Suspension Concentrate Research Articles

Determination of residual behavior of two fungicides in/on tomato and cucumber and their dietary intake risk assessment under open field conditions

A commercial formulation of fluoxapiprolin (30g/L) and fluopicolide (200g/L) as a suspension concentrate (SC) is under registration for its use on tomato and cucumber in India. Both of these active ingredients are fungicides used to control a variety of fungal diseases in crops. The field trials were laid out in an open field at the experimental farm of the university following good agricultural practice (GAP) during the summer of 2021. The study aimed to estimate pesticide residues using a modified QuEChERS method in combination with advanced analytical techniques like liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography with an electron capture detector (GC-ECD). The method showed excellent linearity (R² > 0.99) for fluoxapiprolin, fluopicolide and their metabolites in tomato, cucumber, and soil. The half-life value for fluoxapiprolin ranged between 5.86-7.05 days and for fluopicolide the half-life was between 1.62-1.98 days for tomato and cucumber, respectively. The recoveries ranged between 80-120% with a relative standard deviation <20% for all the analytes. The dietary risk assessment was determined by using the hazard quotient and the HQs values were <1, proving its safety to the consumer.

Laboratory performances during proficiency tests for the analysis of active substances in pesticide formulations during 2021–2023

During the period 2021–2023, the Italian National Institute of Health (ISS) organised, in collaboration with the Italian Health Ministry, proficiency testing (PTs) for about 22 Italian and other EU laboratories involved in the monitoring programmes for Plant Protection Products (PPPs). The aim of the PTs was to determine the amount of active ingredient in various formulations of PPPs. Overall, the type of formulations to be analysed were soluble concentrate (SL), suspension concentrate (SC), capsule suspension (CS), emulsion water oil (EW), soluble water granule (SG), dustable powder (DP), water dispersible granule (WDG) and emulsion concentrate (EC). In 2021, the ISS organised PTs for the determination of Imazamox, Fenhexamid and Trinexapac-ethyl in three different PPPs as soluble concentrate (SL), suspension concentrate (SC), and capsule suspension (CS), respectively. In 2022, PTs for the determination of Bentazone, Spinosad and Tau-Fluvalinate were organised. For this PTs, commercial PPPs were obtained from the Italian market as SC, emulsion oil water (EW) and soluble water granule (SG). In 2023, the PT was organised to determine the active ingredient Trifloxystrobin, Deltamethrin and Cyprodinil in the commercial product as water dispersible granule (WDG), dustable powder (DP) and emulsion concentrate (EC), respectively. Homogeneity and stability, performed for all PT samples, fulfilled the acceptability criteria. The Jarque–Bera test was used to verify the hypothesis of normality of the data distributions before to calculate the z-score values. Laboratory performances, expressed in terms of z-scores, were satisfactory for almost all participants for all substances.

Management of Rhizoctonia blight of groundnut using antagonistic effects of bioagents and organic amendments

Rhizoctonia blight disease caused by Rhizoctonia solani in groundnut crop is one of the most devastating diseases occurring worldwide. The disease affects the morphological and physiological parameters of the crop leading to reduction in pod yield as well as oil yield. The pathogen was isolated locally and identified as Rhizoctonia solani based on molecular characterization. The efficacy of different bioagents in reducing the radial growth of pathogen was tested in vitro and highest mycelia growth inhibition was recorded by Trichoderma asperellum (89.07 %). Among the fungicides tested, 100 % mycelial growth inhibition was observed by use of Carbendazim 50 WP, Tebuconazole 25.9 % EC, Hexaconazole 5 % suspension concentrate (SC) and Tebuconazole 50 % + Trifloxystrobin 25 % water-dispersible granule (WG). Among different organic substances tested in vitro, neem seed cake achieved maximum mycelial growth inhibition of 50.74 % and 54.08 % at 10 % and 20 % concentrations respectively. In the field experiment, treatment with application of neem seed cake to the soil at 500 kg/ha + application of mustard seed cake to the soil at 500 kg/ha + treatment of seeds with Tebuconazole at 1.5 g/kg of seed + treatment of seeds with T. asperellum at 10 g/kg of seed was found to be the best in enhancing plant health, growth promotion and oil yield. The combined treatment of bioagent, fungicide and organic amendment recorded maximum number of branches (14.00), number of leaves (668.33), plant dry weight (64.17 g), 100 pod weight (65.00 g) and oil yield (47.33 %) compared to the control and other treatments along with reduction of the disease (59.61 %). In the physiological parameters study, the same treatment also recorded maximum pigment contents viz. Chlorophyll a (1.843 mg/g), Chlorophyll b (0.555 mg/g), total chlorophyll (2.397 mg/g) and carotenoid content (0.084 mg/g) but with minimum phenol content (1.693 mg/g). Thus, it can be concluded that integration of selective inputs in the combined treatment of Neem seed cake, Mustard seed cake, Tebuconazole and T. asperellum could enhance the plant health, morphological growth and physiological parameters and increased the oil yield in groundnut along with reduction of the disease.

Preparation and Application of Multi-Walled Carbon Nanotube-Supported Metconazole Suspension Concentrate for Seed Coating to Control Wheat Sharp Eyespot

Wheat sharp eyespot is a prevalent soil-borne disease that causes substantial economic losses in agriculture. Metconazole, a new triazole broad-spectrum fungicide, has demonstrated effective control of soil-borne diseases. Multi-walled carbon nanotubes (MWCNTs) are an innovative adsorbent material known for their large surface area and high absorptive capacity. This study identifies MWCNTs as the optimal adsorption material for metconazole, achieving an adsorption rate of 85.27% under optimal conditions (stirring time of 30 min and feeding ratio of 6:1). The optimized formula consists of 1.5% dispersant sodium wood, 1% emulsifier BY-112, 2% AEO-15, 3% glycol, 3% filmogen, and 4% red dyes. A 0.5% MWCNT–metconazole suspension concentrate for seed coating (FSC) significantly enhances the inhibitory effect of metconazole on wheat growth and promotes root development. At the tillering stage, a coating ratio of 1:100 shows a marked impact on wheat growth, and MWCNTs can improve the control effect of metconazole to Rhizoctonia cerealis. This work offers a novel approach for applying metconazole in a wheat suspension concentrate for seed coating.

Glycine-doped metal–organic frameworks as intelligent nanocarriers to enhance pesticide delivery and provide micronutrient in plants

The development of multifunctional pesticide-delivery system is of practical significance for realizing efficient utilization of pesticides and minimizing environmental risks. In this work, methoxyfenozide (Met)-loaded glycine-doped zeolitic imidazolate framework-8 composites (Met@Gly@ZIF-8) for intelligent-release of Met and effective pest management were facilely constructed. The physical properties of Met@Gly@ZIF-8, including ultraviolet (UV) resistance, deposition and release profiles were evaluated. Compared with Met, the residual content after UV irradiation and retention content on cabbage leaves of Met@Gly@ZIF-8 increased by 121.2% and 98.2%, respectively, and the contact angle on foliar decreased by 26.5% compared with Met suspension concentrate (SC), demonstrating better photolysis resistance, deposition and wetting ability. Release experiments indicated that Met@Gly@ZIF-8 possessed significant stimuli-responsive release characteristics which were negatively correlated with pH, due to the acidic degradation of ZIF-8. The biological activity experiments showed that Met@Gly@ZIF-8 possessed elevated control efficacy on Plutella xylostella compared with Met and reduced the LC50 value by 53.2%. The application performance experiments indicated that the penetration amount of Met@Gly@ZIF-8 in cabbage leaves increased by 194.7% and the translocation factor (TFleaf) increased by 63.3%, respectively, as compared with those of Met. Compared with the blank control, Gly@ZIF-8 and Met@Gly@ZIF-8 increased the total biomass of cabbage by 37.8% and 25.7%, respectively, exhibiting nutritional functions for plants. Toxicity test showed that Met@Gly@ZIF-8 was relatively safe for zebrafish compared with Met. The present approach could be strategically promising for constructing functional and environmentally friendly smart-nanopesticide.

Environmental fate and safety analysis of methoxyfenozide application to control litchi and longan pests

Litchi and longan pests significantly affect crop yield and quality. Chemical prevention and control are very effective for production; therefore, it is crucial to study fate assessment and appropriate field efficacy before pesticide application on crops to appropriately assess the health and ecological risks linked with these agents. This study conducted Good Agricultural Practice (GAP) field trials and laboratory experiments to elucidate the dissipation, terminal residues, and efficacy of methoxyfenozide on litchi and longan in six locations throughout China. To detect methoxyfenozide residues on litchi and longan, a QuEChERS/UPLC-MS/MS-based method was designed. The initial methoxyfenozide levels in litchi and longan ranged from 2.21–2.86 to 0.83–0.95 mg kg−1 and indicated half-lives of 5.1–5.3 and 5.3–5.7 days, respectively. After 7 days of foliage treatment, the concentrations of terminal methoxyfenozide residue were 0.78–2.61 and 0.02–1.01 mg kg−1, which were less than the established maximum residue limit for methoxyfenozide in litchi and longan. The chronic (acceptable daily intake = 0.0055–0.0331%) dietary intake risk analysis for methoxyfenozide in longan and litchi indicated acceptable concentrations of terminal residue for the general population. Methoxyfenozide in litchi and longan was readily degraded in first-order kinetics models, the degradation rate on longan was higher than that on litchi, and their dietary risks were negligible to consumers. Two hundred forty grams per liter of methoxyfenozide suspension concentrate (SC) represents a highly efficacious insecticidal dose to control litchi and longan pests and indicates a significant application potential as it is rapidly degraded and linked with reduced post-treatment residue levels.

A perspective fungicide for protection of narrow-leaved lupin from diseases during the growth season

The article presents the laboratory and field tests results for the effectiveness of the fungicide Protazox SC (suspension concentrate) against anthracnose and other lupin diseases. The tests have been done in Bryansk region in 2020–2022. The study objects were seedlings and vegetative plants of the narrow-leaved lupin Vityaz variety. The effectiveness of protective and curative properties of the fungicide Protazox SC (azoxistrobine + protioconazole + dipheconazole, 200 + 125 + 60 g/l) was tested for 0.5; 1.0 and 1.5 l/ha consumption rates under laboratory conditions. The biological effectiveness was evaluated according to the number of infected seedlings grown in paper-and-plastic rolls compared to the control variant (fungicide free). The maximal rate of the fungicide – 1.5 l/ha – had the highest biological effectiveness of protective and curative properties (98.7 and 97.4 %); this corresponds to the effectiveness of the reference fungicide Kolosal Pro with the using rate of 0.4 l/ha. In a field test the fungicide Protazox at using rate of 1.5 l/ha was applied for lupin crops at the growing stages of “1-2 pairs of true leaves” and “bud formation” of lupin. The fungicide effectiveness was evaluated compared to the control without treatment. Biological effectiveness of the tested fungicide against anthracnose made 95.8 %, it was 4.5 % higher than of the reference fungicide Kolosal Pro. To the stage of “shiny pod” the number of anthracnose infected pods treated with the fungicide Protazox decreased to 1.5 % compared to 26.5 % in the control variant. Fusarium infection of plants decreased from 24.6 % in the control to 12.0 % in the variant with the fungicide. The spread of gray and white rot on beans decreased by 5.0 and 6.7 times, respectively. The viability of productive plants by the harvesting period increased by 41.3 %. Thanks to the application of the fungicide Protazox SC (1.5 l/ha) the significant narrow-leaved lupin seed yield rise of 0.91 t/ha was obtained (LSD05 = 0.04); the cost recovery was 2.56 rubles.

Optimization and characterization of pyraclostrobin nanoemulsion for pesticide delivery: Improving activity, reducing toxicity, and protecting ecological environment

Nanoemulsion provides an effective way for the efficient, safe, and environmentally friendly use of pesticides. In this study, the influence of different type emulsifiers on the formation and stability of nanoemulsion were tested and an optimal pyraclostrobin nanoemulsion with long-term stability was obtained. Pyraclostrobin (2.5 %), #602 (phenylethyl phenol polyoxyethylene ether, 6 %), and #600 P (tristyryl- phenol polyoxyethylene ether phosphate, 2 %) were dissolved in methyl benzoate (2.5 %) and co-emulsifier ethanol (20 %) with deionized water replenished to 100 %. Compared with microemulsion (ME), the nanoemulsion using a lower dosage of emulsifier kept the system stable for a long time, reducing pollution of the environment. Compared with the commercial ME and suspension concentrate (SC), the nanoemulsion had a lower contact angle and surface tension, and higher maximum retention. In addition, adding 0.01 % AEO-3 (dodecyl alcohol polyol ethylene ether) to the dilution of nanoemulsion can significantly improve the target deposition of the nanoemulsion and improve the utilization rate of the pesticide. Besides, the use of methyl benzoate, an environmentally friendly solvent, resulted in the nanoemulsion with high bactericidal activity and low acute toxicity to zebrafish, thus reducing the environmental pollution of such chemicals.

Dissipation and residues of 18% imidacloprid + buprofezin SC in citrus and soil

ABSTRACT Eighteen per cent imidacloprid + buprofezin suspension concentrate (SC) has been registered for the control of scale insect on citrus trees, but the dissipation of this pesticide mixture on citrus is still a research blank area. In order to fill the gaps and ensure the safe application of mixture formulation, field trials were conducted in Guangdong, Guangxi and Hunan Provinces of China for 2 consecutive years to evaluate the final residue and dissipation dynamic of imidacloprid and buprofezin in citrus and soil. Both pesticides were extracted by the modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method, while imidacloprid was determined by high-performance liquid chromatography (HPLC) and buprofezin was determined by gas chromatography (GC). The established method achieved a good linearity relationship (r = 0.9999) and high sensitivity, the LODs (limit of detection) of imidacloprid and buprofezin were 0.002–0.013 mg/kg, which can fully meet the need for pesticide residue detection. Average recoveries (AR) of imidacloprid and buprofezin in citrus and soil were 77.64–105.95% and 85.89–102.28%, with relative standard deviations (RSD) of 3.06–7.91% and 3.29–7.25%, respectively. Results of field trials showed that the half-lives of imidacloprid in citrus and soil were 1.90–3.97 and 2.52–16.98 days, and that of buprofezin were 1.69–9.14 and 1.21–8.56 days. On the 21st day after the last application, final residues of imidacloprid and buprofezin in all samples were below their maximum residue limits (MRL) stipulated by China, indicating that it is safe to apply 18% imidacloprid + buprofezin SC on citrus trees. In conclusion, 18% imidacloprid and buprofezin SC was recommended to be spared twice at the intervals of 7 days with dosages of 180 or 270 mg/L, and the citrus fruit can be harvested safely 21 days after the last application. These results help ensure the safe application of imidacloprid and buprofezin in citrus orchards.

Preparation and Comprehensive Evaluation of the Efficacy and Safety of Chlorantraniliprole Nanosuspension.

Chlorantraniliprole is a broad-spectrum insecticide that has been widely used to control pests in rice fields. Limited by its low solubility in both water and organic solvents, the development of highly efficient and environmentally friendly chlorantraniliprole formulations remains challenging. In this study, a low-cost and scalable wet media milling technique was successfully employed to prepare a chlorantraniliprole nanosuspension. The average particle size of the extremely stable nanosuspension was 56 nm. Compared to a commercial suspension concentrate (SC), the nanosuspension exhibited superior dispersibility, as well as superior foliar wetting and retention performances, which further enhanced its bioavailability against Cnaphalocrocis medinalis. The nanosuspension dosage could be reduced by about 40% while maintaining a comparable efficacy to that of the SC. In addition, the chlorantraniliprole nanosuspension showed lower residual properties, a lower toxicity to non-target zebrafish, and a smaller effect on rice quality, which is conducive to improving food safety and the ecological safety of pesticide formulations. In this work, a novel pesticide-reduction strategy is proposed, and theoretical and data-based support is provided for the efficient and safe application of nanopesticides.

Efficacy of Different Pesticides against Fall Armyworm (Spodoptera frugiperda (J.E. Smith) Lepidoptera: Noctuidae) under Laboratory Conditions in Rupandehi, Nepal

The fall armyworm (FAW), Spodoptera frugiperda, is a highly destructive pest recently reported in various Asian countries and originated in the subtropical regions of America. It was first recorded in Nepal on May 9, 2019. This invasive species poses a significant threat to maize production because it can undergo multiple generations, migrate, and feed on a wide range of host plants. A laboratory study was conducted with 3 categories of pesticides: conventional, newer, and bio‐rational. The study focused on evaluating the efficacy of these pesticides on the third‐instar larvae of S. frugiperda. The treatments included (1) newer chemical pesticides: spinosad 45% suspension concentrate (SC) (Tracer 1 ml/3 L of water), spinetoram 11.7% SC (Delegate 0.5 ml/L of water), chlorantraniliprole 18.5% SC (Allcora 1 ml/2.5 L of water), emamectin benzoate 5.7% water dispersible granules (WDG) (top killer 1 g/2.5 L), (2) conventional pesticide: chlorpyrifos 50% EC (Predator 2 ml/L), and (3) bio‐rational pesticides: Bacillus thuringiensis var kurstaki 0.5% wettable powder (WP) (Maharashtra 2gm/L), Metarhizium anisopliae 1.0% WP (Kalichakra 5 ml/L), Beauveria bassiana 2% AS (DamanL 5 ml/L), Azadirachta indica 4.5% (Neemix 5 ml/L), Syzygium aromaticum 100% v/v (Kanti herbal Clove oil 3 ml/L), and spinosad 45% SC (Tracer 0.3 ml/L). Fresh maize leaves were treated using the leaf dip method and then fed to 3rd instar larvae of FAW. The results revealed that spinetoram and spinosad caused 100% larval mortality within the first 24 hours after treatment. Similarly, spinosad (99.99%) and clove oil (76.64%) were the most effective bio‐rational pesticides followed by B. bassiana and B. thuringiensis. The newer and bio‐rational pesticides that showed high efficacy could be suggested for further study in farmers’ fields. They could be recommended for testing as a component of integrated pest management for effective management of FAW in Nepal.

An innovative formulation approach for low-melting ingredients: optimizing an alternative melt suspension technique for Pyraclostrobin suspension concentrate

The agrochemical industry is now focusing more on safer formulations with lowest dose rate. Suspension Concentrate formulations are one of the safest and most commonly utilized type in agrochemical industry. In this study, a suspension concentrate was developed and compared using a novel melt suspension technique alongside the conventional milling process. The objective was to determine the effectiveness of the new technique in terms of particle size reduction, processing time, and storage stability. In the melt suspension process, the low melting active ingredient(fungicide), was melted along with suitable surfactants and antifreeze in water and homogenized at high rotation per minute (2000). The same fungicide suspension concentrate was also prepared using milling process for comparison. Stability studies were conducted following the Food and Agricultural Organization procedure for both suspensions concentrate products. The storage stability results showed that particle size variation was just 0.8 ± 0.84% (w/v), antifungal content variation during storage stability studies was (±3.12 g/L) only, all other physical parameters results variations were < ± 0.5% w/v. Prepared suspension concentrates were further analyzed using three analytical techniques, Ultraviolet-Visible spectroscopy, high-performance liquid chromatography, and Fourier-transform infrared spectroscopy. The study suggests that the melt suspension technique can be an alternative to the normal milling process for preparing stable suspension concentrate, particularly for low melting point compounds.

Enhanced dosage delivery of pesticide under unmanned aerial vehicle condition for peanut plant protection: tank-mix adjuvants and formulation improvement.

Suspension concentrate (SC) is one of the most widely used formulations for agricultural plant protection. With the rapid development of unmanned aerial vehicle (UAV) plant protection, the problems of spray drift, droplet rebound and poor wettability in the application of SC from UAVs have attracted wide attention. Although some tank-mix adjuvants have been used to enhance dosage delivery for UAV, their effects and mechanisms are not fully clear, and few formulations are specifically designed for UAV. The type and concentration of tank-mix adjuvant affect the dosage delivery of SC. MO501 can significantly reduce DV<100μm , and inhibit droplet rebound on peanut leaves at concentrations ≥0.5%. Silwet 408 can achieve complete wetting and superspreading after adding ≥0.2% concentrations, but only ≥0.5% can inhibit rebound. XL-70 shows excellent regulation ability even at low concentration, and 0.2% concentration can simultaneously suppress impact and promote spreading. Besides, the formulation oil dispersion (OD) can significantly reduce the driftable fine fraction and inhibit rebound at dilution ratios of ≤250-fold, thus enhancing dosage delivery. SC is prone to rebound on hydrophobic leaf surfaces and shows poor wetting and spreading properties. Appropriate types and concentrations of tank-mix adjuvants and formulation improvement are two effective strategies for improving the dosage delivery of pesticides, whereas the addition of inappropriate adjuvants may cause potential risks instead. These findings provide guidance for the rational selection of tank-mix adjuvants and potential applications of OD for UAV plant protection. © 2023 Society of Chemical Industry.

Suspension Concentrate crop protection formulation design and performance for low spray volume and UAS spray application.

Unmanned aerial systems (UAS) are providing interesting disruptive solutions for spray application of crop protection products with very-low spray volumes (VLV) down to 8 L/ha that offer improved sustainability through reduced water volumes and reduced soil compaction. However, the efficacy of products can be reduced by the significantly lower crop/plant spray coverage and formulation designs that can compensate for this are highly important here. Suspension Concentrate (SC) formulations designed for VLV use containing and delivering low dose rates (g/ha) of organosilicone alkoxylate high-spreading surfactants were found to result in leaf coverage of VLVs comparable to those observed at higher spray volumes. High spreading was observed on textured leaf surfaces containing sub-micron sized epicuticular wax crystals. Greenhouse fungal disease studies showed enhanced efficacy with these SC formulations compared to standard SC formulations without these additives and maintained the observed increase in efficacy when applied at VLV. Alternatively, SC formulations without high spreading formulants but containing uptake promoting nonionic surfactants showed enhanced cuticle penetration through isolated cuticles at VLV in comparison to higher spray volumes, with coffee-ring spray deposit microstructures present at VLVs. Similarly, greenhouse studies showed enhanced efficacy that was maintained at VLV relative to SCs without these additives. At VLVs, SC formulations applied at relatively low dose rates (g/ha) of formulants (adjuvants) enhancing spreading on the leaf surface and/or uptake of the active ingredient(s) maintained good spreading, uptake and biological efficacy in greenhouse studies overcoming the coverage limitations of SC formulations without these additives. This result is unexpected considering the low dose rate of adjuvants used. © 2023 Bayer AG. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ascendancy of pyraclostrobin nanocapsule formulation against Rhizoctonia solani: From a perspective of fungus

High-performance pesticide formulations are essential for sustainable agriculture. Among these, nano-pesticides exhibit great advantages in pest control because of their unique size effects. However, the direct effects of nano-formulation fungicides on fungal pathogens remain largely unexplored. In this study, three qualified formulations, suspension concentrate (SC), microcapsules (CS), and nanocapsules (NCS) of pyraclostrobin (PYR) were prepared and utilized to reveal their biocontrol activities against Rhizoctonia solani. Among these three formulations, NCS exhibited notable biocontrol efficacy against R. solani exemplified by an EC50 of 0.319 mg/L for mycelia, distortion of mycelia and abnormalities in cell ultrastructure. Moreover, NCS displayed excellent internalization within R. solani mycelia, contributing to severe damage to cell membrane permeability. Importantly, an equivalent quantity of NCS-PYR showed potent inhibitory effects on the target pathogen, as indicated by reduced adenosine triphosphate (ATP) content and mitochondrial Complex III activity. The NCS consistently exhibited superior in vivo protective and curative activities against R. solani compared to those of CS and SC in rice and faba bean. In summary, we uncovered the strength of rapid efficacy and biocontrol activity of NCS against R. solani and elucidated the advantages of NCS-PYR from the perspective of the target pathogen in agriculture.

Chitosan-based nanopesticides enhanced anti-fungal activity against strawberry anthracnose as “sugar-coated bombs”

A chitosan-based nanoparticle was prepared using chitosan (CS) and O-carboxymethyl chitosan (O-CMCS). Our study revealed that chitosan/O-carboxymethyl chitosan/tebuconazole nanoparticles (CS/O-CMCS/TBA NPs) exhibited superior antifungal activity, foliar adhesion, and microbial target adhesion performance compared to commercial suspension concentrate (SC). The antifungal activity of CS/O-CMCS/TBA NPs against C. gloeosporioides, with a 3.13-fold increase in efficacy over TBA (SC). We also found that low concentrations of CS/O-CMCS NPs promoted the growth of C. gloeosporioides and enhanced the fungal catabolism of chitosan. Overall, the CS/O-CMCS/TBA NPs were found to possess the remarkable capability to selectively aggregate around pathogenic microorganisms and CS/O-CMCS NPs can enhance the fungal catabolism of chitosan. CS/O-CMCS/TBA NPs, as a “sugar-coated bomb”, was a promising asset for effective plant disease management and pesticide utilization through the affinity of chitosan-based nanoparticles and C. gloeosporioides, enabling targeted delivery and targeted release of their encapsulated active ingredient, which was important for the development and application of biocompatible chitosan-based nanopesticides.

Enhanced fungicidal activity and mechanism of pyraclostrobin nanoparticle with reactive oxygen species responsiveness against Rhizoctonia solani

The frequent application of pesticides has caused adverse effects on humans and the environment. Stimuli-responsive nanoparticles can enhance the control efficacy of pesticides to pest insects or fungus and reduce impacts on non-target organisms. In the present work, 4-(hydroxymethyl) phenylboronic acid pinacol ester (PBAP) groups were conjugated onto β-cyclodextrin (β-CD) to form a H2O2-eliminating material (Ox-bCD), and then the nanoparticiles (PYR@OxbCD) loaded pyraclostrobin (PYR) were successfully fabricated by a nanoprecipitation. The prepared PYR@OxbCD had excellent reactive oxygen species (ROS) release dependency, and significantly enhanced fungicidal activity against Rhizoctonia solani in vitro. PYR@OxbCD could accurately release PYR at infected rice plants, providing a better control efficacy than PYR suspension concentrate (SC). The contact angle of PYR@OxbCD on leaves was reduced, and the spreading and antiphotolysis properties were increased, which may lead to an increase of deposition and a lower dissipation rate. Furthermore, the released PYR from PYR@OxbCD enhanced the activity of peroxidase (POD) and catalase (CAT), and up-regulated the expression of defense genes including PAL, PR10, CHI, CAT, GluPOD and AsPOD. PYR@OxbCD exhibited a much weaker effect on microbial abundance in rice cropping systems. The study provides an idea for smart delivery of fungicides to prevent plant pathogens and offers a more comprehensive view about the resistance of R. solani-infected rice triggered by PYR@OxbCD in levels of phenotype, enzymatic activity, gene expression, and microbiome.

Formulation of Matrine Oil-Based Suspension Concentrate for Improving the Wetting of Droplets and Spraying Performance

Matrine is an efficient, low-toxicity, and environmentally friendly botanical pesticide; however, it is mainly applied as a soluble concentrate (SL) with a limited utilization rate that is unsuitable for ultra-low-volume spraying and unmanned aerial vehicles. Therefore, a matrine formulation (such as an oil-based suspension concentrate, OD) is more effective. In this study, matrine ODs were prepared with three kinds of emulsifiers (VO/02N, VO/03, and VO/01). The storage stability, suspensibility, viscosity, surface tension, contact angle, droplet density, fraction of coverage, maximum retention, indoor control, effect of adhesion tension, and adhesion work of matrine ODs were studied. All three types of matrine ODs had favorable stability, and the wetting and spraying performance of the matrine ODs were more effective than those of the matrine SLs. Among the three types of matrine ODs, the viscosity, wettability, spray performance, and maximum retention of the suspension made with emulsifier VO/03 were superior to those of the other two emulsifiers, and they were more effective in controlling Spodoptera frugiperda. Increasing the solution concentration improved the spreading velocity of the droplets on the solid surface and the wettability. The matrine OD prepared from emulsifier VO/03 had the most effective wettability and spraying properties, and it can be used for ultra-low-volume spraying and aerial application. This study offers new insights into the efficient use of plant-based pesticides.

Development and Validation of Single Laboratory Ultra Fast Liquid Chromatography Method for Quantification of Buprofezin in Suspension Concentrate (SC) Formulation

A novel ultra fast liquid chromatography (UFLC) method has been developed and validated for quantification of Buprofezin in Suspension Concentrate (SC) formulation, using Shimadzu, packed with C18 (250 mm × 4.6 mm, 5 μm) column. Mixture of acetonitrile:water (80:20 v/v) was used as mobile phase. The flow rate was kept 1.5 ml/min and detection was carried out at 250 nm. The linearity of proposed method was investigated in the range of 200-1002 PPM (r2=0.999). The percentage recovery found to be 99.87%. The % RSD value for precision study was &lt;0.68 as per modified Horwitz equation as requirements by CIPAC. The developed method was found to be specific, linear, precise and accurate. This method is also useful for quantification of Buprofezin in their single or combination formulated products, environmental samples (soil, water), and agricultural products for pesticide residue analysis.

Preparation of Cu-CS@IN@MIL-100 (Fe) for controlled indoxacarb release and reduced non-target organism risks

Control release of pesticides based on target plant characteristics is highly desirable for improving the effective utilization rate and reducing non-target organism risks. Here, the controlled release formulations (Cu-CS@IN@MIL-100 (Fe)) were successfully prepared by employing MIL-100 (Fe) as the carrier material, indoxacarb (IN) as the model pesticide, and chitosan (CS) as a coating to chelate copper ions by chemical crosslinking. The prepared Cu-CS@IN@MIL-100 (Fe) had an acceptable loading content (36.25 %). The introduction of CS and copper ions endowed it with sustained release properties under weak acidity conditions like cotton leaves. The laboratory bioassay experiments showed that Cu-CS@IN@MIL-100 (Fe) had practical good insecticidal activity (LC50 = 4.936 mg/L) in controlling Helicoverpa armigera larvae. For long-term control efficacy experiments, after 14 days of application, the Cu-CS@IN@MIL-100 (Fe) treatment (73 %) mortality of Helicoverpa armigera larvae was significantly higher than the 15 % indoxacarb suspension concentrates (SC) treatment (27 %). Moreover, Cu-CS@IN@MIL-100 (Fe) had no adverse effect on cottonseed germination and the acute toxicity to Chrysopa pallens larvae was significantly lower than IN SC. Therefore, MIL-100 (Fe) could be used as an ecological safety carrier for pesticide delivery to improve IN effective utilization and reduce non-target organism risks.