an broadleaf herbicide in case centaurea diluta is present. “Pyroxsulam” need to be tank mixed with a broadleaf herbicide to widen its weeds spectrum. Treatment with “Pendimethalin”as pre-emergence herbicide allowed an early complete control of weeds and good crop selectivity.

Responses of reniform nematode and browntop millet to tillage, cover crop, and herbicides in cotton

Science.gov (United States)

Cropping practices that reduce competition from reniform nematode (Rotylenchulus reniformis) and browntop millet (Urochlora ramosum) may help minimize losses in cotton (Gossypium hirsutum). The impacts of tillage, rye cover crop, and preemergence and postemergence herbicides on cotton yields, renifo...

Virtual imprinting as a tool to design efficient MIPs for photosynthesis-inhibiting herbicides.

Science.gov (United States)

Breton, Florent; Rouillon, Regis; Piletska, Elena V; Karim, Kal; Guerreiro, Antonio; Chianella, Iva; Piletsky, Sergey A

2007-04-15

Molecular modelling and computational screening were used to identify functional monomers capable of interacting with several different photosynthesis-inhibiting herbicides. The process involved the design of a virtual library of molecular models of functional monomers containing polymerizable residues and residues able to interact with the template through electrostatic, hydrophobic, Van der Waals forces and dipole-dipole interactions. Each of the entries in the virtual library was probed for its possible interactions with molecular models of the template molecules. It was anticipated that the monomers giving the highest binding score would represent good candidates for the preparation of affinity polymers. Strong interactions were computationally determined between acidic functional monomers like methacrylic acid (MAA) or itaconic acid (IA) with triazines, and between vinylimidazole with bentazone and bromoxynil. Nevertheless, weaker interactions were seen with phenylureas. The corresponding blank polymers were prepared using the selected monomers and tested in the solid phase extraction (SPE) of herbicides from chloroform solutions. A good correlation was found between the binding score of the monomers and the affinities of the corresponding polymers. The use of computationally designed blanks can potentially eliminate the need for molecular imprinting, (adding a template to the monomer mixture to create specific binding sites). Data also showed that some monomers have a natural selectivity for some herbicides, which can be further enhanced by imprinting. Thus, in regard to retention on the blank polymer, we can estimate if the resulting imprinted polymer will be effective or not.

Vasogenic edema in striatum following ingestion of glufosinate-containing herbicide.

Science.gov (United States)

Lee, Hui-Young; Song, Seo-Young; Lee, Seung-Hwan; Lee, Seo-Young; Kim, Sung-Hun; Ryu, Sook-Won

2009-10-01

Glufosinate-ammonium (GLA) is a broad-spectrum herbicide used worldwide. We report a patient who attempted suicide by ingesting a liquid herbicide containing GLA. A diffusion-weighted MRI showed cytotoxic edema in the hippocampus as well as vasogenic edema in the striata. To our knowledge, vasogenic edema caused by GLA-containing herbicide involving the striatum has not been reported in association with cytotoxic edema in the hippocampus. We assume that this herbicide affected the central nervous system via different mechanisms to produce both cytotoxic and vasogenic edema in the same patient.

Fluridone: a combination germination stimulant and herbicide for problem fields?

Science.gov (United States)

Goggin, Danica E; Powles, Stephen B

2014-09-01

Problem weeds in agriculture, such as Lolium rigidum Gaud., owe some of their success to their large and dormant seed banks, which permit germination throughout a crop-growing season. Dormant weed seed banks could be greatly depleted by application of a chemical that stimulates early-season germination and then kills the young seedlings. Fluridone, a phytoene desaturase-inhibiting herbicide that can also break seed dormancy, was assessed for its efficacy in this regard. The germination of fluridone-treated Lolium rigidum seeds was stimulated on soils with low organic matter, and almost 100% seedling mortality was observed, while the treatment was only moderately effective on a high-organic-matter potting mix. Seedlings from wheat, canola, common bean and chickpea seeds sown on fluridone-treated sandy loam were bleached and did not survive, but lupins and field peas grew normally. This proof-of-concept study with fluridone suggests that it may be possible to design safe and effective molecules that act as germination stimulants plus herbicides in a range of crop and soil types: a potentially novel way of utilising herbicides to stimulate seed bank germination and a valuable addition to an integrated weed management system. © 2014 Society of Chemical Industry.

Evaluation of generic and branded herbicides : technical report.

Science.gov (United States)

2015-03-01

As with other generic brand products in the marketplace, generic herbicides often have a lower initial product cost than : their brand-name counterparts. While the purchase price of herbicides is important to TxDOT, it is essential to look at : more ...

Characterization of cholinesterases in Chironomus riparius and the effects of three herbicides on chlorpyrifos toxicity.

Science.gov (United States)

Pérez, Joanne; Monteiro, Marta S; Quintaneiro, Carla; Soares, Amadeu M V M; Loureiro, Susana

2013-11-15

In this study, the toxicities of four pesticides (the herbicides atrazine, terbuthylazine, metolachlor and the insecticide chlorpyrifos) previously detected in the Alqueva reservoir/dam (south of Portugal) were evaluated individually and in binary combinations of the herbicides and the insecticide using fourth-instar larvae of the aquatic midge Chironomus riparius. Chlorpyrifos induced toxicity to midges in all the 48 h toxicity bioassays performed. The swimming behaviour of the larvae was impaired, with EC50 values ranging from 0.15 to 0.17 μg/L. However, neither s-triazine (atrazine and terbuthylazine) herbicides nor metolachlor alone at concentrations up to 200 μg/L caused significant toxicity to C. riparius. When combined with both s-triazine herbicides, chlorpyrifos toxicity was enhanced by approximately 2-fold when tested in a binary mixture experimental setup, at the 50% effective concentration levels. To evaluate how chlorpyrifos toxicity was being increased, the cholinesterases (ChE) were characterized biochemically using different substrates and selective inhibitors. The results obtained suggested that the main enzyme present in this species is acetylcholinesterase (AChE) and therefore it was assayed upon C. riparius exposures to all pesticides individually and as binary mixtures. Although atrazine and terbuthylazine are not effective inhibitors of AChE, the potentiation of chlorpyrifos toxicity by the two s-triazine herbicides was associated with a potentiation in the inhibition of AChE in midges; both s-triazine herbicides at 200 μg/L increased the inhibition of the AChE activity by 7 and 8-fold, respectively. A strong correlation was observed between swimming behaviour disturbances of larvae and the inhibition of the AChE activity. In contrast, metolachlor did not affect chlorpyrifos toxicity at any of the concentrations tested. Therefore, the herbicides atrazine and terbuthylazine can act as synergists in the presence of chlorpyrifos, increasing

Herbicidal Spectrum, Absorption and Transportation, and Physiological Effect on Bidens pilosa of the Natural Alkaloid Berberine.

Science.gov (United States)

Wu, Jiao; Ma, Jing-Jing; Liu, Bo; Huang, Lun; Sang, Xiao-Qing; Zhou, Li-Juan

2017-08-02

Berberine is a natural herbicidal alkaloid from Coptis chinensis Franch. Here we characterized its herbicidal spectrum and absorption and transportation in the plant, along with the possible mechanism. Berberine showed no effect on the germination of the 10 tested plants. The IC 50 values of berberine on the primary root length and fresh weight of the 10 tested plants ranged from 2.91 to 9.79 mg L -1 and 5.76 to 35.07 mg L -1 , respectively. Berberine showed a similar herbicidal effect on Bidens pilosa as the commercial naturally derived herbicide cinmethylin. HPLC and fluorescence analysis revealed that berberine was mainly absorbed by B. pilosa root and transported through vascular bundle acropetally. Enzyme activity studies, GC-MS analysis, and SEM and TEM observations indicated that berberine might first function on the cell membrane indicated by variation of the IUFA percent and then cause POD, PPO, and SOD activity changes and cellular structure deformity, which was eventually expressed as the decrease of cell adaptation ability and abnormal cell function and may even result in cell death. Environmental safety evaluation tests revealed that berberine was low in toxicity to Brachydanio rerio. These indicate that berberine has the potential to be a bioherbicide and/or a lead molecule for new herbicides.

Phytotoxicity of Four Photosystem II Herbicides to Tropical Seagrasses

OpenAIRE

Flores, Florita; Collier, Catherine J.; Mercurio, Philip; Negri, Andrew P.

2013-01-01

Coastal waters of the Great Barrier Reef (GBR) are contaminated with agricultural pesticides, including the photosystem II (PSII) herbicides which are the most frequently detected at the highest concentrations. Designed to control weeds, these herbicides are equally potent towards non-target marine species, and the close proximity of seagrass meadows to flood plumes has raised concerns that seagrasses may be the species most threatened by herbicides from runoff. While previous work has identi...

Low Carbon-Economy Development: China's Pattern and Policy Selection

International Nuclear Information System (INIS)

Dou, Xiangsheng

2013-01-01

For a developing country such as China, it is important to select a fair pattern that is suitable for China's national conditions for low carbon-economy development, as it has a direct impact on the success (or not) of low carbon-economy development. This research shows that, under the real-life conditions of China's development, different development patterns should be practised depending on specific socioeconomic conditions. Among them, one of the most critical issues is how to make full use of natural forces, and thus the nature-oriented development pattern should be practised in full. At the same time, China should still practise either the single regional differential or the multi-regional linkage development pattern under different conditions and either the imposed or the induced development pattern at the different stages of development. - Highlights: • It is particularly important to select a suitable development pattern. • Nature-oriented development pattern should be selected. • Single regional differentiation-typed or multi-regional linkage-typed pattern should be selected. • Either the imposed pattern or the induced pattern of development will be selected

Leaf anatomy of cassava (Manihot esculenta Crantz. cv. IAC-12 after herbicides application to control weeds in Minas Gerais, Brazil

Directory of Open Access Journals (Sweden)

Daniel Valadão Silva

2017-07-01

Full Text Available Micro-morphological changes precede the appearance of visible damage after herbicide application and are essential in providing data for the safe recommendation in chemical management of weeds. Therefore, the aim of this research was to verify the anatomical changes of leaf tissue caused by application of herbicides in cassava (Manihot esculenta Crantz. cv. IAC-12. A greenhouse experiment was conducted with post-emergence herbicides treatments as follows: nicossulfuron (60 g a.i ha-1, fluazifop (250 g a.i ha-1, fomesafem (250 g a.i ha-1, metribuzin (480 g a.i ha-1, oxyfluorfen (720 g a.i ha-1 and the mixture fluazifop + fomesafen (200 + 250 g a.i ha-1, and an untreated control, respectively. The results obtained have allowed to affirm the cassava plants (cultivar IAC-12, exhibited changes in leaf anatomy in response to herbicide application even on cassava leaves without no visual toxicity symptoms. The products caused alterations both in tissue thickness as in tissue proportion in the leaf blade. For the fluazifop, a eudicotyledonous selective herbicide, changes were observed in tissue thickness and proportion of leaf blade, even without any visual toxicity detected. Cassava plants (IAC-12, showed structural changes in leaf anatomy in response to application of herbicides. The leaf anatomy of cassava cv. IAC-12, can be used to indicate the herbicide effect on cassava (Manihot esculenta Crantz.cv. IAC-12 plants.

Predicting herbicidal plant mortality with mobile photosynthesis meters

NARCIS (Netherlands)

Kempenaar, C.; Lotz, L.A.P.; Snel, J.F.H.; Smutny, V.; Zhang, H.J.

2011-01-01

Herbicide dose optimisation, i.e. maximising weed control and crop yield with herbicide dose, is an important part of integrated weed management strategies. However, the adoption of optimised dose technology and variable rate application has been limited because of the relatively long period between

Simultaneous determination of low-molecular-weight organic acids and chlorinated acid herbicides in environmental water by a portable CE system with contactless conductivity detection.

Science.gov (United States)

Xu, Yan; Wang, Weilong; Li, Sam Fong Yau

2007-05-01

This report describes a method to simultaneously determine 11 low-molecular-weight (LMW) organic acids and 16 chlorinated acid herbicides within a single run by a portable CE system with contactless conductivity detection (CCD) in a poly(vinyl alcohol) (PVA)-coated capillary. Under the optimized condition, the LODs of CE-CCD ranged from 0.056 to 0.270 ppm, which were better than for indirect UV (IUV) detection of the 11 LMW organic acids or UV detection of the 16 chlorinated acid herbicides. Combined with an on-line field-amplified sample stacking (FASS) procedure, sensitivity enhancement of 632- to 1078-fold was achieved, with satisfactory reproducibility (RSDs of migration times less than 2.2%, and RSDs of peak areas less than 5.1%). The FASS-CE-CCD method was successfully applied to determine the two groups of acidic pollutants in two kinds of environmental water samples. The portable CE-CCD system shows advantages such as simplicity, cost effectiveness, and miniaturization. Therefore, the method presented in this report has great potential for onsite analysis of various pollutants at the trace level.

Response of Saw Palmetto to Three Herbicides

Science.gov (United States)

J.L. Michael; D.G. Neary

1985-01-01

Saw palmetto [Serona repens (Bartram) Small] can be controlled with herbicides. Garion® 4E1/2 and Brush Killer® 800 were evaluated for effectiveness againest saw palmetto when they were applied at three rates in April, June, and August. Oust® was tested at three rates in April only. Herbicides were not effective with April...

Efficacité de quelques séquences d’herbicides contre les mauvaises herbes du pois chiche et de la féverole conduits en semis direct

Directory of Open Access Journals (Sweden)

Badr HAJJAJ

2016-12-01

Full Text Available In order to evaluate the efficacy of 18 sequences of pre and post emergence herbicides on weeds of no till faba bean and chickpea and their impact on crops grain yield, two trials were conducted during 2014-2015 growing season at Sidi El Aidi INRA research station and at a farmer’s farm in Ouled Said (Settat. Dominant species of weed flora in chickpea in Sidi El Aidi were: Bromus rigidus, Lolium rigidum, Avena sterilis, Cichorium endivia, Centaurea diluta, Emex spinosa and Papaver rhoeas. Dominant species of weed flora in faba bean at Ouled Said were: Avena sterilis, Plantago afra, Chrysanthemum coronarium, Centaurea diluta, Sonchus oleraceus and Silybum marianum. The obtained results showed that herbicides react differently on weed and crops. Treatments which showed good weed control and better selectivity provided the best crop yield. “Pendimethalin (1258,5 g/ha + Bentazon (960 g/ha” and “Acetochlor (2100 g/ha + Bentazon (960 g/ha” provided good weed control and good selectivity in horse bean crop. “Pendimethalin (1258,5 g/ha + Bentazon (960 g/ha” needs to be more tested on chickpea before its recommendation on this crop.

75 FR 17857 - Removal of Obsolete References to Herbicides Containing Dioxin

Science.gov (United States)

2010-04-08

... Herbicides Containing Dioxin AGENCY: Department of Veterans Affairs. ACTION: Final rule. SUMMARY: The... health effects of exposure to herbicides containing dioxin and radiation to remove the obsolete references to herbicides containing dioxin. This final rule reflects changes made by the Agent Orange Act of...

Bioactivity of Several Herbicides on the Nanogram Level Under Different Soil Moisture Conditions.

Science.gov (United States)

Jung, S C; Kuk, Y I; Senseman, S A; Ahn, H G; Seong, C N; Lee, D J

2015-01-01

In this study, a double-tube centrifuge method was employed to determine the effects of soil moisture on the bioactivity of cafenstrole, pretilachlor, benfuresate, oxyfluorfen and simetryn. In general, the available herbicide concentration in soil solution (ACSS) showed little change as soil moisture increased for herbicides. The total available herbicide in soil solution (TASS) typically increased as soil moisture increased for all herbicides. The relationship between TASS and % growth rate based on dry weight showed strong linear relationships for both cafenstrole and pretilachlor, with r2 values of 0.95 and 0.84, respectively. Increasing TASS values were consistent with increasing herbicide water solubility, with the exception of the ionizable herbicide simetryn. Plant absorption and % growth rate exhibited a strong linear relationship with TASS. According to the results suggested that TASS was a better predictor of herbicidal bioactivity than ACSS for all herbicides under unsaturated soil moisture conditions.

Rice Transcriptome Analysis to Identify Possible Herbicide Quinclorac Detoxification Genes

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Wenying eXu

2015-09-01

Full Text Available Quinclorac is a highly selective auxin-type herbicide, and is widely used in the effective control of barnyard grass in paddy rice fields, improving the world’s rice yield. The herbicide mode of action of quinclorac has been proposed and hormone interactions affect quinclorac signaling. Because of widespread use, quinclorac may be transported outside rice fields with the drainage waters, leading to soil and water pollution and environmental health problems.In this study, we used 57K Affymetrix rice whole-genome array to identify quinclorac signaling response genes to study the molecular mechanisms of action and detoxification of quinclorac in rice plants. Overall, 637 probe sets were identified with differential expression levels under either 6 or 24 h of quinclorac treatment. Auxin-related genes such as GH3 and OsIAAs responded to quinclorac treatment. Gene Ontology analysis showed that genes of detoxification-related family genes were significantly enriched, including cytochrome P450, GST, UGT, and ABC and drug transporter genes. Moreover, real-time RT-PCR analysis showed that top candidate P450 families such as CYP81, CYP709C and CYP72A genes were universally induced by different herbicides. Some Arabidopsis genes for the same P450 family were up-regulated under quinclorac treatment.We conduct rice whole-genome GeneChip analysis and the first global identification of quinclorac response genes. This work may provide potential markers for detoxification of quinclorac and biomonitors of environmental chemical pollution.

Dinitroaniline herbicide resistance in a multiple-resistant Lolium rigidum population.

Science.gov (United States)

Chen, Jinyi; Yu, Qin; Owen, Mechelle; Han, Heping; Powles, Stephen

2018-04-01

The pre-emergence dinitroaniline herbicides (such as trifluralin and pendimethalin) are vital to Australian no-till farming systems. A Lolium rigidum population collected from the Western Australian grain belt with a 12-year trifluralin use history was characterised for resistance to dinitroaniline, acetyl CoA carboxylase (ACCase)- and acetolactate synthase (ALS)-inhibiting herbicides. Target-site resistance mechanisms were investigated. This L. rigidum population exhibited 32-fold resistance to trifluralin, as compared with the susceptible population. It also displayed 12- to 30-fold cross-resistance to other dinitroaniline herbicides (pendimethalin, ethalfluralin and oryzalin). In addition, this population showed multiple resistance to commonly used post-emergence ACCase- and ALS-inhibiting herbicides. Two target-site α-tubulin gene mutations (Val-202-Phe and Thr-239-Ile) previously documented in other dinitroaniline-resistant weed species were identified, and some known target-site mutations in ACCase (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg) and ALS (Pro-197-Gln/Ser) were found in the same population. An agar-based Petri dish screening method was established for the rapid diagnosis of resistance to dinitroaniline herbicides. Evolution of target-site resistance to both pre- and post-emergence herbicides was confirmed in a single L. rigidum population. The α-tubulin mutations Val-202-Phe and Thr-239-Ile, documented here for the first time in L. rigidum, are likely to be responsible for dinitroaniline resistance in this population. Early detection of dinitroaniline herbicide resistance and integrated weed management strategies are needed to maintain the effectiveness of dinitroaniline herbicides. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Seletividade de herbicidas pré-emergentes ao pinhão-manso (Jatropha curcas Selectivity of pre-emergence herbicides to physic nut (Jatropha curcas

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P.R.R Rocha

2010-12-01

Paraguaçu, and factor B by the herbicides (isoxaflutole, oxyfluorfen, sulfentrazone, pendimethalin and tebuthiuron, plus one non-treated control. Intoxication by the herbicides was evaluated at 19, 32, 40, 48, 56 and 64 days after treatments (DAT. Height, leaf area, and plant dry matter were evaluated at 64 DAT. It was verified that the jatropha genotypes have different tolerance to the herbicides studied. Isoxaflutole and tebuthiuron caused severe injuries to all genotypes and negatively affected all the variables evaluated. On the other hand, oxyfluorfen and pendimethalin proved to be selective to the crop and should be evaluated in further studies to be recommended to the crop.

Potential use of soil-born fungi isolated from treated soil in Indonesia to degrade glyphosate herbicide

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N. Arfarita

2014-01-01

Full Text Available The glyphosate herbicide is the most common herbicides used in palm-oil plantations and other agricultural in Indonesial. In 2020, Indonesian government to plan the development of oil palm plantations has reached 20 million hectares of which now have reached 6 million hectares. It means that a huge chemicals particularly glyphosate has been poured into the ground and continues to pollute the soil. However, there is no report regarding biodegradation of glyphosate-contaminated soils using fungal strain especially in Indonesia. This study was to observe the usage of Round Up as selection agent for isolation of soil-born fungi capable to grow on glyphosate as a sole source of phosphorus. Five fungal strains were able to grow consistently in the presence of glyphosate as the sole phosphorus source and identified as Aspergillus sp. strain KRP1, Fusarium sp. strain KRP2, Verticillium sp. strain KRP3, Acremoniumsp. strain GRP1 and Scopulariopsis sp. strain GRP2. This indicates as their capability to utilize and degrade this herbicide. We also used standard medium as control and get seventeen fungal strains. The seventeen fungal strains were identified as species of Botrytis, Fusarium, Aspergillus, Penicillium, Verticillium, Trichoderma and Paecilomyces. These results show the reduction in the number of fungal strains on solid medium containing glyphosate. Of the five isolated fungal species, Verticillium sp. strain KRP3 and Scopulariopsis sp. strain GRP2 were selected for further study based on their highest ratio of growth diameter. This study indicates that treatment of soil with glyphosate degrading fungus would be useful in some areas where this herbicide is extensively used.

Effect of herbicide clomazone on photosynthetic processes in primary barley (Hordeum vulgare L.) leaves

Czech Academy of Sciences Publication Activity Database

Kaňa, R.; Špundová, M.; Ilík, P.; Lazár, D.; Klem, K.; Tomek, P.; Nauš, J.; Prášil, Ondřej

2004-01-01

Roč. 78, - (2004), s. 161-170 ISSN 0048-3575 R&D Projects: GA ČR GA522/00/1274; GA ČR GP522/01/P098 Institutional research plan: CEZ:AV0Z5020903 Keywords : clomazone * herbicide * photosynthesis Subject RIV: ED - Physiology Impact factor: 1.133, year: 2004

studies on transition metal complexes of herbicidal compounds. ii

African Journals Online (AJOL)

a

derivative of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine, atrazine (ATZ) --- a well known herbicide has ... development while the other is the metal ion associated degradation or deactivation of the herbicides .... Colour M.p./decomp.

Determination of phenmedipham and desmedipham in a commercial herbicide by high performance liquid chromatography

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Lončar Eva S.

2004-01-01

Full Text Available Betanal AM-11 is the herbicide that is using to control one-year old weeds with wide leafs in sugar beet fields. Active ingredients of the herbicide are phenmedipham and desmedipham. Commercial emulsifiable concentrate (EC contains 80 g/L ( 10% of each active compound. We applied high performance liquid chromatography (HPLC with diode array detector (DAD at 254 nm for the determination of phenmedipham and desmedipham in commercial samples of Betanal AM-11. This method involves reversed-phase separation of the components on C-18 bonded silica with methanol-water (51+49, v/v as the eluent. The procedure was highly selective and reproducible and can be successfully used in determining contents of phenmedipham and desmedipham on micro and macro levels.

Integrated Effect of Seeding Rate, Herbicide Dosage and ...

African Journals Online (AJOL)

yield reductions of 26 to 63% across four bread wheat cultivars at 90 weed seedlings m-2 in. Ethiopia. Before herbicides were widely available, farmers employed cultural measures to manage weed population. Wild oat management systems have evolved to the point that producers rely on herbicides to the virtual exclusion ...

Electrochemical incineration of chloromethylphenoxy herbicides in acid medium by anodic oxidation with boron-doped diamond electrode

International Nuclear Information System (INIS)

Boye, Birame; Brillas, Enric; Marselli, Beatrice; Michaud, Pierre-Alain; Comninellis, Christos; Farnia, Giuseppe; Sandona, Giancarlo

2006-01-01

The electrochemical degradation of saturated solutions of herbicides 4-chloro-2-methylphenoxyacetic acid, 2-(4-chlorophenoxy)-2-methylpropionic acid and 2-(4-chloro-2-methylphenoxy)propionic acid in 1 M HClO 4 on a boron-doped diamond (BDD) thin film anode has been studied by chronoamperometry, cyclic voltammetry and bulk electrolysis. At low anodic potentials polymeric products are formed causing the fouling and deactivation of BDD. This is reactivated at high potentials when water decomposes producing hydroxyl radical as strong oxidant of organics. Electrolyses in a batch recirculation system at constant current density ≥8 mA cm -2 yielded overall decontamination of all saturated solution. The effect of current density and herbicide concentration on the degradation rate of each compound, the specific charge required for its total mineralization and instantaneous current efficiency have been investigated. Experimental results have been compared with those predicted by a theoretical model based on a fast anodic oxidation of initial herbicides, showing that at 30 mA cm -2 their degradation processes are completely controlled by mass transfer. Kinetic analysis of the change of herbicide concentration with time during electrolysis, determined by high-performance liquid chromatography, revealed that all compounds follow a pseudo first-order reaction. Aromatic intermediates and generated carboxylic acids have been identified using this technique and a general pathway for the electrochemical incineration of all herbicides on BDD is proposed

Natural compounds with herbicidal activity

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Mariano Fracchiolla

2007-12-01

Full Text Available Research about phytotoxic activity of natural compounds could lead both to find new herbicidal active ingredients and to plan environmental friendly weed control strategies. Particularly, living organisms could be a source of compounds that are impossible, for their complexity, to synthesize artificially. More over, they could have alternative sites of action respect to the known chemical herbicides and, due to their origin, they should be more environmental safe. Many living organism, such as bacteria, fungi, insects, lichens and plants, are able to produce bioactive compounds. They generally are secondary metabolites or simply waste molecules. In this paper we make a review about these compounds, highlighting potential and constraints.

Natural compounds with herbicidal activity

Directory of Open Access Journals (Sweden)

Pasquale Montemurro

2011-02-01

Full Text Available Research about phytotoxic activity of natural compounds could lead both to find new herbicidal active ingredients and to plan environmental friendly weed control strategies. Particularly, living organisms could be a source of compounds that are impossible, for their complexity, to synthesize artificially. More over, they could have alternative sites of action respect to the known chemical herbicides and, due to their origin, they should be more environmental safe. Many living organism, such as bacteria, fungi, insects, lichens and plants, are able to produce bioactive compounds. They generally are secondary metabolites or simply waste molecules. In this paper we make a review about these compounds, highlighting potential and constraints.

Growth stage of Phalaris minor Retz. and wheat determines weed control and crop tolerance of four post-emergence herbicides

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Rubia Rasool

2017-04-01

Full Text Available Phalaris minor Retz. has evolved multiple herbicide resistance in wheat growing areas in northwestern India. An understanding of the effect of growth stage on herbicide tolerance of wheat and control of P. minor will help in selecting the most appropriate herbicide for different situations. The weed control and crop safety of four commonly used wheat herbicides (sulfosulfuron, pinoxaden, fenoxaprop plus metribuzin and mesosulfuron plus iodosulfuron, each applied at four different wheat growth stages was investigated in field studies for two years. P. minor plants were at 1, 2-3, 3-4 and 7-8 leaf stages when the herbicides were applied at Zadok 12-Z12, Z13, Z21 and Z23 stages of wheat, respectively. Sulfosulfuron application at Z12 and Z13 wheat stages (before first irrigation, provided >80% control of P. minor and produced wheat grain yield (4.5-4.7 t/ha similar to the weed-free check (4.9 t/ha in both years. Pinoxaden, fenoxaprop plus metribuzin and mesosulfuron plus iodosulfuron application at Z12 and Z13 wheat stages recorded significantly lower wheat grain yield (3.62-3.95 t/ha due to poor weed control, crop toxicity or both. All the four herbicides were equally effective on P. minor when applied at Z21 wheat stage. At Z23 wheat stage, pinoxaden gave >90% control of P. minor and the highest wheat grain yield (4.82 t/ha. The results are expected to allow changes in the current recommendation of the timing of post-emergence herbicides for the management of P. minor in wheat.

Sarmentine, a natural herbicide from Piper species with multiple herbicide mechanisms of action

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Franck Emmanuel Dayan

2015-04-01

Full Text Available Sarmentine, 1-(1-pyrrolidinyl-(2E,4E-2,4-decadien-1-one, is a natural amide isolated from the fruits of Piper species. The compound has a number of interesting biological properties, including its broad-spectrum activity on weeds as a contact herbicide. Initial studies highlighted a similarity in response between plants treated with sarmentine and herbicidal soaps such as pelargonic acid (nonanoic acid. However, little was known about the mechanism of action leading to the rapid desiccation of foliage treated by sarmentine. In cucumber cotyledon disc-assays, sarmentine induced rapid light-independent loss of membrane integrity at 100 µM or higher concentration, whereas 3 mM pelargonic acid was required for a similar effect. Sarmentine was between 10 and 30 times more active than pelargonic acid on wild mustard, velvetleaf, redroot pigweed and crabgrass. Additionally, the potency of 30 µM sarmentine was greatly stimulated by light, suggesting that this natural product may also interfere with photosynthetic processes. This was confirmed by observing a complete inhibition of photosynthetic electron transport at that concentration. Sarmentine also acted as an inhibitor of photosystem II on isolated thylakoid membranes by competing for the binding site of plastoquinone. This can be attributed in part to structural similarities between herbicides like sarmentine and diuron. While this mechanism of action accounts for the light stimulation of the activity of sarmentine, it does not account for its ability to destabilize membranes in darkness. In this respect, sarmentine has some structural similarity to crotonoyl-CoA, the substrate of enoyl-ACP reductase, a key enzyme in the early steps of fatty acid synthesis. Inhibitors of this enzyme, such as triclosan, cause rapid loss of membrane integrity in the dark. Sarmentine inhibited the activity of enoyl-ACP reductase, with an I50app of 18.3 µM. Therefore, the herbicidal activity of sarmentine appears to

A membrane-based ELISA assay for the herbicide Isoproturon in soil samples

OpenAIRE

Baskeyfield, Damian E. H.; Davis, Frank; Magan, Naresh; Tothill, Ibtisam E.

2012-01-01

A membrane based enzyme linked immunosorbent assay (MELISA) for the detection of a common herbicide, isoproturon is described. A heterogeneous competitive ELISA was the format chosen for isoproturon detection. An immunoassay system with a horseradish peroxidase (HRP) labeled polyclonal antibody preparation was developed and characterized before suitable sensitivity and selectivity for isoproturon were attained. After development as a microtiter plate immunoassay, the system was transferred to...

Effects of the herbicide isoproturon on metallothioneins, growth, and antioxidative defenses in the aquatic worm Tubifex tubifex (Oligochaeta, Tubificidae).

Science.gov (United States)

Mosleh, Yahia Y; Paris-Palacios, Séverine; Couderchet, Michel; Biagianti-Risbourg, Sylvie; Vernet, Guy

2005-07-01

Metallothioneins (MTs) are low molecular weight proteins, mainly implicated in metal ion detoxification. Increase in MT contents is considered to be a specific biomarker of metal exposure. Recently it has been demonstrated that MTs participate in several cellular functions such as regulation of growth, and antioxidative defenses. Therefore, the induction of MTs as biomarkers of exposure to the pesticide isoproturon has been investigated in the aquatic worms Tubifex tubifex. MT levels in exposed worms increased significantly (p isoproturon (maximum increase compared to unexposed controls: +148.56% for 10 mg l(-1) after 4 days of exposure). In response to isoproturon, the activity of glutathione-S-transferase (max. +52%), glutathione-reductase (max. +100%), and catalase (max. +117%) increased, demonstrating the occurrence of an oxidative stress response to the herbicide. Thus, the increase in MT contents caused by isoproturon was interpreted as a defense response towards increased oxidative stress generated by the herbicide. Residues of isoproturon and its metabolites, 1-(4-isopropylphenyl)-3-methylurea, 1-(4-isopropylphenyl) urea, and 4-isopropylanilin were detected in the worm growth medium. Half-life of the herbicide was shorter at a low (0.1 mg l(-1)) initial concentration. The herbicide accumulated in T. tubifex but no metabolite could be detected.

Monitoring of phenylurea and propanil herbicides in river water by solid-phase-extraction high performance liquid chromatography with photoinduced-fluorimetric detection.

Science.gov (United States)

de la Peña, A Muñoz; Mahedero, M C; Bautista-Sánchez, A

2003-06-13

The separation and determination of five herbicides, including propanil and the phenylureas diuron, isoproturon, linuron and neburon, has been performed by an HPLC method, using photochemically-induced fluorescence detection. The non-fluorescent herbicides were transformed into fluorescent compounds by post-column photochemical reaction. A 60:40 (v/v) acetonitrile-buffer solution of potassium phosphate dibasic (pH 7, 0.01 M) was used for the chromatographic elution to separate propanil, linuron and neburon. The overlapping of isoproturon and diuron peaks, in the selected conditions, was resolved by changing the initial movil phase composition to 50:50 (v/v) methanol-buffer solution of potassium phosphate dibasic (pH 7, 0.01 M). The procedure was applied with satisfactory results to the analysis of these herbicides in Guadiana river water samples (Badajoz, Spain), allowing the detection of herbicide residues in the order of mug l(-1), by using a solid-phase extraction (SPE) pre-concentration step.

Removal of triazine herbicides from aqueous systems by a biofilm reactor continuously or intermittently operated.

Science.gov (United States)

Sánchez-Sánchez, R; Ahuatzi-Chacón, D; Galíndez-Mayer, J; Ruiz-Ordaz, N; Salmerón-Alcocer, A

2013-10-15

The impact of pesticide movement via overland flow or tile drainage water on the quality of receiving water bodies has been a serious concern in the last decades; thus, for remediation of water contaminated with herbicides, bioreaction systems designed to retain biomass have been proposed. In this context, the aim of this study was to evaluate the atrazine and terbutryn biodegradation capacity of a microbial consortium, immobilized in a biofilm reactor (PBR), packed with fragments of porous volcanic stone. The microbial consortium, constituted by four predominant bacterial strains, was used to degrade a commercial formulation of atrazine and terbutryn in the biofilm reactor, intermittently or continuously operated at volumetric loading rates ranging from 44 to 306 mg L(-1) d(-1). The complete removal of both herbicides was achieved in both systems; however, higher volumetric removal rates were obtained in the continuous system. It was demonstrated that the adjuvants of the commercial formulation of the herbicide significantly enhanced the removal of atrazine and terbutryn. Copyright © 2013 Elsevier Ltd. All rights reserved.

Resistance risk assessment within herbicide authorisation--a call for sensitivity data.

Science.gov (United States)

Ulber, Lena; Nordmeyer, Henning; Zwerger, Peter

2013-02-01

In most European countries, the risk of herbicide resistance is assessed as part of the authorisation of herbicides in accordance with EPPO Standard PP 1/213(2). Because the susceptibility of weed populations to a certain herbicide may vary greatly, one part of resistance risk assessment is the testing for sensitivity variation among different populations of target weed species with a high resistance risk. This paper emphasises the importance of sensitivity data provision with regard to the recent EU Regulation (EC) 1107/2009 concerning the placing of plant protection products on the market and outlines the main technical requirements for sensitivity data. A useful principle is that sensitivity data should be provided for all herbicides with a high resistance risk regardless of whether resistance has already evolved against the herbicidal substance. Methodical details regarding the generation of sensitivity data are discussed, together with remaining questions that will need to be addressed if a harmonised assessment of herbicide resistance risk is to be achieved. Copyright © 2012 Society of Chemical Industry.

Altered Immune Response of the Rice Frog Fejervarya limnocharis Living in Agricultural Area with Intensive Herbicide Utilization at Nan Province, Thailand

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Khattapan Jantawongsri

2015-01-01

Full Text Available Herbicides (atrazine, glyphosate and paraquat have been intensively used in Nan Province for a long time. Prior observations indicated that herbicide contamination and adverse health effects were found on the rice frog Fejervarya limnocharis living in paddy fields at Nan Province. Contamination of herbicides may influence disease emergence by acting directly or indirectly upon the immune system of amphibian or by causing disruptions in homeostasis, it is thus interesting to investigate potential effects of herbicide contamination in Nan Province on immune responses of the rice frog living in agricultural areas. Frogs were caught from a paddy field with no history of herbicide utilization (reference site and a paddy field with intensive herbicide utilization (contaminated site during 2010-2011. After dissection, frog livers were fixed in 10% neutral buffer formalin, processed by paraffin method and stained with hematoxylin and eosin. Number of melanomacrophage and melanomacrophage center (MMC were counted under a light microscope and used as markers of non-specific immune response. It was found that there was no significant sex-related difference in these numbers. However, there were significant seasonal differences in these numbers in both reference and contaminated site frogs, suggesting that seasonal difference in herbicide usage tend to affect frog's immune system in agricultural areas. Furthermore, numbers of melanomacrophage and MMC in early wet, late wet and early dry periods were markedly higher in the contaminated site frogs compared to those of the reference site frogs. The observation on amphibian's immune response to environmental contaminants could indicate the impacts of herbicide utilization on other vertebrates, as well as its role in amphibian declines.

Aquatic Plant Control Research Program: Aquatic Plant Identification and Herbicide Use Guide. Volume 2. Aquatic Plants and Susceptibility to Herbicides

Science.gov (United States)

1988-11-01

Chronic >0.5 Daphnia Repeat exposure Chronic >0.2 reproduction 0 NOTE; Fluridone was not found to cause genetic mutations or cancer in tested lab...persists. REGISTERED HERBICIDES 95 REGISTERED HERBICIDES GLYPHOSATE A. Chemical Name and Formulation: Chemical name: N-(phosphonomethyl)glycine Formulation...RODEO (53.5% ai, isopropylamine salt of glyphosate , liquid) B. Mode of Action: Not definite. However, investigators have postulated that

Herbicide-resistant weed management: focus on glyphosate.

Science.gov (United States)

Beckie, Hugh J

2011-09-01

This review focuses on proactive and reactive management of glyphosate-resistant (GR) weeds. Glyphosate resistance in weeds has evolved under recurrent glyphosate usage, with little or no diversity in weed management practices. The main herbicide strategy for proactively or reactively managing GR weeds is to supplement glyphosate with herbicides of alternative modes of action and with soil-residual activity. These herbicides can be applied in sequences or mixtures. Proactive or reactive GR weed management can be aided by crop cultivars with alternative single or stacked herbicide-resistance traits, which will become increasingly available to growers in the future. Many growers with GR weeds continue to use glyphosate because of its economical broad-spectrum weed control. Government farm policies, pesticide regulatory policies and industry actions should encourage growers to adopt a more proactive approach to GR weed management by providing the best information and training on management practices, information on the benefits of proactive management and voluntary incentives, as appropriate. Results from recent surveys in the United States indicate that such a change in grower attitudes may be occurring because of enhanced awareness of the benefits of proactive management and the relative cost of the reactive management of GR weeds. Copyright © 2011 Society of Chemical Industry.

Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

Science.gov (United States)

Steinheimer, T.R.; Brooks, M.G.

1984-01-01

A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 ??g/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0. 1 mu g/L in a 1-litre sample. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

Exposure to a glyphosate-based herbicide during pregnancy and lactation induces neurobehavioral alterations in rat offspring.

Science.gov (United States)

Gallegos, Cristina E; Bartos, Mariana; Bras, Cristina; Gumilar, Fernanda; Antonelli, Marta C; Minetti, Alejandra

2016-03-01

The impact of sub-lethal doses of herbicides on human health and the environment is a matter of controversy. Due to the fact that evidence particularly of the effects of glyphosate on the central nervous system of rat offspring by in utero exposure is scarce, the purpose of the present study was to assess the neurobehavioral effects of chronic exposure to a glyphosate-containing herbicide during pregnancy and lactation. To this end, pregnant Wistar rats were exposed through drinking water to 0.2% or 0.4% of a commercial formulation of glyphosate (corresponding to a concentration of 0.65 or 1.30g/L of glyphosate, respectively) during pregnancy and lactation and neurobehavioral alterations in offspring were analyzed. The postnatal day on which each pup acquired neonatal reflexes (righting, cliff aversion and negative geotaxis) and that on which eyes and auditory canals were fully opened were recorded for the assessment of sensorimotor development. Locomotor activity and anxiety levels were monitored via open field test and plus maze test, respectively, in 45- and 90-day-old offspring. Pups exposed to a glyphosate-based herbicide showed early onset of cliff aversion reflex and early auditory canal opening. A decrease in locomotor activity and in anxiety levels was also observed in the groups exposed to a glyphosate-containing herbicide. Findings from the present study reveal that early exposure to a glyphosate-based herbicide affects the central nervous system in rat offspring probably by altering mechanisms or neurotransmitter systems that regulate locomotor activity and anxiety. Copyright © 2015 Elsevier Inc. All rights reserved.

Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group : determination of selected herbicides and their degradation products in water using solid-phase extraction and gas chromatography/mass spectrometry

Science.gov (United States)

Kish, J.L.; Thurman, E.M.; Scribner, E.A.; Zimmerman, L.R.

2000-01-01

A method for the extraction and analysis of eight herbicides and five degradation products using solid-phase extraction from natural water samples followed by gas chromatography/mass spectrometry is presented in this report. This method was developed for dimethenamid; flufenacet; fluometuron and its degradation products, demethylfluometuron (DMFM), 3-(trifluromethyl)phenylurea (TFMPU), 3-(trifluromethyl)-aniline (TFMA); molinate; norflurazon and its degradation product, demethylnorflurazon; pendamethalin; the degradation product of prometryn, deisopropylprometryn; propanil; and trifluralin. The eight herbicides are used primarily in the southern United States where cotton, rice, and soybeans are produced. The exceptions are dimethenamid and flufenacet, which are used on corn in the Midwest. Water samples received by the U.S. Geological Survey's Organic Geochemistry Research Group in Lawrence, Kansas, are filtered to remove suspended particulate matter and then passed through disposable solid-phase extraction columns containing octadecyl-bonded porous silica (C-18) to extract the compounds. The herbicides and their degradation products are removed from the column by ethyl acetate elution. The eluate is evaporated under nitrogen, and components then are separated, identified, and quantified by injecting an aliquot of the concentrated extract into a high-resolution, fused-silica capillary column of a gas chromatograph/mass spectrometer under selected-ion mode. Method detection limits ranged from 0.02 to 0.05 ?g/L for all compounds with the exception of TFMPU, which has a method detection limit of 0.32 ?g/L. The mean absolute recovery is 107 percent. This method for the determination of herbicides and their degradation products is valuable for acquiring information about water quality and compound fate and transport in water.

Degradation of Herbicides in the Tropical Marine Environment: Influence of Light and Sediment.

Science.gov (United States)

Mercurio, Philip; Mueller, Jochen F; Eaglesham, Geoff; O'Brien, Jake; Flores, Florita; Negri, Andrew P

2016-01-01

Widespread contamination of nearshore marine systems, including the Great Barrier Reef (GBR) lagoon, with agricultural herbicides has long been recognised. The fate of these contaminants in the marine environment is poorly understood but the detection of photosystem II (PSII) herbicides in the GBR year-round suggests very slow degradation rates. Here, we evaluated the persistence of a range of commonly detected herbicides in marine water under field-relevant concentrations and conditions. Twelve-month degradation experiments were conducted in large open tanks, under different light scenarios and in the presence and absence of natural sediments. All PSII herbicides were persistent under control conditions (dark, no sediments) with half-lives of 300 d for atrazine, 499 d diuron, 1994 d hexazinone, 1766 d tebuthiuron, while the non-PSII herbicides were less persistent at 147 d for metolachlor and 59 d for 2,4-D. The degradation of herbicides was 2-10 fold more rapid in the presence of a diurnal light cycle and coastal sediments; apart from 2,4-D which degraded more slowly in the presence of light. Despite the more rapid degradation observed for most herbicides in the presence of light and sediments, the half-lives remained > 100 d for the PS II herbicides. The effects of light and sediments on herbicide persistence were likely due to their influence on microbial community composition and its ability to utilise the herbicides as a carbon source. These results help explain the year-round presence of PSII herbicides in marine systems, including the GBR, but more research on the transport, degradation and toxicity on a wider range of pesticides and their transformation products is needed to improve their regulation in sensitive environments.

Herbicide volatilization trumps runoff losses, a multi-year investigation

Science.gov (United States)

Surface runoff and volatilization are two processes critical to herbicide off-site transport. To determine the relevance of these off-site transport mechanisms, runoff and turbulent vapor fluxes were simultaneously monitored on the same site for eight years. Site location, herbicide formulations, ...

Herbicidas no transplante de mudas de sisal (Agave sisalana perr. Weed control and herbicide selectivity to sisal (Agave sisalana perr.

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Antonio Luiz de Barros Salgado

1980-01-01

Full Text Available Com o objetivo de verificar a eficiência de hebraicas no controle de plantas daninhas e sua seletividade à cultura do sisal, foi instalado, em setembro de 1976, um experimento de campo em solo argiloso, com os seguintes tratamentos (i.a./hectare trifluralin a 0,84 e 0,96kg em pré-plantio com incorporação; alachlor a 2,40 e 3,26kg; metribuzin a 0,70 e 0,84kg; bromacil a 1,60 e 2,40kg; terbacil a 1,60 e 2,40kg; diuron a 2,40 e 3,20kg; simazine a 3,20 e 4,00kg; fluometuron a 1,20 e 1,60kg, todos em pré-emergência; uma testemunha carpida e outra sem capina. Foram feitas avaliações de controle do mato aos 67 e 114 dias e da condição da cultura aos 600 dias após a aplicação. Aos 114 dias, o controle de gramíneas foi acima de 90% pelo trifluralin, bromacil e terbacil, em torno de 80% pelo simazine, e inferior a 75% pelos demais; para dícotiledôneas, o controle foi de 90 a 100% pelo bromacil e terbacil, e de 80 a 85%o pelo simazine. Nenhum dos tratamentos afetou a cultura durante o período considerado, que foi de 600 dias. Aos 550 dias, fez-se avaliação da área coberta por reinfestação do mato, tendo o terbacil controlado ainda 75 e 95% do total, respectivamente, para as doses menor e maior; o trifluralin, 60 e 70% e, os demais, abaixo de 45%. Na avaliação final da cultura, aos 600 dias, foram considerados: população de plantas, número de plantas com perfilhos e condição da cultura. Os tratamentos que realizaram melhor controle do mato apresentaram também os melhores índices de desenvolvimento da cultura, atestando sua seletividade.The weed control with herbicides and its selectivity to sisal were studied on a clay soil field trial. The treatments (in a.i./ha were: 0.84 and 0.96kg of pre-plant incorporated trifluralin; 2.40 and 3.26kg of alachlor; 0.70 and 0.84kg of metribuzin; 1.60 and 2.40kg of bromacil; 1.60 and 2.40kg of terbacil; 2.40 and 3.20k- of diuron; 3.20 and 4.00kg of simazine; 1.20 and 1.60kg of fluometuron

Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

Science.gov (United States)

Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

2002-10-01

The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.

Vertical small scale variations of sorption and mineralization of three herbicides in subsurface limestone and sandy aquifer

Science.gov (United States)

Janniche, G. S.; Mouvet, C.; Albrechtsen, H.-J.

2011-04-01

Vertical variation in sorption and mineralization potential of mecoprop (MCPP), isoproturon and acetochlor were investigated at low concentrations (μg-range) at the cm-scale in unsaturated sub-surface limestone samples and saturated sandy aquifer samples from an agricultural catchment in Brévilles, France. From two intact core drills, four heterogenic limestone sections were collected from 4.50 to 26.40 m below surface (mbs) and divided into 12 sub-samples of 8-25 cm length, and one sandy aquifer section from 19.20 to 19.53 m depth divided into 7 sub-samples of 4-5 cm length. In the sandy aquifer section acetochlor and isoproturon sorption increased substantially with depth; in average 78% (acetochlor) and 61% (isoproturon) per 5 cm. Also the number of acetochlor and isoproturon degraders (most-probable-number) was higher in the bottom half of the aquifer section (93-> 16 000/g) than in the upper half (4-71/g). One 50 cm long limestone section with a distinct shift in color showed a clear shift in mineralization, number of degraders and sorption: In the two brown, uppermost samples, up to 31% mecoprop and up to 9% isoproturon was mineralized during 231 days, the numbers of mecoprop and isoproturon degraders were 1300 to > 16 000/g, and the sorption of both isoproturon and acetochlor was more than three times higher, compared to the two deeper, grayish samples just below where mineralization (≤ 4%) and numbers of degraders (1-520/g) were low for all three herbicides. In both unsaturated limestone and sandy aquifer, variations and even distinct shifts in both mineralization, number of specific degraders and sorption were seen within just 4-15 cm of vertical distance. A simple conceptual model of herbicides leaching to groundwater through a 10 m unsaturated limestone was established, and calculations showed that a 30 cm active layer with the measured sorption and mineralization values hardly impacted the fate of the investigated herbicides, whereas a total

Analysis of the metabolic resistance of Ambrosia artemisiifolia L. to the herbicides action

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Y.V. Lykholat

2018-03-01

Full Text Available Action and aftereffect of the herbicides with different modes of action on the common ragweed population were studied in the field and greenhouse experiments. Activation of glutathione S-transferase has been detected due to the action of herbicides Harness and Guardian-Tetra both in leaves of juvenile plants and in ragweed seeds, which indicates intensive detoxification of herbicides during weed ontogenesis. Electrophoretic analysis showed that four components in protein spectra of ragweed seeds were inherent in seeds collected from herbicides-treated plants only. Using the method of isoelectric focusing, three specific peroxidase isoforms associated with a certain mechanism of herbicidal action on the parent plants were found in leaves of the next generation plants. The results confirm the intensive adaptive changes in A. artemisiifolia population that could provide the metabolic resistance to different modes of the herbicide action. Keywords: Common ragweed, Metabolic resistance, Herbicide, Mode of action, Isoforms, Isoelectric

A risk index for multicriterial selection of a logging system with low environmental impact

Energy Technology Data Exchange (ETDEWEB)

Horodnic, Sergiu Andrei, E-mail: horodnic@usv.ro

2015-02-15

Setting up the working stages in forest operations is conditioned by environmental protection and forest health requirements. This paper exposes a method for improving the decision-making process by choosing the most environmentally effective logging systems according to terrain configuration and stand characteristics. Such a methodology for selecting machines or logging systems accounting for environment, safety as well as economics, becomes mandatory in the context of sustainable management of forest with multiple functions. Based on analytic hierarchy process analysis the following classification of the environmental performance for four considered alternatives was obtained: skyline system (42.43%), forwarder system (20.22%), skidder system (19.92%) and horse logging system (17.43%). Further, an environmental risk matrix for the most important 28 risk factors specific to any work equipment used in forest operations was produced. In the end, a multicriterial analysis generated a risk index RI ranging between 1.0 and 3.5, which could help choosing the optimal combination of logging system and logging equipment with low environmental impact. In order to demonstrate the usefulness of the proposed approach, a simple application in specific conditions of a harvesting site is presented. - Highlights: • We propose a decision-making algorithm to select eco-friendly logging systems. • Analytic hierarchy process was applied for ranking 4 types of logging systems. • An environmental risk matrix with 28 risk factors in forest operations was made up.

A risk index for multicriterial selection of a logging system with low environmental impact

International Nuclear Information System (INIS)

Horodnic, Sergiu Andrei

2015-01-01

Setting up the working stages in forest operations is conditioned by environmental protection and forest health requirements. This paper exposes a method for improving the decision-making process by choosing the most environmentally effective logging systems according to terrain configuration and stand characteristics. Such a methodology for selecting machines or logging systems accounting for environment, safety as well as economics, becomes mandatory in the context of sustainable management of forest with multiple functions. Based on analytic hierarchy process analysis the following classification of the environmental performance for four considered alternatives was obtained: skyline system (42.43%), forwarder system (20.22%), skidder system (19.92%) and horse logging system (17.43%). Further, an environmental risk matrix for the most important 28 risk factors specific to any work equipment used in forest operations was produced. In the end, a multicriterial analysis generated a risk index RI ranging between 1.0 and 3.5, which could help choosing the optimal combination of logging system and logging equipment with low environmental impact. In order to demonstrate the usefulness of the proposed approach, a simple application in specific conditions of a harvesting site is presented. - Highlights: • We propose a decision-making algorithm to select eco-friendly logging systems. • Analytic hierarchy process was applied for ranking 4 types of logging systems. • An environmental risk matrix with 28 risk factors in forest operations was made up

Effects of acetochlor (herbicide) on the survival and avoidance ...

African Journals Online (AJOL)

Jane

2011-07-06

Jul 6, 2011 ... These results suggested that acetochlor residues had negligible effects on P. birmanica and L. terrestris. Michalkova and Pekar (2009) and Yardim and Edwards (1998) also reported negligible effects of herbicide (glyphosate) on Pardosa agrestis. Although, we also observed negligible effects of herbicide.

GROWTH AND NUTRITIONAL ANALYSIS OF TREE SPECIES IN CONTAMINATED SUBSTRATE BY LEACHABLE HERBICIDES

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Rebecca de Araújo Fiore

Full Text Available ABSTRACT Ecosystems contamination by residues of pesticides requires special attention to the herbicides subject to leaching. The objective was to select tree species to rhizodegradation contaminated by residues of 2,4-D and atrazine and to recompose riparian areas to agricultural fields, then reducing the risk of contamination of water courses. A total of 36 treatments consisted of the combinations of forest species were evaluated [Inga marginata (Inga, Schizolobium parahyba (guapuruvu, Handroanthus serratifolius (ipê amarelo, Jacaranda puberula (carobinha, Cedrela fissilis (cedro, Calophyllum brasiliensis (landin, Psidium mirsinoides (goiabinha, Tibouchina glandulosa (quaresmeira, Caesalpinia férrea (pau-ferro, Caesalpinia pluviosa (sibipiruna, Terminalia argêntea (capitão and Schinopsis brasiliensis (braúna] and three solutions simulating leachate compound (atrazine, 2,4-D and water - control, with four replicates each. The characteristics measured were plant height, stem diameter, number of leaves, leaf area and dry biomass, and foliar nutrition. Forest species survived the herbicide application, and most showed an increase in macronutrients even under an herbicide application, and the Inga had the highest tolerance regarding growth analysis. It is recommended to use species that are more tolerant to Atrazine and 2,4-D in field experiments to confirm previous results of this simulation.

Transgenic rice expressing a codon-modified synthetic CP4-EPSPS confers tolerance to broad-spectrum herbicide, glyphosate.

Science.gov (United States)

Chhapekar, Sushil; Raghavendrarao, Sanagala; Pavan, Gadamchetty; Ramakrishna, Chopperla; Singh, Vivek Kumar; Phanindra, Mullapudi Lakshmi Venkata; Dhandapani, Gurusamy; Sreevathsa, Rohini; Ananda Kumar, Polumetla

2015-05-01

Highly tolerant herbicide-resistant transgenic rice was developed by expressing codon-modified synthetic CP4--EPSPS. The transformants could tolerate up to 1% commercial glyphosate and has the potential to be used for DSR (direct-seeded rice). Weed infestation is one of the major biotic stress factors that is responsible for yield loss in direct-seeded rice (DSR). Herbicide-resistant rice has potential to improve the efficiency of weed management under DSR. Hence, the popular indica rice cultivar IR64, was genetically modified using Agrobacterium-mediated transformation with a codon-optimized CP4-EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) gene, with N-terminal chloroplast targeting peptide from Petunia hybrida. Integration of the transgenes in the selected rice plants was confirmed by Southern hybridization and expression by Northern and herbicide tolerance assays. Transgenic plants showed EPSPS enzyme activity even at high concentrations of glyphosate, compared to untransformed control plants. T0, T1 and T2 lines were tested by herbicide bioassay and it was confirmed that the transgenic rice could tolerate up to 1% of commercial Roundup, which is five times more in dose used to kill weeds under field condition. All together, the transgenic rice plants developed in the present study could be used efficiently to overcome weed menace.

Induction and selection of mutants from in vitro cultured plant cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-07-01

Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author).

Induction and selection of mutants from in vitro cultured plant cells

International Nuclear Information System (INIS)

Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae

1994-07-01

Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author)

Effect of Mycorrhizal Fungi and Trifluralin Herbicide on Emergence, Growth and Root Colonization of Clover (Trifolium repens L.

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Hassan Shahgholi

2016-09-01

emergence increased significantly with increasing herbicide dose. The maximum emergence (Emax value and clover shoot dry matter was obtained with inoculation by mycorrhiza species in all levels of herbicide doses than non-inoculation treatments (figures 1 and 3. Inoculation of clover with G. intraradices increased root length by 34 and 57% at the herbicide doses of 1000 and 1500 ml ha-1 than non-inoculation treatments, respectively (figure 2. Results showed that, the root colonization percentage improved in low rate of Treflan by inoculation of mycorrhizal than non-inoculation treatment significantly (figure 4. These results are in agreement with the results reported by Garcia-Romeria et al. (14. They reported that shoot dry weights of AM fungi infected pea plants, were higher when the cyanazine was applied at the rate of 0.05mg ml -1 than applied at the rate of 0.1 ml per pot (14. Busse et al. (6, reported that triclorpyr, imazapyr and sulfometuron methyl herbicides did not alter the capability of mycorrhizal fungi to infect roots, even at concentrations detrimental to seedling growth. Makarian et al., (21 reported that herbicide application significantly decreased the growth (dry matter, chlorophyll content and height of maize and barley plants but mycorrhizal colonization increased plant growth at low levels of herbicide concentration. It seems that, one of the main reasons that enable the mycorrhizal plant to partially or completely overcome the stress of herbicides as compared with non-mycorrhizal plant is the enhanced nutrient uptake (6. Enhanced nutrients uptake is due, in part, to the hyphal extension into the soil and subsequent transfer of them back to the root (30. Recent researches have established that AM fungi are able to absorb organic compounds, macro and micro nutrients from the soil and transfer them to plants (29. Pesticides have also been reported to stimulate colonization of plant roots by AM fungi. This may be due to a reduction or elimination of

Surface plasmon resonance application for herbicide detection

Science.gov (United States)

Chegel, Vladimir I.; Shirshov, Yuri M.; Piletskaya, Elena V.; Piletsky, Sergey A.

1998-01-01

The optoelectronic biosensor, based on Surface Plasmon Resonance (SPR) for detection of photosynthesis-inhibiting herbicides in aqueous solutions is presented. The pesticide capability to replace plastoquinone from its complex with D1 protein is used for the detection. This replacement reaction results in the changes of the optical characteristics of protein layer, immobilized on the gold surface. Monitoring of these changes with SPR-technique permit to determine 0.1 - 5.0 mkg/ml herbicide in solution within one hour.

Herbicidal Activity of Coumarin When Applied as a Pre-plant Incorporated into Soil

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Amir-Hossein NAZEMI

2015-06-01

Full Text Available Due to having a short half-life and novel site of action, the herbicidal potential of natural compounds are lionized. Coumarin is a secondary metabolite from Lavandula sp., family Lamiacae. The impact of eight concentrations of coumarin (0, 100, 200, 400, 800, 1600, 3200 and 6400 ppm were separately used as a pre-plant incorporated into soil on six plant species under greenhouse conditions. Generally, coumarin had phytotoxic effect against all plant species. The phytotoxic effect was concentration-dependent. The high concentrations could inhibit the emergence of seedlings (probably by stopping germination of seeds. Based on ED50 parameter, the ranking of plant species for tolerance to coumarin was S. halepense > Z. mays > C. album > A. retroflexus > E. cruss-gali > P. oleracea. Based on selectivity index, coumarin at a concentration of 365.69 ppm can control P. oleracea without damaging Z. mays, whereas any concentration it cannot control other weeds without damaging Z. mays.

Comparative Cytotoxicity of the Herbicide Atrazine to Four Inbred Maize Lines (Zea mays L.)

International Nuclear Information System (INIS)

Shehata, Afaf I; AlGhethar, Haila A; AlHomaidan, Ali A; Arif, Ibrahim A

2008-01-01

Atrazine is one of the most widely used herbicides in the world. Recent reports have indicated that it has adverse impacts on the endocrine systems and on the early developments of wild animals and it has been banned in many European countries including Switzerland, the home of the manufacturing company. The genotoxic effects of Atrazine on four inbred lines of maize (Zea mays L.) were investigated. The herbicide showed mitoinhibition and clastogenic effects on the mitotic index of maize lines and they were proportional to the concentrations and time. The frequency of abnormality, chromosomal breakage, stickiness, lagging, C-metaphase and C-anaphase were observed at different stages of mitosis in treated cells. The harmful effect of this environmental pollutant proved that it may act as a strong mutagen. (author)

Using a Hydrological Model to Determine Environmentally Safer Windows for Herbicide Application

Science.gov (United States)

J.L. Michael; M.C. Smith; W.G. Knisel; D.G. Neary; W.P. Fowler; D.J. Turton

1996-01-01

A modification of the GLEAMS model was used to determine application windows which would optimise efficacy and environmental safety for herbicide application to a forest site. Herbicide/soil partition coefficients were determined using soil samples collected from the study site for two herbicides (imazapyr, Koc=46, triclopyr ester, K

Comparisons of Herbicide Treated and Cultivated Herbicide-Resistant Corn

OpenAIRE

H. Arnold Bruns; Hamed K. Abbas

2010-01-01

Four glyphosate resistant corn (Zea mays L.) hybrids, a glufosinate-ammonium resistant hybrid, and a conventional atrazine resistant hybrid gown at Stoneville, MS in 2005, 2006, and 2007 with furrow irrigation were treated with their respective herbicides and their growth, yield, and mycotoxin incidence were compared with untreated cultivated plots. Leaf area index (LAI) and dry matter accumulation (DMA) were collected on a weekly basis beginning at growth stage V3 and terminating at anthesi...

Seletividade de herbicidas aplicados na grama Batatais e na grama São Carlos Selectivity of herbicides applied on Bahiagrass and Broadleaf Carpetgrass turfs

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N.V. Costa

2010-06-01

Full Text Available Objetivou-se avaliar a seletividade de herbicidas aplicados na grama Batatais (Paspalum notatum e na grama São Carlos (Axonopus compressus em campo. O delineamento experimental utilizado foi o de blocos casualizados com quatro repetições. As gramas foram cortadas a 3 cm de altura e, em seguida, realizaram-se as aplicações dos herbicidas. Os tratamentos utilizados foram: testemunha (sem aplicação, fluazifop-p-butil (125 g ha-1, sethoxydim+óleo mineral (276 g ha-1 + 0,5% v v-1 de Assist, bispyribac-sodium (25 g ha-1, chlorimuron-ethyl (15 g ha-1, ethoxysulfuron (150 g ha-1, halosulfuron (112,5 g ha-1, iodosulfuron-methyl (10 g ha-1, metsulfuron-methyl (2,4 g ha-1, nicosulfuron (125 g ha-1, pyrithiobac-sodium (140 g ha-1, trifloxysulfuron-sodium (22,5 g ha-1, 2,4-D (720 g ha-1, quinclorac (375 g ha-1, atrazina (1.250 g ha-1, bentazon (600 g ha-1, linuron (1.350 g ha-1, fomesafen (187,5 g ha-1, lactofen (120 g ha-1, oxadiazon (600 g ha-1 e oxyfluorfen (720 g ha-1. Os herbicidas que apresentaram potencial de seletividade para o gramado de P. notatum foram o chlorimuron-ethyl, ethoxysulfuron, pyrithiobac-sodium, 2,4-D, bentazon e fomesafen; já para o gramado de A. compressus foram o chlorimuron-ethyl, ethoxysulfuron, halosulfuron, iodosulfuron-methyl, metsulfuron-methyl, pyrithiobac-sodium, 2,4-D, quinclorac, atrazina, bentazon, além do fomesafen.The objective of this study was to evaluate the selectivity of herbicides applied on Bahiagrass (Paspalum notatum and Broadleaf Carpetgrass (Axonopus compressus turfgrasses under field conditions. The experiment was arranged in a randomized block design, with four replications. The turfgrasses were cut to the height of 3 cm, followed by herbicide application.. The treatments were: control, fluazifop-p-butyl (125 g ha-1, sethoxydim+mineral oil (276 g ha-1 + 0.5% v v-1 of Assist, bispyribac-sodium (25 g ha-1, chlorimuron-ethyl (15 g ha-1, ethoxysulfuron (150 g ha-1, halosulfuron (112.5 g ha-1

Joint action of some usable important broadleaf herbicides in sugar beet

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AliAsghar Chitband

2018-01-01

Full Text Available Introduction: The assessment of the effect of mixtures could be based on various concepts whether we work within toxicology, pharmacology or weed control. Combinations of certain herbicides can give better weed control than use of the individual herbicide alone and/or loss of weed control when use of certain other herbicides in combination. Predicting the joint action of mixtures is extremely difficult, unless the compounds are known to interact at the same site of action. These most common methods to analyze the joint action of herbicide mixtures are the Additive Dose Model (ADM or the Multiplicative Survival Model (MSM. The ADM assumes the two compounds have similar modes of action (do not interact in the receiver plant, i.e. effective doses of each component will not change by mixing. ADM has been widely accepted as a valid method to estimate joint action of mixtures sharing the same or similar action mechanisms in the receiver plant. MSM has been reported to yield more accurate results for mixture toxicity than ADM do when the components exhibited different or dissimilar modes of action in the receiver plant. ADM or Concentration Addition (CA is used here to test for deviation of additivity of doses using the ADM isoboles as reference; any deviation from the ADM is characterized by antagonism when the efficacy of a mixture is lower than predicted by the reference model and synergistic when the efficacy is higher than predicted. Materials and Methods: In order to determine joint action of some usable important broadleaf herbicides in sugar beet, six experiments were conducted at the research glasshouse in Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. The plants were sprayed with seven doses of commercial formulation of desmedipham + phenmedipham + ethofumesate (Betanal Progress- OF®, 427 g a.i. L-1, Tragusa, Spain, chloridazon (Pyramin®, 1361 g a.i. L-1, BASF, Germany, clopyralid (Lontrel®, 149 g a.i. L-1, Golsam, Gorgan

Effects of the herbicides linuron and S-metolachlor on Perez's frog embryos.

Science.gov (United States)

Quintaneiro, Carla; Soares, Amadeu M V M; Monteiro, Marta S

2018-03-01

Presence of pesticides in the environment and their possible effects on aquatic organisms are of great concern worldwide. The extensive use of herbicides in agricultural areas are one of the factors contributing to the known decline of amphibian populations. Thus, as non-target species, amphibians can be exposed in early life stages to herbicides in aquatic systems. In this context, this study aims to evaluate effects of increasing concentrations of two maize herbicides, linuron and S-metolachlor on embryos of the Perez' frog (Pelophylax perezi) during 192 h. Apical endpoints were determined for each herbicide: mortality, hatching rate, malformations and length. Frog embryos presented a LC 50 of 21 mg/l linuron and 37.5 mg/l S-metolachlor. Furthermore, sub-lethal concentrations of both herbicides affected normal embryonic development, delaying hatching, decreasing larvae length and causing several malformations. Length of larvae decreased with increasing concentrations of each herbicide, even at the lower concentrations tested. Malformations observed in larvae exposed to both herbicides were oedemas, spinal curvature and deformation, blistering and microphtalmia. Overall, these results highlight the need to assess adverse effects of xenobiotics to early life stages of amphibians regarding beside mortality the embryonic development, which could result in impairments at later stages. However, to unravel mechanisms involved in toxicity of these herbicides further studies regarding lower levels of biological organisation such as biochemical and genomic level should be performed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Triazine herbicides inhibit relaxin signaling and disrupt nitric oxide homeostasis

Energy Technology Data Exchange (ETDEWEB)

Park, Si Eun; Lim, Sa Rang; Choi, Hyung-kyoon; Bae, Jeehyeon, E-mail: jeehyeon@cau.ac.kr

2016-09-15

Triazines are herbicides that are widely used worldwide, and we previously observed that the maternal exposure of mice to simazine (50 or 500 μg/kg) resulted in smaller ovaries and uteri of their female offspring. Here, we investigated the underlying mechanism that may account for the reproductive dysfunction induced by simazine. We found that following maternal exposure, simazine is transmitted to the offspring, as evidenced by its presence in the offspring ovaries. Analyses of the simazine-exposed offspring revealed that the expression of the relaxin hormone receptor, relaxin-family peptide receptor 1 (RXFP1), prominently decreased in their ovaries and uteri. In addition, downstream target genes of the relaxin pathway including nitric oxide (NO) synthase 2 (Nos2), Nos3, matrix metallopeptidase 9 (Mmp9), and vascular endothelial growth factor (Vegf) were downregulated in their ovaries. Moreover, AKT and extracellular signal-regulated kinases (ERK) levels and their phosphorylated active forms decreased in simazine-exposed ovaries. In vitro exposure of the human ovarian granulosa cells (KGN) and uterine endometrium cells (Hec-1A) to very low concentrations (0.001 to 1 nM) of triazines including atrazine, terbuthylazine, and propazine repressed NO production with a concurrent reduction in RXFP1, NOS2, and NOS3. The inhibitory action of triazines on NO release was dependent on RXFP1, phosphoinositol 3-kinase (PI3K)/AKT, and ERK. Radioligand-binding assay also confirmed that triazines competitively inhibited the binding of relaxin to its receptor. Therefore, the present study suggests that triazine herbicides act as endocrine disrupters by interfering with relaxin hormone signaling. Thus, further evaluation of their impact on human health is imperative. - Highlights: • Triazines downregulate critical molecules involved in the relaxin signaling pathway. • Triazines act as potent antagonists of binding of relaxin to its receptor. • Triazines disrupt nitric oxide

Herbicidal activity of pre and post emergent herbicide on control of Eleusine indica in aerobic rice system

International Nuclear Information System (INIS)

Selvarajh, G.; Zain, N.M.; Aminudin, A.; Seng, C.T.

2018-01-01

Aerobic rice system can be an alternate way to cultivate rice in less water conditions. However, weeds are a major constrain in aerobic rice field which decline its success. Weeds are being controlled by herbicides in aerobic rice but not all herbicides are effective in controlling various types of weeds. In this study, two pre-emergent (pretilachor and pendimethalin) and two post-emergent (cyhalofop-butyl and bispyribac-sodium) herbicides were evaluated for effective control of the bioassay species, Eleusine indica. It was found that pendimethalin at a higher application rate of 1.0 kg ai ha-1 strongly inhibit the emergence and shoot growth of E. indica by >75% with negligible effect on the rice growth with stimulation on the leaf greenness. Conversely, pretilachor, cyhalofop-butyl and bispyribac-sodium gave moderate inhibition (55-60% inhibition) on weed emergence and shoot growth at higher application rates of 0.44, 0.1 and 0.035 kg ai ha-1, respectively. Significant inhibitory effects on rice root growth were noticed at highest application rates of pretilachor, cyhalofop-butyl and bispyribac-sodium (40-50% inhibition) across the growth stage of rice seedlings. Great reduction in shoot height, shoot fresh weight, and greenness of rice plant also was evident at 0 DAS across herbicides rates. However, with increasing growth stages, the rice plant became less susceptible to the applied treatments. The finding suggested that pendimethalin at 1.0 kg ai ha-1 was the most suitable application rate for inhibiting E. indica without injuring the rice seedlings. (author)

Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Chen, Zunwei; Zou, Yuqin; Wang, Jia [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Li, Meichao [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032 (China); Wen, Yuezhong, E-mail: wenyuezhong@zju.edu.cn [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

2016-04-01

With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

International Nuclear Information System (INIS)

Chen, Zunwei; Zou, Yuqin; Wang, Jia; Li, Meichao; Wen, Yuezhong

2016-01-01

With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

Impact of low molecular weight organic acids and dissolved organic matter on sorption and mobility of isoproturon in two soils.

Science.gov (United States)

Ding, Qing; Wu, Hai Lang; Xu, Yun; Guo, Li Juan; Liu, Kai; Gao, Hui Min; Yang, Hong

2011-06-15

Isoproturon is a selective herbicide belonging to the phenylurea family and widely used for pre- and post-emergence control of annual weeds. Soil amendments (e.g. organic compounds or dissolved organic matter) may affect environmental behavior and bioavailability of pesticides. However, whether the physiochemical process of isoproturon in soils is affected by organic amendments and how it is affected in different soil types are unknown. To evaluate the impact of low molecular weight organic acids (LMWOA) and dissolved organic matter (DOM) on sorption/desorption and mobility of isoproturon in soils, comprehensive analyses were performed using two distinct soil types (Eutric gleysols and Hap udic cambisols). Our analysis revealed that adsorption of isoproturon in Eutric gleysols was depressed, and desorption and mobility of isoproturon were promoted in the presence of DOM and LMWOA. However, the opposite result was observed with Hap udic cambisols, suggesting that the soil type affected predominantly the physiochemical process. We also characterized differential components of the soils using three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy and Fourier transform infrared (FT-IR) spectroscopy and show that the two soils displayed different intensity of absorption bands for several functional groups. Copyright © 2011 Elsevier B.V. All rights reserved.

Hyperammonemia following glufosinate-containing herbicide poisoning: a potential marker of severe neurotoxicity.

Science.gov (United States)

Mao, Yan-Chiao; Wang, Jiaan-Der; Hung, Dong-Zong; Deng, Jou-Fang; Yang, Chen-Chang

2011-01-01

Glufosinate-ammonium (GLA) is the active ingredient of certain widely used non-selective contact herbicides ("e.g.," Basta). Although it is thought to be much less toxic to humans than to plants, deliberate ingestion of GLA could still lead to serious effects ("e.g.," neurotoxicity) or even death. Three cases presented with delayed-onset neurotoxicity including stupor, delirium, seizures, coma, and amnesia after ingesting large amount of Basta. Considering that GLA could irreversibly inhibit glutamine synthetase (GS) in plants, we performed serial measurements of serum ammonia in those patients and revealed marked hyperammonemia in all of them. All patients recovered with the sequelae of persistent amnesia after receiving intensive care and hemodialysis. We speculated that the occurrence of hyperammonemia might at least be partially related to GS inhibition in humans. Moreover, hyperammonemia could serve as a potential marker of severe neurotoxicity, especially prolonged amnesia, following massive ingestion of GLA-containing herbicides. The possible dose-response relation between GLA exposure and serum ammonia level, however, needs more investigations.

Integration of Agronomic Practices with Herbicides for Sustainable Weed Management in Aerobic Rice

Science.gov (United States)

Anwar, M. P.; Juraimi, A. S.; Mohamed, M. T. M.; Uddin, M. K.; Samedani, B.; Puteh, A.; Man, Azmi

2013-01-01

Till now, herbicide seems to be a cost effective tool from an agronomic view point to control weeds. But long term efficacy and sustainability issues are the driving forces behind the reconsideration of herbicide dependent weed management strategy in rice. This demands reappearance of physical and cultural management options combined with judicious herbicide application in a more comprehensive and integrated way. Keeping those in mind, some agronomic tools along with different manual weeding and herbicides combinations were evaluated for their weed control efficacy in rice under aerobic soil conditions. Combination of competitive variety, higher seeding rate, and seed priming resulted in more competitive cropping system in favor of rice, which was reflected in lower weed pressure, higher weed control efficiency, and better yield. Most of the herbicides exhibited excellent weed control efficiency. Treatments comprising only herbicides required less cost involvement but produced higher net benefit. On the contrary, treatments comprising both herbicide and manual weeding required high cost involvement and thus produced lower net benefit. Therefore, adoption of competitive rice variety, higher seed rate, and seed priming along with spraying different early-postemergence herbicides in rotation at 10 days after seeding (DAS) followed by a manual weeding at 30 DAS may be recommended from sustainability view point. PMID:24223513

Persistence of auxinic herbicides applied on pasture and toxicity for succeeding crops

Directory of Open Access Journals (Sweden)

ARNON H.C. ANÉSIO

2018-04-01

Full Text Available ABSTRACT The aim of this work was to determine the persistence of auxinic herbicides applied on tropical pasture and toxicity for succeeding crops. The herbicides were applied in an area of dystrophic red‒yellow latosol with pasture infested of weeds. At 40, 80, and 280 days after application of herbicide, the soil samples were collected at depths of 0 to 20 cm. Soil with residues of 2,4-D, 2,4-D + picloram, triclopyr, and a soil without herbicide application were analyzed with six replicates. Seven crops were cultivated in these soils: cucumber (Cucumis sativus L., velvet bean [Mucuna pruriens (L. DC.], pigeon pea [Cajanus cajan (L. Millsp.], alfalfa (Medicago sativa L., lablab bean [Lablab purpureus (L. Sweet], corn (Zea mays L., and sorghum [Sorghum bicolor (L. Moench]. The plants of cucumber, pigeon pea, and alfalfa were the most susceptible to the auxinic herbicide residues. However, the lablab bean was the only one among the dicot evaluated that showed tolerance to the 2,4-D + picloram residual when cultivated in soils at 280 days after application of herbicide. Corn and sorghum showed lower chlorophyll content in soils with 2,4-D + picloram residual up to 80 days after application of herbicide.

Herbicide Orange Site Characterization Study, Eglin AFB

Science.gov (United States)

1987-01-01

F THIS PAGE Availabilit o this r is sp f o.n" the reverse of fo cove* . - .’.r. 717 CSAT CO ES ’SU JEC TE MS Coninu onrevrseif ece~ar an idntiy b...of Hardstand 7 and Surface Water Drainages ......... 4 3 Hardstand 7 Herbicide Oran&e Storage Locations .............. 5 4 Concentrations (in ppb) of...insoluble in water . The formula contained an approximate 50/50 mixture of the herbicides 2,4-dichlorophenoxyacetic acid (2,4,-D) and 2,4,5

Three-parameter modeling of the soil sorption of acetanilide and triazine herbicide derivatives.

Science.gov (United States)

Freitas, Mirlaine R; Matias, Stella V B G; Macedo, Renato L G; Freitas, Matheus P; Venturin, Nelson

2014-02-01

Herbicides have widely variable toxicity and many of them are persistent soil contaminants. Acetanilide and triazine family of herbicides have widespread use, but increasing interest for the development of new herbicides has been rising to increase their effectiveness and to diminish environmental hazard. The environmental risk of new herbicides can be accessed by estimating their soil sorption (logKoc), which is usually correlated to the octanol/water partition coefficient (logKow). However, earlier findings have shown that this correlation is not valid for some acetanilide and triazine herbicides. Thus, easily accessible quantitative structure-property relationship models are required to predict logKoc of analogues of the these compounds. Octanol/water partition coefficient, molecular weight and volume were calculated and then regressed against logKoc for two series of acetanilide and triazine herbicides using multiple linear regression, resulting in predictive and validated models.

Determination of Low Concentrations of Acetochlor in Water by Automated Solid-Phase Extraction and Gas Chromatography with Mass-Selective Detection

Science.gov (United States)

Lindley, C.E.; Stewart, J.T.; Sandstrom, M.W.

1996-01-01

A sensitive and reliable gas chromatographic/mass spectrometric (GC/MS) method for determining acetochlor in environmental water samples was developed. The method involves automated extraction of the herbicide from a filtered 1 L water sample through a C18 solid-phase extraction column, elution from the column with hexane-isopropyl alcohol (3 + 1), and concentration of the extract with nitrogen gas. The herbicide is quantitated by capillary/column GC/MS with selected-ion monitoring of 3 characteristic ions. The single-operator method detection limit for reagent water samples is 0.0015 ??g/L. Mean recoveries ranged from about 92 to 115% for 3 water matrixes fortified at 0.05 and 0.5 ??g/L. Average single-operator precision, over the course of 1 week, was better than 5%.

Degradation and Movement in Soil of the Herbicide Isoproturon Analyzed by a Photosystem II-Based Biosensor

Czech Academy of Sciences Publication Activity Database

Malý, Jan; Klem, K.; Lukavská, Alena; Masojídek, Jiří

2005-01-01

Roč. 34, - (2005), s. 1780-1788 ISSN 0047-2425 R&D Projects: GA ČR GA522/03/0659; GA MPO FT-TA/089 Institutional research plan: CEZ:AV0Z50200510 Keywords : Photosystem II * Herbicide-detection Subject RIV: EE - Microbiology, Virology Impact factor: 2.121, year: 2005

Intraregional and inter-regional variability of herbicide sensitivity in common arable weed populations

DEFF Research Database (Denmark)

de Mol, Friederike; Gerowitt, Bärbel; Kaczmarek, Sylwia

2015-01-01

The question on intraregional versus inter-regional variability in herbicide sensitivity for weed populations is of major importance, both in extrapolation of model parameters and in herbicide zonal approval procedures. We hypothesised that inter-regional variability in herbicide sensitivity for ...

Low velocity impact of 6082-T6 aluminum plates

Science.gov (United States)

Mocian, Oana Alexandra; Constantinescu, Dan Mihai; Sandu, Marin; Sorohan, Ştefan

2018-02-01

The low velocity domain covers vehicle impacts, ship collisions and even accidentally tool drops. Even though more and more research is needed into these fields, most of the papers concerning impact problems focus on impact at medium and high velocities. Understanding the behavior of structures subjected to low velocity impact is of major importance when referring to impact resistance and damage tolerance. The paper presents an experimental and numerical investigation on the low velocity behavior of 6082-T6 aluminum plates. Impact tests were performed using an Instron Ceast 9340 drop-weight testing machine. In the experimental procedure, square plates were mounted on a circular support, fixed with a pneumatic clamping system and impacted with a hemispherical steel projectile. Specimens were impacted at constant weight and different impact velocities. The effect of different impact energies was investigated. The impact event was then simulated using the nonlinear finite element code LS_DYNA in order to determine the effect of strain rate upon the mechanical behavior of the aluminum plates. Moreover, in order to capture the exact behavior of the material, a special attention has been given to the selection of the correct material model and its parameters, which, in large extent, depend on the observed behavior of the aluminum plate during the test and the actual response of the plate under simulation. The numerical predictions are compared with the experimental observations and the applicability of the numerical model for further researches is analyzed.

Degradation and enantiomeric fractionation of mecoprop in soil previously exposed to phenoxy acid herbicides - New insights for bioremediation

Czech Academy of Sciences Publication Activity Database

Frková, Zuzana; Johansen, A.; de Jonge, L.W.; Olsen, P.; Gosewinkel, U.; Bester, K.

2016-01-01

Roč. 569, November (2016), s. 1457-1465 ISSN 0048-9697 Institutional support: RVO:60077344 Keywords : phenoxy acids * nitrate-reducing conditions * herbicide biodegradation * enantioselectivity * biostimulation Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 4.900, year: 2016

Mucilage from seeds of chia (Salvia hispanica L.) used as soil conditioner; effects on the sorption-desorption of four herbicides in three different soils.

Science.gov (United States)

Di Marsico, A; Scrano, L; Amato, M; Gàmiz, B; Real, M; Cox, L

2018-06-01

The objective of this work was to determine the effect of the mucilage extracted from Chia seeds (Salvia hispanica L.) as soil amendment on soil physical properties and on the sorption-desorption behaviour of four herbicides (MCPA, Diuron, Clomazone and Terbuthylazine) used in cereal crops. Three soils of different texture (sandy-loam, loam and clay-loam) were selected, and mercury intrusion porosimetry and surface area analysis were used to examine changes in the microstructural characteristics caused by the reactions that occur between the mucilage and soil particles. Laboratory studies were conducted to characterise the selected herbicides with regard their sorption on tested soils added or not with the mucilage. Mucilage amendment resulted in a reduction in soil porosity, basically due to a reduction in larger pores (radius>10μm) and an important increase in finer pores (radius<10μm) and in partcles' surface. A higher herbicide sorption in the amended soils was ascertained when compared to unamended soils. The sorption percentage of herbicides in soils treated with mucilage increased in the order; sandy-loamherbicides was highly inhibited in the soils treated with mucilage; only Terbuthylazine showed a slight desorption in the case of loam and clay loam-soils. This study leads to the conclusion that mucilage from Chia seeds used as soil conditioner can reduce the mobility of herbicides tested in agricultural soils with different physico-chemical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of a method based on the measurement of radiation reflectance when estimating the sensitivity of selected grain maize hybrids to the herbicide CALLISTO 480 SC + ATPLUS 463

Directory of Open Access Journals (Sweden)

Michal Vondra

2009-01-01

Full Text Available The application of methods based on measurements of photosynthesis efficiency is now more and more popular and used not only for the evaluation of the efficiency of herbicides but also for the estimation of their phytotoxicity to the cultivated crop. These methods enable to determine also dif­fe­ren­ces in the sensitivity of cultivars and/or hybrids to individual herbicides. The advantage of these methods consists above all in the speed and accuracy of measuring.In a field experiment, the sensitivity of several selected grain maize hybrids (EDENSTAR, NK AROBASE, NK LUGAN, LG 33.30 and NK THERMO to the herbicide CALLISTO 480 SC + ATPLUS 463 was tested for a period of three years. The sensitivity to a registered dose of 0.25 l . ha−1 + 0.5 % was measured by means of the apparatus PS1 meter, which could measure the reflected radiation. Measurements of sensitivity of hybrids were performed on the 2nd, 3rd, 4th, 5th and 8th day after the application of the tested herbicide, i.e. in the growing stage of the 3rd–5th leaf. Plant material was harvested using a small-plot combine harvester SAMPO 2010. Samples were weighed and converted to the yield with 15 % of moisture in grain DM.The obtained three-year results did not demonstrate differences in sensitivity of tested hybrids to the registered dose of the herbicide CALLISTO 480 SC + ATPLUS 463 (i.e. 0.25 l . ha−1 + 0,5 %. Recorded results indicated that for the majority of tested hybrids the most critical were the 4th and the 5th day after the application; on these days the average PS1 values were the highest at all. In years 2005 and 2007, none of the tested hybrids exceeded the limit value 15 (which indicated a certain decrease in the efficiency of photosynthesis. Although in 2006 three of tested hybrids showed a certain decrease in photosynthetic activity (i.e. EDENSTAR and NK AROBASE on the 3rd day and NK LUGAN on the 2nd–4th day after the application, no visual symptoms

Regularity of mitosis in different varieties of winter bread wheat under the action of herbicides

Directory of Open Access Journals (Sweden)

Tatyana Eugenivna KOPYTCHUK

2012-05-01

Full Text Available The influence of the most widespread herbicides on winter wheat in Ukraine was studied by anaphase test. Treatment with herbicides reduced the germination of the seeds and disturbed the regularity of mitosis in all varieties of wheat. The range of violations of mitosis was demonstrated by the formation of chromosomal aberrations and dysfunctions of cell cytoskeleton which occurred while processing herbicides. Varietal differences between investigated wheat by sensitivity to herbicides were discovered. The most resistant to herbicides was variety Fantasya Odesskaya, and the most sensitive – Nikoniya, while the most harmful herbicide for wheat was Napalm.

Determination of Two Sulfonylurea Herbicides Residues in Soil Environment Using HPLC and Phytotoxicity of These Herbicides by Lentil Bioassay.

Science.gov (United States)

Mehdizadeh, Mohammad; Alebrahim, Mohammad Taghi; Roushani, Mahmoud

2017-07-01

A HPLC-UV detection system was used for determination of sulfosulfuron and tribenuron methyl residues from soils. The soils were fortified with sulfosulfuron and tribenuron methyl at rates of 26 and 15 g a.i. ha -1 respectively and samples were taken randomly on 0 (2 h), 1, 2, 4, 10, 20, 40, 60, 90 and 120 days after treatment. The final extracts were prepared for analysis by HPLC. The results showed that degradation of both herbicides in the silty loam soil was faster than sandy loam soil. Half-life of sulfosulfuron was ranged from 5.37 to 10.82 days however this value for tribenuron methyl was ranged from 3.23 to 5.72 days on different soils. The residue of both herbicides at 120 days after application in wheat field had no toxicitic effect on lentil. It was concluded that HPLC analysis procedure was an appropriate method for determination of these herbicides from soils.

Use of image analysis to assess color response on plants caused by herbicide application

DEFF Research Database (Denmark)

Asif, Ali; Streibig, Jens Carl; Duus, Joachim

2013-01-01

by herbicides. The range of color components of green and nongreen parts of the plants and soil in Hue, Saturation, and Brightness (HSB) color space were used for segmentation. The canopy color changes of barley, winter wheat, red fescue, and brome fescue caused by doses of a glyphosate and diflufenican mixture...... for the green and nongreen parts of the plants and soil were different. The relative potencies were not significantly different from one, indicating that visual and image analysis estimations were about the same. The comparison results suggest that image analysis can be used to assess color changes of plants......In herbicide-selectivity experiments, response can be measured by visual inspection, stand counts, plant mortality, and biomass. Some response types are relative to nontreated control. We developed a nondestructive method by analyzing digital color images to quantify color changes in leaves caused...

Combined effects of temperature and the herbicide diuron on Photosystem II activity of the tropical seagrass Halophila ovalis

Science.gov (United States)

Wilkinson, Adam D.; Collier, Catherine J.; Flores, Florita; Langlois, Lucas; Ralph, Peter J.; Negri, Andrew P.

2017-03-01

Tropical seagrasses are at their highest risk of exposure to photosystem II (PSII) herbicides when elevated rainfall and runoff from farms transports these toxicants into coastal habitats during summer, coinciding with periods of elevated temperature. PSII herbicides, such as diuron, can increase the sensitivity of corals to thermal stress, but little is known of the potential for herbicides to impact the thermal optima of tropical seagrass. Here we employed a well-plate approach to experimentally assess the effects of diuron on the photosynthetic performance of Halophila ovalis leaves across a 25 °C temperature range (36 combinations of these stressors across 15-40 °C). The thermal optimum for photosynthetic efficiency (▵) in H. ovalis was 31 °C while lower and higher temperatures reduced ▵ as did all elevated concentrations of diuron. There were significant interactions between the effects of temperature and diuron, with a majority of the combined stresses causing sub-additive (antagonistic) effects. However, both stressors caused negative responses and the sum of the responses was greater than that caused by temperature or diuron alone. These results indicate that improving water quality (reducing herbicide in runoff) is likely to maximise seagrass health during extreme temperature events that will become more common as the climate changes.

Phytotoxicity of four herbicides on Ceratophyllum demersum, Vallisneria natans and Elodea nuttallii.

Science.gov (United States)

Pan, Huiyun; Li, Xiaolu; Xu, Xiaohua; Gao, Shixiang

2009-01-01

The physiological effects of 4 herbicides (butachlor, quinclorac, bensulfuron-methyl and atrazine) on 3 submerged macrophytes (Ceratophyllum demersum, Vallisneria natans and Elodea nuttallii) were tested in laboratory. The variables of the relative growth rate and the photosynthetic pigment content showed that all of the tested herbicides affected the growth of the plants obviously, even at the lowest concentration (0.0001 mg/L). Except for the C. demersum treated with quinclorac at 0.005 and 0.01 mg/L, the relative growth rates of the plants were inhibited significantly (p < 0.01). Statistical analysis of chlorophyll a (Chl-a) contents was carried out with both the t-test and one-way ANOVA to determine the difference between the treatment and control. The results showed that Chl-a contents of the plants in all treatment groups were affected by herbicides significantly, except for the C. demersum treated with bensulfuron-methyl at 0.0005 mg/L. The decrease in Chl-a content was positively correlated to the dosage of the herbicides in most treatment groups. It was suggested that herbicides in water bodies might potentially affect the growth of aquatic macrophytes. Since the Chl-a content of submerged macrophytes responded to the stress of herbicides sensitively and directly, it could be used as a biomaker in environmental monitoring or in the ecological risk assessment of herbicide contamination.

Phytotoxicity induced in isolated zooxanthellae by herbicides extracted from Great Barrier Reef flood waters.

Science.gov (United States)

Shaw, C M; Brodie, J; Mueller, J F

2012-01-01

To date there has been limited evidence anthropogenically sourced pollution from catchments reaching corals of the Great Barrier Reef (GBR). In this study, freshly isolated zooxanthellae were exposed to polar chemicals (chiefly herbicides) extracted from water samples collected in a flood plume in the GBR lagoon. Photosynthetic potential of the isolated zooxanthellae declined after exposure to concentrated extracts (10 times) from all but one of the sampling sites. Photosynthetic potential demonstrated a significant positive relationship with the concentration of diuron in the concentrated extracts and a significant inverse relationship with salinity measured at the sampling site. This study demonstrates that runoff from land based application of herbicides may reduce photosynthetic efficiency in corals of inshore reefs in the GBR. The ecological impacts of the chemicals in combination with other potential stressors on corals remain unclear. Copyright © 2012 Elsevier Ltd. All rights reserved.

Controlling herbicide-susceptible, -tolerant and -resistant weeds with microbial bioherbicides

Science.gov (United States)

The management of weeds is a necessary but expensive challenge. Public concerns of health, safety, and sustainability have increased interest in reducing the use of synthetic chemicals for weed control. Alternatives to chemical herbicides, such as bioherbicides, may offer an alternative to herbicide...

Biotechnology: herbicide-resistant crops

Science.gov (United States)

Transgenic, herbicide-resistant (HR) crops are planted on about 80% of the land covered by transgenic crops. More than 90% of HR crios are glyphosate-resistant (GR) crops, the others being resistant to glufosinate. The wide-scale adoption of HR crops, largely for economic reasons, has been the mos...

An innovative bovine odorant binding protein-based filtering cartridge for the removal of triazine herbicides from water.

Science.gov (United States)

Bianchi, Federica; Basini, Giuseppina; Grolli, Stefano; Conti, Virna; Bianchi, Francesco; Grasselli, Francesca; Careri, Maria; Ramoni, Roberto

2013-01-01

Odorant binding protein (OBP) is a multi-functional scavenger for small hydrophobic molecules dissolved in the mucus lining the nasal epithelia of mammals, characterized by broad ligand binding specificity towards a large number of structurally unrelated natural and synthetic molecules of different chemical classes. Here, we demonstrate for the first time the application of OBP as the active element of an innovative filtering matrix for the removal of environmental pollutants such as triazine herbicides from water samples. The filtering device, obtained by coupling histidine-tagged bovine OBP to a nickel nitrilotriacetic acid (Ni-NTA) agarose resin, was characterized in terms of retention capacity for the herbicides atrazine, simazine, and propazine. Analysis of these herbicides at trace levels with solid-phase microextraction followed by gas chromatography-mass spectrometry using the selected ion monitoring mode proved the capabilities of the proposed device for the decontamination of surface and groundwater samples in the 0.2-2,300 μg/L concentration range, obtaining a reduction in the triazine content greater than 97 %, thus suggesting its possible use for the potabilization of water.

The effects of s-triazines on selected marine macroalgae

International Nuclear Information System (INIS)

Lewey, S.A.; Nummela, E.C.

1999-01-01

Although s-triazines have been used as herbicides for many years, their use and that of other herbicides and fungicides, in antifouling compounds is only fairly recent. The Hamble estuary, Hampshire UK has been identified as one such site. Investigations were conducted into the effects of s-triazines on selected marine macroalgae, local to that area

Effects of herbicides on Behr's metalmark butterfly, a surrogate species for the endangered butterfly, Lange's metalmark

International Nuclear Information System (INIS)

Stark, John D.; Chen Xuedong; Johnson, Catherine S.

2012-01-01

Lange's metalmark butterfly, Apodemia mormo langei Comstock, is in danger of extinction due to loss of habitat caused by invasive exotic plants which are eliminating its food, naked stem buckwheat. Herbicides are being used to remove invasive weeds from the dunes; however, little is known about the potential effects of herbicides on butterflies. To address this concern we evaluated potential toxic effects of three herbicides on Behr's metalmark, a close relative of Lange's metalmark. First instars were exposed to recommended field rates of triclopyr, sethoxydim, and imazapyr. Life history parameters were recorded after exposure. These herbicides reduced the number of adults that emerged from pupation (24–36%). Each herbicide has a different mode of action. Therefore, we speculate that effects are due to inert ingredients or indirect effects on food plant quality. If these herbicides act the same in A. mormo langei, they may contribute to the decline of this species. - Highlights: ► We evaluated the effects of three herbicides on the butterfly, Behr's metalmark. ► These herbicides are used to control invasive weeds in butterfly habitat. ► The herbicides reduced adult butterfly emergence. - Herbicides are used to remove invasive weeds from butterfly habitat. Certain herbicides may be having a negative effect on butterflies.

Determination of solid-liquid partition coefficients (Kd) for the herbicides inspiration and trifluralin in five UK agricultural soils

International Nuclear Information System (INIS)

Cooke, Cindy M.; Shaw, George; Collins, Chris D.

2004-01-01

Isoproturon and trifluralin are herbicides of contrasting chemical characters and modes of action. Standard batch sorption procedures were carried out to investigate the individual sorption behaviour of 14 C-isoproturon and 14 C-trifluralin in five agricultural soils (1.8-4.2% OC), and the soil solid-liquid partition coefficients (K d values) were determined. Trifluralin exhibited strong partitioning to the soil solid phase (K d range 106-294) and low desorption potential, thus should not pose a threat to sensitive waters via leaching, although particle erosion and preferential flow pathways may facilitate transport. For isoproturon, soil adsorption was low (K d range 1.96-5.75) and desorption was high, suggesting a high leaching potential, consistent with isoproturon being the most frequently found pesticide in UK surface waters. Soil partitioning was directly related to soil organic carbon (OC) content. Accumulation isotherms were modelled using a dual-phase adsorption model to estimate adsorption and desorption rate coefficients. Associations between herbicides and soil humic substances were also shown using gel filtration chromatography. - Capsule: Herbicide soil sorption described by a dual-phase adsorption model reflected soil partitioning, as influenced by soil OC and humic substances

Seletividade de herbicidas pós-emergentes aplicados na soja geneticamente modificada Selectivity of post-emergence herbicides applied on genetically modified soybeans

Directory of Open Access Journals (Sweden)

M.E.F. Neto

2009-06-01

pelo fato de o herbicida ser registrado para controle em pré-emergência e ter sido aplicado em pós-emergência. Nenhum dos tratamentos influenciou significativamente a produção de grãos da cultura da soja. A aplicação única ou a complementação com aplicação sequencial de glyphosate promoveram excelente controle de Commelina benghalensis e Ipomoea triloba.The experiment was carried out in a Roundup Ready® commercial soybean field in the Pontal do Paranapanema region in Euclides da Cunha Paulista-SP, located 20º 43' 11'' S and 50º 10' 20'' W, 270 m altitude. The experimental phase was carried out from December 2006 to April 2007, under no-tillage system. The soil classification is sandy clay loam Argisol. This work aimed to evaluate the efficiency of Roundup Transorb® glyphosate formulation selectivity associated with the herbicides diclosulam, cloransulam-methyl, flumioxazina and S-metolachlor under two spray modalities (single, with glyphosate associated to the herbicides and sequential, with only glyphosate in tropical Spiderwort (Commelina benghalensis and little bell (Ipomoea triloba management during soybean cultivation. The experiment was arranged in a randomized block design, with 12 treatments and 4 replications. Treatments were distributed in a factorial scheme + 2 controls (no control and clean field. The factorial scheme 2 x 5 comprises two herbicide sprays (single and sequential and five herbicides (glyphosate, glyphosate + diclosulam, glyphosate + cloransulam-methyl, glyphosate + flumioxazin and glyphosate + S-metolachlor. Under the conditions and time the herbicides were used as well as spray dosage, the results showed that glyphosate sprayed in a single dose or sequentially, in combination with diclosulan and cloransulam-methyl in the first spray did not cause phyto-intoxication in the soybean plants. The flumioxazin and S-metolachlor combination promoted delay in the growing plants as well as in the complete formation of the culture due

Herbicide spring treatments for the control of brome grasses (Bromus spp. in winter cereals

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Gehring, Klaus

2014-02-01

Full Text Available The efficacy of different ALS-inhibiting herbicides for the control of brome species (Bromus spp. was tested in three field trials in the year 2010 – 2012 in the region of North-West-Bavaria Franken. As a result of the trials the standard herbicide Attribut (Propoxycarbazone was confirmed for the control of brome. In case of infestation with brome and black grass the herbicide Broadway (Pyroxsulam offers a certain control of both problematic grass weeds. This illustrates the high dependency of sufficient brome control in winter cereals on the effectiveness of specific ALS-Inhibitor herbicides. Because of the high risk of herbicide resistance to ACCaseand ALS-inhibiting herbicides in brome, integrated weed management is essential for the sustainable control of brome in winter cereals, respectively winter wheat.

Effect of Butachlor Herbicide on Earthworm Eisenia fetidaIts Histological Perspicuity

International Nuclear Information System (INIS)

Gobi, M.; Gunasekaran, P.

2010-01-01

With the advent of the Green Revolution, there has been a quantum leap in the use of synthetic herbicides and pesticides throughout the world to sustain high yielding crop varieties. Continuous use of these synthetic chemicals leads to loss of soil fertility and soil organisms. To explore the effect of exposure to commercial herbicide (Butachlor) on the life history parameters (biomass, clitellum development, and cocoon production) and the histological changes in the earthworm Eisenia fetida over 60 days, the dried cow dung was contaminated with 0.2575 mg/ kg -1 , 0.5150 mg/ kg -1 , and 2.5750 mg/ kg -1 of butachlor based on the LC 50 value, and a control was maintained. The mean earthworm biomass was found to be decreased with increasing herbicide concentration. Similarly, cocoon production was also reduced by the increasing herbicide concentration. A possible explanation is an increased demand for energy, needed for the regulation and detoxification of herbicide. All earthworms in the exposed group were found to have glandular cell enlargement and to be vacuolated

Effect of Butachlor Herbicide on Earthworm Eisenia fetida—Its Histological Perspicuity

Directory of Open Access Journals (Sweden)

Muthukaruppan Gobi

2010-01-01

Full Text Available With the advent of the Green Revolution, there has been a quantum leap in the use of synthetic herbicides and pesticides throughout the world to sustain high yielding crop varieties. Continuous use of these synthetic chemicals leads to loss of soil fertility and soil organisms. To explore the effect of exposure to commercial herbicide (Butachlor on the life history parameters (biomass, clitellum development, and cocoon production and the histological changes in the earthworm Eisenia fetida over 60 days, the dried cow dung was contaminated with 0.2575 mg kg−1, 0.5150 mg kg−1, and 2.5750 mg kg−1 of butachlor based on the LC50 value, and a control was maintained. The mean earthworm biomass was found to be decreased with increasing herbicide concentration. Similarly, cocoon production was also reduced by the increasing herbicide concentration. A possible explanation is an increased demand for energy, needed for the regulation and detoxification of herbicide. All earthworms in the exposed group were found to have glandular cell enlargement and to be vacuolated.

Herbicide effects on the growth and photosynthetic efficiency of Cassiopea maremetens.

Science.gov (United States)

Rowen, David J; Templeman, Michelle A; Kingsford, Michael J

2017-09-01

Herbicides from agricultural run-off have been measured in coastal systems of the Great Barrier Reef over many years. Non-target herbicide exposure, especially photosystem II herbicides has the potential to affect seagrasses and other marine species. The symbiotic benthic jellyfish Cassiopea maremetens is present in tropical/sub-tropical estuarine and marine environments. Jellyfish (n = 8 per treatment) were exposed to four separate concentrations of agricultural formulations of diuron or hexazinone to determine their sensitivity and potential for recovery to pulsed herbicide exposure. Jellyfish growth, symbiont photosynthetic activity and zooxanthellae density were analysed for herbicide-induced changes for 7 days followed by a 7 day recovery period. Both the jellyfish and endosymbiont were more sensitive to diuron than hexazinone. The 7-day EC 50 for jellyfish growth was 0.35 μg L -1 for Diuron and 17.5 μg L -1 for Hexazinone respectively. Diuron exposure caused a significant decrease (p diuron and hexazinone caused significant decreases in photosynthetic efficiency (effective quantum yield) in all treatment concentrations (0.1 μg L -1 and above) and this effect continued in the post-exposure period. As this species is frequently found in near-shore environments, they may be particularly vulnerable to herbicide run-off. Copyright © 2017 Elsevier Ltd. All rights reserved.

Seletividade de herbicidas registrados para a cultura do milho a adultos de Trichogramma pretiosum (Hymenoptera: Trichogrammatidae Selectivity of herbicides registered on corn to Trichogramma pretiosum (Hymenoptera: Trichogrammatidae

Directory of Open Access Journals (Sweden)

G.J. Stefanello Júnior

2008-06-01

Full Text Available A seletividade de 24 herbicidas registrados para a cultura do milho foi avaliada a Trichogramma pretiosum em condições de laboratório (temperatura de 25±1 ºC, umidade relativa de 70±10%, fotofase de 14 horas e luminosidade de 500 lux. Adultos de T. pretiosum foram colocados em contato com uma película seca dos herbicidas pulverizados sobre placas de vidro e avaliou-se a capacidade de parasitismo das fêmeas. A redução na capacidade de parasitismo dos tratamentos foi comparada com a da testemunha (água destilada e utilizada para classificar os herbicidas em 1, inócuo (99%. Os herbicidas Callisto, Equip Plus, Extrazin SC, Primóleo, Provence 750 WG e Siptran 500 SC são inócuos (classe 1; Agrisato 480 SL, Gesaprim GrDA, Glifos, Glyphosate Nortox, Gliz 480 SL, Polaris, Primatop SC, Sanson 40 SC, Trop e Zapp Qi, levemente nocivos (classe 2; Finale, Herbadox, Poast, Roundup Original, Roundup Transorb e Roundup WG, moderadamente nocivos (classe 3; e Gramoxone 200 e Primestra Gold, nocivos (classe 4 aos adultos de T. pretiosum, nas dosagens utilizadas. Os herbicidas nocivos (classes 2, 3 e 4 deverão passar para as etapas seguintes, que envolverão testes sobre as fases imaturas do parasitóide em condições de laboratório e adultos a campo.The selectivity of 24 herbicides registered on corn to Trichogramma pretiosum (Hymenoptera: Trichogrammatidae was assessed under laboratory conditions (25 ± 1 ºC temperature, 70 ± 10% relative humidity, 14 4 photophase and brightness 500 lux. The adult parasitoids were submitted to a dry film of the herbicides applied on glass plates and the parasitism capacity of the females was evaluated. Reduced parasitism capacity in the treatments was compared with the negative control (distilled water and used to classify the herbicides into four categories: 1, harmless ( 99%. The herbicides Callisto, Equip Plus, Extrazin SC, Primóleo, Provence 750 WG and Siptran 500 SC were found to be harmless (class 1

Low-level waste disposal site selection demonstration

International Nuclear Information System (INIS)

Rogers, V.C.

1984-01-01

This paper discusses the results of recent studies undertaken at EPRI related to low-level waste disposal technology. The initial work provided an overview of the state of the art including an assessment of its influence upon transportation costs and waste form requirements. The paper discusses work done on the overall system design aspects and computer modeling of disposal site performance characteristics. The results of this analysis are presented and provide a relative ranking of the importance of disposal parameters. This allows trade-off evaluations to be made of factors important in the design of a shallow land burial facility. To help minimize the impact of a shortage of low-level radioactive waste disposal sites, EPRI is closely observing the development of bellweather projects for developing new sites. The purpose of this activity is to provide information about lessons learned in those projects in order to expedite the development of additional disposal facilities. This paper describes most of the major stems in selecting a low-level radioactive waste disposal site in Texas. It shows how the Texas Low-Level Radioactive Waste Disposal Authority started with a wide range of potential siting areas in Texas and narrowed its attention down to a few preferred sites. The parameters used to discriminate between large areas of Texas and, eventually, 50 candidate disposal sites are described, along with the steps in the process. The Texas process is compared to those described in DOE and EPRI handbooks on site selection and to pertinent NRC requirements. The paper also describes how an inventory of low-level waste specific to Texas was developed and applied in preliminary performance assessments of two candidate sites. Finally, generic closure requirements and closure operations for low-level waste facilities in arid regions are given

Herbicide resistance-endowing ACCase gene mutations in hexaploid wild oat (Avena fatua): insights into resistance evolution in a hexaploid species

Science.gov (United States)

Yu, Q; Ahmad-Hamdani, M S; Han, H; Christoffers, M J; Powles, S B

2013-01-01

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids. PMID:23047200

Performance of Different Herbicides in Dry-Seeded Rice in Bangladesh

Science.gov (United States)

Ahmed, Sharif; Chauhan, Bhagirath Singh

2014-01-01

A field study was conducted in the boro season of 2011-12 and aman season of 2012 at Jessore, Bangladesh, to evaluate the performance of sequential applications of preemergence herbicides (oxadiargyl 80 g ai ha−1, pendimethalin 850 g ai ha−1, acetachlor + bensulfuranmethyl 240 g ai ha−1, and pyrazosulfuron 15 g ai ha−1) followed by a postemergence herbicide (ethoxysulfuron 18 g ai ha−1) in dry-seeded rice. All evaluated herbicides reduced weed density and biomass by a significant amount. Among herbicides, pendimethalin, oxadiargyl, and acetachlor + bensulfuranmethyl performed very well against grasses; pyrazosulfuron, on the other hand, was not effective. The best herbicide for broadleaf weed control was oxadiargyl (65–85% control); pendimethalin and acetachlor + bensulfuraonmethyl were not effective for this purpose. The best combination for weed control was oxadiargyl followed by ethoxysulfuron in the boro season and oxadiargyl followed by a one-time hand weeding in the aman season. Compared with the partial weedy plots (hand weeded once), oxadiargyl followed by ethoxysulfuron (4.13 t ha−1) provided a 62% higher yield in the boro season while oxadiargyl followed by a one-time hand weeding (4.08 t ha−1) provided a 37% higher yield in the aman season. PMID:24688423

Cloud based, Open Source Software Application for Mitigating Herbicide Drift

Science.gov (United States)

Saraswat, D.; Scott, B.

2014-12-01

The spread of herbicide resistant weeds has resulted in the need for clearly marked fields. In response to this need, the University of Arkansas Cooperative Extension Service launched a program named Flag the Technology in 2011. This program uses color-coded flags as a visual alert of the herbicide trait technology within a farm field. The flag based program also serves to help avoid herbicide misapplication and prevent herbicide drift damage between fields with differing crop technologies. This program has been endorsed by Southern Weed Science Society of America and is attracting interest from across the USA, Canada, and Australia. However, flags have risk of misplacement or disappearance due to mischief or severe windstorms/thunderstorms, respectively. This presentation will discuss the design and development of a cloud-based, free application utilizing open-source technologies, called Flag the Technology Cloud (FTTCloud), for allowing agricultural stakeholders to color code their farm fields for indicating herbicide resistant technologies. The developed software utilizes modern web development practices, widely used design technologies, and basic geographic information system (GIS) based interactive interfaces for representing, color-coding, searching, and visualizing fields. This program has also been made compatible for a wider usability on different size devices- smartphones, tablets, desktops and laptops.

Low-impact chemical weed control techniques in UNESCO World Heritage Sites of Cuba.

Science.gov (United States)

Hernandez-Enriquez, O; Alvarez, R; Morelli, F; Bastida, F; Camacho, D; Menendez, J

2012-01-01

Dichrostachys cinerea is a thorny, acacia-like, fast-growing woody bush which invades fields, wasteland, road sides and other disturbed areas. This gregarious species has become a very aggressive invasive weed in Cuba, where no native predators or pathogens are found. It often encroaches in fallows, overgrazed areas and mismanaged veld. D. cinerea is a very difficult weed to eliminate because of its active suckering, and is liable to produce dense thickets which are quite impenetrable on account of the density and abundance of its long, stiff, sharp thorns. In the Valle de los Ingenios area (Cuba Central), the tree is unchecked and forms veritable forests in areas on which cane growing has been discontinued. Physical management by cutting and burning the plants is not a very efficient control method, since the seeds survive in the soil, and they grow very fast. Therefore, chemical methods via the use of herbicides are often necessary to eradicate this weed. A preliminary study using glyphosate and auxin-like herbicides (2,4-D + picloram, MCPA, and MCPA + 2,4-D) plus adjuvants has been carried out in order to elucidate the best mixtures rendering maximum weed control with minimum herbicide rate and environmental stress. None of the herbicides used except glyphosate and 2,4-D + picloram showed acceptable mortality rates (75-80%) at the recommended doses tested. In the failed herbicide treatments, only the use of double herbicide rates succeeded in controlling marabou. The herbicide mixture of 2,4-D + picloram formulated with either a non-ionic surfactant or a mixture of fatty acid esters was the best option to control D. cinerea in terms of maximum effectiveness and minimum environmental stress, as the reduction in active ingredients applied to the environment was x3 in these two adjuvant-amended formulations compared to 2,4-D + picloram alone.

Effect of four herbicides on microbial population, soil organic matter ...

African Journals Online (AJOL)

The effect of four herbicides (atrazine, primeextra, paraquat and glyphosate) on soil microbial population, soil organic matter and dehydrogenase activity was assessed over a period of six weeks. Soil samples from cassava farms were treated with herbicides at company recommended rates. Soil dehydrogenase activity was ...

Crops with target-site herbicide resistance for Orobanche and Striga control.

Science.gov (United States)

Gressel, Jonathan

2009-05-01

It is necessary to control root parasitic weeds before or as they attach to the crop. This can only be easily achieved chemically with herbicides that are systemic, or with herbicides that are active in soil. Long-term control can only be attained if the crops do not metabolise the herbicide, i.e. have target-site resistance. Such target-site resistances have allowed foliar applications of herbicides inhibiting enol-pyruvylshikimate phosphate synthase (EPSPS) (glyphosate), acetolactate synthase (ALS) (e.g. chlorsulfuron, imazapyr) and dihydropteroate synthase (asulam) for Orobanche control in experimental conditions with various crops. Large-scale use of imazapyr as a seed dressing of imidazolinone-resistant maize has been commercialised for Striga control. Crops with two target-site resistances will be more resilient to the evolution of resistance in the parasite, if well managed.

Seletividade de herbicidas aplicados em pós-emergência sobre capim-braquiária Selectivity of post-emergence herbicides applied on signalgrass and palisadegrass

Directory of Open Access Journals (Sweden)

Dagoberto Martins

2007-12-01

Full Text Available O estudo foi conduzido com o objetivo de avaliar a seletividade de alguns herbicidas inibidores de ALS e FS II aplicados em pós-emergência em plantas de Brachiaria brizantha cv. Marandu e Brachiaria decumbens cv. Basilisk em condições de campo e seu efeito na qualidade das sementes. Os herbicidas testados (em g/ha foram: imazethapyr a 100; chlorimuronethyl a 15; nicosulfuron a 50; bentazon a 720; e atrazine a 3.000, além de uma testemunha, sem aplicação de herbicidas. Dois experimentos em campo foram instalados em delineamento em blocos casualizados com quatro repetições e os ensaios de laboratório em delineamento inteiramente casualizado, com 16 repetições. Todos os herbicidas testados tiveram algum efeito de fitointoxicação visual aos cultivares avaliados. O nicosulfuron foi o herbicida que visualmente proporcionou os níveis mais elevados de injúrias às plantas de B. decumbens e B. brizantha. A produção de MS de B. brizantha nos estádios iniciais de crescimento foi reduzida pelos herbicidas nicosulfuron e atrazine, enquanto, em B. decumbens, apenas o herbicida nicosulfuron ocasionou redução da produção de MS. A qualidade das sementes de ambos os cultivares foi afetada pelo nicosulfuron, que induziu a dormência em sementes de B. decumbens, reduziu a porcentagem de sementes normais e, assim como o atrazine, aumentou a porcentagem de sementes mortas.This work evaluated the herbicides selectivity acetolactate synthase inhibitors and photosynthetic II applied in post- emergency in palisadegrass (Brachiaria brizantha cv. Marandu and signalgrass (Brachiaria decumbens cv. Basilisk plants in field conditions and their effect in seed quality. Treatments tested in g ha-1 were: imazethapyr at 100, chlorimuron-ethyl at 15, nicosulfuron at 50, bentazon at 720, atrazine at 3.000, and control plot. Two field trials were set up on complete randomized block design with four replicates; laboratory studies were carried out in a complete

Herbicides effect on the nitrogen fertilizer assimilation by sensitive plants

International Nuclear Information System (INIS)

Ladonin, V.F.; Samojlov, L.N.

1976-01-01

It has been established in studying the effect of herbicides on pea plants that the penetration of the preparations into the tissues of leaves and stems results in a slight increase of the rate of formation of dry substance in the leaves of the treated plants within 24 hours after treatment as compared with control, whereas in the last period of the analysis the herbicides strongly inhibit the formation of dry substance in leaves. The applied herbicide doses have resulted in drastic changes of the distribution of the plant-assimilated nitrogen between the protein and non-protein fractions in the leaves and stems of pea. When affected by the studied herbicides, the fertilizer nitrogen supply to the pea plants changes and the rate of the fertilizer nitrogen assimilation by the plants varies noticeably. The regularities of the fertilizer nitrogen inclusion in the protein and non-protein nitrogen compounds of the above-ground pea organs have been studied

Plant Community Diversity After Herbicide Control of Spotted Knapweed

OpenAIRE

United States Department of Agriculture, Forest Service

1992-01-01

Herbicides were applied to four west-central Montana sites with light to moderate spotted knapweed (Centaurea maculosa Lam.) infestations. Althought knapweed suppression was high, 2 years after the spraying the communities were not converted to grass monocultures. No large declines in plant diversity were caused by the herbicides, and small depressions were probably transitory. By the third year, diversity had increased.

Runoff of the herbicides triclopyr and glufosinate ammonium from oil palm plantation soil.

Science.gov (United States)

Tayeb, M A; Ismail, B S; Khairiatul-Mardiana, J

2017-10-11

This study focused on the residue detection of the herbicides triclopyr and glufosinate ammonium in the runoff losses from the Tasik Chini oil palm plantation area and the Tasik Chini Lake under natural rainfall conditions in the Malaysian tropical environment. Triclopyr and glufosinate ammonium are post-emergence herbicides. Both herbicides were foliar-sprayed on 0.5 ha of oil palm plantation plots, which were individualized by an uneven slope of 10-15%. Samples were collected at 1, 3, 7, 15, 30, 45, 60, 90, and 120 days after treatment. The concentrations of both herbicides quickly diminished from those in the analyzed sample by the time of collection. The highest residue levels found in the field surface leachate were 0.031 (single dosage, triclopyr), 0.041 (single dosage, glufosinate ammonium), 0.017 (double dosage, triclopyr), and 0.037 μg/kg (double dosage, glufosinate ammonium). The chromatographic peaks were observed at "0" day treatment (2 h after herbicide application). From the applied active ingredients, the triclopyr and glufosinate losses were 0.025 and 0.055%, respectively. The experimental results showed that both herbicides are less potent than other herbicides in polluting water systems because of their short persistence and strong adsorption onto soil clay particles.

Effect of some soil herbicides on vegetative habits of almond trees of 'Nonpareil' cultivar grown in a second-year nursery field

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M. Tityanov

2016-09-01

Full Text Available Abstract. The study was carried out in the period 2010 – 2012 in a nursery field established on the territory of the Fruit-Growing Institute, Plovdiv. The effect of the combined soil-applied herbicide metolachlor + oxyfluorfen (Metofen and the contact soil herbicide with foliar activity flumioxazine (Pledge 50 WP on the vegetative habits of 'Nonpareil' almond cultivar grafted on almond seedling rootstock was evaluated. In the period 15-25 March, before beginning of vegetation, soil herbicides were applied in the row strip in the second-year nursery field. The following variants were included in the study: 1. Control (untreated, handweeded; 2. Metofen – 120 ml/da; 3. Metofen – 240 ml/da; 4. Pledge 50 WP – 8.0 g/da; 5. Pledge 50 WP – 20.0 g/da. The effect of the herbicides on weed infestation and on the vegetative habits of the cultivar/rootstock combination 'Nonpareil'/almond seedling rootstock was followed up. The results showed that the herbicides applied at the tested rates had a good control on weed infestation and the herbicide activity continued for 3.5-4 months. That makes it possible to eliminate the competitive impact of weeds on the development of the grafted trees for 4-5 months after beginning of vegetation. Visual symptoms of phytotoxicity (chlorosis or necrosis in the leaves and shoots or an obvious suppression of the development of the grafted trees in the treated variants were not established. A depressing effect on growth of the grafted trees was reported after treatment with Metofen. The contact herbicide with soil and foliar activity Pledge 50 WP – 8.0 g/da can be applied for weed control in a second-year nursery field of almond trees grafted on bitter almond seedling rootstock.

Intrauterine growth retardation in Iowa communities with herbicide-contaminated drinking water supplies

Science.gov (United States)

Munger, R.; Isacson, P.; Hu, S.; Burns, T.; Hanson, J.; Lynch, C.F.; Cherryholmes, K.; Van Dorpe, P.; Hausler, W.J.

1997-01-01

In a statewide survey of 856 Iowa municipal drinking water supplies in 1986-1987 the Rathbun rural water system was found to contain elevated levels of triazine herbicides. Rates of low birth weight, prematurity, and intrauterine growth retardation (IUGR) in live singleton births during the period 1984-1990 by women living in 13 communities served by the Rathbun water system were compared to other communities of similar size in the same Iowa counties. The Rathbun communities had a greater risk of IUGR than southern Iowa communities with other surface sources of drinking water (relative risk = 1.8; 95% CI = 1.3, 2.7). Multiple linear regression analyses revealed that levels of the herbicides atrazine, metolachlor, and cyanazine were each significant predictors of community IUGR rates in southern Iowa after controlling for several potentially confounding factors including maternal smoking and socioeconomic variables. The association with IUGR was strongest for atrazine, but all three herbicides were intercorrelated and the independent contributions of each to IUGR risk could not be determined. We conclude that communities in southern Iowa with drinking water supplies contaminated with herbicides have elevated rates of IUGR compared to neighboring communities with different water supplies. Because of the limitations of the ecologic design of this study, including aggregate rather than individual measures of exposure and limited ability to control for confounding factors related to source of drinking water and risk of IUGR, a strong causal relationship between any specific water contaminant and risk of IUGR cannot yet be inferred. The association between the water supplied to the Rathbun communities and the increased risk of IUGR should be considered a preliminary finding that needs to be verified by more detailed epidemiologic studies.

Sarmentine, a natural herbicide from Piper species with multiple herbicide mechanisms of action

Science.gov (United States)

Sarmentine, 1-(1-pyrrolidinyl)-(2E,4E)-2,4-decadien-1-one, is a natural amide isolated from the fruits of Piper species. The compound has a number of interesting biological properties, including its broad-spectrum activity on weeds as a contact herbicide. Initial studies highlighted a similarity in ...

Study of different herbicide molecules for the control of durum wheat weed

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Michele Perniola

2008-07-01

Full Text Available In order to enhance the chances to rotate the herbicide molecules, the effectiveness of a new molecule, pinoxaden, was tested, comparing it with other herbicides used in wheat weed control. The trial was carried out comparing the following herbicide mixtures: 1 no weed control treatment; 2 Tribenuron Methyl (TM; 3 Clodinafop (C; 4 Tribenuron Methyl + Clodinafop (TM+C; 5 Pinoxaden + clodinafop + propargile (PCP; 6 Pinoxaden + clodinafop + propargile + Triasulfuron (PCP+T; 7 Pinoxaden + clodinafop + propargile + absolute Ioxinil and Mecoprop (PCP+IM. The new PCP+T herbicides mixture didn’t differ statistically from the traditional TMC treatment in terms of effectiveness, but the agronomic result of the new mixture was totally satisfactory, even taking into account that the marketing of this mixture is not aimed to compete with other existing herbicides but to widen the chance to rotate active principles in time and space, in order to control the onset of resistance phenomena.

Study of different herbicide molecules for the control of durum wheat weed

Directory of Open Access Journals (Sweden)

Michele Perniola

Full Text Available In order to enhance the chances to rotate the herbicide molecules, the effectiveness of a new molecule, pinoxaden, was tested, comparing it with other herbicides used in wheat weed control. The trial was carried out comparing the following herbicide mixtures: 1 no weed control treatment; 2 Tribenuron Methyl (TM; 3 Clodinafop (C; 4 Tribenuron Methyl + Clodinafop (TM+C; 5 Pinoxaden + clodinafop + propargile (PCP; 6 Pinoxaden + clodinafop + propargile + Triasulfuron (PCP+T; 7 Pinoxaden + clodinafop + propargile + absolute Ioxinil and Mecoprop (PCP+IM. The new PCP+T herbicides mixture didn’t differ statistically from the traditional TMC treatment in terms of effectiveness, but the agronomic result of the new mixture was totally satisfactory, even taking into account that the marketing of this mixture is not aimed to compete with other existing herbicides but to widen the chance to rotate active principles in time and space, in order to control the onset of resistance phenomena.

Study of different herbicide molecules for the control of durum wheat weed

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Vittorio Filì

2011-02-01

Full Text Available In order to enhance the chances to rotate the herbicide molecules, the effectiveness of a new molecule, pinoxaden, was tested, comparing it with other herbicides used in wheat weed control. The trial was carried out comparing the following herbicide mixtures: 1 no weed control treatment; 2 Tribenuron Methyl (TM; 3 Clodinafop (C; 4 Tribenuron Methyl + Clodinafop (TM+C; 5 Pinoxaden + clodinafop + propargile (PCP; 6 Pinoxaden + clodinafop + propargile + Triasulfuron (PCP+T; 7 Pinoxaden + clodinafop + propargile + absolute Ioxinil and Mecoprop (PCP+IM. The new PCP+T herbicides mixture didn’t differ statistically from the traditional TMC treatment in terms of effectiveness, but the agronomic result of the new mixture was totally satisfactory, even taking into account that the marketing of this mixture is not aimed to compete with other existing herbicides but to widen the chance to rotate active principles in time and space, in order to control the onset of resistance phenomena.

Efficacy and economics of different herbicides in aerobic rice system ...

African Journals Online (AJOL)

Aerobic rice system, the most promising irrigation water saving rice production technology, is highly impeded by severe weed pressure. Weed control through the use of same herbicide causes development of herbicide resistant weed biotypes and serious problem in weed management. This study was aimed at finding out ...

Seletividade de herbicidas aplicados em pós-emergência sobre capim-colonião e efeito na qualidade das sementes: effects on seed germination Selectivity of herbicides applied in post-emergence on grass forage

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L.R.C. Trigueiro

2007-01-01

Full Text Available Este estudo foi conduzido para avaliar a seletividade de herbicidas aplicados em pós-emergência sobre plantas de Panicum maximum, cultivares Tanzânia e Mombaça, e os seus efeitos na qualidade das sementes. Os tratamentos testados (em g ha-1 foram: diclofopmethyl (284, ametryne (1.250, propanil (3.600, chlorimuron-ethyl (15, nicosulfuron (50, bentazon (720 e atrazine (3.000, além de uma testemunha sem aplicação de herbicidas. Foram instalados dois experimentos a campo, um para cada cultivar, no delineamento em blocos casualizados com quatro repetições, e um em laboratório, no delineamento inteiramente casualizado, com 16 repetições. O nicosulfuron foi o herbicida que mais causou injúrias visuais e redução de massa seca de plantas em ambos os cultivares. No cultivar Mombaça, todos os herbicidas reduziram a produção de sementes, mas não afetaram a germinação. Para o cultivar Tanzânia, todos os herbicidas foram seletivos, não afetando a produção e a qualidade fisiológica.This study aimed to evaluate the selectivity of some herbicides applied in post-emergence on Panicum maximum cv. Tanzânia and Mombaça and their effect on seed quality. The treatments tested in g ha-1 were: diclofop-methyl at 284, ametryn at 1.250, propanyl at 3.600, chlorimuron-ethyl at 15, nicosulfuron at 50, bentazon at 720 and atrazine at 3.000, and a control plot without herbicide application. Two field trials, one to each cultivar, were carried out in a randomized complete block design, with 4 replications and one laboratory trial was carried out in a randomized complete design, with 16 replications. Nicosulfuron showed the highest levels of visual damage and largest plant dry matter reduction in both cultivars. All the herbicides showed seed production decrease in Mombaca but did not affect seed germination. All the herbicides were selective to cultivar Tanzania, with no damages to plant production and physiological quality.

Delayed degradation in soil of foliar herbicides glyphosate and sulcotrione previously absorbed by plants: Consequences on herbicide fate and risk assessment

OpenAIRE

Doublet, Jeremy; Mamy, Laure; Barriuso Benito, Enrique

2009-01-01

Following application, pesticides can be intercepted and absorbed by weeds and/or crops. Plants containing pesticides residues may then reach the soil during the crop cycle or after harvest. However, the fate in soil of pesticides residues in plants is unknown. Two commonly used foliar herbicides, glyphosate and sulcotrione, 14C-labeled, were applied on leaves of oilseed rape and/or maize, translocation was studied, and then soil incubations of aerial parts of plants containing herbicides res...

Weed emergence on long years’ not herbicide treated fields - duration of the after-effects

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Schwarz, Jürgen

2016-02-01

Full Text Available In a long-term field trial plots were not treated with herbicides for 12 years (from 1996 to 2007. Two different crop rotations with 50% or 66% of cereals in the rotation were tested. At the same time in each crop rotation two different plant protection strategies were established. Since autumn 2007 the former controls not sprayed with any herbicide have been treated with herbicides. The crop rotation was unified. In that long-term field trial plots always treated with herbicides exist also. Weeds were counted by number and species before herbicide treatments. The comparison of these two different plots (treated and untreated shows what after-effect exists on the formerly untreated plots even after eight years. The emergence of weeds is still higher. Also the different crop rotations are still perceptible. For the plant protection strategy with the lower herbicide amounts the differences blur now.

Toxicidad en peces de herbicidas formulados con glifosato Toxicity in fishes of herbicides formulated with glyphosate

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Maria Alvarez

2012-07-01

Full Text Available En nuestro país existe una gran extensión de hectáreas cultivadas con soja transgénica, la misma ha sido modificada genéticamente para soportar la acción de un herbicida denominado glifosato. Debido a la gran cantidad de formulaciones comerciales que incluyen glifosato es de importancia analizar el impacto ambiental producido por éstas. La evaluacion de la toxicidad aguda de dos herbicidas comerciales formulados con glifosato y de una solución del mismo; frente a peces de la especie Poecilia reticulata "lebistes" acusa que una de las soluciones produce mortalidad del 100 % de los especimenes a 100 μl/l (equivalente a 48 mg/l de principio activo; la otra a 50 μl/l (equivalente a 24 mg/l de principio activo y la solución formulada con glifosato puro no produce mortalidad aún a concentraciones de 400 mg/l. Utilizando dosis sub letales en función de los datos obtenidos en el ensayo de toxicidad aguda se determinó que a largo plazo especimenes de Cyprinus carpio haematopterus "carpa koi", manifestaron severas alteraciones hematológicas principalmente frente a una de las formulaciones evaluadas.Nowadays, transgenic soya, modified in order to withstand the impact of the herbicide glyphosate, in one of the main crops grown in Argentina. Due to the large number of commercial formulations that include this drug, is important to analyze both, the acute and chronic environmental impact that they cause. Here the acute toxicity of two commercial herbicides glyphosatebased toward the fish Poecilia reticulate "guppy" was evaluated and compared with pure glyphosate solutions. Interestingly, while commercial herbicides formulations induce a 100% of mortality at concentration ranged between 50 and 100 μl/l, the pure glyphosathe does not present mortality even at doses higher than 400 mg/l. When some long term effects toward Cyprinus carpio haematopterus "koi" were determined by using the sub-lethal doses already calculated it was demonstrated that

Crystal structure of plant acetohydroxyacid synthase, the target for several commercial herbicides.

Science.gov (United States)

Garcia, Mario Daniel; Wang, Jian-Guo; Lonhienne, Thierry; Guddat, Luke William

2017-07-01

Acetohydroxyacid synthase (AHAS, EC 2.2.1.6) is the first enzyme in the branched-chain amino acid biosynthesis pathway. Five of the most widely used commercial herbicides (i.e. sulfonylureas, imidazolinones, triazolopyrimidines, pyrimidinyl-benzoates and sulfonylamino-cabonyl-triazolinones) target this enzyme. Here we have determined the first crystal structure of a plant AHAS in the absence of any inhibitor (2.9 Å resolution) and it shows that the herbicide-binding site adopts a folded state even in the absence of an inhibitor. This is unexpected because the equivalent regions for herbicide binding in uninhibited Saccharomyces cerevisiae AHAS crystal structures are either disordered, or adopt a different fold when the herbicide is not present. In addition, the structure provides an explanation as to why some herbicides are more potent inhibitors of Arabidopsis thaliana AHAS compared to AHASs from other species (e.g. S. cerevisiae). The elucidation of the native structure of plant AHAS provides a new platform for future rational structure-based herbicide design efforts. The coordinates and structure factors for uninhibited AtAHAS have been deposited in the Protein Data Bank (www.pdb.org) with the PDB ID code 5K6Q. © 2017 Federation of European Biochemical Societies.

Dynamics of herbicide transport and partitioning under event flow conditions in the lower Burdekin region, Australia

International Nuclear Information System (INIS)

Davis, Aaron M.; Lewis, Stephen E.; Bainbridge, Zoë T.; Glendenning, Lionel; Turner, Ryan D.R.; Brodie, Jon E.

2012-01-01

This study examined the temporal variability in herbicide delivery to the Great Barrier Reef (GBR) lagoon (Australia) from one of the GBR catchment’s major sugarcane growing regions. Annual loads of measured herbicides were consistently in the order of 200+ kg. Atrazine, it’s degradate desethylatrazine, and diuron contributed approximately 90% of annual herbicide load, with early ‘first-flush’ events accounting for the majority of herbicide loads leaving the catchment. Assessment of herbicide water–sediment partitioning in flood runoff highlighted the majority of herbicides were transported in predominantly dissolved form, although a considerable fraction of diuron was transported in particulate-bound form (ca. 33%). Diuron was also the herbicide demonstrating the highest concentrations and frequency of detection in sediments collected from catchment waterways and adjacent estuarine–marine environments, an outcome aligning with previous research. Herbicide physico-chemical properties appear to play a crucial role in partitioning between water column and sediment habitat types in GBR receiving ecosystems.

Rationale for Selection of Pesticides, Herbicides, and Related Compounds from the Hanford SST/DST Waste Considered for Analysis in Support of the Regulatory DQO (Privatization)

International Nuclear Information System (INIS)

Wiemers, K.D.; Daling, P.; Meier, K.

1999-01-01

Regulated pesticides, herbicides, miticides, and fungicides were evaluated for their potential past and current use at the Hanford Site. The starting list of these compounds is based on regulatory analyte input lists discussed in the Regulatory DQO. Twelve pesticide, herbicide, miticide, and fungicide compounds are identified for analysis in the Hanford SST and DST waste in support of the Regulatory DQO. The compounds considered for additional analyses are non-detected, considered stable in the tank waste matrix, and of higher toxicity/carcinogenicity

Rationale for Selection of Pesticides, Herbicides, and Related Compounds from the Hanford SST/DST Waste Considered for Analysis in Support of the Regulatory DQO (Privatization)

Energy Technology Data Exchange (ETDEWEB)

Wiemers, K.D.; Daling, P.; Meier, K.

1999-01-04

Regulated pesticides, herbicides, miticides, and fungicides were evaluated for their potential past and current use at the Hanford Site. The starting list of these compounds is based on regulatory analyte input lists discussed in the Regulatory DQO. Twelve pesticide, herbicide, miticide, and fungicide compounds are identified for analysis in the Hanford SST and DST waste in support of the Regulatory DQO. The compounds considered for additional analyses are non-detected, considered stable in the tank waste matrix, and of higher toxicity/carcinogenicity.

The crush and spray: a patented design for herbicide application with less waste

Science.gov (United States)

Cherie LeBlanc Fisher; Adam H. Wiese

2009-01-01

The USDA Forest Service recently patented an equipment design to deliver herbicides more efficiently and cost-effectively. Towed by a standard all-terrain vehicle, the Crush and Spray can access out-of-the-way or wet locations. An adjustable roller first knocks down the unwanted plants. A low-set spray boom with wide angle sprayer nozzles then provides precise, close-...

Herbicides in environmental pollution

International Nuclear Information System (INIS)

Qureshi, M.J.; Haq, A.; Maqbool, U.

1997-01-01

Herbicide effectiveness on the most pernicious weeds including cyperus rotundus may be limited because spray droplets are not well retained or because penetration and/or translocation is restricted. As a result, chemical pollute the environment and is hazardous to the human health. Monitoring studies ad undertaken to check that the flate and environmental effects of herbicides under field condition are consistent with prediction. Studies on /sup 14/-glyphosate in Cyperus rotundus using radiotracer methods indicated that out of five formulations studies formulation No.3 was the best from penetration point of view of the chemical whereas formulation No. 4 with the high dose showed effective retention and uniform translocation of the chemical after five days of the treatment. Cuticular penetration and translocation of glyphosate in the formulations with or without surfactants have also been studied in C. rotundus. It is also concluded that synperonic surfactants, diesel oil or glycerol did not influence the translocation of glyphosate within the weed. The translocation mainly occurred down swards and accumulated in the plant parts located below the treated zone. (author)

Screening of photosynthetic pigments for herbicidal activity with a new computational molecular approach.

Science.gov (United States)

Krishnaraj, R Navanietha; Chandran, Saravanan; Pal, Parimal; Berchmans, Sheela

2013-12-01

There is an immense interest among the researchers to identify new herbicides which are effective against the herbs without affecting the environment. In this work, photosynthetic pigments are used as the ligands to predict their herbicidal activity. The enzyme 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase is a good target for the herbicides. Homology modeling of the target enzyme is done using Modeler 9.11 and the model is validated. Docking studies were performed with AutoDock Vina algorithm to predict the binding of the natural pigments such as β-carotene, chlorophyll a, chlorophyll b, phycoerythrin and phycocyanin to the target. β-carotene, phycoerythrin and phycocyanin have higher binding energies indicating the herbicidal activity of the pigments. This work reports a procedure to screen herbicides with computational molecular approach. These pigments will serve as potential bioherbicides in the future.

The Effect of Herbicides on Hydrogen Peroxide Generation in Isolated Vacuoles of Red Beet Root (Beta vulgaris L.

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E.V. Pradedova

2015-12-01

Full Text Available Influence of herbicides on the hydrogen peroxide generation in vacuolar extracts of red beet root (Beta vulgaris L. was investigated. Belonging to different chemical classes of herbicide compounds have been used. Herbicides differ from each other in the mechanism of effects on plants. Clopyralid (aromatic acid herbicide, derivative of picolinic acid and 2.4-D (phenoxyacetic herbicide, characterized by hormone-like effects, contributed to the formation of H2O2 in vacuolar extracts. Fluorodifen (nitrophenyl ether herbicide and diuron (urea herbicide also have increased contents H2O2. These compounds inhibit the electron transport, photosynthesis, and photorespiration in sensitive plants. Herbicidal effect of glyphosate (organophosphorus herbicide is due to the inhibition of amino acid synthesis in plant cells. Glyphosate did not affect the content of H2O2 in vacuolar extracts. Herbicide dependent H2O2-generation did not occur with oxidoreductase inhibitors, potassium cyanide and sodium azide. The results suggest that the formation of ROS in the vacuoles due to activity of oxidoreductases, which could interact with herbicides.

EFFECT OF CRUDE CASSAVA WATER EXTRACT AS A NATURAL HERBICIDE ON PROXIMATE COMPOSITION AND BIOACCUMULATION OF HYDROCYANIC ACID IN FOOD COMPONENTS OF COWPEA -VIGNA UNGUICULATA (L WALP

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Olajumoke Oke FAYINMINNU

2013-06-01

Full Text Available This study was a field trial of two experiments to examine the effect of crude cassava water extract (CCWE as a natural post-emergence herbicide on nutritional quality and bioaccumulation of hydrocyanic acid in cowpea seeds. The spraying of CCWE on cowpea plants was carried out weekly for 5weeks. Treatments of CCWE at 25 and 50% concentrations of MS6 (Manihot Selection, TMS30555 (Tropical Manihot Selection and Bulk CCWE (different cassava varieties, hand weeded and unweeded (controls were laid in randomised complete block design with three replications respectively. At maturity, dry samples of cowpea `Ife brown` seeds were ground to fine powder and the proximate composition and bioaccumulation of hydrocyanic acid in the two experiments were determined. Significant variations (p0.05 among the herbicide treatments. It was therefore recommended that CCWE could be used as a natural post-emergence herbicide in cowpea production without altering the nutritional quality and residue of hydrocyanic acid in cowpea seeds.

METHOD DEVELOPMENT FOR ALACHLOR ESA AND OTHER ACENTANILIDE HERBICIDE DEGRADATION PRODUCTS

Science.gov (United States)

Introduction: Acetanilide herbicides are frequently applied in the U.S. on crops (corn, soybeans, popcorn, etc.) to control broadleaf and annual weeds. The acetanilide and acetamide herbicides currently registered for use in the U.S. are alachlor, acetochlor, metolachlor, propa...

Lawn Weed Control with Herbicides. Home and Garden Bulletin No. 123.

Science.gov (United States)

Agricultural Research Service (USDA), Washington, DC.

Information and diagrams are given for identification and treatment of weed grasses and broadleaf weeds. Herbicides are suggested for use against each weed and instructions are given for proper application. Information is given for buying herbicides, and applying sprays and cleaning sprayers. (BB)

Photostabilization of the herbicide norflurazon microencapsulated with ethylcellulose in the soil-water system

Energy Technology Data Exchange (ETDEWEB)

Sopena, Fatima, E-mail: fsopenav@irnase.csic.es [Institute of Natural Resources and Agrobiology (CSIC), Reina Mercedes 10, Apdo 1052, 41080 Seville, ES (Spain); Villaverde, Jaime; Maqueda, Celia; Morillo, Esmeralda [Institute of Natural Resources and Agrobiology (CSIC), Reina Mercedes 10, Apdo 1052, 41080 Seville, ES (Spain)

2011-11-15

Highlights: {yields} Herbicide photodegradation studies using ethylcellulose-microencapsulated formulations (ECF) in soil and water. {yields} Greater herbicide photo-protection observed from EFC than from its commercial form. {yields} Photo-protective effect due to the gradual herbicide release and the presence of ethylcellulose. {yields} Herbicide photo-stability conditioned by soil colloidal components, especially by goethite and humic acids. {yields} EFC could reduce the field herbicide losses by photolysis. - Abstract: Ethylcellulose-microencapsulated formulations (ECFs) of norflurazon have been shown to reduce leaching, maintaining a threshold concentration in the topsoil than the commercial formulation (CF). Since photodegradation contributes to field dissipation of norflurazon, the objective of the present work was to study if such formulations can also protect from its photodescomposition. For this purpose, aqueous solutions of CF and ECFs, containing the most important soil components (goethite, humic and fulvic acids and montmorillonite) were tested. To get a more realistic approach, studies in soil were also performed. The results were well explained by a simple first order model. DT{sub 50} value was 3 h for CF under irradiation, which was considerably lower than those corresponding to the systems where ECF was used (35 h for ECF; 260 h for ECF-goethite; 53 h for ECF-humic acids; 33 h for ECF-montmorillonite; and 28 h for ECF-fulvic acids). ECF protected against photodegradation in both aqueous solution and soil due to the gradual release of the herbicide, which reduced the herbicide available to be photodegraded. These lab-scale findings proved that ECF could reduce the herbicide dosage, minimizing its photolysis, which would be especially advantageous during the first hours after foliar and soil application.

Photostabilization of the herbicide norflurazon microencapsulated with ethylcellulose in the soil-water system

International Nuclear Information System (INIS)

Sopena, Fatima; Villaverde, Jaime; Maqueda, Celia; Morillo, Esmeralda

2011-01-01

Highlights: → Herbicide photodegradation studies using ethylcellulose-microencapsulated formulations (ECF) in soil and water. → Greater herbicide photo-protection observed from EFC than from its commercial form. → Photo-protective effect due to the gradual herbicide release and the presence of ethylcellulose. → Herbicide photo-stability conditioned by soil colloidal components, especially by goethite and humic acids. → EFC could reduce the field herbicide losses by photolysis. - Abstract: Ethylcellulose-microencapsulated formulations (ECFs) of norflurazon have been shown to reduce leaching, maintaining a threshold concentration in the topsoil than the commercial formulation (CF). Since photodegradation contributes to field dissipation of norflurazon, the objective of the present work was to study if such formulations can also protect from its photodescomposition. For this purpose, aqueous solutions of CF and ECFs, containing the most important soil components (goethite, humic and fulvic acids and montmorillonite) were tested. To get a more realistic approach, studies in soil were also performed. The results were well explained by a simple first order model. DT 50 value was 3 h for CF under irradiation, which was considerably lower than those corresponding to the systems where ECF was used (35 h for ECF; 260 h for ECF-goethite; 53 h for ECF-humic acids; 33 h for ECF-montmorillonite; and 28 h for ECF-fulvic acids). ECF protected against photodegradation in both aqueous solution and soil due to the gradual release of the herbicide, which reduced the herbicide available to be photodegraded. These lab-scale findings proved that ECF could reduce the herbicide dosage, minimizing its photolysis, which would be especially advantageous during the first hours after foliar and soil application.

The role of herbicides in the erosion of salt marshes in eastern England

International Nuclear Information System (INIS)

Mason, C.F.; Underwood, G.J.C.; Baker, N.R.; Davey, P.A.; Davidson, I.; Hanlon, A.; Long, S.P.; Oxborough, K.; Paterson, D.M.; Watson, A.

2003-01-01

Herbicide run-off stresses saltmarsh diatoms and higher plants and may increase erosion. - Laboratory studies and field trials were conducted to investigate the role of herbicides on saltmarsh vegetation, and their possible significance to saltmarsh erosion. Herbicide concentrations within the ranges present in the aquatic environment were found to reduce the photosynthetic efficiency and growth of both epipelic diatoms and higher saltmarsh plants in the laboratory and in situ. The addition of sublethal concentrations of herbicides resulted in decreased growth rates and photosynthetic efficiency of diatoms and photosynthetic efficiency of higher plants. Sediment stability also decreased due to a reduction in diatom EPS production. There was qualitative evidence that diatoms migrated deeper into the sediment when the surface was exposed to simazine, reducing surface sediment stability by the absence of a cohesive biofilm. Sediment loads on leaves severely reduced photosynthesis in Limonium vulgare. This, coupled with reduced carbon assimilation from the effects of herbicides, could have large negative consequences for plant productivity and over winter survival of saltmarsh plants. The data support the hypothesis that sublethal herbicide concentrations could be playing a role in the increased erosion of salt marshes that has occurred over the past 40 years

Predator-induced physiological responses in tadpoles challenged with herbicide pollution

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Pablo BURRACO, Lidia Jiménez DUARTE, Ivan GOMEZ-MESTRE

2013-08-01

Full Text Available Predators induce plastic responses in multiple prey taxa, ranging from morphological to behavioral or physiological changes. In amphibians, tadpoles activate plastic responses to reduce predation risk by reducing their activity rate and altering their morphology, specifically tail depth and pigmentation. Furthermore, there is now evidence that tadpoles’ defenses are modified when predators combine with other stressful factors such as pollutants or competitors, but our knowledge on the physiological responses underlying these responses is still scarce. Here we study physiological responses in Pelobates cultripes tadpoles exposed to a natural predator (larvae of the aquatic beetle Dytiscus circumflexus, non-lethal concentrations of herbicide (glyphosate, 0.5 mg/L and 1.0 mg/L or both factors combined. We measured corticosterone levels, standard metabolic rate, oxidative damage (TBARS and activity of antioxidant enzymes, and immune response (via leukocyte count. Tadpoles reduced their corticosterone concentration by ca. 24% in the presence of predator cues, whereas corticosterone did not change in the presence of glyphosate. Two enzymes involved in antioxidant response also decreased in the presence of predators (14.7% and 13.2% respectively but not to glyphosate. Herbicide, however, increased the number of neutrophils and reduced that of lymphocytes, and had an interaction effect with predator presence. Standard metabolic rate did not vary across treatments in our experiment. Thus we show a marked physiological response to the presence of predators but little evidence for interaction between predators and low levels of herbicide. Multiple assessment of the physiological state of animals is important to understand the basis and consequences of phenotypic plasticity [Current Zoology 59 (4: 475–484, 2013].

Sorption of Pharmaceuticals, Heavy Metals, and Herbicides to Biochar in the Presence of Biosolids.

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Bair, Daniel A; Mukome, Fungai N D; Popova, Inna E; Ogunyoku, Temitope A; Jefferson, Allie; Wang, Daoyuan; Hafner, Sarah C; Young, Thomas M; Parikh, Sanjai J

2016-11-01

Agricultural practices are increasingly incorporating recycled waste materials, such as biosolids, to provide plant nutrients and enhance soil functions. Although biosolids provide benefits to soil, municipal wastewater treatment plants receive pharmaceuticals and heavy metals that can accumulate in biosolids, and land application of biosolids can transfer these contaminants to the soil. Environmental exposure of these contaminants may adversely affect wildlife, disrupt microbial communities, detrimentally affect human health through long-term exposure, and cause the proliferation of antibiotic-resistant bacteria. This study considers the use of biochar co-amendments as sorbents for contaminants from biosolids. The sorption of pharmaceuticals (ciprofloxacin, triclocarban, triclosan), and heavy metals (Cu, Cd, Ni, Pb) to biochars and biochar-biosolids-soil mixtures was examined. Phenylurea herbicide (monuron, diuron, linuron) sorption was also studied to determine the potential effect of biochar on soil-applied herbicides. A softwood (SW) biochar (510°C) and a walnut shell (WN) biochar (900°C) were used as contrasting biochars to highlight potential differences in biochar reactivity. Kaolinite and activated carbon served as mineral and organic controls. Greater sorption for almost all contaminants was observed with WN biochar over SW biochar. The addition of biosolids decreased sorption of herbicides to SW biochar, whereas there was no observable change with WN biochar. The WN biochar showed potential for reducing agrochemical and contaminant transport but may inhibit the efficacy of soil-applied herbicides. This study provides support for minimizing contaminant mobility from biosolids using biochar as a co-amendment and highlights the importance of tailoring biochars for specific characteristics through feedstock selection and pyrolysis-gasification conditions. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science

Electrochemical degradation and mineralization of glyphosate herbicide.

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Tran, Nam; Drogui, Patrick; Doan, Tuan Linh; Le, Thanh Son; Nguyen, Hoai Chau

2017-12-01

The presence of herbicide is a concern for both human and ecological health. Glyphosate is occasionally detected as water contaminants in agriculture areas where the herbicide is used extensively. The removal of glyphosate in synthetic solution using advanced oxidation process is a possible approach for remediation of contaminated waters. The ability of electrochemical oxidation for the degradation and mineralization of glyphosate herbicide was investigated using Ti/PbO 2 anode. The current intensity, treatment time, initial concentration and pH of solution are the influent parameters on the degradation efficiency. An experimental design methodology was applied to determine the optimal condition (in terms of cost/effectiveness) based on response surface methodology. Glyphosate concentration (C 0  = 16.9 mg L -1 ) decreased up to 0.6 mg L -1 when the optimal conditions were imposed (current intensity of 4.77 A and treatment time of 173 min). The removal efficiencies of glyphosate and total organic carbon were 95 ± 16% and 90.31%, respectively. This work demonstrates that electrochemical oxidation is a promising process for degradation and mineralization of glyphosate.

A miniature bioassay for testing the acute phytotoxicity of photosystem II herbicides on seagrass.

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Adam D Wilkinson

Full Text Available Photosystem II (PSII herbicides have been detected in nearshore tropical waters such as those of the Great Barrier Reef and may add to the pressure posed by runoff containing sediments and nutrients to threatened seagrass habitats. There is a growing number of studies into the potential effects of herbicides on seagrass, generally using large experimental setups with potted plants. Here we describe the successful development of an acute 12-well plate phytotoxicity assay for the PSII herbicide Diuron using isolated Halophila ovalis leaves. Fluorescence images demonstrated Diuron affected the entire leaf surface evenly and responses were not influenced by isolating leaves from the plant. The optimum exposure duration was 24 h, by which time the inhibition of effective quantum yield of PSII (∆F/F(m' was highest and no deterioration of photosystems was evident in control leaves. The inhibition of ∆F/F(m' by Diuron in isolated H. ovalis leaves was identical to both potted and hydroponically grown plants (with leaves remaining attached to rhizomes, indicating similar reductions in photosynthetic activity in these acute well-plate assays. The sensitivity of the assay was not influenced by irradiance (range tested 40 to 400 μmol photons m(-2 s(-1. High irradiance, however, caused photo-oxidative stress in H. ovalis and this generally impacted in an additive or sub-additive way with Diuron to damage PSII. The bioassay using isolated leaves is more rapid, uses far less biological material and does not rely on specialised aquarium facilities in comparison with assays using potted plants. The development and validation of this sensitive bioassay will be useful to reliably screen and monitor the phytotoxicity of existing and emerging PSII herbicides and contribute to risk assessments and water quality guideline development in the future.

A Miniature Bioassay for Testing the Acute Phytotoxicity of Photosystem II Herbicides on Seagrass

Science.gov (United States)

Wilkinson, Adam D.; Collier, Catherine J.; Flores, Florita; Mercurio, Phil; O’Brien, Jake; Ralph, Peter J.; Negri, Andrew P.

2015-01-01

Photosystem II (PSII) herbicides have been detected in nearshore tropical waters such as those of the Great Barrier Reef and may add to the pressure posed by runoff containing sediments and nutrients to threatened seagrass habitats. There is a growing number of studies into the potential effects of herbicides on seagrass, generally using large experimental setups with potted plants. Here we describe the successful development of an acute 12-well plate phytotoxicity assay for the PSII herbicide Diuron using isolated Halophila ovalis leaves. Fluorescence images demonstrated Diuron affected the entire leaf surface evenly and responses were not influenced by isolating leaves from the plant. The optimum exposure duration was 24 h, by which time the inhibition of effective quantum yield of PSII (∆F/Fm’) was highest and no deterioration of photosystems was evident in control leaves. The inhibition of ∆F/Fm’ by Diuron in isolated H. ovalis leaves was identical to both potted and hydroponically grown plants (with leaves remaining attached to rhizomes), indicating similar reductions in photosynthetic activity in these acute well-plate assays. The sensitivity of the assay was not influenced by irradiance (range tested 40 to 400 μmol photons m-2 s-1). High irradiance, however, caused photo-oxidative stress in H. ovalis and this generally impacted in an additive or sub-additive way with Diuron to damage PSII. The bioassay using isolated leaves is more rapid, uses far less biological material and does not rely on specialised aquarium facilities in comparison with assays using potted plants. The development and validation of this sensitive bioassay will be useful to reliably screen and monitor the phytotoxicity of existing and emerging PSII herbicides and contribute to risk assessments and water quality guideline development in the future. PMID:25674791

Seletividade de herbicidas aplicados em pré-emergência na cultura do algodão Selectivity of herbicides applied to pre-emergent cotton crops

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Miriam Hiroko Inoue

2013-03-01

Full Text Available A cultura do algodão tem grande importância econômica e social, visto que é a fibra mais utilizada no setor têxtil. Contudo é uma cultura que apresenta alta sensibilidade a plantas daninhas e há poucos herbicidas seletivos à cultura. Neste contexto o trabalho objetivou avaliar a seletividade de herbicidas aplicados em pré-emergência na cultura do algodão. Os herbicidas alachlor, S-metolachlor, diuron, prometryne, trifluralin e oxyfluorfen foram aplicados isoladamente e em misturas sobre a variedade FMT-701, nas localidades de Diamantino-MT e Campos de Júlio-MT. O delineamento experimental utilizado foi em blocos casualizados com 16 tratamentos e 4 repetições. Para avaliar a seletividade foram realizadas avaliações de altura aos 36; 66 e 150 dias após a aplicação (DAA, fitointoxicação aos 14; 21; 29 e 36 DAA, estande aos 21 e 49 DAA, número de maçãs aos 141 DAA e produtividade do algodão em caroço aos 193 DAA. Os dados foram submetidos à análise conjunta e ao teste de agrupamento Scott-Knott (p>0,05. Os resultados indicaram que alguns tratamentos proporcionaram menor altura de plantas em determinadas avaliações e grande parte dos tratamentos causou injúrias na fase inicial da cultura. Verificou-se que os tratamentos não proporcionaram diferença significativa para as características de estande de plantas, número de maçãs e produtividade de algodão em caroço, comprovando que todos os tratamentos avaliados podem ser utilizados no manejo de plantas daninhas.The cultivation of cotton has great economic and social importance as it is the most widely used fibre in the textile sector. It is however a crop that is highly sensitive tweeds, and there are few selective herbicides for the crop. With this in mind, this study aimed to evaluate the selectivity of herbicides applied to pre-emergent cotton crops. The herbicides, alachlor, S-metolachlor, diuron, prometryne, trifluralin and oxyfluorfen were applied both

Manejo da Planta Daninha Brachiaria plantaginea Resistente aos herbicidas Inibidores da ACCase Management of the Weed Brachiaria plantaginea Resistant to ACCase Inhibitor Herbicides

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P.J. Christoffoleti

2001-04-01

study a population of alexandergrass (Brachiaria plantaginea resistant to ACCase inhibitor herbicides (ariloxyphenoxypropionic and cyclohexanodiones, usually sprayed on soybean under the conservation tillage system. Two experiments were conducted, one under field conditions, comparing the efficacy of non-selective herbicides to ACCase inhibitors, and another under greenhouse conditions, using ACCase inhibitors with nitrogenous additives in the spray solution. Resistant seeds were collected from a site of suspected resistant population, and compared to a population of alexandergrass that had never been sprayed with ACCase inhibitors, the susceptible population. The experiment with non-selective herbicides was conducted under field conditions, but plants were confined to pots of 50 L capacity, avoiding the dissemination of the seeds to adjacent areas. It was then concluded that resistant plants did not show multiple resistance to non selective herbicides with alternative mechanisms of action, with glyphosate, paraquat, paraquat + diuron, MSMA and glufosinate alternative herbicides being possible to be used to control the weed during the winter to manage populations of alexandergrass resistant to ACCase inhibitor herbicides. The additive experiment was conducted under greenhouse conditions in pots, using seeds from the same populations used in the non selective experiment. The herbicides tested were ACCase inhibitors, and the additive treatments were ammonium sulfate and urea. It was then concluded that the additives did not enhance ACCase inhibitor herbicide efficacy in neither of the alexandergrass populations.

Determination of solid-liquid partition coefficients (K{sub d}) for the herbicides inspiration and trifluralin in five UK agricultural soils

Energy Technology Data Exchange (ETDEWEB)

Cooke, Cindy M. [Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY (United Kingdom)]. E-mail: cindy.cooke@imperial.ac.uk; Shaw, George [Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY (United Kingdom); Collins, Chris D. [Department of Environmental Science and Technology, Faculty of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY (United Kingdom)

2004-12-01

Isoproturon and trifluralin are herbicides of contrasting chemical characters and modes of action. Standard batch sorption procedures were carried out to investigate the individual sorption behaviour of {sup 14}C-isoproturon and {sup 14}C-trifluralin in five agricultural soils (1.8-4.2% OC), and the soil solid-liquid partition coefficients (K{sub d} values) were determined. Trifluralin exhibited strong partitioning to the soil solid phase (K{sub d} range 106-294) and low desorption potential, thus should not pose a threat to sensitive waters via leaching, although particle erosion and preferential flow pathways may facilitate transport. For isoproturon, soil adsorption was low (K{sub d} range 1.96-5.75) and desorption was high, suggesting a high leaching potential, consistent with isoproturon being the most frequently found pesticide in UK surface waters. Soil partitioning was directly related to soil organic carbon (OC) content. Accumulation isotherms were modelled using a dual-phase adsorption model to estimate adsorption and desorption rate coefficients. Associations between herbicides and soil humic substances were also shown using gel filtration chromatography. - Capsule: Herbicide soil sorption described by a dual-phase adsorption model reflected soil partitioning, as influenced by soil OC and humic substances.

Perinatal Exposure to Glufosinate Ammonium Herbicide Impairs Neurogenesis and Neuroblast Migration through Cytoskeleton Destabilization.

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Herzine, Ameziane; Laugeray, Anthony; Feat, Justyne; Menuet, Arnaud; Quesniaux, Valérie; Richard, Olivier; Pichon, Jacques; Montécot-Dubourg, Céline; Perche, Olivier; Mortaud, Stéphane

2016-01-01

Neurogenesis, a process of generating functional neurons from neural precursors, occurs throughout life in restricted brain regions such as the subventricular zone (SVZ). During this process, newly generated neurons migrate along the rostral migratory stream to the olfactory bulb to replace granule cells and periglomerular neurons. This neuronal migration is pivotal not only for neuronal plasticity but also for adapted olfactory based behaviors. Perturbation of this highly controlled system by exogenous chemicals has been associated with neurodevelopmental disorders. We reported recently that perinatal exposure to low dose herbicide glufosinate ammonium (GLA), leads to long lasting behavioral defects reminiscent of Autism Spectrum Disorder-like phenotype in the offspring (Laugeray et al., 2014). Herein, we demonstrate that perinatal exposure to low dose GLA induces alterations in neuroblast proliferation within the SVZ and abnormal migration from the SVZ to the olfactory bulbs. These disturbances are not only concomitant to changes in cell morphology, proliferation and apoptosis, but are also associated with transcriptomic changes. Therefore, we demonstrate for the first time that perinatal exposure to low dose GLA alters SVZ neurogenesis. Jointly with our previous work, the present results provide new evidence on the link between molecular and cellular consequences of early life exposure to the herbicide GLA and the onset of ASD-like phenotype later in life.

Characterization of acetanilide herbicides degrading bacteria isolated from tea garden soil.

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Wang, Yei-Shung; Liu, Jian-Chang; Chen, Wen-Ching; Yen, Jui-Hung

2008-04-01

Three different green manures were added to the tea garden soils separately and incubated for 40 days. After, incubation, acetanilide herbicides alachlor and metolachlor were spiked into the soils, separately, followed by the isolation of bacteria in each soil at designed intervals. Several bacterial strains were isolated from the soils and identified as Bacillus silvestris, B. niacini, B. pseudomycoides, B. cereus, B. thuringiensis, B. simplex, B. megaterium, and two other Bacillus sp. (Met1 and Met2). Three unique strains with different morphologies were chosen for further investigation. They were B. megaterium, B. niacini, and B. silvestris. The isolated herbicide-degrading bacteria showed optimal performance among three incubation temperatures of 30 degrees C and the best activity in the 10 to 50 microg/ml concentration of the herbicide. Each bacterial strain was able to degrade more than one kind of test herbicides. After incubation for 119 days, B. cereus showed the highest activity to degrade alachlor and propachlor, and B. thuringiensis to degrade metolachlor.

Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

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Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

2014-01-01

Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services. PMID:25005713

Impact of agricultural management on bacterial laccase-encoding genes with possible implications for soil carbon storage in semi-arid Mediterranean olive farming

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Beatriz Moreno

2016-07-01

Full Text Available Background: In this work, we aimed to gain insights into the contribution of soil bacteria to carbon sequestration in Mediterranean habitats. In particular, we aimed to use bacterial laccase-encoding genes as molecular markers for soil organic C cycling. Using rainfed olive farming as an experimental model, we determined the stability and accumulation levels of humic substances and applied these data to bacterial laccase-encoding gene expression and diversity in soils under four different agricultural management systems (bare soils under tillage/no tillage and vegetation cover under chemical/mechanical management. Materials and Methods: Humic C (> 104 Da was subjected to isoelectric focusing. The GC-MS method was used to analyze aromatic hydrocarbons. Real-Time PCR quantification and denaturing gradient gel electrophoresis (DGGE for functional bacterial laccase-like multicopper oxidase (LMCO-encoding genes and transcripts were also carried out. Results: Soils under spontaneous vegetation, eliminated in springtime using mechanical methods for more than 30 years, showed the highest humic acid levels as well as the largest bacterial population rich in laccase genes and transcripts. The structure of the bacterial community based on LMCO genes also pointed to phylogenetic differences between these soils due to the impact of different management systems. Soils where herbicides were used to eliminate spontaneous vegetation once a year and those where pre-emergence herbicides resulted in bare soils clustered together for DNA-based DGGE analysis, which indicated a certain amount of microbial selection due to the application of herbicides. When LMCO-encoding gene expression was studied, soils where cover vegetation was managed either with herbicides or with mechanical methods showed less than 10% similarity, suggesting that the type of weed management strategy used can impact weed community composition and consequently laccase substrates derived from

Seletividade de herbicidas registrados para a cultura do milho aos estádios imaturos de Trichogramma pretiosum (Hymenoptera: Trichogrammatidae Selectivity of herbicides registered for corn at the immature stages of Trichogramma pretio sum (Hymenoptera: Trichogrammatidae

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G.J Stefanello Jr

2011-01-01

Full Text Available O controle químico tem sido um dos métodos mais utilizados para o manejo de plantas daninhas na cultura do milho, no entanto o uso de herbicidas pode ocasionar efeitos adversos aos insetos benéficos, como os parasitoides de ovos. Nesse sentido, foi avaliada a seletividade de 12 herbicidas registrados para a cultura do milho para as fases imaturas de Trichogramma pretiosum em condições de laboratório (temperatura de 25±1 ºC, umidade relativa de 70±10% e fotofase de 14 horas. Os herbicidas foram diluídos em um volume proporcional a 200 L de água por hectare e pulverizados sobre ovos de lepidóptero contendo formas imaturas do parasitoide em seu interior, nas fases de ovo-larva, pré-pupa e pupa. Avaliou-se, então, a porcentagem de emergência dos parasitoides e, em função da comparação com a testemunha, classificaram-se os herbicidas em inócuo (classe 1, 99%. Os herbicidas Agrisato 480 SL, Finale, Glifos, Glifosato Nortox, Gliz 480 SL, Polaris, Roundup Original, Roundup Transorb, Roundup WG, Trop e Zapp Qi foram inócuos (classe 1 às diferentes fases imaturas de T. pretiosum e são considerados seletivos ao parasitoide. Gramoxone 200, embora tenha sido inócuo para as fases de ovo-larva e pré-pupa, foi considerado levemente nocivo (classe 2 para a fase de pupa. Nesse sentido, para melhor compatibilização do manejo químico das plantas daninhas e controle biológico de insetos, sugere-se que sejam utilizados, sempre que possível, aqueles herbicidas que permitem maior sobrevivência de T. pretiosum.- Chemical control has been one of the most widely used methods for weed mana gement in corn. However, the use of herbicides can cause adverse effects on beneficial insects, such as egg parasitoids. Thus, this work aimed to evaluate the selectivity of 12 herbicides regis tered for corn at the immature stages of Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae under laboratory conditions (temperature 25±1 o C

Contribution of transformation products towards the total herbicide toxicity to tropical marine organisms.

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Mercurio, Philip; Eaglesham, Geoff; Parks, Stephen; Kenway, Matt; Beltran, Victor; Flores, Florita; Mueller, Jochen F; Negri, Andrew P

2018-03-19

The toxicity of herbicide degradation (transformation) products is rarely taken into account, even though these are commonly detected in the marine environment, sometimes at concentrations higher than the parent compounds. Here we assessed the potential contribution of toxicity by transformation products of five photosystem II herbicides to coral symbionts (Symbiodinium sp.), the green algae Dunaliella sp., and prawn (Penaeus monodon) larvae. Concentration-dependent inhibition of photosynthetic efficiency (∆F/F m ') was observed for all herbicides in both microalgal species. The toxicity of solutions of aged diuron solutions containing transformation products to Symbiodinium sp. and Dunaliella sp. was greater than could be explained by the concentrations of diuron measured, indicating transformation products contributed to the inhibition of ∆F/F m '. However, the toxicity of aged atrazine, simazine, hexazinone, and ametryn solutions could be explained by the concentration of parent herbicide, indicating no contribution by transformation products. Prawn larval metamorphosis was not sensitive to the herbicides, but preliminary results indicated some toxicity of the transformation products of atrazine and diuron. Risk assessments should take into account the contribution of herbicide transformation products; however, further studies are clearly needed to test the toxicity of a far wider range of transformation products to a representative diversity of relevant taxa.

Enrichment and molecular characterization of a bacterial culture that degrades methoxy-methyl urea herbicides and their aniline derivatives.

Science.gov (United States)

El-Fantroussi, S; Verstraete, W; Top, E M

2000-12-01

Soil treated with linuron for more than 10 years showed high biodegradation activity towards methoxy-methyl urea herbicides. Untreated control soil samples taken from the same location did not express any linuron degradation activity, even after 40 days of incubation. Hence, the occurrence in the field of a microbiota having the capacity to degrade a specific herbicide was related to the long-term treatment of the soil. The enrichment culture isolated from treated soil showed specific degradation activity towards methoxy-methyl urea herbicides, such as linuron and metobromuron, while dimethyl urea herbicides, such as diuron, chlorotoluron, and isoproturon, were not transformed. The putative metabolic intermediates of linuron and metobromuron, the aniline derivatives 3, 4-dichloroaniline and 4-bromoaniline, were also degraded. The temperature of incubation drastically affected degradation of the aniline derivatives. Whereas linuron was transformed at 28 and 37 degrees C, 3,4-dichloroaniline was transformed only at 28 degrees C. Monitoring the enrichment process by reverse transcription-PCR and denaturing gradient gel electrophoresis (DGGE) showed that a mixture of bacterial species under adequate physiological conditions was required to completely transform linuron. This research indicates that for biodegradation of linuron, several years of adaptation have led to selection of a bacterial consortium capable of completely transforming linuron. Moreover, several of the putative species appear to be difficult to culture since they were detectable by DGGE but were not culturable on agar plates.

Effects of fertilizers, fungicides and herbicides on the fate of 14C-parathion and 14C-fonofos in soils and crops

International Nuclear Information System (INIS)

Lichtenstein, E.P.; Ferris, I.; Liang, T.T.; Koeppe, M.

1983-01-01

The fate of 14 C-parathion and 14 C-fonofos in soil is significantly affected by the presence of organic and inorganic fertilizers, fungicides and herbicides, possibly via the effect of soil microflora. Soil microorganisms are responsible for the oxidative as well as the reductive degradation of the insecticide. Using 14 carbon, the authors studied the effects of selected fungicides (benlate, captafol and manzate) herbicides (2,4-D parathion) and fertilizers ((NH 4 ) 6 SO 4 , KNO 3 , urea) on pesticides in Cromberry soils. Results of the study stress the importance of investigating the environmental fate of a particular pesticide in relation to the presence of the agricultural chemicals

Cofirmation of resistance in littleseed canarygrass (phalaris minor retz) to accase inhibitors in central punjab-pakistan and alternative herbicides for its management

International Nuclear Information System (INIS)

Abbas, T.; Burgos, N. R.; Nadeem, M. A.; Matloob, A.; Farooq, N.; Chauhan, B. S.

2017-01-01

Littleseed canarygrass (Phalaris minor) infests wheat and other winter crops in Pakistan and many other countries. Studies were conducted in Pakistan to confirm littleseed canarygrass resistance to fenoxaprop-P-ethyl and to appraise the efficacy of other postemergence herbicides against this grassy weed. A field survey was conducted to collect putative fenoxaprop-resistant seeds from various districts of the central Punjab in March 2015. Dose-response assays were conducted in the greenhouse to confirm resistance to fenoxaprop. The response of fenoxaprop-resistant littleseed canarygrass to diverse herbicide molecules like clodinafop-propargyl, metribuzin, pinoxaden, and sulfosulfuron was also evaluated in further dose-response bioassays. All accessions manifested variable resistance to fenoxaprop, which ranged from 2.52- to 6.00-fold. The resistant accessions also showed low-level cross-resistance (two-fold) to clodinafop. Metribuzin, pinoxaden, and sulfosulfuron were still effective in controlling fenoxaprop-resistant canarygrass. This is the first scientific documentation of resistance to ACCase inhibitor herbicides in central Punjab, Pakistan. The use of alternative herbicides in conjunction with other agronomic practices is crucial for sustainable wheat production in the country. (author)

Assessing the Economic Impact of inversion tillage, cover crops, and herbicide regimes in palmer amaranth (Amaranthus palmeri) infested cotton

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Cotton (Gossypium hirsutum L.) producers in Alabama and across the Cotton Belt are faced with a rapidly expanding problem that decreases yields and increases production costs: herbicide-resistant weeds. Producers are increasingly relying on production methods that raise production costs, such as add...

Weed interference with peppermint (Mentha x piperita L.) and spearmint (Mentha spicata L.) crops under different herbicide treatments: effects on biomass and essential oil yield.

Science.gov (United States)

Karkanis, Anestis; Lykas, Christos; Liava, Vasiliki; Bezou, Anna; Petropoulos, Spyridon; Tsiropoulos, Nikolaos

2018-01-01

'Minor crops' such as spearmint and peppermint are high added value crops, despite the fact that their production area is comparably small worldwide. The main limiting factor in mint commercial cultivation is weed competition. Thus, field experiments were carried out to evaluate the effects of weed interference on growth, biomass and essential oil yield in peppermint and spearmint under different herbicide treatments. The application of pendimethalin and oxyfluorfen provided better control of annual weeds resulting in higher crop yield. Additionally, when treated with herbicides both crops were more competitive against annual weeds in the second year than in the first year. All pre-emergence herbicides increased biomass yield, since pendimethalin, linuron and oxyfluorfen reduced the density of annual weeds by 71-92%, 63-74% and 86-95%, respectively. Weed interference and herbicide application had no effect on essential oil content; however, a relatively strong impact on essential oil production per cultivated area unit was observed, mainly due to the adverse effect of weed interference on plant growth. Considering that pendimethalin and oxyfluorfen were effective against annual weeds in both spearmint and peppermint crops, these herbicides should be included in integrated weed management systems for better weed management in mint crops. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor

Energy Technology Data Exchange (ETDEWEB)

Elsayed, O.F. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Maillard, E. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Vuilleumier, S. [Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Imfeld, G., E-mail: imfeld@unistra.fr [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France)

2014-11-15

Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold{sup ®} contaminated water (960 g L{sup −1} of the herbicide S-metolachlor, > 80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was > 40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93–97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p = 0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems. - Highlights: • We evaluated the bacterial composition in wetlands treating S-metolachlor • Hydraulic regime impacted biogeochemical processes and S-metolachlor removal �

Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor

International Nuclear Information System (INIS)

Elsayed, O.F.; Maillard, E.; Vuilleumier, S.; Imfeld, G.

2014-01-01

Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold ® contaminated water (960 g L −1 of the herbicide S-metolachlor, > 80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was > 40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93–97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p = 0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems. - Highlights: • We evaluated the bacterial composition in wetlands treating S-metolachlor • Hydraulic regime impacted biogeochemical processes and S-metolachlor removal �

Resistência de plantas daninhas aos herbicidas Weed resistance to herbicides

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Pedro J. Christoffoleti

1994-01-01

Full Text Available A resistência de plantas daninhas aos herbicidas ocorre em função de um processo evolutivo. O desenvolvimento de biótipos de plantas daninhas resistentes é imposto pela agricultura moderna, através da pressão de seleção causada pelo uso intensivo dos herbicidas. O conhecimento dos mecanismos e fatores que favorecem o aparecimento de biótipos de plantas daninhas resistentes é fundamental para que técnicas de manejo sejam utilizadas no sentido de evitar ou retardar o aparecimento de plantas resistentes em uma área. São poucos os relatos ou citações de literatura no Brasil. Sendo assim, este trabalho de revisão procura relatar os principais avanços e descobertas na área de plantas daninhas resistentes aos herbicidas.Weed herbicide resistance has evolved from weed evolution. The modern agriculture is responsible for this evolution because of the intensive use of herbicides. The knowledge of mechanisms and factors that influence the weed herbicide resistance play an important role in the weed manegement techniques used to avoid or delay herbicide resistance appearence. There are not many report or scientific papers about herbi cide resistance in Brasil. Therefore, this literature review aims to provide information about the main advances and discoveries in the field of weed herbicide resistance.

Inheritance and mechanism of resistance to herbicides inhibiting acetolactate synthase in Sonchus oleraceus L.

Science.gov (United States)

Boutsalis, P; Powles, S B

1995-07-01

A biotype of Sonchus oleraceus L. (Compositae) has developed resistance to herbicides inhibiting acetolactate synthase (ALS) following field selection with chlorsulfuron for 8 consecutive years. The aim of this study was to determine the inheritance and mechanism of resistance in this biotype. Determination of ALS activity and inhibition kinetics revealed that Km and Vmax did not vary greatly between the resistant and susceptible biotypes. ALS extracted from the resistant biotype was resistant to five ALS-inhibiting herbicides in an in vitro assay. ALS activity from the resistant biotype was 14 19, 2, 3 and 3 times more resistant to inhibition by chlorsulfuron, sulfometuron, imazethapyr, imazapyr and flumetsulam, respectively, than the susceptible biotype. Hybrids between the resistant and a susceptible biotype were produced, and inheritance was followed through the F1, F2 and F3 generations. F1 hybrids displayed a uniform intermediate level of resistance between resistant and susceptible parents. Three distinct phenotypes, resistant, intermediate and susceptible, were identified in the F2 generation following chlorsulfuron application. A segregation ratio of 1∶2∶1 was observed, indicative of the action of a single, nuclear, incompletely dominant gene. F3 families, derived from intermediate F2 individuals, segregated in a similar manner. Resistance to herbicides inhibiting ALS in this biotype of S. oleraceus is due to the effect of a single gene coding for a resistant form of the target enzyme, ALS.

A further evaluation of herbicides for post-emergence use in short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Turnbull, D.J.

2002-07-01

This report describes a study of the safety and efficacy of a range of herbicides and mixtures of herbicides (with both contact and residual activity) for the post-emergence control of weeds in newly planted willow short rotation coppice (SRC). Severe competition from weeds that have not been controlled adequately by pre-emergence herbicide application is one of the commonest causes of SRC crop failure. In the study, the effects of 11 herbicide treatments currently recommendation for weed control with cereals, legumes or potatoes were compared with an untreated control. There was minimal crop death from any treatment, though most of the treatments caused varying degrees of phytotoxicity. Two commercial products, Reflex T and Impuls, gave the best overall crop safety and weed control results. The report provides growers of SRC and their advisors with some information on how to achieve improved weed control in SRC fields, and recommends that British Biogen (the trade industry body) should consider the compilation of a technical register of herbicide applications based on information supplied by growers and advisers, including field treatment details.

Seasonal variability in irradiance affects herbicide toxicity to the marine flagellate Dunaliella tertiolecta

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Sascha eSjollema

2014-06-01

Full Text Available Photosynthetically Active Radiation (PAR and Ultraviolet Radiation (UVR of the solar spectrum affect microalgae directly and modify the toxicity of phytotoxic compounds present in water. As a consequence seasonal variable PAR and UVR levels are likely to modulate the toxic pressure of contaminants in the field. Therefore the present study aimed to determine the toxicity of two model contaminants, the herbicides diuron and Irgarol®1051, under simulated irradiance conditions mimicking different seasons. Irradiance conditions of spring and autumn were simulated with a set of Light Emitting Diodes (LEDs. Toxicity of both herbicides was measured individually and in a mixture by determining the inhibition of photosystem II efficiency (ΦPSII of the marine flagellate Dunaliella teriolecta using Pulse Amplitude Modulation (PAM fluorometry. Toxicity of the single herbicides was higher under simulated spring irradiance than under autumn irradiance and this effect was also observed for mixtures of the herbicides. This irradiance dependent toxicity indicates that herbicide toxicity in the field is seasonally variable. Consequently toxicity tests under standard light conditions may overestimate or underestimate the toxic effect of phytotoxic compounds.

Seletivicty of eucalyptus genotypes to herbicides rates / Seletividade de genótipos de eucalipto a doses de herbicidas

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Siumar Pedro Tironi

2010-09-01

Full Text Available The aim of this work was to quantify the herbicide selectivity applied at post-emergence of eucalyptus in different rates. The experiment was conducted in greenhouse conditions in the period from January to March 2007 at the Faculdade de Agronomia Eliseu Maciel in Universidade Federal de Pelotas – Capão do Leão-RS. Experimental design was completely randomized, with four replications. Treatments were in a factorial scheme: factor A - eucalyptus genotypes (E. globulus e E. saligna, factor B - herbicides (isoxaflutole, oxyfluorfen, bispyribac-sodium and sethoxydim+diclosulam, and factor C – rates of the registered average for weed control (0, 50, 100, 150 e 200%. Phytotoxicity, height, stem diameter and dry matter were evaluated. E. globulus genotype was more sensitive to herbicides than E. saligna. The mixture of the herbicides sethoxydim plus diclosulam showed potential to be used in eucalyptus. Bispyribac-sodium herbicide was the most toxic and isoxaflutole was the most selective to the studied genotypes.O objetivo deste trabalho foi quantificar a seletividade de herbicidas aplicados em pós-emergência na cultura do eucalipto em função de diferentes doses. O experimento foi realizado em casa de vegetação, pertencente a Faculdade de Agronomia Eliseu Maciel da Universidade Federal de Pelotas, no Município de Capão do Leão – RS, no período de janeiro a março de 2007. O delineamento experimental utilizado foi completamente casualizado, com quatro repetições. Os tratamentos foram arranjados em esquema fatorial, onde o fator A testou genótipos de eucalipto (E. globulus e E. saligna, o fator B comparou quatro herbicidas (isoxaflutole, oxyfluorfen, bispyribac-sodium e sethoxydim+diclosulam e o fator C doses (0, 50, 100, 150 e 200% da dose média registrada para controle de plantas daninhas. As variáveis avaliadas foram fitotoxicidade, estatura, diâmetro do caule e matéria seca da parte aérea das plantas de eucalipto. O gen

Evaluation of herbicides photodegradation by photo-Fenton process using multivariate analysis

Energy Technology Data Exchange (ETDEWEB)

Paterlini, W.C.; Nogueira, R.F.P. [Inst. of Chemistry, Sao Paulo State Univ., R. Prof. Francisco Degni s/n, Araraquara, SP (Brazil)

2003-07-01

The photodegradation of herbicides in aqueous medium by photo-Fenton process using ferrioxalate complex (FeOx) as a source of Fe{sup 2+} was evaluated under blacklight irradiation. The commercial products of the herbicides tebuthiuron, 2,4-D and diuron were used. Multivariate analysis was used to evaluate the role of two variables in the photodegradation process, FeOx and hydrogen peroxide concentrations, and to define the concentration ranges that result in the most efficient photodegradation of the herbicides. The photodegradation of the herbicides was followed by monitoring the decrease of the original compounds concentration by HPLC, by the determination of remaining total organic carbon content (TOC), and by the chloride ion release. Under optimised conditions, 20 minutes irradiation was enough to remove 92.7% of TOC for 2,4 D and 89.5% for diuron. Complete dechlorination of these compounds was achieved after 10 minutes of irradiation. It was observed that the initial concentration of these compounds and tebuthiuron was reduced to less than 15% after only 1 minute of irradiation. (orig.)

Advanced oxidation of commercial herbicides mixture: experimental design and phytotoxicity evaluation.

Science.gov (United States)

López, Alejandro; Coll, Andrea; Lescano, Maia; Zalazar, Cristina

2017-05-05

In this work, the suitability of the UV/H 2 O 2 process for commercial herbicides mixture degradation was studied. Glyphosate, the herbicide most widely used in the world, was mixed with other herbicides that have residual activity as 2,4-D and atrazine. Modeling of the process response related to specific operating conditions like initial pH and initial H 2 O 2 to total organic carbon molar ratio was assessed by the response surface methodology (RSM). Results have shown that second-order polynomial regression model could well describe and predict the system behavior within the tested experimental region. It also correctly explained the variability in the experimental data. Experimental values were in good agreement with the modeled ones confirming the significance of the model and highlighting the success of RSM for UV/H 2 O 2 process modeling. Phytotoxicity evolution throughout the photolytic degradation process was checked through germination tests indicating that the phytotoxicity of the herbicides mixture was significantly reduced after the treatment. The end point for the treatment at the operating conditions for maximum TOC conversion was also identified.

A glutathione s-transferase confers herbicide tolerance in rice

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Tingzhang Hu

2014-07-01

Full Text Available Plant glutathione S-transferases (GSTs have been a focus of attention due to their role in herbicide detoxification. OsGSTL2 is a glutathione S-transferase, lambda class gene from rice (Oryza sativa L.. Transgenic rice plants over-expressing OsGSTL2 were generated from rice calli by the use of an Agrobacterium transformation system, and were screened by a combination of hygromycin resistance, PCR and Southern blot analysis. In the vegetative tissues of transgenic rice plants, the over-expression of OsGSTL2 not only increased levels of OsGSTL2 transcripts, but also GST and GPX expression, while reduced superoxide. Transgenic rice plants also showed higher tolerance to glyphosate and chlorsulfuron, which often contaminate agricultural fields. The findings demonstrate the detoxification role of OsGSTL2 in the growth and development of rice plants. It should be possible to apply the present results to crops for developing herbicide tolerance and for limiting herbicide contamination in the food chain.

In vitro sensitivity of antagonistic Trichoderma atroviride to herbicides

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Patricia Helena Santoro

2014-04-01

Full Text Available Trichoderma atroviride was tested in vitro for its sensitivity to different herbicides. The dosages tested were recommended dosage (RD, half dosage (½RD, and double dosage (2RD. Germination, colony-forming units (CFU, radial growth, and spore production were evaluated. Carfentrazone-ethyl and sulfentrazone inhibited the germination at RD and 2RD. A reduction in the CFU was observed for glufosinate-ammonium, atrazine, carfentrazone-ethyl, diuron + paraquat dichloride, imazapyr, oxyfluorfen, and sulfentrazone at each of the tested dosages. Radial growth was influenced by ametryn, atrazine, carfentrazone-ethyl, oxyfluorfen, and sulfentrazone herbicides, with an 80% reduction of the colonial area. Spore production was affected by carfentrazone-ethyl, oxyfluorfen, and sulfentrazone with colonial area reductions of over 70%. It was concluded that 2,4 D, clomazone, and imazapyr herbicides showed the least toxicity to T. atroviride and should be used in the crops where the fungus has been applied for phytopathogen control.

The role of herbicides for enhancing productivity and conserving land for biodiversity in North America

Science.gov (United States)

Robert G. Wagner; Michael Newton; Elizabeth C. Cole; James H. Miller; Barry D. Shiver

2004-01-01

Herbicide technology has evolved with forest management in North America over the past 60 years and has become an integral part of modern forestry practice. Forest managers have prescribed herbicides to increase reforestation success and long-term timber yields. Wildlife managers and others interested in conserving biodi- versity, however, have often viewed herbicide...

Determination of fluorate pesticides concentration in commercial formulas by Fluorine-19 low resolution NMR

International Nuclear Information System (INIS)

Colnago, Luiz A.; Vaz, Carlos M.P.

1997-01-01

The utilization of herbicides in the agriculture has been becoming a practice more and more controlled by national and international laws, as these compounds are highly toxic and used in large amounts. Therefore, it is necessary to establish accurate, low cost, and fast analytical chemical procedures for the correct determination of commercial composition of herbicides. This work evaluated the utilization of low resolution nuclear magnetic resonance for the quantitative chemical analysis of trifluraline herbicide in commercial formulas. Results are presented

iMAR: An Interactive Web-Based Application for Mapping Herbicide Resistant Weeds.

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Silvia Panozzo

Full Text Available Herbicides are the major weed control tool in most cropping systems worldwide. However, the high reliance on herbicides has led to environmental issues as well as to the evolution of herbicide-resistant biotypes. Resistance is a major concern in modern agriculture and early detection of resistant biotypes is therefore crucial for its management and prevention. In this context, a timely update of resistance biotypes distribution is fundamental to devise and implement efficient resistance management strategies. Here we present an innovative web-based application called iMAR (interactive MApping of Resistance for the mapping of herbicide resistant biotypes. It is based on open source software tools and translates into maps the data reported in the GIRE (Italian herbicide resistance working group database of herbicide resistance at national level. iMAR allows an automatic, easy and cost-effective updating of the maps a nd provides two different systems, "static" and "dynamic". In the first one, the user choices are guided by a hierarchical tree menu, whereas the latter is more flexible and includes a multiple choice criteria (type of resistance, weed species, region, cropping systems that permits customized maps to be created. The generated information can be useful to various stakeholders who are involved in weed resistance management: farmers, advisors, national and local decision makers as well as the agrochemical industry. iMAR is freely available, and the system has the potential to handle large datasets and to be used for other purposes with geographical implications, such as the mapping of invasive plants or pests.

An evaluation of herbicides for post-emergence use in short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Turnbull, D.J.

2000-07-01

The objective of the project was to evaluate the safety and efficacy of a range of herbicides and mixtures of herbicides, with both contact and residual activity, for the post-emergence control of weeds in newly planted willow short rotation coppice (SRC). This report provides growers and advisers of short rotation coppice with important (but still limited) information on how to achieve improved weed control of problem weeds increasingly prevalent in SRC fields. This may provide guidance towards often-essential emergency treatments when the crop establishment is under considerable pressure and the potential safety, or otherwise, of certain weed-specific herbicides. (author)

Selecting downscaled climate projections for water resource impacts and adaptation

Science.gov (United States)

Vidal, Jean-Philippe; Hingray, Benoît

2015-04-01

variables - climate change signal in temporally and spatially integrated variables - has been carefully made with respect their relevance for water resource management. This work proposes a twofold assessment of this selection approach. First, a climate validation allows checking the selection response of more extreme climate variables critical for hydrological impacts as well as spatially distributed ones. Second, a hydrological validation allows checking the selection response of streamflow variables relevant for water resource management. Findings highlight that such validations may critically help preventing misinterpretations and misuses of impact model ensemble outputs for integrated adaptation purposes. This work is part of the GICC R2D2-2050 project (Risk, water Resources and sustainable Development of the Durance catchment in 2050) and the EU FP7 COMPLEX project (Knowledge Based Climate Mitigation Systems for a Low Carbon Economy). Christierson, B. v., Vidal, J.-P., & Wade, S. D. (2012) Using UKCP09 probabilistic climate information for UK water resource planning}. J. Hydrol., {424-425}, 48-67. doi: 10.1016/j.jhydrol.2011.12.020} Lafaysse, M.; Hingray, B.; Terray, L.; Mezghani, A. & Gailhard, J. (2014) Internal variability and model uncertainty components in future hydrometeorological projections: The Alpine Durance basin. Water Resour. Res., {50}, 3317-3341. doi: 10.1002/2013WR014897 Vidal, J.-P. & Hingray, B. (2014) A framework for identifying tailored subsets of climate projections for impact and adaptation studies. EGU2014-7851

Degradation and movement in soil of the herbicide isoproturon analyzed by a Photosystem II-based biosensor.

Science.gov (United States)

Malý, J; Klem, K; Lukavská, A; Masojídek, J

2005-01-01

We have examined the persistence and movement of a urea-type herbicide, isoproturon [IPU; 3-(4-isopropylphenyl)-1,1'-dimethylurea], in soil using a novel herbicide-detection device, the prototype of a portable electrochemical biosensor based on Photosystem II particles immobilized on printed electrodes, and evaluated its results against two other methods: (i) chlorophyll-fluorescence bioassay based on polyphasic induction curves, and (ii) standard analysis represented by liquid chromatography. The data of the herbicide's content determined in soil extracts from field experiments correlated in all three methods. The biosensor assay was effective in determining the herbicide's concentration to as low as 10(-7) M. The results of our experiments also showed the kinetics of movement, degradation, and persistence of isoproturon in various depths of soil. After 6 to 9 wk, almost half of the isoproturon was still actively present in the upper soil layers (0-10 and 10-20 cm) and only 5 to 10% of biological activity was inhibited in the deeper soil layer tested (20-30 cm). Thus, inhibition within the limit of detection of both bioassays could be observed up to 9 wk after application in all profiles (0-30 cm), whereas inhibition persisted for up to 11 wk in the upper soil profile (0-10 cm). The use of the biosensor demonstrated its possibility for making rapid and cheap phytotoxicity tests. Our biosensor can give preliminary information about the biological activity of isoproturon in hours--much faster than growth biotests that may take several days or more.

Integrated Palmer Amaranth Management in Glufosinate-Resistant Cotton: I. Soil-Inversion, High-Residue Cover Crops and Herbicide Regimes

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Michael G. Patterson

2012-11-01

Full Text Available A three year field experiment was conducted to evaluate the role of soil-inversion, cover crops and herbicide regimes for Palmer amaranth between-row (BR and within-row (WR management in glufosinate-resistant cotton. The main plots were two soil-inversion treatments: fall inversion tillage (IT and non-inversion tillage (NIT. The subplots were three cover crop treatments: crimson clover, cereal rye and winter fallow; and sub subplots were four herbicide regimes: preemergence (PRE alone, postemergence (POST alone, PRE + POST and a no herbicide check (None. The PRE herbicide regime consisted of a single application of pendimethalin at 0.84 kg ae ha−1 plus fomesafen at 0.28 kg ai ha−1. The POST herbicide regime consisted of a single application of glufosinate at 0.60 kg ai ha−1 plus S-metolachlor at 0.54 kg ai ha−1 and the PRE + POST regime combined the prior two components. At 2 weeks after planting (WAP cotton, Palmer amaranth densities, both BR and WR, were reduced ≥90% following all cover crop treatments in the IT. In the NIT, crimson clover reduced Palmer amaranth densities >65% and 50% compared to winter fallow and cereal rye covers, respectively. At 6 WAP, the PRE and PRE + POST herbicide regimes in both IT and NIT reduced BR and WR Palmer amaranth densities >96% over the three years. Additionally, the BR density was reduced ≥59% in no-herbicide (None following either cereal rye or crimson clover when compared to no-herbicide in the winter fallow. In IT, PRE, POST and PRE + POST herbicide regimes controlled Palmer amaranth >95% 6 WAP. In NIT, Palmer amaranth was controlled ≥79% in PRE and ≥95% in PRE + POST herbicide regimes over three years. POST herbicide regime following NIT was not very consistent. Averaged across three years, Palmer amaranth controlled ≥94% in PRE and PRE + POST herbicide regimes regardless of cover crop. Herbicide regime effect on cotton yield was highly significant; the maximum cotton yield was

Low light and low ammonium are key factors for guayule leaf tissue shoot organogenesis and transformation.

Science.gov (United States)

Dong, Niu; Montanez, Belen; Creelman, Robert A; Cornish, Katrina

2006-02-01

A new method has been developed for guayule tissue culture and transformation. Guayule leaf explants have a poor survival rate when placed on normal MS medium and under normal culture room light conditions. Low light and low ammonium treatment greatly improved shoot organogenesis and transformation from leaf tissues. Using this method, a 35S promoter driven BAR gene and an ubiquitin-3 promoter driven GUS gene (with intron) have been successfully introduced into guayule. These transgenic guayule plants were resistant to the herbicide ammonium-glufosinate and were positive to GUS staining. Molecular analysis showed the expected band and signal in all GUS positive transformants. The transformation efficiency with glufosinate selection ranged from 3 to 6%. Transformation with a pBIN19-based plasmid containing a NPTII gene and then selection with kanamycin also works well using this method. The ratio of kanamycin-resistant calli to total starting explants reached 50% in some experiments.

Biological Efficacy of Herbicides for Weed Control in Noncropped Areas

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Tsvetanka Dimitrova

2009-01-01

Full Text Available An increasing problem facing agricultural producers is the invasion of weeds, perennial in particular, so that implementation of industrial technologies is impossible without their highly efficient and rational control. For the purpose of studying efficient herbicides for weed control in noncropped areas (stubbles, a biological study of five total systemic herbicides was conducted in areas under natural weed infestation and pressure from othersurrounding weeds at the Institute of Forage Crops in Pleven in 2005-2007. The trials were carried out in field conditions using the block method with plot size of 20 m². Treatment was conducted at the predominant stage of budding of perennial dicotyledonous weeds and earing of monocotyledonous weeds. Herbicidal efficacy was recorded on the EWRS 9-score scale (0-100% killed weeds = score 9-1. It was found that treatment of noncropped areas (stubbles with the total systemic herbicides Touchdown System 4 (360 g/l glyphosate; Cosmic (360 g/l glyphosate; Roundup Plus (441 g/l glyphosate potassium salt; Leon 36 SL (360 g/l glyphosate and Glyphos Super 45 SL (450 g/l glyphosate was highly efficient, so that it was a successful element of a strategy for controlling weeds of different biological groups, and was especially effective against perennial weeds.

Perinatal exposure to glufosinate ammonium herbicide impairs neurogenesis and neuroblast migration through cytoskeleton destabilization

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Ameziane Herzine

2016-08-01

Full Text Available Neurogenesis, a process of generating functional neurons from neural precursors, occurs throughout life in restricted brain regions such as the subventricular zone (SVZ. During this process, newly generated neurons migrate along the rostral migratory stream to the olfactory bulb to replace granule cells and periglomerular neurons. This neuronal migration is pivotal not only for neuronal plasticity but also for adapted olfactory based behaviors. Perturbation of this highly controlled system by exogenous chemicals has been associated with neurodevelopmental disorders. We reported recently that perinatal exposure to low dose herbicide glufosinate ammonium (GLA, leads to long lasting behavioral defects reminiscent of Autism Spectrum Disorder-like phenotype in the offspring (Laugeray, Herzine et al. 2014 . Herein, we demonstrate that perinatal exposure to low dose GLA induces alterations in neuroblast proliferation within the SVZ and abnormal migration from the SVZ to the olfactory bulbs. These disturbances are not only concomitant to changes in cell morphology, proliferation and apoptosis, but are also associated with transcriptomic changes. Therefore, we demonstrate for the first time that perinatal exposure to low dose GLA alters SVZ neurogenesis. Jointly with our previous work, the present results provide new evidence on the link between molecular and cellular consequences of early life exposure to the herbicide GLA and the onset of ASD-like phenotype later in life.

A further evaluation of herbicides for post-emergence use in short rotation coppice

Energy Technology Data Exchange (ETDEWEB)

Turnbull, D.J.

2002-07-01

This report summarises the findings of a project evaluating the safety and efficiency of eleven herbicides for controlling weeds in newly plated willow short rotation coppices, and provides growers with information on post-emergence herbicide options, control of problem weeds, and emergency treatments. Weed germination, crop safety, and the encouraging results obtained using Reflex T and Impuls are discussed. It is suggested that a Technical Register of herbicide applications with contributions by growers and advisers should be considered by the British Biogen trade industry body.

OPERATION RANCH HAND. The Air Force and Herbicides in Southeast Asia, 1961-1971

Science.gov (United States)

1982-01-01

the development of the capability to deliver chemical sprays and powders from aircraft. Spraying poisonous liquids on leaf -eating insect pests ucing...the use the fol- lowing year of the airplane to control leaf worms on cotton plants in Louisi- ana. Air Service planes and pilots were also involved in...attributed to herbicides. The report cautioned, however, that there was some browning of about fifty coconut palm, banana, and betel nut trees that may