Clothianidin loaded TA/Fe (III) controlled-release granules: improve pesticide bioavailability and alleviate oxidative stress

Preparation of Emamectin Benzoate·Hexaflumuron Granules Based on Response Surface Methodology

In order to obtain particles with an optimal loading rate and encapsulation efficiency and to explore the effects of sodium alginate, carboxymethyl chitosan, and bentonite on the particle loading rate and encapsulation rate, the preparation parameters of particles were optimized by the response surface method. A series of particles with constantly changing components were prepared, and the particle loading rate and encapsulation rate were determined. The release experiment of granules in different mass release media was implemented, and the optimal loading rate and encapsulation efficiency of particles were used to control the fall armyworm (FAW). The results showed that when the amount of sodium alginate was 1.83%, that of carboxymethyl chitosan was 0.41% and that of bentonite was 0.37%. The maximum theoretical value based on the response surface simulation was 92.63%, and the actual value at this ratio was 91.61%, which was 98.90% of the theoretical value. The release assay indicated that the mechanism of particle release in 2, 4, and 6 mL of the release medium was non-Fickian diffusion, and the controlled mechanism in 25 mL of the medium was Fickian diffusion. The beads were spread directly into maize leaf whorls in field production; at 14 days after application, the efficacy reached 91.28-98.82%. The combination of emamectin benzoate and hexaflumuron granules has a good control effect on the FAW.

Adsorption-desorption behavior of florpyrauxifen-benzyl on three microplastics in aqueous environment as well as its mechanism and various influencing factors

Microplastics (MPs) and pesticides are two categories contaminants with proposed negative impacts to aqueous ecosystems, and adsorption of pesticides on MPs may result in their long-range transport and compound combination effects. Florpyrauxifen-benzyl, a novel pyridine-2-carboxylate auxin herbicide has been widely used to control weeds in paddy field, but the insights of which are extremely limited. Therefore, adsorption and desorption behaviors of florpyrauxifen-benzyl on polyvinyl chloride (PVC), polyethylene (PE) and disposable face masks (DFMs) in five water environment were investigated. The impacts of various environmental factors on adsorption capacity were evaluated, as well as adsorption mechanisms. The results revealed significant variations in adsorption capacity of florpyrauxifen-benzyl on three MPs, with approximately order of DFMs > PE > PVC. The discrepancy can be attributed to differences in structural and physicochemical properties, as evidenced by various characterization analysis. The kinetics and isotherm of florpyrauxifen-benzyl on three MPs were suitable for different models, wherein physical force predominantly governed adsorption process. Thermodynamic analysis revealed that both high and low temperatures weakened PE and DFMs adsorption, whereas temperature exhibited negligible impact on PVC adsorption. The adsorption capacity was significantly influenced by most environmental factors, particularly pH, cations and coexisting herbicide. This study provides valuable insights into the fate of florpyrauxifen-benzyl in presence of MPs, suggesting that PVC, PE and DFMs can serve as carriers of florpyrauxifen-benzyl in aquatic environment.

Exogenous tannic acid relieves imidacloprid-induced oxidative stress in tea tree by activating antioxidant responses and the flavonoid biosynthetic pathway

Pesticide stress on plants is receiving increased scrutiny due to its effect on plant secondary metabolism and nutritional quality. Tannic acid (TA) is a natural polyphenolic compound showing excellent antioxidant properties and is involved in alleviating stress. The present study thoroughly investigated the effects and mechanism of exogenous TA on relieving imidacloprid (IMI) stress in tea plants. Our research found that TA(10 mg/L) activated the antioxidant defense system, enhanced the antioxidant ability, reduced the accumulation of ROS and membrane peroxidation, and notably promoted tea plant tolerance to imidacloprid stress. Additionally, TA boosted photosynthetic capacity, strengthened the accumulation of nutrients. regulated detoxification metabolism, and accelerated the digestion and metabolism of imidacloprid in tea plants. Furthermore, TA induced significant changes in 90 important metabolites in tea, targeting 17 metabolic pathways through extensively targeted metabolomics. Specifically, TA activated the flavonoid biosynthetic pathway, resulting in a 1.3- to 3.1-fold increase in the levels of 17 compounds and a 1.5- to 63.8-fold increase in the transcript level of related genes, such as ANR, LAR and CHS in this pathway. As a potential tea health activator, TA alleviates the oxidative damage caused by imidacloprid and improves the yield and quality of tea under pesticide stress.

Redox and Near-Infrared Light-Responsive Nanoplatform for Enhanced Pesticide Delivery and Pest Control in Rice: Construction, Efficacy, and Potential Mechanisms

The brown planthopper, Nilaparvata lugens (Stål), is a major rice pest in various Asian countries, causing significant negative impacts on rice yield and quality. In this study, we developed a novel nanoplatform (NIT@MON@CuS) for pesticide delivery that responds to redox and near-infrared light stimuli. The nanoplatform consisted of CuS nanoparticles with mesoporous organic silica (MON), loaded with nitenpyram (NIT). With an average size of 190 nm and a loading efficiency of 22%, NIT@MON@CuS exhibited remarkable thermal response in the near-infrared region, demonstrating excellent photothermal conversion ability and stability. In vitro release kinetics demonstrated the rapid release of nitenpyram under near-infrared light and glutathione conditions, facilitating a satisfactory temperature increase and accelerated drug release. The NIT@MON@CuS-treated group exhibited a higher mortality of N. lugens, increasing from 62 to 88% compared to the group treated with nitenpyram technical after 96 h. Bioassay revealed that NIT@MON@CuS significantly enhanced nitenpyram toxicity by more than 1.4-fold against both laboratory insecticide-resistant and field strains of N. lugens. Furthermore, RT-qPCR results demonstrated that MON@CuS had the capability to reduce P450 gene expression, thereby improving the sensitivity of N. lugens to insecticides. These findings suggest that MON@CuS holds great potential as an intelligent pest control platform, offering a sustainable and efficient approach to protect crops against pests.

Recent Development of Versatile Polyphenol Platforms in Fertilizers and Pesticides

The utilization of agrochemicals has been of significant importance in both the cultivation and disease control of crops. The development of advanced agrochemicals that are both effective and eco-friendly has been made possible through the use of slow delivery platforms and surface modification technology. Inspired by the nature of mussel adhesion, polyphenolic platforms with versatile properties have been extensively employed in various applications, including agro-food, owing to their ability to flexibly modulate chemical and surface characteristics. This mini-review highlights the development of polyphenols, such as polydopamine and tannic acid, in the field of agrochemicals, particularly in the design and production of novel fertilizers and pesticides. The synthetic approach, active ingredient release performance, foliar adhesion, and design of polyphenolic-based agrochemicals in recent years have been discussed to explore their potential applications and limitations. We believe that utilizing versatile polyphenolic materials and their characteristics for agro-food applications can provide innovative ideas and suggestions for developing novel agrochemicals suitable for modern and sustainable horticulture and agriculture.

Modification of sedimentation and bioaccumulation behavior as an efficient strategy to modulate the toxicity of pyraclostrobin to zebrafish (Danio rerio)

The behavior of pesticide particles or droplets might significantly influence their environmental risks. However, studies on the risk of different pesticide formulations in aqueous environments have rarely been reported. In this study, we prepared three types of pyraclostrobin formulations to evaluate their behavior in the aqueous environment and toxicological risks to zebrafish. The results showed that pyraclostrobin emulsifiable concentrate (EC) sank faster in water with increasing hydrophilicity and density of the solvent. The particles also sank faster with increasing particle size and particle density for suspension concentrate (SC) and microcapsules (MCs). Diverse behavior in water results in different temporal and spatial distributions of the active ingredient. EC-EGDA, SC-5 μm, CS-Large and EC-MO sink or float over time, therefore reducing the effective dose suspended in water. Lower toxicological risks of the pesticides were also observed by reducing the enrichment of pyraclostrobin in zebrafish. In addition to the direct toxicity of the active ingredient, the type of pesticide formulations and their specific compositions might also influence the integrated toxicity. The environmental behavior of pesticide formulations should also be considered for their systematic assessment of environmental risks to ensure the scientific application of pesticides in different scenarios.

The simple strategy to improve pesticide bioavailability and minimize environmental risk by effective and ecofriendly surfactants

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.

Degradable Self-Destructive Redox-Responsive System Based on Mesoporous Organosilica Nano-Vehicles for Smart Delivery of Fungicide

The development of stimuli-responsive controlled release formulations is a potential method of improving pesticide utilization efficiency and alleviating current pesticide-related environmental pollution. In this study, a self-destruction redox-responsive pesticide delivery system using biodegradable disulfide-bond-bridged mesoporous organosilica (DMON) nanoparticles as the porous carriers and coordination complexes of gallic acid (GA) and Fe(III) ions as the capping agents were established for controlling prochloraz (PRO) release. The GA-Fe(III) complexes deposited onto the surface of DMON nanoparticles could effectively improve the light stability of prochloraz. Due to the decomposition of GA-Fe(III) complexes, the nano-vehicles had excellent redox-responsive performance under the reducing environments generated by the fungus. The spreadability of PRO@DMON-GA-Fe(III) nanoparticles on the rice leaves was increased due to the hydrogen bonds between GA and rice leaves. Compared with prochloraz emulsifiable concentrate, PRO@DMON-GA-Fe(III) nanoparticles showed better fungicidal activity against Magnaporthe oryzae with a longer duration under the same concentration of prochloraz. More importantly, DMON-GA-Fe(III) nanocarriers did not observe obvious toxicity to the growth of rice seedlings. Considering non-toxic organic solvents and excellent antifungal activity, redox-responsive pesticide controlled release systems with self-destruction properties have great application prospects in the field of plant disease management.

Influence of polyphenol-metal ion-coated ovalbumin/sodium alginate composite nanoparticles on the encapsulation of kaempferol/tannin acid

In this research, ovalbumin (OVA) and sodium alginate (SA) were used as the materials to prepare OVA-SA composite carriers, which protected and encapsulated the hydrophobic kaempferol (KAE) and the hydrophilic tannic acid (TA). To achieve the purpose of targeted delivery, the TA-Fe³⁺ coating film was prepared. Results showed that the observation of small diffraction peaks in carriers proved the formation of TA/Fe³⁺ coating film on the surface of four composite nanoparticles (pOVA, pOVA-SA, pOVA-KAE-SA, and pOVA-KAE-TA-SA). The protein structure of the composite nanoparticles coated with TA/Fe³⁺ changed, and the order of the changes was pOVA-KAE > pOVA > pOVA-KAE-SA > pOVA-KAE-TA-SA > pOVA-SA. This phenomenon is due to the fact that the chromophore -C=O and the auxo-chromophore -OH are in the opposite position in the benzene ring of TA, and the two substituents have opposite effects and synergize, resulting in the different degrees of redshift of the composite nanoparticle λ_max. Additionally, pOVA-SA had the highest α-helix content and the lowest random coils, conferring the protein structure the strongest stability. The coating of TA/Fe³⁺ increased the system stability and the thermal stability of the composite nanoparticles. Additionally, the carriers were endowed with antioxidant activity, and their antibacterial ability against Staphylococcus aureus and Escherichia coli was pOVA-KAE-TA-SA > pOVA-KAE-SA > pOVA-KAE > pOVA-SA > pOVA based on the difference in antibacterial diameter (D, mm) and square (S, mm²). pOVA-KAE-TA-SA had the strongest antioxidant activity and antibacterial ability, which improved the bioavailability of TA/KAE. These results provide a theoretical basis for the application of OVA-SA composite nanoparticles in the delivery of bioactive compounds.

Adsorption-desorption and transport behavior of pydiflumetofen in eight different types of soil

Pydiflumetofen, a fungicide of the class of succinate dehydrogenase inhibitors, can disrupt energy metabolism by inhibiting the synthesis of succinate dehydrogenase, thus effectively inhibiting pathogenic fungal growth and related yield losses.We studied the adsorption and desorption behaviors and interaction mechanisms of pydiflumetofen in eight different arable soils by the infrared spectroscopy and batch equilibrium method. Pydiflumetofen adsorption and desorption property of soils conformed with the Freundlich isotherm model and the values for the adsorption capacity KF-ads were in the range of 14.592-102.610. The adsorption constants (KF-ads) exhibited a significantly positive and linear correlation (p < 0.1) with soil organic matter and organic carbon content. Both high and low temperatures weakened the pydiflumetofen sorption capacity of the soil. In addition, the initial pH of the solution, its ionic strength, and the addition of exogenous biochar, humic acid, and different types of surfactants at different concentrations also affected the sorption property of the soil. Pydiflumetofen is weakly mobile and leachable in most soils, and, poses some threat to surface soil and water organisms, but does not contaminate groundwater.