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1.
Soft Matter ; 16(24): 5650-5658, 2020 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-32514509

RESUMO

The development of an emulsion is an important challenge in many fields, such as agrochemicals, pharmaceutics, paints, cosmetics, inkjet printing, and food science. However, the traditional strategies that refer to the empirical value and complex secondary additives cannot reflect the influence of the structure, content, compound, and adsorption of emulsifiers. Here, we propose a simple and effective strategy to develop the emulsion, wherein the emulsifiers are chosen based on the dilational rheological properties of the interfacial films at the molecular level. The dilational rheological properties of polyoxyethylene (80) castor oil (EL-80), sorbitan monostearate (Span 60), and their emulsions were explored by the oscillating drop method. Based on the dilational rheological properties, the emulsions were prepared by the phase inversion emulsification technique. The results showed that the emulsion was stable and realized effective solid-liquid interfacial interaction, which was attributed to the large dilational modulus (intermolecular interaction) at the oil/water interface and loss modulus (molecular diffusion exchange) at the air/water interface. These factors reduced the Ostwald ripening and coalescence, and finally increased the spreading diameter. Additionally, the prochloraz 25% emulsion in water (EW) and difenoconazole 20% EW were developed to verify the feasibility of the strategy. Therefore, this research advances the understanding of an emulsion by interfacial dilational rheological properties, which can provide a simple and effective strategy to develop a stable emulsion and achieve an effective solid-liquid interfacial interaction of the emulsion.

2.
Molecules ; 24(11)2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31159412

RESUMO

In this research, the maximum retention and wetting behavior of surfactant solutions (N-200, N-300, Tween-80, Morwet EFW, DTAB, SDS) on the surfaces of tea leaves was investigated based on surface free energy, surface tension, the contact angle, adhesion work, and adhesion force. The results showed that the contact angles of all surfactant solutions were kept constant with low adsorption at the tea leaf-liquid interfaces below 0.005%. With an increase in concentration, the contact angle of Tween-80 decreased sharply because the adsorption of molecules at the solid-liquid interfaces (ΓSL') was several times greater than that at the liquid-air interfaces (ΓLV). Adhesion work decreased sharply and then reached a minimum at the critical micelle concentration (CMC), but then increased until reaching a constant. Moreover, a high adhesion force did not indicate better wettability, as it does with rose petals and peanut leaves. For tea leaf surfaces, an increase in the contact angle brought about an increase in the adhesion force. In addition, the maximum retention for Morwet EFW is at different concentrations compared to N-200, N-300, Tween-80, DTAB, and SDS, where the maximum retention of Morwet EFW on tea leaves was 6.05 mg/cm2 at 0.005%.According to the mechanisms of wetting behavior on plant surfaces, a recipe for pesticide formulation can be adjusted with better wettability to reduce loss, improve utilization efficiency, and alleviate adverse effects on the environment.


Assuntos
Folhas de Planta/química , Tensão Superficial , Tensoativos/química , Chá/química , Molhabilidade , Adsorção , Algoritmos , Modelos Teóricos , Folhas de Planta/ultraestrutura
3.
Chemistry ; 24(45): 11703-11710, 2018 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-29878522

RESUMO

The abuse of chemical surfactants in pesticide formulations is a potential threat to agricultural development and environmental safety. Thereby, developing an efficient eco-friendly pesticide formulation is of great significance. In this research, a biocompatible and ultrastable pesticide formulation has been developed in which merely 1 wt % natural glycyrrhizic acid (GA) was used to emulsify and stabilize 80 wt % agricultural oils. During the preparation process, amphiphilic GA molecules initially self-assembled into 1D nanofibers with a favorable surfactivity, and then afforded GA-based Pickering emulsions with fine droplets. Consequently, the Pickering emulsions transformed into gel-like Pickering emulsions as a result of the formation of a 3D network of nanofibers. On account of the unique chemical structure and admirable assembly behavior of GA, the gel-like Pickering emulsions exhibit ultrastability, thixotropy, and broad pH resistance. In addition, this formulation was investigated for its potential application to pesticides by using pure carbosulfan as the oil phase; up to 60 wt % carbosulfan could be coated, which is more than in the current commercial formulations. This work not only provides new insights into the application of natural biosurfactants to pesticides, but also proposes a biocompatible and eco-friendly pesticide formulation for use in ecological agriculture.

4.
Int J Mol Sci ; 19(10)2018 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-30241357

RESUMO

Mesoporous silica nanoparticles (MSNs) can be used as carriers to deliver pesticides into plants, which is considered to be one method of improving the efficacy of pesticide usage in agricultural production. In the present work, MSNs with an average diameter of 258.1 nm were synthesized and loaded with Fenoxanil. The structure of the nanocarriers was observed by scanning electron microscopy. The loading content of Fenoxanil-loaded MSNs was investigated. After rice plants in a hydroponic system were treated with loaded MSNs, the concentrations of Fenoxanil in different samples were determined using high-performance liquid chromatography⁻tandem mass spectrometry. The results suggested that rice plants can absorb MSNs from water through their roots, and the dosage has almost no effect on the distribution of Fenoxanil in rice plants. The application of pesticide-loaded nanoparticles in a hydroponic system poses a low risk of Fenoxanil accumulation in rice.


Assuntos
Fungicidas Industriais/análise , Nanopartículas/metabolismo , Oryza/metabolismo , Dióxido de Silício/metabolismo , Transporte Biológico , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Medição de Risco
5.
Soft Matter ; 13(2): 503-513, 2017 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-27934995

RESUMO

In this research the wetting behavior of agro-surfactant solutions (Triton X-100, SDS, DTAB) on wheat leaf surfaces have been investigated based on the surface free energy, surface tension, and the contact angle. The results show that the contact angle of those surfactant solutions keeps constant with low adsorption at interfaces below 1 × 10-5 mol L-1. With the increase in concentration, the contact angles of Triton X-100 decrease sharply because the adsorption of molecules at solid-liquid interfaces (ΓSL') is several times greater than that at liquid-air interfaces (ΓLV). With regards to SDS and DTAB, the contact angle also decreases but is even larger than 90° above the CMC, while the ratio of ΓSL' to ΓLV is about 1.20, demonstrating that the Gibbs surface excess is related to the structure of surfactant molecules. Obviously, besides the properties of wheat leaf surfaces and surfactant solutions, the wetting behavior mainly depends on their noncovalent interactions. Among these, the hydrophobic interaction is the main force promoting molecules to adsorb on the surface, with the assistance of the Lifshitz-van der Waals interactions and the electrostatic interactions. According to the mechanism of their wetting behavior on plant surfaces, the recipe of pesticide formulation can be adjusted with better wettability to reduce its loss, consequently improving pesticide utilization and decreasing environmental contamination.


Assuntos
Folhas de Planta/química , Tensoativos/química , Triticum/química , Água/química , Molhabilidade , Adsorção , Ar , Soluções , Tensão Superficial
6.
Langmuir ; 30(46): 13744-53, 2014 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-25357256

RESUMO

The interfacial behavior of ß-casein and lysozyme solutions has been investigated in the presence of an ionic liquid-type imidazolium surfactant ([C16mim]Br) at the decane/water interface. The dynamic dilational properties of the protein/surfactant solutions are investigated by the oscillating drop method and interfacial tension relaxation method. The interfacial tension isotherms for the mixed adsorption layers indicate that the increased addition of [C16mim]Br to a pure protein changes the properties of the complex formed at the decane/water interface. Whereas the interfacial tension data of the protein/surfactant mixed layers do not clearly show differences with changing bulk composition, the dilational rheology provides undoubted evidence that the structure and, in particular, the dynamics of the adsorbed layers depend on the bulk surfactant concentration. The experiment data for ß-casein/[C16mim]Br solutions indicate that at higher bulk [C16mim]Br concentrations, ß-casein in the interfacial layer is subject to conformational changes, where it gives space to [C16mim]Br molecules in the form of coadsorb rather than replacement; in contrast, in lysozyme/[C16mim]Br solutions some lysozyme molecules desorb from the interface due to the competitive adsorption of free [C16mim]Br molecules. Experimental results related to the interfacial dilational properties of the protein/surfactant solutions show that the dilational modulus turns out to be more sensitive to the conformation of protein/surfactant mixture at the liquid interface than the interfacial tension.


Assuntos
Alcanos/química , Caseínas/química , Imidazóis/química , Muramidase/química , Tensoativos/química , Água/química
7.
Soft Matter ; 10(44): 8896-904, 2014 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-25278154

RESUMO

The dynamic interfacial properties of mixed solutions of bovine serum albumin (BSA) and the ionic liquid-type imidazolium surfactant ([C16mim]Br) were measured as a function of the interface age, surfactant concentration and solution pH. Three BSA conformers were investigated: the normal N form as well as the fast F and aged A forms, corresponding to the different solution pH, respectively. The interfacial tension and the interfacial dilational elasticity isotherms for the mixed adsorption layers indicate that the addition of [C16mim]Br to the different structures of BSA isomers influences the properties of the adsorption layer at the decane/water interface. The addition of [C16mim]Br does not influence the structure of the protein at pH below the isoelectric point of BSA, but at higher solution pH, the addition of surfactants significantly influences the dynamic interfacial properties of BSA solutions due to the electrostatic interaction between the components.


Assuntos
Imidazóis/química , Soroalbumina Bovina/química , Tensoativos/química , Adsorção , Elasticidade , Concentração de Íons de Hidrogênio , Concentração Osmolar
8.
Soft Matter ; 10(35): 6810-9, 2014 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-25079107

RESUMO

The interfacial rheological property is closely related to the stabilities of foams and emulsions, yet there have been limited studies on the interaction between proteins with ionic liquid-type imidazolium surfactants at the decane-water interface as well as in the bulk. Herein, we investigated the interfacial and bulk properties of pepsin (PEP) and an ionic liquid (IL), 1-hexadecyl-3-methylimidazolium bromide, [C(16)mim]Br. The interfacial pressure and dilational rheology studies were performed to describe the formation of [C(16)mim]Br-pepsin complexes. The influence of the oscillating frequency and the bulk concentration of [C(16)mim]Br on the dilational properties were explored. The conformational changes were studied by monitoring the fluorescence and far UV-CD spectra. The results reveal that the globular structure of pepsin is one of the decisive factors controlling the nature of the interfacial film. The monotonous increase in the dilational elastic modulus of pepsin-[C(16)mim]Br solutions with the surface age indicates that no loops and tails had formed. Interestingly, with an increase in the concentration of [C(16)mim]Br, the εd-c curve first passes through a plateau value due to steric hindrance and the electrostatic barrier of already absorbed tenacious pepsin-[C(16)mim]Br complexes. With the further addition of [C(16)mim]Br, the remarkable decrease in dilational elastic modulus indicates that the compact structure is destroyed gradually. The results of the fluorescence spectra and far UV-CD spectra confirm that [C(16)mim]Br did not produce perceptible changes in pepsin at the concentrations studied in the dilational experiment. Possible schematic programs of the pepsin-[C(16)mim]Br interaction model at the interface and in bulk phase are proposed.


Assuntos
Imidazóis/química , Pepsina A/química , Reologia/métodos , Animais , Bromo/química , Dicroísmo Circular , Mucosa Gástrica/metabolismo , Concentração de Íons de Hidrogênio , Líquidos Iônicos , Cinética , Espectroscopia de Ressonância Magnética , Oscilometria , Pressão , Conformação Proteica , Proteínas/química , Espectrometria de Fluorescência , Espectrofotometria , Espectrofotometria Ultravioleta , Eletricidade Estática , Tensoativos/química , Suínos , Água/química
9.
Sci Total Environ ; 942: 173697, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-38851350

RESUMO

Surfactants as synergistic agents are necessary to improve the stability and utilization of pesticides, while their use is often accompanied by unexpected release into the environment. However, there are no efficient strategies available for screening low-toxicity surfactants, and traditional toxicity studies rely on extensive experimentation which are not predictive. Herein, a commonly used agricultural adjuvant Triton X (TX) series was selected to study the function of amphipathic structure to their toxicity in zebrafish. Molecular dynamics (MD) simulations, transcriptomics, metabolomics and machine learning (ML) were used to study the toxic effects and predict the toxicity of various TX. The results showed that TX with a relatively short hydrophilic chain was highly toxic to zebrafish with LC50 of 1.526 mg/L. However, TX with a longer hydrophilic chain was more likely to damage the heart, liver and gonads of zebrafish through the arachidonic acid metabolic network, suggesting that the effect of surfactants on membrane permeability is the key to determine toxic results. Moreover, biomarkers were screened through machine learning, and other hydrophilic chain lengths were predicted to affect zebrafish heart health potentially. Our study provides an advanced adjuvants screening method to improve the bioavailability of pesticides while reducing environmental impacts.


Assuntos
Aprendizado de Máquina , Simulação de Dinâmica Molecular , Praguicidas , Peixe-Zebra , Animais , Praguicidas/toxicidade , Tensoativos/toxicidade , Poluentes Químicos da Água/toxicidade , Octoxinol/toxicidade
10.
ACS Nano ; 18(13): 9486-9499, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38497998

RESUMO

Agrichemical losses are a severe threat to the ecological environment. Additionally, some agrichemical compounds contain abundant salt, which increases the instability of formulations, leading to a lower agrichemical utilization and soil hardening. Fortunately, the biological amphiphilic emulsifier sodium deoxycholate alleviates these problems by forming stable Janus core-shell emulsions through salinity-driven interfacial self-assembly. According to the interfacial behavior, dilational rheology, and molecular dynamics simulations, Janus-emulsion molecules are more closely arranged than traditional-emulsion molecules and generate an oil-water interfacial film that transforms into a gel film. In addition, at the same spray volume, the deposition area of the Janus emulsion increased by 37.70% compared with that of the traditional emulsion. Owing to the topology effect and deformation, the Janus emulsion adheres to rice micropapillae, achieving better flush resistance. Meanwhile, based on response of the Janus emulsion to stimulation by carbon dioxide (CO2), the emulsion lost to the soil can form a rigid shell for inhibiting the release of pesticides and metal ions from harming the soil. The pyraclostrobin release rate decreased by 50.89% at 4 h after the Janus emulsion was exposed to CO2. The Chao1 index of the Janus emulsion was increased by 12.49% as compared to coconut oil delivery in soil microbial community. The Janus emulsion ingested by harmful organisms can be effectively absorbed in the intestine to achieve better control effects. This study provides a simple and effective strategy, which turns waste into treasure, by combining metal ions in agrichemicals with natural amphiphilic molecules to prepare stable emulsions for enhancing agrichemical rainfastness and weakening environmental risk.


Assuntos
Agroquímicos , Salinidade , Emulsões/química , Dióxido de Carbono , Íons , Solo
11.
J Sep Sci ; 36(13): 2196-202, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23596154

RESUMO

An ultrasound-enhanced in situ solvent formation microextraction has been developed first time and compared with ultrasound-enhanced ionic-liquid-assisted dispersive liquid-liquid microextraction for the HPLC analysis of acaricides in environmental water samples. A ionic liquid ([C8MIM][PF6]) was used as the green extraction solvent through two pathways. The experimental parameters, such as the type and volume of both of the extraction solvent disperser solvent, ultrasonication time, and salt addition, were investigated and optimized. The analytical performance using the optimized conditions proved the feasibility of the developed methods for the quantitation of trace levels of acaricides by obtaining limits of detection that range from 0.54 to 3.68 µg/L. The in situ solvent formation microextraction method possesses more positive characteristics than the ionic-liquid-assisted dispersive liquid-liquid microextraction method (except for spirodiclofen determination) when comparing the validation parameters. Both methods were successfully applied to determining acaricides in real water samples.


Assuntos
Acaricidas/análise , Cromatografia Líquida de Alta Pressão/métodos , Ultrassom , Poluentes Químicos da Água/análise , Limite de Detecção
12.
Pest Manag Sci ; 79(7): 2603-2610, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36883550

RESUMO

BACKGROUND: Neonicotinoids are among the most essential chemical insecticides worldwide because of their high activity against many important pests and wide application. However, their application is limited by their toxicity to honeybees. Therefore, the development of a facile route to fabricate efficient and eco-friendly pesticide formulations is of great significance. RESULTS: In this study, clothianidin-loaded zeolitic imidazolate framework-8 (CLO@ZIF-8) nanoparticles were fabricated by a facile one-pot route using zinc nitrate as a Zn2+ source and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, energy-dispersive spectrometry and Fourier transform infrared spectroscopy. Based on the pH response of ZIF-8, a 'burst release effect' was observed for CLO@ZIF-8 at pH 3 and 5 within 12 h, in contrast to the slow and sustainable release at pH 8. CLO@ZIF-8 improved the retention ability of the pesticide liquid and remained 70% control efficacy on Nilaparvata lugens after water rinsed of sprayed CLO@ZIF-8. The pH response of CLO@ZIF-8 allowed it to maintain 43% control efficacy against N. lugens after 10 days of application, which was twice the efficacy of clothianidin solution (SCA). Moreover, CLO@ZIF-8 reduced the acute toxicity to honeybees (Apis mellifera) by ≥120-fold compared with SCA. CONCLUSION: This study provides new insights into the application of ZIF-8 to neonicotinoids and suggests the need for the development of a biocompatible and eco-friendly pesticide formulation. © 2023 Society of Chemical Industry.


Assuntos
Inseticidas , Zeolitas , Animais , Abelhas , Neonicotinoides , Guanidinas , Tiazóis , Zeolitas/química
13.
J Agric Food Chem ; 71(3): 1348-1359, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36629458

RESUMO

Glyphosate, one of the most widely used herbicides, plays an important role in controlling weeds and ensuring crop production. While using glyphosate, adjuvants are commonly added to improve its deposition on weeds and control efficacy. However, changes in weed leaf surface characteristics may reduce glyphosate penetration and contribute to evolved glyphosate resistance. Therefore, it is significant to introduce an improved method for regularizing leaf surface characterization and guide adjuvant selection to improve glyphosate efficacy. In this work, surface characteristics of typical weed leaves have been systematically investigated by 3D surface analysis and scanning electron microscopy, finally quantified by apparent surface free energy (ASFE) due to its comprehensive and quantitative evaluation of leaf surfaces. Moreover, the relationship between the weed leaf surface characteristics and the retention of glyphosate on weeds was established, further related to the control efficacy against weeds. To maximize the utilization rate of glyphosate, the types and concentrations of adjuvants should be regulated according to the ASFE of weeds. Our findings not only regularize the surface properties of weed leaves but also reveal their influencing mechanism on the deposition and biological activity of glyphosate, which provide effective guidance for the use of glyphosate.


Assuntos
Herbicidas , Controle de Plantas Daninhas , Controle de Plantas Daninhas/métodos , Resistência a Herbicidas , Produtos Agrícolas , Herbicidas/farmacologia , Plantas Daninhas , Adjuvantes Imunológicos , Folhas de Planta , Glifosato
14.
ACS Appl Mater Interfaces ; 15(30): 37093-37106, 2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37488063

RESUMO

Various strategies have been developed to improve the applicability of hydrophobic pesticides for better effectiveness in agriculture. However, existing formulations of hydrophobic pesticides still suffer from complicated processing, abused organic solvents, indispensable surfactants, or inescapable ecotoxicity, which strictly limit their applications. Herein, a dynamic covalent bond tailored pesticide (fipronil) amphiphile is constructed to address the above issues, which accomplishes the nanodispersion, full wetting, and precise delivery without organic solvents, surfactants, and materials simultaneously. By introducing a hydrophilic ligand on the hydrophobic fipronil through an imine bond, the cleavable fipronil amphiphile (FPP) exhibits superior water solubility and can even self-assemble into micelles at higher concentrations, which can be directly applied in powder form without organic solvents. Attributed to the suitable hydrophilic/hydrophobic ratio, FPP achieves full wetting and effective deposition on superhydrophobic rice leaves without surfactants. Moreover, benefiting from the unique dynamic nature of the imine bond, FPP maintains good storage stability while sensitively releasing back to fipronil under the humidity and pH trigger, consequently implementing the precise delivery for nontarget Apis cerana and target Chilo suppressalis without materials. To our knowledge, this dynamic covalent bond tailored amphiphile strategy is the first idea that simultaneously takes the dispersibility, wettability, and responsiveness of hydrophobic pesticides into account, providing a possibility to control the entire journey of field application and even promising to be incorporated into the synthesis process, thus paving the way for modern sustainable agriculture.

15.
Ecotoxicol Environ Saf ; 79: 75-79, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22195761

RESUMO

A simple analytical method based on QuEChERs was established for diafenthiuron residues in packhoi and soil. The residue levels and diaaipation rates of diafenthiuron in packhoi and soil were detected by HPLC-MS. And ultrasonic extraction was employed in the study to improve extraction effectiveness. At three fortification levels of 0.02, 0.1 and 1 mg/kg in packhoi and soil, recoveries were in the range 74.0 percent-100 percent, with relative standard deviations (RSD) of 6.1-14.8 percent. The limit of quantification (LOQ) of method was 0.02 mg/kg for packhoi and soil. In the supervised field trials, the half-lives of diafenthiuron in packhoi and soil were 1.27 and 5.94 day, respectively. The final residue levels of diafenthiuron could not be detected in soil, while only trace amount of diafenthiuron residues were detected in pakchoi.


Assuntos
Brassica rapa/química , Resíduos de Praguicidas/análise , Feniltioureia/análogos & derivados , Solo/química , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental , Feniltioureia/análise , Poluentes do Solo/análise
16.
Ecotoxicol Environ Saf ; 78: 260-4, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22197645

RESUMO

A LC-ESI-MS/MS method with QuEChERS for analysis of emamectin benzoate in cabbage, apple and soil was established. At fortification levels of 0.001, 0.01 and 0.1 mg/kg in cabbage, apple and soil, it was shown that recoveries ranged from 75.9 to 97.0 percent with relative standard deviation (RSD) of 4.4-19.0 percent. The limit of quantification (LOQ) was 0.001 mg/kg for cabbage, apple and soil. The dissipation half-lives of emamectin benzoate in cabbage, apple and soil were 1.34-1.72 day, 2.75-3.09 day and 1.89-4.89 day, respectively. The final residues of emamectin benzoate ranged from 0.001 to 0.052 mg/kg in cabbages, 0.003 to 0.090 mg/kg in apples and 0.001 to 0.089 mg/kg in soils, respectively. Therefore, it would be unlikely to cause health problems if emamectin benzoate was applied according to the use pattern suggested by the manufactures on the label.


Assuntos
Brassica/química , Inseticidas/análise , Ivermectina/análogos & derivados , Malus/química , Resíduos de Praguicidas/análise , Meia-Vida , Inseticidas/química , Ivermectina/análise , Espectrometria de Massas , Resíduos de Praguicidas/química , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/química , Espectrometria de Massas em Tandem
17.
ACS Appl Mater Interfaces ; 14(49): 55062-55074, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36472305

RESUMO

Hydrogels have been extensively used in agriculture to improve crop yields for their excellent properties. However, they are currently used either as pesticide delivery platforms or water retention agents alone; the combination of these two functions into one agricultural hydrogel formulation has never been reported, which is crucial to promote sustainable development in agriculture. Herein, using poly(ß-cyclodextrin) and adamantane-grafted poly(acrylic acid) (PAA-Ada) as the host and guest, respectively, an easy operating, multi-responsive, and safer hydrogel delivery system for insecticides is fabricated by the host-guest interaction between cyclodextrin and adamantane, which can load uniformly dispersed insecticides (fipronil, imidacloprid, and thiamethoxam) up to 60%. Benefiting from the carboxyl and hydroxyl groups on polymer chains, different temperatures (25, 35, and 45 °C) and pH values (5.0, 6.8, and 10.0) change the intermolecular forces within the hydrogel network and then the diffusion of the content, finally resulting in controlled release behaviors. Besides, this platform can rapidly release the insecticides in the presence of amyloglucosidase due to its ring-opening effect on cyclodextrin. Moreover, this platform exhibits high water-retaining capacity toward soil, which can increase the maximum water absorption of nutrient soil and quartz sand by 31.6 and 13.9%, respectively, and slows down the water loss. Compared with commercial formulation, this smart system reduces the acute toxicity to non-target organism earthworms by 52.4% and improves the efficacy against target organism aphids by 47.3%, showing better durability, lower environmental toxicity, and higher efficiency. To our knowledge, this is the first idea that simultaneously adopts the water-retaining capacity and controlled release ability of hydrogels to improve insecticide efficacy. In this regard, this smart hydrogel platform holds great potentials as slow-release granules with water-holding ability for protection against insect pests, providing an alternative platform for the sustainable development in green agriculture.


Assuntos
Adamantano , Ciclodextrinas , Inseticidas , Água/química , Preparações de Ação Retardada , Solo/química , Hidrogéis/química , Controle de Pragas
18.
Sci Total Environ ; 851(Pt 1): 158169, 2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-35995160

RESUMO

Low pesticide efficiency has caused serious environmental pollution and economic loss, which are closely related to each link in the targeted delivery of pesticides. However, the existing strategies for improving pesticide utilization rate are not comprehensive, and the regulation of foliar absorption and biological activity has been neglected. As surfactants are the most important agricultural synergists, the impact, wetting, adhesion, and leaf retention behaviors of pyraclostrobin (PYR) droplets containing the surfactant Triton X (TX) series on hydrophobic scallion leaf surfaces were studied. The results showed that TX-102 can sufficiently reduce the splash and roll of droplets when they impact inclined leaves, owing to its low dynamic surface tension. Moderate wetting ability and high adhesion also maximizes leaf retention of the TX-102-added PYR solution sprayed on scallion leaves. Furthermore, TX-102 improved the permeation and absorption of PYR in scallion leaves through the synergistic effects of opening the stomata and dissolving the waxy layer. The synergistic bioactivity of TX-102 against pathogenic fungi Alternaria porri and its safety to non-target organism zebrafish have also been demonstrated. Our study provides a more comprehensive theoretical rationale for screening adjuvants to improve the effectiveness and bioavailability of pesticides and reduce the risk of pesticides entering the environment.


Assuntos
Praguicidas , Tensoativos , Animais , Disponibilidade Biológica , Octoxinol , Praguicidas/análise , Estrobilurinas , Tensoativos/química , Molhabilidade , Peixe-Zebra
19.
Pest Manag Sci ; 77(11): 5120-5128, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34240529

RESUMO

BACKGROUND: The wettability of the target surfaces affects the wetting and deposition of pesticides on them. The properties of leaf surfaces change after infestation by Tetranychus urticae Koch. Studying the surface wettability of T. urticae and the changes in leaf wettability after infestation is important to guide the use of acaricides. RESULTS: The body surface of T. urticae is an ellipsoidal crown covered with dense cuticle striations and hairs arranged in different directions, which makes the surface of T. urticae rough and hydrophobic. The abaxial surfaces of the leaves are rougher and more hydrophobic than the adaxial surfaces. After infestation by T. urticae, the faded spots were sunken on the adaxial surface and raised on the abaxial surface, where they had formed new wide peaks and valleys. The adaxial surface became obviously rougher and more hydrophobic, while the roughness of the abaxial surface became slightly larger, and the change in hydrophobicity was not obvious. The contact angles of the studied commercial acaricide on these surfaces were greater than 65° and were affected by the infestation. Reducing the surface tension can allow for better wetting of these surfaces and eliminate changes in leaf wettability. CONCLUSION: The surfaces of kidney bean leaves became more hydrophobic after infestation by T. urticae with hydrophobic surface. The wettability of the acaricide solution should be adjusted according to the changes in leaf wettability. This study has important theoretical guiding significance for improving effective deposition of acaricide.


Assuntos
Acaricidas , Phaseolus , Tetranychidae , Animais , Folhas de Planta , Propriedades de Superfície
20.
Pest Manag Sci ; 77(11): 5246-5254, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34310012

RESUMO

BACKGROUND: Neonicotinoids comprise one of the most extensively used classes of pesticides worldwide owing to their broad insecticidal spectrum and excellent biological performance. However, their toxicity to honeybee (Apis mellifera Linnaeus) and silkworm (Bombyx Mori) limits their further application. To address this issue, clothianidin as a model neonicotinoid was developed into a novel controlled-release formulation employing advantaged solid dispersion (SD) technology using composite carriers. RESULTS: In this research, the clothianidin-loaded SD was characterized using integrated methods to elucidate its formation mechanism, showing that clothianidin was embedded into the carrier homogeneously in small crystalline entities. The composite carriers, which are both renewable and environmentally friendly, can significantly prolong the release of clothianidin from seven to 25 days, compared with that of PEG 8000 as a single carrier. Based on the excellent controlled release profiles, it reduced the acute toxicity to A. mellifera and B. mori by 57.68- and 85.32-fold (respectively) compared with that of the conventional formulation. Furthermore, the SD displayed favorable efficacy and persistency against Asian citrus psyllid (Hemiptera: Psyllidae). CONCLUSION: This novel strategy opens up a simple and powerful avenue for improving efficacy and promoting the environmental safety of neonicotinoid insecticides to be used in sustainable crop protection.


Assuntos
Hemípteros , Animais , Abelhas , Guanidinas/toxicidade , Neonicotinoides/toxicidade , Tiazóis/toxicidade
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