Suspension Concentrate Formulation Research Articles

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.

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.

Assessment of Bacillus thuringiensis var. kurstaki (Bt-127) SC formulation as a component of IPM in soybean through farmer's participatory approach

Insect pests are major biotic constraints limiting soybean production and quality. Soybean growers rely heavily on synthetic chemical insecticides to combat insect pests. Increasing concern for environmental awareness about the use of chemical insecticides has sparked interest in eco-friendly pest management alternatives. An experiment was conducted to assess Bt-127 suspension concentrate (SC) formulation as a component of IPM under real farm situation in Hegdoli village of Kotgiri Mandal, Nizamabad District, Telangana during kharif 2017-18. Incidence of semiloopers (Chrysodeixis acuta and Mocis undata) and tobacco caterpillar (Spodoptera litura) was lowered by 99.5% and 92.9% with the first spray of Bt-127 SC formulation while their incidence was lowered by 99.6% and 97.3%, respectively in farmer's practice with spray of emamectin benzoate. After second spray of Bt-127 SC formulation, incidence of S. litura was lowered by 91.3% and found on par with 91.5% lowering from spray of chlorantraniliprole in farmer's practice. Incidence of natural enemies in IPM field after first and second spray was higher at 0.84 and 0.72 per meter row length in comparison to 0.12 and 0.40, respectively in farmer's practice. The IPM module resulted in higher cost-benefit ratio (1: 2.36) as compared with farmer's practice (1: 1.61).

Evaluation of Two Formulations of Chlorantraniliprole as Maize Protectants for the Management of Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae).

Simple SummaryProstephanus truncatus (Horn) (Coleoptera: Bostrychidae) is a major insect pest of stored maize and dried tubers of cassava, but also a wood-boring species. In the current study, we evaluated two chlorantraniliprole formulations, WG (wettable granule) and SC (suspension concentrate), as maize protectants against P. truncatus adults at 20, 25 and 30 °C. Both formulations performed similarly. The highest mortality was noted in chlorantraniliprole WG, at 10 ppm and 30 °C (98.9%), followed by chlorantraniliprole SC (96.1%), at the same dose and temperature. WG formulation was more effective at 10 ppm and 25 °C (92.8%) than SC formulation (89.4%). No progeny production was noted on maize treated the WG formulation at 20 and 30 °C. The SC formulation caused complete offspring suppression at 10 ppm at all three tested temperatures. The results indicate that chlorantraniliprole is an effective compound with a high insecticidal activity against T. truncatus that depends on temperature, dose and exposure.The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) is one of the most destructive insect pests of stored maize and dried tubers of cassava, and a wood-boring species. In the present study, we examined two chlorantraniliprole formulations, WG (wettable granule) with 350 g/kg active ingredient (a.i.) and SC (suspension concentrate) with 200 g/L a.i., as maize protectants against P. truncatus adults. Chlorantraniliprole formulations were applied as solutions at 0.01, 0.1, 1 and 10 ppm, and tested at 20, 25 and 30 °C. Both formulations performed similarly. After 7 days of exposure, the overall mortality provided by both formulations was very low (<17%). Seven days later, mortality was remarkably increased on maize treated with 1 and 10 ppm at 25 and 30 °C for both formulations. The highest mortality was noted in chlorantraniliprole WG, at 10 ppm and 30 °C (98.9%), followed by chlorantraniliprole SC (96.1%), at the same dose and temperature. WG formulation was more effective at 10 ppm and 25 °C (92.8%) than SC formulation (89.4%). No progeny production was noted on maize treated with the WG formulation at 20 and 30 °C. The SC formulation caused complete offspring suppression at 10 ppm at all three tested temperatures. The results of the present work indicate that chlorantraniliprole is an effective compound with a high insecticidal activity against T. truncatus on stored maize that depends on temperature, dose and exposure interval. The fact that chlorantraniliprole is a broad-spectrum insecticide, exhibiting low toxicity to mammals and beneficial arthropods, could be a valuable management tool in storage facilities.

Effect of florpyrauxifen-benzyl formulation and rate for waterhyacinth (Eichhornia crassipes) control in a mesocosm setting

AbstractWaterhyacinth [Eichhornia crassipes (Mart.) Solms] has been the focus of national legislation efforts and has been listed as noxious, invasive, potentially invasive, or prohibited by at least seven U.S. states. Auxinic herbicides are one of the most effective control methods labeled for use in aquatic sites. In the United States, florpyrauxifen-benzyl, a synthetic auxin, was recently (2018) registered for use in aquatic sites, but limited information has been published on efficacy, especially differences between the two formulations. Therefore, the purpose of this work was to evaluate two formulations of florpyrauxifen-benzyl—suspension concentrate (SC) and emulsifiable concentrate (EC)—at three rates each (14.8, 29.5, and 58.9 g ai ha−1) for control of E. crassipes under outdoor and greenhouse conditions. All rates of each florpyrauxifen-benzyl formulation reduced E. crassipes biomass by 90% to 100% when compared with nontreated plants at 5 wk after treatment. Based on plant recovery in the outdoor trial, there was some evidence that the lowest rate (14.8 g ai ha−1) of florpyrauxifen-benzyl SC and EC may not be as efficacious at reducing E. crassipes biomass as the SC and EC formulations when applied at 29.5 and 58.9 g ai ha−1. Future work should evaluate the florpyrauxifen-benzyl rates tested in this research against E. crassipes in field trials and/or an operational setting to confirm findings.

Novel formulations of Bacillus thuringiensis var. kurstaki: an eco-friendly approach for management of lepidopteran pests.

Bacillus thuringiensis (Bt) and entomopathogenic fungi (EPF) are in use for management of insect pests. Continuous use of Bt can lead to problem of resistance development in insect pests. Hence use of combination formulations (CF) of microbials with diverse modes of action has been attempted to slow down the process of resistance development. Suspension concentrate (SC) formulations of a local strain of Bt var. kurstaki DOR Bt-127 were developed singly and in combination with conidia of the EPF Nomuraea rileyi (Nr) and Beauveria bassiana (Bb). Electron microscopy of Bt + Bb CF treated larvae of Helicoverpa armigera revealed simultaneous infection by both microbials indicating their compatibility. Endotoxin contents in Bt-SC, Bt + Bb and Bt + Nr CFs were 5.0, 4.7 and 4.7%, respectively. These formulations were effective against larvae of Spodoptera litura, H. armigera and Achaea janata coupled with a lowering of the effective requirement of Bt and EPF. In multi-location field trials, Bt-SC and Bt + Nr CF were highly effective against S. litura and A. janata on castor as well as H. armigera and Thysanoplusia orichalcea on sunflower. However, Bt + Bb CF was highly effective only on sunflower against H. armigera and T. orichalcea. All formulations had 24months shelf-life at room temperature. DOR Bt-127 based SC formulations developed singly and in combination with Nr and Bb were effective against major lepidopteran pests of castor and sunflower and did not lose viability under storage at room temperature. The CFs of Bt with EPF could prove promising for mitigating resistance development to Bt.

Development of a Vortex-Assisted Dispersive Liquid-Liquid Microextraction (VA-DLLME) and LC-MS/MS Procedure for Simultaneous Determination of Fipronil and its Metabolite Fipronil Sulfone in Tomato Fruits

A rapid, simple, inexpensive, and reliable vortex-assisted dispersive liquid-liquid microextraction (VA-DLLME) method was developed for the determination of fipronil and its major metabolite, fipronil sulfone, in tomato fruits using liquid chromatography tandem mass spectrometry (LC-MS/MS). No salting-out or cleanup steps were required after extraction. Average recoveries ranged from 89.8 to 96.3% with relative standard deviation (RSD) values below 11.6%. The limit of quantitation (LOQ) of the method was 0.25 μg/kg, which is 20 times below the European Union-defined maximum residue limit (MRL) of 5 μg/kg. Good linearity was achieved, with a correlation coefficient ≥ 0.996 based on matrix-matched calibration. We investigated the dissipation and residue distribution of fipronil in tomato fruits after one application of suspension concentrate (SC) or emulsifiable concentrate (EC) formulations over 28 days under field conditions using the VA-DLLME method. The half-life (t1/2) of fipronil dissipation was 2.4 and 2.8 days, and the estimated pre-harvest interval (PHI) was 23 and 32 days for the SC and EC formulation, respectively. A risk assessment was conducted by evaluating the health risk index (HRI); the estimated PHIs values indicate it is safe to consume tomatoes after the recommended application of fipronil.

Viscosity, surface tension and droplet size of sprays of different formulations of insecticides and fungicides

The influence of three types of commercial formulation of insecticides and fungicides, emulsifiable concentrate (EC) formulation, suspension concentrate (SC) formulation and water dispersible granule (WG) formulation on the surface tension, viscosity and the droplet size spectra of sprays was evaluated using thirty commercial insecticide and fungicide products. The concentration of sprays was based on application water spray volume of 50 L ha−1 using an XR 8003VS flat fan nozzle, operated at 200 kPa pressure. The lowest surface tensions were obtained with EC formulations, while the SCs had the highest viscosities. Emulsions were the most effective at decreasing the percentage of droplets smaller than 100 μm and relative span, while increasing the DV0.1 and DV0.5 values than the dispersion-type formulations, represented by WG and SC formulations. These factors should be considered for planning spray applications and reducing drift.

Enhanced bioefficacy of Bacillus thuringiensis var. kurstaki against Spodoptera litura (Lepidoptera: Noctuidae) through particle size reduction and formulation as a suspension concentrate

ABSTRACTTechnical powder of DOR Bt-127, a local isolate of Bacillus thuringiensis (Bt) var. kurstaki, containing 105 µm particles was subjected to milling in a planetary ball mill. Dynamic light scattering of samples drawn at 30 min intervals revealed reduced particle sizes ranging 1171–210 nm. Alkali-soluble protein was higher at 153–175 mg/g in milled Bt powders over 140 mg/g in unmilled Bt powder. All milled powders gave higher mortality of Spodoptera litura (Fabricius) larvae in comparison to the unmilled Bt powder. Bt powder from 60 min milling containing 559 nm particles with a low polydispersity index of 0.338 gave a lower LC50 value of 1.35 mg/ml against third instar S. litura larvae in comparison to 2.04 mg/ml for unmilled Bt powder. LC50 value of the suspension concentrate (SC) formulation developed with 559 nm Bt particles was 2.84 µl/ml containing only 0.95 mg Bt. Field evaluation of the SC formulation against S. litura on castor revealed highest per cent larval reduction of 92.4 and 96.2 at concentrations of 2.5 and 3.0 ml/l, respectively.

TENACITY AND PERSISTENCE OF COPPER FUNGICIDES IN CITRUS SEEDLINGS UNDER SIMULATED RAINFALL

ABSTRACT The amount of fungicide that adheres to the leaf during spraying and the amount that remain on the leaf after weathering are the main factors that defines the amount of active residue on the leaf surface to effectively control plant pathogens. Thus, the objective of this work was to evaluate the tenacity and persistence of copper in citrus seedling leaves under simulated rainfall in Jaboticabal, State of São Paulo, Brazil. The evaluated variables were copper content, solution retention, surface tension and drop spectrum. A significant and inversely proportional linear relationship to drops &lt;100 µm was found. The percentage of copper retained in leaves of citrus seedlings with copper fungicides of suspension concentrate (SC) formulations after simulated rainfall was greater than 80%. Copper fungicides of SC formulations presented the lowest surface tension, allowing greater tenacity and persistence of copper on seedlings of citrus leaves after simulated rainfall and increased contact between the drops and leaf surface.

Liquid Formulation of Trichoderma Species for Management of Gray Mold in Castor (Ricinus communis L.) and Alternaria Leaf Blight in Sunflower (Helianthus annuus L.)

The composition, concentration, shelf life and inconsistent performance are the major concern in formulation of bioagents in general and Trichoderma spp. in particular. To overcome some of these problems, Suspension Concentrate (SC) formulation of a potential isolates of Trichoderma viz., T. harzianum Th4dSC and consortium of T. harzianum Th4d SC and another species T .asperellum Tv5 SC were developed using conidial biomass of these bioagents produced by a production process supporting a higher quantities of biomass and viable propagules with better shelf life and persistence on sprayed surfaces. In this study, twenty five selected strains of Trichoderma were screened in vivo against foliar diseases (Alternaria Leaf Blight (ALB) of sunflower and Botryotinia Gray Mold (BGM) of castor). Among these strains, T. harzianum Th4d and T. asperellum Tv5 were able to produce mycolytic, defense enzymes and able to control two diseases effectively. Further a study was conducted to standardize the dose of SC formulation of Trichoderma for foliar application and seed treatment. The highest antagonistic activity was achieved with concentration of 2x107 conidia/ml. The two selected strains were able to reduce severity of BGM and ALB under greenhouse conditions. In field trials (rainy season of the years 2009-10 and 2010-11), seed treatment, foliar application of T. harzianum Th4d SC at 2 ml/l and consortium formulations (T. harzianum Th4dSC+ T. asperellum Tv5SC at 1 ml/l) effectively reduced disease severity (ALB reduction up to 50-55% and BGM up to 55-65%). In addition, these applications enhanced yield of sunflower and castor compared to untreated control. Application of T. harzianum Th4dSC at 2 ml/l and consortia T. harzianum Th4dSC + T. asperellum Tv5SC at 1 ml/l showed better persistence with log CFU (colony forming unit) 7.61 and 8.45 respectively on sprayed leaves of sunflower population levels of log CFU 10.73 and 10.71 on capsules of castor at 15 days after first spray. The liquid formulations of both the strains retained good shelf life with viable spore counts of log CFU of 8.0 to 7.4 at 540 days when stored at room temperature. Thus, the efforts resulted in identification and development of suspension concentrate formulation with long shelf life of two potential Trichoderma strains for the first time for foliar disease management.

Effect of two formulations on the decline curves and residue levels of rotenone in cabbage and soil under field conditions

The dissipation and residue levels of rotenone with suspension concentrate (SC) as well as water dispersible granule (WDG) formulations in cabbage and soil were investigated under field conditions. The decline curves of rotenone residues in cabbage and soil corresponded with first-order kinetics. The dissipation rate of rotenone in cabbage was faster than that in soil. The half-lives of the SC formulations in cabbage and soil were 1.14d to 1.85d and 2.26d to 3.98d, respectively. For the WDG formulation, the values were 1.33d to 1.96d and 2.41d to 3.38d. Less spraying, lower dosage, and longer pre-harvest intervals could reduce terminal residue levels. Terminal residues below the MRL (0.5mgkg−1) were achieved after pre-harvest intervals of 3d at either once (45ga.i.ha−1) or twice (90ga.i.ha−1) the recommended dosage. The different dissipation processes of rotenone in cabbage and soil under field conditions could be attributed to the different climate and soil properties, and the types of formulation had no apparent effect on half-life. Formulation type affected the initial concentrations and finally led to different terminal residues. Prolonged pre-harvest intervals are necessary to ensure that the products are sufficiently safe for consumption.

Effect of Short Exposures to Spinetoram Against Three Stored-Product Beetle Species

Laboratory bioassays were carried out to evaluate the effectiveness of two formulations of spinetoram, water dispersible granules (WG), and suspension concentrate (SC-NC), against three major stored-grain beetle species, the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae); the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); and the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae). Adults of the above species were exposed on wheat treated with spinetoram at 1 ppm (1 mg/kg of wheat) for 0, 2, 4, 6, 8, 16, 40, and 72 h. After this interval, mortality was recorded (immediate mortality) and the surviving individuals were transferred in untreated wheat, where mortality was recorded again 7 d later (delayed mortality). Then, all adults were removed, and the number of progeny production in the untreated substrate was measured 65 d later. From the species tested, R. dominica was by far the most susceptible, given that immediate and delayed mortality for the 72-h exposure interval reached 44 and 97%, respectively. At the same time, progeny production was low, in most of the exposure intervals tested. In contrast, for S. oryzae, delayed mortality was negligible, with the exception of 72 h at the SC-NC formulation. However, in most of the cases examined, progeny production for S. oryzae was high. Finally, adult mortality for T. confusum was extremely low, regardless of the exposure interval and the type of the formulation. Nevertheless, offspring emergence of this species was low. By combining the results of the current study and the data that are available from the literature for short exposures to spinosad, we can conclude that the two ingredients were equally effective against these three stored-grain beetle species.

Stabilization of Suspension Concentrate Formulations via Specialized Double-comb Polymers

Abstract Alkyl naphthalene sulfonate condensates, lignosulfonates, block copolymers, and alkoxylated polyarylphenol derivatives are used as dispersants in pesticide suspension concentrate (SC) and suspoemulsion formulations. Typically, a pesticide formulation could contain either type of dispersant, with the final selection being driven by the active ingredient and the desired performance characteristics of the final formulation. Until now, little attention has been focused to the use of stabilizing polymers to improve the quality and shelf life of these formulations. Comparative data were generated on selected aqueous SC formulations to better understand the particle stabilization effects of a specialized double-comb polymer. Significant improvement of suspension stability is possible over the standard formulations.

Effects of sodium bisulphate, acidic buffers and ammonium sulphate on imazamethabenz phytotoxicity to wild oats

Greenhouse studies determined the effects of sodium bisulphate (NaB), acidic buffers and ammonium sulphate on the phytotoxicity of imazamethabenz, (±)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1 H-imidazol-2-yl]-4(and 5)-methylbenzoic acid (3:2), applied to wild oat plants at the 2- to 3-leaf stage. At an equivalent dosage of imazamethabenz the liquid concentrate (LC) formulation had higher herbicidal activity and much lower pH than did the suspension concentrate (SC) formulation. NaB added to the SC formulation lowered solution pH by > 3 units to ∼ 2.2 and enhanced herbicidal activity at 200–300 g ha −1 active ingredient (a.i.), but not at 400 g a.i. ha −1. NaB did not improve the activity of the LC formulation. Increasing the spray solution pH from 5.6 to ∼ 7.3 with 1 m KOH antagonized phytotoxicity of both LC and SC formulations of imazamethabenz alone, and imazamethabenz-SC plus NaB. Citric acid-phosphate buffers at pH 3–6, or HCl-KCl buffers at pH 1 and 2, either had no effect or antagonized the activity of the SC formulation of imazamethabenz. However, the same HCl-KCl buffers plus 1% (v/v) ammonium sulphate enhanced herbicidal activity at 250 g a.i. ha −1, while 1% ammonium sulphate, alone, enhanced herbicidal activity at both 200 and 250 g ha −1. NaB provided both bisulphate ion and low pH concurrently. Acidic buffers did not improve the activity of the SC formulation except in the presence of bisulphate or sulphate ions. It is suggested that at low pH the herbicide becomes cationic, forms the bisulphate or sulphate salt of the methyl ester of imazamethabenz, and enters true solution. In this form it readily penetrates the cuticle. High solution pH acts against this process.

Fate and persistence of residues on wheat used to explain efficacy differences between deltamethrin suspension concentrate and emulsifiable concentrate formulations

AbstractTo help explain the increased residual activity of a deltamethrin suspension concentrate (SC) formulation against grasshoppers, the persistence, location and nature of residues from the SC and an emulsifiable concentrate (EC) formulation have been compared. Wheat plants were sprayed in a cabinet sprayer at 7.6 g ha−1 for the EC and 5.6 g ha−1 for the SC, then weathered outdoors for 16 days. With the SC formulation, residues were more persistent, more residues were located on the exterior of the leaves, and less deltamethrin was converted to inactive isomers. Eight days after spraying, the exterior deltamethrin residues were 0.13 μg plant−1 from the SC versus 0.06 μg plant−1 from the EC. Thus, more residual deltamethrin is available to grasshoppers with the SC formulation.