Validation of a multi-residue method to determine deltamethrin and alpha-cypermethrin in mosquito nets by gas chromatography with electron capture detection (GC-µECD)

Background: Nowadays long-lasting insecticidal mosquito nets (LNs) are frequently used around the world to protect people against malaria vectors. As they contain insecticide, laboratory control is needed to check whether the content of the active ingredient follows the conditions of the manufacturer and also if the active ingredient is still present after some time of use. For this purpose, an analytical method had to be developed. The fact that LNs include a range of polymers for the yarn and use coated or incorporated technologies for the active ingredient, it is a challenge to find only one analytical method determining the active ingredient in LNs, which takes into account both impregnation technologies. Some methods are provided by international organizations but are limited by the determination of only one pesticide per method. The aim of this study was to optimize a short time extraction method for deltamethrin and alpha-cypermethrin from coated and incorporated mosquito nets and also to detect both insecticides in one analytical run, using gas chromatography with electron capture detection (GC-mu ECD). Methods: Based on the literature, the most suitable solvent and the adequate extraction process for the insecticides used for net making were identified and adapted for the new multi-residue method. Results: The validation data of the multi-residue method to determine deltamethrin and alpha-cypermethrin in mosquito nets by GC-mu ECD are given. Depending on the concentration of the active ingredient spiked on the nets, the mean recovery for alpha-cypermethrin ranged between 86% and 107% with a relative standard deviation below 3.5%. For deltamethrin it ranged between 90% and 108% with a relative standard deviation also below 3.5%. The limit of detection is 0.009 g.a.i/kg of net (0.3 mg a.i./m(2) of net) both for alpha-cypermethrin and deltamethrin. Conclusions: Data obtained are excellent. A 30 minutes reflux extraction method with xylene was developed to determine alpha-cypermethrin and deltamethrin in long-lasting insecticidal mosquito nets (LNs) by gas chromatography with electron capture detection (GC-mu ECD). The method can be easily extended to others pyrethroid used for mosquito net treatment. This paper also presents an overview of the studies dealing with pesticide determination in mosquito nets

Effect of Organosilicone Surfactant on Uptake and Translocation of Glyphosate in Pennisetum Polystachion L

The effect of adding organosilicone surfactant, Pulse® on efficacy, uptake and translocation of glyphosate (Roundup®) for the control of Pennisetum polystachion was evaluated in the glasshouse. The dose-response study with glyphosate on 9-week old P. polystachion showed that at the rate of 1.08 kg a.e.iha, glyphosate caused complete mortality of the plants. It was estimated that dosage between 360 to 540 g a.e./ha gave 50% mortality. When Pulse® was added to the glyphosate spray solutions, the bioefficacy of glyphosate on P. polystachion increased as the concentration of Pulse® increased. The optimum concentration ofPulse® was 0.2 % w/w above which no significant increase in the bioefficacy was observed. Spray deposition studies using tlourescent tracer technique revealed that the mixture of glyphosate and Pulse® gave 42% higher spray deposition compared to glyphosate alone, thus contributing to the increase in bioefficacy of glyphosate observed in the mixture

Variation in the susceptibility of Anopheles gambiae to botanicals across a metropolitan region of Nigeria

Pesticide resistance is normally associated with genetic changes, resulting in varied responses to insecticides between different populations. There is little evidence of resistance to plant allelochemicals; it is likely that their efficacy varies between genetically diverse populations, which may lead to the development of resistance in the future. This study evaluated the response of Anopheles gambiae (larvae and adults) from spatially different populations to acetone extracts of two botanicals, Piper guineense and Eugenia aromatica. Mosquito samples from 10 locations within Akure metropolis in Southwest Nigeria were tested for variation in susceptibility to the toxic effect of botanical extracts. The spatial distribution of the tolerance magnitude (T.M.) of the mosquito populations to the botanicals was also mapped. The populations of An. gambiae manifested significant differences in their level of tolerance to the botanicals. The centre of the metropolis was the hot spot of tolerance to the botanicals. There was a significant positive correlation between the adulticidal activities of both botanicals and initial knockdown. Hence, knockdown by these botanicals could be a predictor of their subsequent mortality. In revealing variation in response to botanical pesticides, our work has demonstrated that any future use of botanicals as alternative environmentally friendly vector control chemicals needs to be closely monitored to ensure that resistance does not develop

Fungicidal management of Alternaria alternata (Fr.) Keissler causing blight of gerbera (Gerbera jamesonii H. Bolus ex J.D. Hook)

Alternaria, the fungal pathogen has wide host range generally attacks the aerial parts of plants causing leaf spots and blights. Gerbera is a genus of ornamental flower plants. Gerbera plants are infected by many diseases. Different disease management practices are adopted in gerbera cultivation. The fungicidal management of Alternaria blight is one of the important strategies for the disease management in gerbera in polyhouse condition. In this study, preventive and curative fungicidal sprays were adopted for the management of blight disease in polyhouse. This study revealed that preventive fungicidal sprays were significant over curative fungicidal sprays for the management of Alternaria alternata blight of gerbera (Gerbera jamesonii H. Bolus ex J.D. Hook) in polyhouse. The preventive sprays made of Bordeaux mixture (0.6 %), tricyclazole (0.1%) and iprodione + carbendazim (0.1%) fungicides were found effective with 95.85 %, 96.59 % and 95.88 % disease control respectively, under polyhouse condition

A Systematic Review of Mosquito Coils and Passive Emanators: Defining Recommendations for Spatial Repellency Testing Methodologies.

Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control

Human metabolism and elimination of the anthocyanin, cyanidin-3-glucoside: a 13C-tracer study

BACKGROUND: Evidence suggests that the consumption of anthocyanin-rich foods beneficially affects cardiovascular health; however, the absorption, distribution, metabolism, and elimination (ADME) of anthocyanin-rich foods are relatively unknown. OBJECTIVE: We investigated the ADME of a (13)C5-labeled anthocyanin in humans. DESIGN: Eight male participants consumed 500 mg isotopically labeled cyanidin-3-glucoside (6,8,10,3',5'-(13)C5-C3G). Biological samples were collected over 48 h, and (13)C and (13)C-labeled metabolite concentrations were measured by using isotope-ratio mass spectrometry and liquid chromatography-tandem mass spectrometry. RESULTS: The mean +/- SE percentage of (13)C recovered in urine, breath, and feces was 43.9 +/- 25.9% (range: 15.1-99.3% across participants). The relative bioavailability was 12.38 +/- 1.38% (5.37 +/- 0.67% excreted in urine and 6.91 +/- 1.59% in breath). Maximum rates of (13)C elimination were achieved 30 min after ingestion (32.53 +/- 14.24 mug(13)C/h), whereas (13)C-labeled metabolites peaked (maximum serum concentration: 5.97 +/- 2.14 mumol/L) at 10.25 +/- 4.14 h. The half-life for (13)C-labeled metabolites ranged between 12.44 +/- 4.22 and 51.62 +/- 22.55 h. (13)C elimination was greatest between 0 and 1 h for urine (90.30 +/- 15.28 mug/h), at 6 h for breath (132.87 +/- 32.23 mug/h), and between 6 and 24 h for feces (557.28 +/- 247.88 mug/h), whereas the highest concentrations of (13)C-labeled metabolites were identified in urine (10.77 +/- 4.52 mumol/L) and fecal samples (43.16 +/- 18.00 mumol/L) collected between 6 and 24 h. Metabolites were identified as degradation products, phenolic, hippuric, phenylacetic, and phenylpropenoic acids. CONCLUSION: Anthocyanins are more bioavailable than previously perceived, and their metabolites are present in the circulation fo

Bioefficacy of controlled release formulations of diuron on Brassica rapa

Controlled-release formulations (CRF) of diuron were prepared in laboratory using the concept of physical matrix utilizing sodium alginate and kaolin. The release rates of diuron from the formulations were determined by chemical assay its efficacy on plant was tested on Brassica rapa. In the chemical assay using high performance chromatography with UV detector, significant differences in the release rate between formulations were observed from 3 to 7 days after the granules had been placed in distilled water. The formulation having a 1:1 ratio of alginate to kaolin with 1mm granule size showed the fastest release of diuron, while release from the 2mm granules was slower. Increasing the proportion of kaolin to sodium alginate in the CRF reduced the release rate of active agent. The bioefficacy using Brassica rapa as a bioindicator showed that CRF released slower than the conventional formulation at the beginning of the treatments. In the 3rd week after the treatment (WAT), there was no significant difference in the mortality as compared to the conventional formulation at 16 WAT. The same results were also observed up to 24 WAT, the CRF caused between 40-70% mortality, while the conventional formulation treatment caused only 6% mortality. Among the CRF, the AK-2 with 1:1 ration of alginate:kaolin was found to have given the best result with the highest percentage mortality of the seedlings

Significance of dietary antioxidants for health

Since evidence became available that free radicals were involved in mechanisms for the development of major diseases, including cardiovascular disease and cancer, there has been considerable research into the properties of natural dietary antioxidants. However, it has become clear that dietary antioxidants can only have beneficial effects in vivo by radical scavenging or effects on redox potential if they are present in tissues or bodily fluids at sufficient concentrations. For many dietary components, absorption is limited or metabolism into derivatives reduces the antioxidant capacity. For many dietary phytochemicals, direct antioxidant effects may be less important for health than other effects including effects on cell signalling or gene expression in vivo

Efficacy of anthranilic insecticide E2Y45 20 SC (Chlorantraniliprole) against Plutella xylostella L. in cabbage, Brassica oleracea var. capitata

Experiments were conducted at farmer’s cabbage fields to evaluate the bioefficacy of anthranilic insecticide i.e. E2Y45 20 SC (Chlorantraniliprole) having novel mode of action against the diamondback moth Plutella xylostella L. E2Y45 20 SC was applied @ 25.0, 37.5 and 50.0 ml/ha and was compared with Padan 50 SP (cartap hydrochloride) @ 500 g/ha and the untreated control. Lowest mean larval population after two sprays was recorded in higher dose of E2Y 45 20 SC i.e. @ 50.0 ml/ha (0.08 larvae/plant) at 7 days after treatment followed by medium and lower dose of E2Y 45 20 SC i.e. @ 37.5ml/ha (0.10 larvae/plant) and 25.0 ml/ha (0.33 larvae/plant). The larval population in these treatments was significantly lower than standard check, Padan 50 SP (2.56 larvae/plant), and untreated control (9.73 larvae/plant). The highest marketable yield (262.89 q/ha) was recorded in E2Y 45 20 SC @ 50.0 ml/ha which was significantly higher than Padan 50 SP (239.65 q/ha). Lowest yields were recorded in untreated control (106.00 q/ha). Conclusively, medium (37.5 ml/ha) and higher (50.0 ml/ha) dose of E2Y 45 20 SC (chlorantraniliprole) significantly reduced the larval population of P. xylostella and increased the cabbage yield