Study of potential activity of clove oil 10 % emulsifiable concentrate formulation on Two-spotted spider Mite Tetranychus urticae Koch (Acari: Tetranychidae)

Clove oil is reported to have a great range of biological activities against many species of pests; termites, cockroaches, aphids, weevils and moths, and many different usages such as perfume and food flavoring agent. This study aimed to determine the acaricidal activity of clove oil emulsifiable concentrate new formulation against two-spotted spider mites Tetranychus urticae. Clove oil was formulated as 10 % emulsifiable concentrate (EC). The new formula passed successfully all physical and chemical tests reported for emulsifiable concentrates. It was then tested biologically on the individuals of two-spotted spider mite T. urticae Koch (Acari: Tetranychidae) on two host plants beans and squash under laboratory conditions. In both cases, there were a direct relationship between the increase in the concentration of the formulation and the percentage of inhibition on the individuals of the two-spotted spider mite, after 72 hours of treatment, at concentrations of 20, 40, and 80 mg/ml the new formulation showed 10.30, 44.8, and 75 percent inhibition, respectively in case of beans, while squash at the same concentrations and for the same period of treatment showed 33.3, 40.7, and 51.9 percent inhibition, but the effect in case of beans was greater than that in case of squash as its EC50 value was lower than that in case of squash. In the case of the former, it was 39.81 mg/ml, whereas in the case of the latter, it was 79.43 mg/ml. Therefore, the new clove oil formulation can be used to combat the two-spotted spider mite.

Assessment of methyl ester as a green carrier solvent in pesticide emulsifiable concentrate formulation

The conventional pesticide emulsifiable concentrate (EC) formulations usually contain a large amount of aromatic solvents. This causes adverse effects to environment and human health due to the toxicity of such organic solvents. In this study, a cypermethrine 25EC formulation was developed using methyl ester as a green solvent. The physicochemical characterizations, emulsion properties and storage stabilities of the methyl ester EC formulations were investigated and compared with those of the EC formulation using naphtha A100 as a solvent, evidencing excellent emulsion properties and storage stabilities of such methyl ester EC formulations.

Sorption, Desorption and Mobility of Microencapsulated Chlorpyrifos in Two Typical Soils

The sorption, desorption, and mobility of microencapsulated chlorpyrifos (CPF-MC) in two typical soils, namely, silt loam and sandy, were investigated in this study. Sorption/desorption experiments were carried out by using the batch equilibration method. Results showed that the sorption isotherms of CPF-MC and emulsifiable concentrate of chlorpyrifos (CPF-EC) in silt loamy soil were similar. However, a considerable difference was observed in the sorption isotherms of two chlorpyrifos (CPF) formulations in sandy soil. The amounts of CPF desorbed from two soils in four desorption steps decreased sequentially in CPF-EC treatments, while the desorbed amounts remained stable in CPF-MC treatments. Hence, the sorption/desorption processes of CPF-EC were mainly controlled by soil affinity to CPF. However, these processes of CPF-MC were affected by the release rate of CPF from capsules. The mobility of two CPF formulations in soil were estimated in vertical columns packed with soils. Results showed that there was leaching of CPF-EC in silt loam column, whereas CPF-MC was not vertically mobile in silt loam column under the same leaching conditions. However, in column with sandy soil, the percentage of CPF-MC leaching from the column was 86.54%, which was higher than the 73.75% that leached from the column in the treatment with CPF-EC.

Development and validation of a GC–MS method for the simultaneous determination of acetochlor, fluorochloridone, and pendimethalin in a herbicide emulsifiable concentrate formulation

This paper describes a rapid method to simultaneously determine acetochlor, fluorochloridone and pendimethalin present in a herbicide emulsifiable concentrate (EC) formulation using gas chromatography–mass spectrometry (GC–MS). Selected ion monitoring mode was performed to increase the sensitivity, with dibutyl phthalate as an internal standard. The method was validated with respect to linearity, accuracy, precision, and stability. Chromatographic separation was carried out on a TG-5 MS column (30 m × 0.25 mm × 0.25 μm) with helium as the carrier gas at a flow rate of 1.0 mL/min. Calibration curves were linear over 2.0–20.0 μg/mL for each analyte, and the limit of quantification was below 20 ng/mL. Good performance in terms of recovery ranging from 94.5% to 102.5% at 3 concentration levels proved excellent accuracy. The intra- and inter-day relative standard deviations for 6 replicate measurements were always less than 5%. The developed method is simple and efficient for the routine determination of the ternary mixtures in a compound herbicide EC formulation product.

Efficacy of extended release formulations of Natular™ (spinosad) against larvae and adults of Anopheles mosquitoes in western Kenya

Background Larval source management is recommended as a supplementary vector control measure for the prevention of malaria. Among the concerns related to larviciding is the feasibility of implementation in tropical areas with large numbers of habitats and the need for frequent application. Formulated products of spinosad that are designed to be effective for several weeks may mitigate some of these concerns. Methods In a semi-field study, three formulations of spinosad (emulsifiable concentrate, extended release granules and tablet formulations) were tested in naturalistic habitats in comparison to an untreated control. Cohorts of third instar Anopheles gambiae (Diptera: Culicidae) were introduced into the habitats in screened cages every week up to four weeks after application and monitored for survivorship over three days. A small-scale field trial was then conducted in two villages. Two of the spinosad formulations were applied in one village over the course of 18 months. Immature mosquito populations were monitored with standard dippers in sentinel sites and adult populations were monitored by pyrethrum spray catches. Results In the semi-field study, the efficacy of the emulsifiable concentrate of spinosad waned 1 week after treatment. Mortality in habitats treated with the extended release granular formulation of spinosad was initially high but declined gradually over 4 weeks while mortality in habitats treated with the dispersable tablet formulation was low immediately after treatment but rose to 100% through four weeks. In the field study, immature and adult Anopheles mosquito populations were significantly lower in the intervention village compared to the control village during the larviciding period. Numbers of collected mosquitoes were lower in the intervention village compared to the control village during the post-intervention period but the difference was not statistically significant. Conclusions The extended release granular formulation and the dispersible tablet formulations of spinosad are effective against larval Anopheles mosquitoes for up to four weeks and may be an effective tool as part of larval source management programmes for reducing adult mosquito density and malaria transmission.

Effect of Hydrophilic-Lipophilic Balance (HLB) Values of Surfactant Mixtures on the Physicochemical Properties of Emulsifiable Concentrate Formulations of Difenoconazole

This study was designed to investigate the effect of hydrophilic-lipophilic balance (HLB) values of different surfactant mixtures on the physicochemical properties of emulsifiable concentrate formulations of difenoconazole. Physical tests of emulsion characteristics and storage stability studies were performed for the different samples to predict the stability of these formulations. Different parameters such as active ingredient content, pH, refractive index, surface tension, viscosity, flash point, persistent foam was determined for the prepared samples. The results showed that difenoconazole could be formulated as a stable emulsifiable concentrate by using a mixture of surfactants at HLB values 9.7, 11.9, 12.5 and 13.1. The storage stability test showed that the decomposition rate of the active ingredient content of difenoconazole in different stable formulations was within the acceptable limits of FAO Specifications. The physical and chemical properties of the stable formulations fulfilled the requirements of EC formulation.