Making the Complicated Simple: A Minimizing Carrier Strategy on Innovative Nanopesticides.

The flourishing progress in nanotechnology offers boundless opportunities for agriculture, particularly in the realm of nanopesticides research and development. However, concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides. It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return, and if the complex material composition genuinely improves the efficiency, safety, and circularity of nanopesticides. Herein, we introduced the concept of nanopesticides with minimizing carriers (NMC) prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations, and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers (NNC). We further summarized the current development strategy of NMC and examined potential challenges in its preparation, performance, and production. Overall, we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides, offering a way out of the current predicament.

Modeling long-term transfers of radiocesium in farmland under different tillage and cover crop treatments.

The 2011 nuclear accident at Japan's Fukushima Daiichi Nuclear Power Plant (FDNPP) prompted inquiries about the long-term transfer of Cesium-137 (137Cs) from soil to agricultural plants. In this context, numerical modeling is particularly useful for the long-term evaluation of the consequences of agroecosystem contamination. Agricultural practices, such as tillage and cover cropping, play key roles in 137Cs recycling in agroecosystems. In this study, we used 10-year monitoring data to develop a dynamic model to predict 137Cs redistribution (via uptake, litterfall, translocation, and percolation) under different tillage (no-tillage, NT; rotary cultivation, RC; moldboard plow, MP) and cover crop (rye; hairy vetch; fallow weed) treatments. The verification exercise and assessment results indicated the model's reliability, as the temporal dynamics of predicted values agreed with observed values. Tillage significantly influenced the 137Cs distribution in soil, thereby decreasing plant uptake of 137Cs, whereas cover crop exerted a minimal effect on 137Cs cycling. Furthermore, while the 137Cs concentrations in soybean grain under RC and NT treatments were comparable 62 years after the FDNPP accident, the concentration under MP treatment remained consistently the lowest. Despite natural decay being the main cause of the decreased global 137Cs level in the agroecosystem, with minimal losses from percolation to deeper soil layers and soybean harvesting, adopting an appropriate tillage practice was shown to promote a long-term reduction of 137Cs concentration in crops. Finally, to improve the model's accuracy, further research should consider incorporating the effects of soil properties and extreme weather events on 137Cs flow into the model, as these factors are essential for realizing improved agroecosystem predictions.

Nano-Micro Core-Shell Fibers for Efficient Pest Trapping.

Insect sex pheromones as an alternative to chemical pesticides hold promising prospects in pest control. However, their burst release and duration need to be optimized. Herein, pheromone-loaded core-shell fibers composed of degradable polycaprolactone and polyhydroxybutyrate were prepared by coaxial electrospinning. The results showed that this core-shell fiber had good hydrophobic performance and thermal stability, and the light transmittance in the ultraviolet band was only below 40%, which provided protection to pheromones. The core-shell structure alleviated the burst release of pheromone in the fiber and extended the release time to about 133 days. In the field, the pheromone-loaded core-shell fibers showed the same continuous and efficient trapping of Spodoptera litura as the commercial carriers. More importantly, the electrospun fibers combined with biomaterials had a degradability unmatched by commercial carriers. The structure design strategy provides ideas for the innovative design of pheromone carriers and is a potential tool for the management of agricultural pests.

Multifunctional Borax Cross-Linked Hydroxypropyl Guar Gum Hydrogels with Crop Nutritional Function as Carriers for Dual-Responsive Acaricide Release.

Hydrogels with porous networks have received considerable attention in smart pesticide delivery due to their inherent versatility. In this study, acaricide cyetpyrafen (CPF)-loaded borax (BO) cross-linked hydroxypropyl guar gum (HPG) (CPF@BO-co-HPG, CBG) hydrogels were prepared by cross-linking and pesticide loading simultaneously. The flowable CBG hydrogels with 3D porous network structures had better wetting and spreading ability on Citrus reticulata Blanco leaves and a hydrophobic interface. The nonflowable CBG hydrogels had pH- and temperature-responsive release properties. Meanwhile, the acaricidal efficacy of CBG against Panonychus citri (McGregor) at both 24 and 48 h was significantly higher than those of CPF-loaded BO-free HPG hydrogels. Furthermore, CBG had a nutritional function for cotton growth and environmental safety for zebrafish. This research developed a BO cross-linked HPG hydrogel as a smart pesticide delivery vehicle and crop nutrient replenishment, which can be widely applied in sustainable agriculture.

Biodegradable electrospun fibers as sustained-release carriers of insect pheromones for field trapping of Spodoptera litura (Lepidoptera: Noctuidae).

BACKGROUND: Insect pheromones are highly effective and environmentally friendly, and are widely used in the monitoring and trapping of pests. However, many researchers have found that various factors such as ultraviolet light and temperature in the field environment can accelerate the volatilization of pheromones, thus affecting the actual control effect. In recent years, electrospinning technology has demonstrated remarkable potential in the preparation of sustained carriers. Moreover, the utilization of biodegradable materials in electrospinning presents a promising avenue for the advancement of eco-friendly carriers. RESULTS: In this study, homogeneous and defect-free pheromone carriers were obtained by electrospinning using fully biodegradable polyhydroxybutyrate materials and pheromones of Spodoptera litura. The electrospun fibers with porous structure could continuously release pheromone (the longest can be ≤80 days). They also had low light transmission, hydrophobic protection. More importantly, the pheromone-loaded electrospun fiber carriers showed stable release and good trapping effect in the field. They could trap pests for at least 7 weeks in the field environment without other light stabilizers added. CONCLUSION: Sustained-release carriers constructed by electrospinning and green materials could improve the efficacy of pheromones and ensure environmental friendliness, and provided a tool for the management of S. litura and other pests and sustainable development of agricultural. © 2023 Society of Chemical Industry.

Preparation of Thifluzamide Polylactic Acid Glycolic Acid Copolymer Microspheres and Its Effect on the Growth of Cucumber Seedlings.

The polylactic acid-glycolic acid copolymer (PLGA) has been proven to be applicable in medicine, but there is limited research on its application and safety in the agricultural field. In this paper, thifluzamide PLGA microspheres were prepared via phacoemulsification and solvent volatilization, using the PLGA copolymer as the carrier and thifluzamide as the active component. It was found that the microspheres had good slow-release performance and fungicidal activity against Rhizoctonia solani. A comparative study was conducted to show the effect of thifluzamide PLGA microspheres on cucumber seedlings. Physiological and biochemical indexes of cucumber seedlings, including dry weight, root length, chlorophyll, protein, flavonoids, and total phenol content, indicated that the negative effect of thifluzamide on plant growth could be mitigated when it was wrapped in PLGA microspheres. This work explores the feasibility of PLGA as carriers in fungicide applications.

Metabolic pathways reveal the effect of fungicide loaded metal-organic frameworks on the growth of wheat seedlings.

Metal-organic frameworks (MOF) are an emerging class of hybrid inorganic-organic porous materials used in various fields, especially in molecule delivery system. As iron is an essential micronutrient for plant growth, iron-based MOF (Fe-MOF) is developed for agricultural application as fungicide carriers. However, fungicides may have various effect on the plant growth, which may be different from Fe-MOF. When they are combined with the carriers, the effects on target plants will change. In this work, tebuconazole-loaded Fe-MOF was prepared and used to treat wheat seedlings. The physiological, biochemical and metabolic levels of wheat roots and shoots were shown by a comparative study. Related metabolic pathways were analyzed by non-targeted metabolomic method. Many metabolites in wheat roots and shoots showed an upward trend after Fe-MOF treatment, but tebuconazole had a negative impact on these indicators. Related metabolic pathways in Fe-MOF and tebuconazole treatment were different, and the related pathway of tebuconazole-loaded Fe-MOF was closer to that of Fe-MOF. The metabolic pathways study revealed that the negative impact from tebuconazole was mitigated when wheat seedlings were treated with tebuconazole-loaded Fe-MOF. This research firstly explores the mechanism of MOF as carriers to help plant reduce the negative effects from fungicide by regulating metabolic pathways.

Effects of Methoxyfenozide-Loaded Fluorescent Mesoporous Silica Nanoparticles on Plutella xylostella (L.) (Lepidoptera: Plutellidae) Mortality and Detoxification Enzyme Levels Activities.

The diamond back moth, Plutella xylostella, causes severe damage at all crop stages, beside its rising resistance to all insecticides. The objective of this study was to look for a new control strategy such as application of insecticide-loaded carbon dot-embedded fluorescent mesoporous silica nanoparticles (FL-SiO2 NPs). Two different-sized methoxyfenozide-loaded nanoparticles (Me@FL-SiO2 NPs-70 nm, Me@FL-SiO2 NPs-150 nm) were prepared, with loading content 15% and 16%. Methoxyfenozide was released constantly from Me@FL-SiO2 NPs only at specific optimum pH 7.5. The release of methoxyfenozide from Me@FL-SiO2 NPs was not observed other than this optimum pH, and therefore, we checked and controlled a single release condition to look out for the different particle sizes of insecticide-loaded NPs. This pH-responsive release pattern can find potential application in sustainable plant protection. Moreover, the lethal concentration of the LC50 value was 24 mg/L for methoxyfenozide (TC), 14 mg/L for Me@FL-SiO2 NPs-70 nm, and 15 mg/L for Me@FL-SiO2 NPs-150 nm after 72 h exposure, respectively. After calculating the LC50, the results predicted that Me@FL-SiO2 NPs-70 nm and Me@FL-SiO2 NPs-150 nm exhibited better insecticidal activity against P. xylostella than methoxyfenozide under the same concentrations of active ingredient applied. Moreover, the activities of detoxification enzymes of P. xylostella were suppressed by treatment with insecticide-loaded NPs, which showed that NPs could also be involved in reduction of enzymes. Furthermore, the entering of FL-SiO2 NPs into the midgut of P. xylostella was confirmed by confocal laser scanning microscope (CLSM). For comparison, P. xylostella under treatment with water as control was also observed under CLSM. The control exhibited no fluorescent signal, while the larvae treated with FL-SiO2 NPs showed strong fluorescence under a laser excitation wavelength of 448 nm. The reduced enzyme activities as well as higher cuticular penetration in insects indicate that the nano-based delivery system of insecticide could be potentially applied in insecticide resistance management.

Dimensionally Stable Polyimide Frameworks Enabling Long-Life Electrochemical Alkali-Ion Storage.

Organic electrode materials hold unique advantages for electrochemical alkali-ion storage but cannot yet fulfill their potential. The key lies in the design of structurally stable candidates that have negligible solution solubility and can withstand thousands of cycles under operation. To this end, we demonstrate here the preparation of dimensionally stable polyimide frameworks from the two-dimensional cross-linking of tetraaminobenzene and dianhydride. The product consists of hierarchically assembled nanosheets with thin thickness and abundant porosity. Its robust molecular frameworks and advantageous nanoscale features render our polymeric material a promising cathode candidate for both sodium-ion and potassium-ion batteries. Most strikingly, an extraordinary cycle life of up to 6000 cycles at 2 A g-1 is demonstrated, outperforming most of its competitors. Theoretical simulations support the great activity of our polymeric product for the electrochemical alkali-ion storage.

Fungicide-loaded mesoporous silica nanoparticles promote rice seedling growth by regulating amino acid metabolic pathways.

Mesoporous silica nanoparticles (MSN) are widely researched as carriers for pesticides (including fungicides, insecticides and herbicides) to improve their effective utilization rate in the target plant. However, pesticides enter the target crops and may bring some impacts on the growth and physiological function of plants. When they are loaded to nanoparticles, different effects on the metabolic properties of target plants will be produced. In this study, thifluzamide-loaded MSN was prepared with average diameter of 80-120 nm. Rice seedlings were exposed for 7 days to different treatments of MSN, thifluzamide, and thifluzamide-loaded MSN. After treatment, non-targeted metabolomic method was employed to explore the metabolic pathways. It was found that the negative effect of thifluzamide to rice seedling was alleviated by thifluzamide-loaded MSN, since it increased amino acid metabolic pathways, which improved purine and pyrimidine metabolism and induced the production of total protein. Thifluzamide-loaded MSN can also relieve the damage of thifluzamide to rice seedlings by altering the chlorophyll, phenols and flavonoids content. In conclusion, it was proposed that the mechanism of fungicide-loaded MSN prevent plant from negative effects of fungicides by regulating the amino acid metabolic pathways.

Enhanced Fungicidal Efficacy by Co-Delivery of Azoxystrobin and Diniconazole with Cauliflower-Like Metal-Organic Frameworks NH2-Al-MIL-101.

Long-term use of a single fungicide increases the resistance risk and causes adverse effects on natural ecosystems. Controlled release formulations of dual fungicides with different modes of action can afford a new dimension for addressing the current issues. Based on adjustable aperture and superhigh surface area, metal-organic frameworks (MOFs) are ideal candidates as pesticide release carriers. This study used Al3+ as the metal node and 2-aminoterephthalic acid as the organic chain to prepare aluminum-based metal-organic framework material (NH2-Al-MIL-101) with "cauliflower-like" structure and high surface area of 2359.0 m2/g. Fungicides of azoxystrobin (AZOX) and diniconazole (Dini) were simultaneously encapsulated into NH2-Al-MIL-101 with the loading content of 6.71% and 29.72%, respectively. Dual fungicide delivery system of AZOX@Dini@NH2-Al-MIL-101 demonstrated sustained and pH responsive release profiles. When the maximum cumulative release rate of AZOX and Dini both reached about 90%, the release time was 46 and 136 h, respectively. Furthermore, EC50 values as well as the percentage of inhibition revealed that AZOX@Dini@NH2-Al-MIL-101 had enhanced germicidal efficacy against rice sheath blight (Rhizoctonia solani), evidenced by the synergistic ratio of 1.83. The present study demonstrates a potential application prospect in sustainable plant protection through co-delivery fungicides with MOFs as a platform.

Reducing pesticide spraying drift by folate/Zn2+ supramolecular hydrogels.

BACKGROUND: The purpose of this study was to use folic acid and zinc nitrate to construct a biocompatible supramolecular hydrogel loaded with the herbicide dicamba as an ultra-low-volume spray formulation. The drift potential of the hydrogel was studied by simulating the field environment in a wind tunnel. RESULTS: The three-dimensional network structure of the successfully prepared dicamba hydrogel system was observed using cryo-scanning electron microscopy. A rheological study of the dicamba hydrogel showed that it has shear-thinning and self-healing properties. Using a laser particle size analyzer, it was shown that the droplet size of the dicamba gel (approximately 100 µm) was significantly larger than that of the control group water and dicamba-KOH droplets. Droplet collectors and water-sensitive papers were arranged in the wind tunnel to evaluate the drift-reduction performance of the dicamba gel. Compared with dicamba-KOH aqueous solution, dicamba gel has a good effect in reducing drift. CONCLUSION: This hydrogel containing no organic solvents showed biocompatibility and biodegradability due to its natural and readily available raw materials. The main way in which hydrogels reduce drift is by increasing the droplet size and this is due to the three-dimensional network structure inside the gel. This research provides a new strategy to reduce spray drift from the perspective of pesticide formulation, and also has prospects for the application of supramolecular hydrogels in agriculture.

Multifunctional manganese-based carboxymethyl chitosan hydrogels for pH-triggered pesticide release and enhanced fungicidal activity.

Carboxymethyl chitosan (CMCS) has emerged as a promising biopolymer carrier for controlled release formulations of pesticide. In this study, manganese-based carboxymethyl chitosan hydrogel was facilely prepared to encapsulate and release fungicide prothioconazole in a controllable manner. The loading content (LC) and encapsulation efficiency (EE) of prothioconazole were optimized by orthogonal test. When scaled up under the optimal condition, the corresponding LC and EE were 22.17 % and 68.38 %, respectively. The result showed that the pH-triggered release behavior of prothioconazole for the hydrogels was consistent with swelling behavior. The pesticide rapidly released in neutral and slightly alkaline solutions than in acidic conditions. Moreover, the prepared hydrogel showed enhanced fungicidal ability against wheat take-all pathogen (Gaeumannomyces graminis var. tritic) compared to that of prothioconazole technical material. This research seeks to provide a promising approach to develop metal and polysaccharide-based hydrogels to control the pesticide release and reduce pesticide use in sustainable agriculture application.

Efficient pesticide formulation and regulation mechanism for improving the deposition of droplets on the leaves of rice (Oryza sativa L.).

BACKGROUND: The effective deposition of pesticide droplets on the target leaf surface is critical for improving the utilization of pesticides. We proposed a new way to enhance the droplet deposition on the target leaf surface by changing the properties of pesticide formulation, and this formulation can be sprayed directly or at a low dilution. In addition, it is a simple method to select a suitable concentration and formulation by evaluating the interfacial dilational rheological properties of pesticide droplets. RESULTS: The wetting behavior of two types of pesticide formulations prepared by oil-based solvent on the rice leaf surface was investigated based on the surface free energy, surface tension, contact angle, adhesion tension, and adhesion work. The interfacial dilational rheological properties of different pesticide solutions were measured as a function of concentration. This study clearly demonstrates the fact that water-in-oil emulsion has a better wettability than oil-in-water emulsion, especially with the increase of the concentration of the solution, the droplets can be wetted and spread faster on the leaves. Compared with vegetable oil (methyl oleate), mineral oil (solvent oil No. 200) has smaller dilational modulus and surface tension, showing excellent wetting properties. CONCLUSION: The water-in-oil emulsion prepared with solvent oil No. 200 has the smallest dilational modulus, and the spray droplets spread rapidly to the maximum wetting area on the rice leaves, which can be used in an ultra-low volume spray. The results provide new insights into how to increase the deposition of droplets on superhydrophobic leaf surfaces by screening formulations and concentrations. © 2021 Society of Chemical Industry.

Effective and Sustained Control of Soil-Borne Plant Diseases by Biodegradable Polyhydroxybutyrate Mulch Films Embedded with Fungicide of Prothioconazole.

Soil-borne diseases and plant rhizosphere nematode have caused many crop yield losses. Increased environmental awareness is leading to more restrictions on the use of certain fumigants and root irrigation methods due to their impact on human health and soil system. Therefore, it is necessary to find alternative treatments to maintain crop economic yields and environmental sustainability. In the present work, biodegradable antifungal mulches were prepared by blending poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PHB) with fungicide of prothioconazole (PRO), which were used for effective and sustained control of soil-borne plant diseases. To reveal the application prospect of the PHB/PRO composite films in the management of soilborne plant diseases, some physical and biological properties were evaluated. The proper mulch film of PHB/PRO was assessed based on its mechanical and optical properties, while water solubility and the film micromorphology was further characterized. The release patterns of composite films under different pH levels were investigated. Moreover, the in vitro antifungal bioassay and pot experiment showed satisfactory bioactivity of the PHB/PRO films against Sclerotium rolfsii Sacc., a soil-borne disease in peanut fields. This study demonstrated that the biodegradable mulch films containing PRO fungicide are capable of inhibiting soil-borne plant pathogenic fungi effectively, and this facile but powerful strategy may find wide applicability in sustainable plant and horticulture protection.

Polydopamine-Modified Metal-Organic Frameworks, NH2-Fe-MIL-101, as pH-Sensitive Nanocarriers for Controlled Pesticide Release.

Recently, metal-organic frameworks (MOFs) have become a dazzling star among porous materials used in many fields. Considering their intriguing features, MOFs have great prospects for application in the field of sustainable agriculture, especially as versatile pesticide-delivery vehicles. However, the study of MOF-based platforms for controlled pesticide release has just begun. Controlled pesticide release responsive to environmental stimuli is highly desirable for decreased agrochemical input, improved control efficacy and diminished adverse effects. In this work, simple, octahedral, iron-based MOFs (NH2-Fe-MIL-101) were synthesized through a microwave-assisted solvothermal method using Fe3+ as the node and 2-aminoterephthalic acid as the organic ligand. Diniconazole (Dini), as a model fungicide, was loaded into NH2-Fe-MIL-101 to afford Dini@NH2-Fe-MIL-101 with a satisfactory loading content of 28.1%. The subsequent polydopamine (PDA) modification could endow Dini with pH-sensitive release patterns. The release of Dini from PDA@Dini@NH2-Fe-MIL-101 was much faster in an acidic medium compared to that in neutral and basic media. Moreover, Dini@NH2-Fe-MIL-101 and PDA@Dini@NH2-Fe-MIL-101 displayed good bioactivities against the pathogenic fungus causing wheat head scab (Fusarium graminearum). This research sought to reveal the feasibility of versatile MOFs as a pesticide-delivery platform in sustainable crop protection.

Indoxacarb-loaded fluorescent mesoporous silica nanoparticles for effective control of Plutella xylostella L. with decreased detoxification enzymes activities.

BACKGROUND: Plutella xylostella L. is a cosmopolitan lepidopteron insect pest for numerous vegetables and crops. The extensive use of insecticides has resulted in the emergence of resistance in P. xylostella. Thus, development of innovative strategies to overcome the insecticide resistance and control P. xylostella effectively is highly desirable. Inspired by the concept and breakthrough of nanomedical strategies to treat multidrug resistance, nanotechnology may find potential application in overcoming or delaying insecticide resistance. RESULTS: Carbon dots-embedded fluorescent mesoporous silica nanoparticles (FL-SiO2 NPs) were successfully developed. Indoxacarb-loaded nanoparticles (IN@FL-SiO2 NPs) were facilely prepared with loading content of 24%. The release of indoxacarb from IN@FL-SiO2 NPs was pH sensitive. IN@FL-SiO2 NPs exhibited better insecticidal activity against P. xylostella than indoxacarb technical under the same doses of active ingredient applied. Moreover, the activities of detoxification enzymes including GST, CarE, and P450 of P. xylostella were suppressed by treatment with IN@FL-SiO2 NPs. Furthermore, the entry of FL-SiO2 NPs into the midgut of P. xylostella was confirmed by CLSM observation. CONCLUSIONS: Although there is no absolute correlation between the enzyme activity and resistance, the change in corresponding enzyme activity can afford valuable information on the resistance situation. IN@FL-SiO2 NPs treated P. xylostella displayed higher mortality, along with decreased enzymes activities, which indicates that nano-based delivery system of insecticide could be potentially applied in insecticide resistance management. © 2020 Society of Chemical Industry.

Iron-based porous metal-organic frameworks with crop nutritional function as carriers for controlled fungicide release.

Metal-organic frameworks (MOFs) are an emerging class of hybrid inorganic-organic porous materials used in various fields. Considering their excellent performance, MOFs have a considerable application potential in sustainable agriculture. Research projects of MOFs-based platforms for plant protection and nutrition have just started. Environmental stimuli-responsive pesticide release is highly desirable for improved efficacy and decreased side effects. Iron-based MOFs (Fe-MOFs) have a considerable prospect in agriculture as multifunctional materials both for pesticide delivery and plant nutrient replenishment because iron is an essential micronutrient for crop growth. In this work, a simple octahedral Fe-MOFs built from trimers of iron octahedra linked by 1, 3, 5-benzenetricarboxylate (Fe-MIL-100) have been prepared as carriers for fungicide azoxystrobin. Due to the high surface area of 2251 m2/g, the loading content of azoxystrobin into Fe-MIL-100 is satisfactory up to 16.2%. Azoxystrobin-loaded Fe-MOFs (AZOX@Fe-MIL-100) exhibit a pH-responsive initial burst and a subsequent sustained release pattern. Moreover, AZOX@Fe-MIL-100 exhibits good fungicidal activities against two pathogenic fungi-wheat head scab (Fusarium graminearum) and tomato late blight (Phytophthora infestans). The nutritional function of Fe-MIL-100 as iron micronutrient for the enhanced wheat growth was also observed. This research explores the feasibility of MOFs as a platform for potential application in sustainable plant protection.

Wetting Behavior and Maximum Retention of Aqueous Surfactant Solutions on Tea Leaves.

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.

Biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) microcapsules for controlled release of trifluralin with improved photostability and herbicidal activity.

Microencapsulation of pesticide is a promising technology to reduce the negative environmental impact and benefit the sustainable development. Trifluralin, commonly used as a selective pre-emergence herbicide, is vulnerably subject to loss by volatilization and decomposition by sunlight when applied to the surface of soils. In the present study, trifluralin has been encapsulated using biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (PHB) polymers as carriers to develop controlled release formulations. PHB trifluralin microcapsules were obtained using a convenient solvent evaporation method. The influences of preparation parameters on the size and its distribution of the microcapsules were discussed. The particle size decreased from 4.44 µm to 2.50 µm as the shearing speeds increased from 4000 r/min to 12,000 r/min, and the value decreased from 3.64 µm to 3.23 µm as the mass fraction of emulsifier polyvinyl alcohol increased from 0.5% to 2.0%. The loading content (LC) as well as the encapsulation efficiency (EE) of trifluralin microcapsules are multiple factors dependent. Orthogonal table L9(34) was designed and range analysis was used to suggest the optimal preparation parameters. When performed under the optimized conditions, the corresponding LC and EE were 16.50% and 90.65%, respectively. The release of trifluralin from PHB microcapsules showed slow and sustained patterns, which could be easily achieved by modifying the preparation parameters including shearing speed and concentration of emulsifier. Compared to conventional trifluralin formulation of emulsifiable concentrate, trifluralin microcapsules exhibited significantly improved photostability and herbicidal activity against target weed barnyardgrass. These results demonstrated that microencapsulation with PHB could dramaticlly improve the effective utilization rate and decrease the dosage of such agricultural chemicals.