Suspension Concentrate Research Articles

Dissipation study and dietary risk assessment of dinotefuran, DN, and UF in wolfberry

ABSTRACT In this study, a reliable and efficient residue analytical method to determine dinotefuran and its metabolites [1-methyl-3-(tetrahydro-3-furylmethyl) guanidine (DN) and 1-methyl-3-(tetrahydro-3-furylmethyl) urea (UF)] in wolfberry and soil was established. The mean recoveries from soil and wolfberry matrices ranged from 84.7 to 98.9%, with intra-day relative standard deviations (RSDr) in the range of 0.9–2.5% for three test compounds. The limits of quantification (LOQs) were 0.005 mg kg−1 for dinotefuran, DN, and UF in wolfberry and soil matrices, and the limits of detection (LODs) were 0.0001 mg kg−1 for three compounds in two matrices. The dissipation and residual assay in 2016 with the commercial formulation of dinotefuran • thiamethoxam 30% suspension concentrate (SC) was conducted at four locations of Qinghai, Gansu, Inner Mongolia, and Ningxia province. The dissipation rates of dinotefuran were rapid in wolfberry with the half-lives were 1.4–3.1 days. The dissipation in soil were relatively slow with half-lives 7.5–17.4 days. According to the results of dietary risk assessment, the residue of dinotefuran at the recommended dosage is safe for human

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.

Effect of insecticide formulation and adjuvant combination on agricultural spray drift

Loss of crop protection products when agricultural spray applications drift has economic and ecological consequences. Modification of the spray solution through tank additives and product formulation is an important drift reduction strategy that could mitigate these effects, but has been studied less than most other strategies. Therefore, an experimental field study was conducted to evaluate spray drift resulting from agricultural ground applications of an insecticide formulated as a suspension concentrate (SC) and as a wettable powder (WP), with and without two adjuvants. Droplet sizes were also measured in a wind tunnel to determine if indirect methods could be substituted for field experimentation to quantify spray drift from these technologies. Results suggest that spray drift was reduced by 37% when comparing the SC to the WP formulation. As much as 63% drift reduction was achieved by incorporating certain spray adjuvants, but this depended on the formulation/adjuvant combination. The wind tunnel data for droplet spectra showed strong agreement with field deposition trends, suggesting that droplet statistics could be used to estimate drift reduction of spray solutions. These findings can be used to develop a classification scheme for formulated products and tank additives based on their potential for reducing spray drift.

Simultaneous determination of thiamethoxam and its metabolite clothianidin by LC-MS/MS in goji berry and soil

ABSTRACT In this study, an effective analytical method for simultaneous determination of thiamethoxam and its metabolite clothianidin in goji berry and soil was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The recoveries of the compounds in goji berry and soil at the levels of 0.005, 0.02, and 0.1 μg kg−1 were 84.7–98.9% and the relative standard deviations (RSDs) were 0.9–3.2%. The limits of detection (LOD) for both compounds in goji berry and soil matrices were 0.001 mg kg−1; the limits of quantification (LOQ) were 0.005 mg kg−1 for both compounds in two matrices. The dissipation and final residual experiments in 2016 with the commercial formulation of dinotefuran • thiamethoxam 30% suspension concentrate (SC) was conducted in goji berries in northwest China (Qinghai, Gansu, Inner Mongolia, and Ningxia). Thiamethoxam was dissipated fast in goji plant ecosystem with half-lives were 1.08–1.01 and 2.04–4.25 days in goji berry and soil. The final residues of thiamethoxam were <0.005–0.382 and <0.005–1.120 mg kg−1 in goji berry and soil, respectively.

Efficacy of Combinations of Methoprene and Deltamethrin as Long-Term Commodity Protectants.

Wheat, corn, and brown rice were treated with different combinations of a deltamethrin suspension concentrate (SC) formulation and a new emulsifiable concentrate (EC) formulation, at rates of either 0.5 or 1.0 ppm alone or in combination with 1.25 and 2.5 ppm methoprene (10 treatments in all, including an untreated control). Treated commodities were stored at ambient conditions on the floor of an empty grain bin in Manhattan, KS, USA, in 5-kg lots for individual replicates. The commodities were sampled and bio-assayed every three months for 15 months by exposing 10 mixed-sex parental adults of selected adult stored product insects on 70–80 g of the commodity. For all treatments, there was no regression of declining efficacy with respect to the month. Therefore, the data were combined for analysis. On wheat and brown rice, there was no reproduction of Rhyzopertha dominica (Fabricius) in any of the treatments, and there was no weight loss in either commodity that was caused by feeding of the parental adults or developing progeny. There was reproduction of Sitophilus oryzae (L.) on wheat but, for several combinations, the EC formulation gave better suppression of progeny compared to the standard SC. However, on brown rice, only the combination of 1.0 ppm deltamethrin EC and 2.5 ppm methoprene was different than other treatments with respect to progeny development, sample weight loss caused by feeding, and weight of the feeding damage itself. Progeny production was correlated with grain damage. No progeny of Tribolium castaneum (Herbst) developed on the treated corn, but there was some variation in insect damage, with less damage in those treatments involving the EC formulation. Progeny production of Sitophilus zeamais (Motschulsky) was at the lowest in the combination of 1.0 ppm deltamethrin EC and 2.5 ppm methoprene. The resulting insect damage was the lowest in this combination as well. Results of this study were used by the registrant (Central Life Sciences) in the United States (US) to modify the commercial formulation to replace the deltamethrin SC with the EC, at label rates of either 0.5 ppm EC + 1.25 ppm methoprene, or 1.0 ppm EC + 2.5 ppm methoprene, on wheat, corn, and rice.

Synthesis of nonylphenol polyoxyethylene oligomer and application as an effective dispersant in pyraclostrobin suspension concentrate

ABSTRACTA versatile dispersant plays a critical role in suspension stability of pesticide aqueous suspension concentrate (SC), thus it is extremely important to design and synthesize an effective dispersant for SC. Herein, nonionic trimeric nonylphenol polyoxyethylene (10) (TNP10) was successfully synthesized using nonylphenol polyoxyethylene(10) ethers (NP10) as raw materials. The surface activities of TNP10 were evaluated according to critical micelle concentration (CMC), and the surface tension at CMC (γCMC). TNP10 showed higher surface activity due to its lower CMC value compared with that of NP10. In addition, the dispersing and stabilizing properties of TNP10 in 25 wt.% pyraclostrobin SC system were investigated. The results showed that TNP10 as a dispersant exhibited more excellent dispersion performance than NP10. Meanwhile, the obtained SC system exhibits shear thinning behavior under high-speed shearing showing typical features of pseudo-plastic non-Newtonian fluids, which conforms to the Herschel-Buckley model. The nonionic trimeric nonylphenol polyoxyethylene (10 can effectively improve the surface activities and the suspension rate and stability of SC compared with its monomer NP10.

Natural green-peel orange essential oil enhanced the deposition, absorption and permeation of prochloraz in cucumber.

Pesticides have long been used in agricultural production and will continue to be used long into the future. Enhancing their efficient use in agricultural production is an effective method to avoid their loss to non-target areas, such as soil, water and air. Here natural green-peel orange essential oil (GOEO) was used as a spray adjuvant to improve the efficient use of pesticides. A comparative study between a conventional formulation and a conventional formulation with GOEO was conducted. Conventional formulations of prochloraz were chosen as control groups. It was obvious that the concentrations of prochloraz and its metabolite in cucumber leaves treated by conventional formulations with GOEO were much higher than those treated without GOEO. The data also showed, for both emulsifiable concentrate (EC) and suspension concentrate (SC), that the spreading and penetration performance were improved when GOEO was used as a spray adjuvant, but with SC the impact was more significant. GOEO improved the deposition, absorption and degradation performance of prochloraz on cucumber leaves. It was more applicable to those pesticide formulations without a good wetting and spreading effect, such as SC. As a plant source extract, GOEO is much safer for crops and more friendly to the environment than other synthetic adjuvants. The application of GOEO as a spray adjuvant has great potential to increase the pesticide utilization rate.

嗪草酮·砜嘧·烯草酮28%悬浮剂高效液相色谱分析方法

嗪草酮·砜嘧·烯草酮28%悬浮剂高效液相色谱分析方法

Dissipation behavior and dietary risk assessment of lambda-cyhalothrin, thiamethoxam and its metabolite clothianidin in apple after open field application

The dissipation dynamics and residue amounts of lambda-cyhalothrin, thiamethoxam and clothianidin in apple were investigated by using rapid resolution liquid chromatography triple quadrupole mass spectrometer (RRLC-MS/MS) and gas chromatography mass spectrometry (GC-MS). The developed method performed satisfactory recoveries of 88%–105% and the limit of quantitation (LOQ) was 0.01 mg kg−1. The suspension concentrate (SC) formulation of lambda-cyhalothrin and thiamethoxam was applied on apple field in accordance with good agricultural practice (GAP). The half-lives of two pesticides ranged from 7.01 d to 17.3 d and the terminal residues were <0.01–0.21 mg kg−1. Based on the Chinese dietary pattern, the dietary risk of lambda-cyhalothrin and total thiamethoxam were predicted by comparing intake amounts with the toxicological data, namely acceptable daily intake (ADI) and acute reference dose (ARfD). The chronic and acute risk quotients were 0.1080–0.4463 and 0.0008–0.2005, respectively, which showed negligible risk for general consumers. The pre-harvest interval (PHI) of 21 d was suggested for the formulation in compliance with maximum residue limit (MRL) and dietary risk assessment, meanwhile, the MRL of 0.1 mg kg−1 was recommended for thiamethoxam in apple. These results were vital for guiding reasonable usage of two insecticides and for approval of formulation use.

Dissipation and residues of fluazinam and dimethomorph in potatoes, potato plants, and soil, determined by QuEChERS ultra-performance liquid chromatography tandem mass spectrometry.

Fluazinam and dimethomorph 35% suspension concentrate (SC) is a new combined fungicide formulation introduced in China to improve fungicidal efficacy and decrease the risk of resistance in potatoes. Fluazinam and dimethomorph dissipation and residues in potatoes, potato plants, and soil under field conditions were determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Fluazinam and dimethomorph 35% SC was applied at two doses to potatoes and soil in Ningxia Autonomous Region and Anhui Province, China. Fluazinam and dimethomorph dissipation fitted first-order kinetics, and the fluazinam half-lives in potato plants and soil were 3.3-5.4 and 9.4-9.5days, respectively. The dimethomorph half-lives in potato plants and soil were 2.1-2.6 and 5.9-8.6days, respectively. Fluazinam and dimethomorph 35% SC was sprayed onto potato plants three or four times at application rates of 420 and 630ga.i.ha-1 with 7days between applications. Potato and soil samples were collected at 3, 7, and 14days after the last application. Potatoes and soil had fluazinam concentrations of < 0.01 and < 0.05-0.183mgkg-1, respectively, and dimethomorph concentrations of < 0.01 and 0.129-0.677mgkg-1, respectively. The final fluazinam and dimethomorph concentrations in potatoes were below the EU maximum residue limits (0.02 and 0.05mgkg-1, respectively) 3days after application. Fluazinam and dimethomorph can therefore be applied to potatoes at the recommended doses.

The control effect of fungicide pyraclostrobin against freckle disease of banana and its residue dynamics under field conditions

ABSTRACTFungicide pyraclostrobin has been widely employed to control plant diseases by inhibiting the mitochondrial respiration of pathogenic fungi. Due to its broad spectrum, the extensive use of pyraclorstrobin was reported to cause emerging resistance on crops. Here, we evaluated the control effect of 250 g L−1 of pyrachlostrobin suspension concentrate (SC) against freckle disease (caused by Phyllosticta spp) on banana. Meanwhile, the dissipation and residue dynamics of pyraclostrobin in banana and soil under field conditions were determined by high performance liquid chromatography (HPLC) with DAD detection in different locations. The analytical method was validated using spiked samples at three levels, which indicated the recoveries ranged from 92.0% to 99.0% with relative standard deviations (RSDs) below 5%, providing a sensitive, precise and reliable method to monitor pyraclostrobin in banana fruit and soil. The dissipation of pyraclostrobine followed the first-order kinetics and its half-lives were 5.25 to 9.90 days. In addition, the terminal residues of pyraclostrobin in banana, banana sarcocarp and soil were below the maximum residue limit (MRL) (0.02 mg kg−1) after a pre-harvest interval (PHI) of 42 days, which suggesting that the use of pyraclostrobin at recommended dosages was safe to banana and the environment. In summary, we demonstrated the integrated evaluation on the disease control capacity of pyraclostrobin and its environmental behavior on banana, aiming to provide solid and basic data for the safe use of fungicide pyraclostrobin.

Compound pesticide controlled release system based on the mixture of poly(butylene succinate) and PLA

Controlled release system has been widely developed and utilised in agriculture to optimise efficacy and minimise environmental pollution. Here, the azoxystrobin and difenoconazole compound pesticide microsphere was constructed by the solvent evaporation method. Blending poly (butylene succinate) (PBS) and poly (lactic acid) (PLA) as shells, in order to increase its entrapment efficiency and match the goal of complex synergism. The resulting microsphere processes high entrapment efficiency with a mean diameter of 7.2 μm. Acute toxicity suggested microsphere on zebrafish was moderate toxicity. Comparative studies revealed that the microsphere had a longer period of sustained release than difenoconazole–azoxystrobin (5:8) 32.5% w/v suspension concentrate (SC). In addition, the concentration ratio of active ingredients closed to the optimum compound stoichiometry, which can achieve the objective of improving the efficacy of the pesticides. These results demonstrated that such a compound pesticide microsphere delivery system may be a considerable potential for further exploration.

FRACTION AND DETERMINATION OF CAPSAICINOIDS FROM RED PEPPER FRUITS WITH INSECTICIDAL ACTIVITY AGAINST MEALWORM, Tenebrio molitor, AND SUPERWORM, Zophobas morio

Green chemistry has recently been an active area of research and it is expected to replace the chemical synthesis in agriculture. In this study, our attempt is to fractionate and determine the capsaicinoids from red pepper fruit to control mealworm Tenebrio molitor and superworm Zophobas morio. The methanol extraction of red pepper fruit (Capsicum annuum L.) effectively killed T. molitor and Z. morio at the concentration of 10000 ppm. The insecticidal activity of n-hexane, dichloromethane and aqueous layers derived from the extract by liquid-liquid partitioning were evaluated. Among them, only dichloromethane layer showed insecticidal activity; whereas n-hexane and aqueous layers were inactive against tested pests. The dichloromethane layer was successively fractionated by silica gel column chromatography to afford insecticidal compounds. The chemical structures of active compounds in dichloromethane layer were elucidated by the analysis of NMR and MS spectroscopic data. The active compounds were determined to be as capsaicinoids and their insecticidal activity was also evaluated using the in vitro residual contact bioassay method. The extracts containing capsaicinoids were formulated into a suspension concentrate (SC) biopesticide and evaluated for efficacy against T. molitor and Z. morio. The biopesticide caused mortalities by 95-100 % against tested pests at 1000 µg/mL. The study results suggested that extracts containing capsaicinoids could be used as active ingredients for the preparation of the biopesticide to control insect pests thereby preserving stored products in sustainable agriculture.

Plant Virus-Based Nanoparticles for theDelivery of Agronomic Compounds as aSuspension Concentrate.

Nanoparticle formulations of agrichemicals may enhance their performance while simultaneously mitigating any adverse environmental effects. Red clover necrotic mosaic virus (RCNMV) is a soil-transmitted plant virus with many inherent attributes that allow it to function as a plant virus-based nanoparticle (PVN) when loaded with biologically active ingredients. Here we describe how to formulate a PVN loaded with the nematicide abamectin (Abm) beginning with the propagation of the virus through the formulation, deactivation, and characterization of the finished product.

Field evaluation of the biolarvicide, spinosad 20 per cent emulsifiable concentrate in comparison to its 12 per cent suspension concentrate formulation against Culex quinquefasciatus, the vector of bancroftian filariasis in India.

Background & objectives:Biolarvicides may offer alternatives to chemical larvicides as these are known to be safe to environment and selective against the target species. However, only a limited number of biolarvicides have been approved for mosquito larval control. In the current study, a new formulation of spinosad, 20 per cent emulsifiable concentrate (EC) was tested for its efficacy against Culex quinquefasciatus, in comparison to its 12 per cent suspension concentrate (SC).Methods:Spinosad 20 per cent EC was tested against Cx. quinquefasciatus immature at 25, 50, 100 and 150 mg active ingredient (ai)/m[2] in cesspits, drains and abandoned wells in comparison with spinosad 12 per cent SC at the optimum field application dosage of 50 mg ai/m[2].Results:The 20 per cent EC caused 90-100 per cent reduction of pupal density for 7-14 days in cesspits, 10-17 days in drains and 14-30 days in abandoned wells at all dosages tested. At lower dosages of 25 and 50 mg ai/m[2], >90 per cent reduction of pupal density was observed for one week in cesspits and street drains and for two weeks in abandoned wells. The effective duration of control provided by the higher dosages, 100 and 150 mg ai/m[2] was 1.4 to 2 times greater than the lower dosages, 25 and 50 mg ai/m[2].Interpretation & conclusions:The findings showed that the spinosad 20 per cent EC can be used for larval control against Cx. quinquefasciatus, at the dosage of 25 mg ai/m[2] at weekly interval in cesspits and drains and at fortnightly interval in abandoned wells. Spinosad 20 per cent EC could be one of the options to be considered for larval control under integrated vector management.

Field testing &amp; evaluation of the efficacy &amp; duration of effectiveness of a biolarvicide, Bactivec® SC (Bacillus thuringiensis var. israelensis SH-14) in Bengaluru, India

Background & objectives:Different formulations of Bacillus thuringiensis var. israelensis (Bti) have been tested against different mosquito vectors and other insects for their residual activity. In the present study, the efficacy and residual activity of a new formulation of Bti (Bactivec Suspension Concentrate) were evaluated against immature stages of Anopheles stephensi Liston (Diptera: Culicidae), Aedes aegypti Linnaeus (Diptera: Culicidae) and Culex quinquefasciatus Say (Diptera: Culicidae), in natural habitats in Phase II and Phase III in Bengaluru, India.Methods:Preferential breeding habitats of the mosquito species were selected and four dosages (0.25, 0.5, 1 and 2 ml/50 l) were tested in Phase II trial. Two most effective dosages, 0.5 and 1 ml/50 l were selected for Phase III trial. The evaluation was carried out essentially following the guidelines of the World Health Organization Pesticide Evaluation Scheme. Pre-treatment and post-treatment densities were recorded at regular intervals, and >80 per cent reduction in pupae was taken as the duration of effectiveness.Results:Bactivec SC treated at the dosage of 1 ml/50 l could produce 10-17 days efficacy (>80% reduction in pupae) in clean water habitats tested, whereas 0.5 ml/50 l dosage showed residual activity from 7 to 14 days against Ae. aegypti and An. stephensi in Phase III studies. In polluted water habitats, 4-7 days efficacy could be recorded against Cx. quinquefasciatus in Phase III.Interpretation & conclusions:The Bactivec SC formulation was operationally feasible and easy to handle. For the control of Anopheles and Aedes mosquitoes in freshwater habitats, 1 ml/50 l dosage was found effective, whereas in polluted water habitats against Cx. quinquefasciatus 5 ml/m2 was found effective.

Ecotoxicity evaluation of modern herbicides by their effect on the soil mesofauna

Pesticides, as biologically active substances, can influence on biota of agroecosystems, in particular on fauna of invertebrate animals that play an important role in soil-forming process. The work is devoted to study of the ecotoxicity of herbicidal preparations, belonging to the class of chloroacetanilide (chloro-acetamides), on the representatives of soil mesofauna. In laboratory conditions the behavioral response and quantitative changes of earthworms Eisenia foetida were investigated under the influence of herbicides of selective action in dependence on a concentration and time of display (7 and a 14 days), using the artificial substrates of following composition: sphagnum peat moss (10%), kaolin clay (20%) and quartz sand (70%). Based on the study of acute toxicity it was found that herbicidal preparations with active ingredient propisochlor (720 g/l) or active ingredient acetochlor (900 g/l) that used in the form of the emulsion concentrate (EC) are slightly toxic. Нerbicidal preparations used in the form of suspension concentrate (SC) with active substance metazachlor (400 g/l) is safe for the representatives of soil mesofauna. The obtained results concerning the ecotoxicity of new generation of herbicidal preparations are necessary to consider when using them taking into account the forms of preparations and recommended doses.

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.

Integrating uniform design and response surface methodology to optimize thiacloprid suspension

A model 25% suspension concentrate (SC) of thiacloprid was adopted to evaluate an integrative approach of uniform design and response surface methodology. Tersperse2700, PE1601, xanthan gum and veegum were the four experimental factors, and the aqueous separation ratio and viscosity were the two dependent variables. Linear and quadratic polynomial models of stepwise regression and partial least squares were adopted to test the fit of the experimental data. Verification tests revealed satisfactory agreement between the experimental and predicted data. The measured values for the aqueous separation ratio and viscosity were 3.45% and 278.8 mPa·s, respectively, and the relative errors of the predicted values were 9.57% and 2.65%, respectively (prepared under the proposed conditions). Comprehensive benefits could also be obtained by appropriately adjusting the amount of certain adjuvants based on practical requirements. Integrating uniform design and response surface methodology is an effective strategy for optimizing SC formulas.

Application of Polycarboxylate and Naphthalenesulfonate Dispersants in High Concentration Suspension Concentrate

Application of Polycarboxylate and Naphthalenesulfonate Dispersants in High Concentration Suspension Concentrate