•The microcapsules were prepared using pectin conjugated hollow silica spheres.•The obtained microcapsules had a high loading ability for kasugamycin.•The microcapsules displayed excellent pectinase and GSH dual-responsive properties.•The prepared microcapsules had good photo- and thermal stability.•The kasugamycin microcapsules showed sustained antimicrobial efficacy.Kasugamycin is an aminoglycoside antibiotic originally isolated from Streptomyces kasugaensis, which has been widely used for the management of plant diseases. However, photo-thermal instability and low efficiency limit its application. Therefore, it is an urgent task to prevent unwanted loss of kasugamycin and ensure maximum bioactivity at target site. In this work, a novel formulation of kasugamycin that responds to different biological stimuli produced by pests was prepared using silica microcapsules crosslinked with pectin via special disulfide bonds. The results demonstrated that the silica-SS-pectin microcapsules had a high loading efficiency (20% w/w) and could effectively enhance the thermal and light stability of kasugamycin. The microcapsules displayed excellent pectinase and glutathione dual-responsive properties and the release kinetics investigated by Riger-Peppas model suggested combination of various release mechanisms. Compared with kasugamycin wettable powder, the microcapsules possessed sustained and improved antimicrobial efficacy against Erwinia carotovora. Thus, the dual-responsive microcapsules potentially have agricultural application as a controlled release system.Download high-res image (135KB)Download full-size image

•In-situ IL-DLLME combined ultrasmall Fe3O4 MNPs method was developed for the detection of pyrethroids in water samples.•New anion-exchange reagents were studied and showed enhanced microextraction performance.•Various parameters affecting extraction efficiency were optimized systematically.•The proposed method is nanometer-level microextraction with the advantages of simplicity, rapidity, and sensitivity.In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe3O4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN)2] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P4448][Br] (aqueous solution, 200 μL, 0.2 mmol mL−1) reaction in-situ with anion-exchange reagent Na[N(CN)2] (aqueous solution, 300 μL, 0.2 mmol mL−1) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176–213) and good recoveries (80.20–117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L−1. The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity.Download high-res image (220KB)Download full-size image

Controlled release formulations of pesticides is highly desirable for maximising the utilization of the pesticide, as well as remarkably reducing environmental pollution. A stimuli-responsive controlled release formulation can intelligently respond to the stimuli produced by pests and trigger the release of the active ingredients to control pests effectively. In this work, a novel enzyme-responsive emamectin benzoate microcapsule was prepared using silica cross-linked with carboxymethylcellulose using epichlorohydrin. The results showed that the obtained microcapsules had a remarkable loading ability for emamectin benzoate (about 35% w/w) and could protect emamectin benzoate against photo- and thermal degradation effectively. The silica–epichlorohydrin–carboxymethylcellulose microcapsules displayed excellent cellulase stimuli-responsive properties and a sustained insecticidal efficacy against Myzus persicae. Allium cepa chromosome aberration assays demonstrated that the microcapsules had less genotoxicity than the technical grade emamectin benzoate (referred to throughout the manuscript as the technical). Given these advantages, the enzyme-responsive emamectin benzoate microcapsules are worth extending as a novel safe strategy for sustainable crop protection.

Bentazone is one of the widely used herbicides for controlling sedges and broad-leaf weeds. Due to its high mobility in soils, bentazone has been frequently found among the contaminants detected in surface and ground water and poses a potential threat to aquatic organisms by runoff and leaching. In this work, novel herbicidal ionic liquids (HILs) based on bentazone with four typical cations were synthesized and characterized. The physicochemical properties (water solubility, surface activity, leaching and soil adsorption) and herbicidal activity of HILs were investigated. The result showed that the water solubility of HILs was reduced along with the increasing length of alkyl chains in cations. Compared with bentazone sodium, HILs showed higher adsorption capacity, weaker mobility, and excellent surface activity and Pyr-1 substantially performed higher efficacy under field condition. With high activity of weed control and fascinating physicochemical properties, HILs can reduce the risk of bentazone in aquatic environment and they will be applied widely in the future.

Controlled release formulation of pesticides is an effective approach to achieve the desirable purpose of increasing the utilization of pesticides and reducing the environmental residuals. In this work, a novel functionalized microcapsule using silica cross-linked with alginate, and some beneficial elements to crops, was prepared. The microcapsules were structurally characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The results showed that the microcapsules had a high loading efficiency of prochloraz (about 30% w/w) and could effectively protect prochloraz against degradation under UV irradiation and alkaline conditions, showed sustainable release for at least 60 days, and also likely increased disease resistance due to the element on the surface. Given the advantages of the microcapsules, this delivery system may be extended to other photosensitive or pH-sensitive pesticides in the future.Keywords: alginate; microcapsule; prochloraz; silica; trace element

The excessive application of pesticides increases the pollution potential, which leads to groundwater contamination and spreading of toxic substances in the environment by leaching or in runoff. In this study, new herbicide ionic liquids (HILs) based on fomesafen with multifunctions were prepared to improve the herbicidal activity and reduce the risk to the aquatic organisms. The octanol–water partition coefficient (Kow), surface activity, soil adsorption and herbicidal activity of HILs were tested and a comparative analysis with fomesafen was made. The results show that HILs have low water solubility, excellent Kow, low surface tension, and good adsorption ability, and these properties can be regulated and optimized by selecting different counter cations. The physico-chemical properties of HILs were related to the carbon chain length of the cation. Compared with fomesafen sodium, ionic liquids N-1 showed a higher and faster herbicidal activity because of its good lipophilicity and low surface tension. HILs with lower water solubility and greater adsorption capacity in soil have less risk to algae, snail and other aquatic organisms than fomesafen sodium. The HILs will be a candidate in fomesafen applications in the future.