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Simple Summary: The widespread use of broad-spectrum insecticides reduces the capabilities of ecological self-regulation of phytophages in agrocoenoses and in the adjacent natural territories. Those ecosystems suffer disruption of trophic relations that have been forming over long periods of time. At the same time, the numbers of non-target invertebrates affected by pesticides are declining. Pirimiphos-methyl is one of the cheapest, most effective, and widely used insecticides in the world. Its effect on invertebrate species is useful for agriculture; however, its effect on arthropods that improve soil fertility remains virtually unstudied. This article establishes that this insecticide can have a strong effect on some species useful for plant growing and a weak effect on others. As a result of such an effect of pirimiphos-methyl, the taxonomic structure of invertebrate communities in agrocenoses should change dramatically. The use of this insecticide in fields gives an advantage to species that are relatively more resistant to it and causes a faster disappearance of sensitive invertebrate species. The effects of pirimiphos-methyl have previously been assessed on blood-sucking insect species, pollinating insects, and target crop pest species. The sensitivity of non-target zoophagous and saprophage species to this insecticide remains largely unstudied. In laboratory conditions, we assessed the susceptibility of 43 species of invertebrates to pirimiphos-methyl. The most tolerant species to this insecticide were Pyrrhocoris apterus (LC50 measured over 60 mg/m2), Cylindroiulus truncorum, Pterostichus niger, Harpalus rufipes, Lithobius forficatus, and Carabus hortensis (LC50 ranged from 25 to 50 mg/m2). Average tolerance to pirimiphos-methyl was displayed by Ophonus rufibarbis, Teuchestes fossor, Silpha carinata, Badister sodalis, Rugilus rufipes, Phosphuga atrata, Porcellio laevis, Pterostichus oblongopunctatus, Aphodius foetens, Lasius fuliginosus, Oxypselaphus obscurus, Platydracus fulvipes, Myrmica ruginodis, Xantholinus tricolor, and Megaphyllum sp. (LC50 for those species ranged from 12 to 24 mg/m2). Higher sensitivity to this insecticide was seen for Amara nitida, Leistus ferrugineus, Harpalus xanthopus winkleri, Philonthus nitidus, Pterostichus melanarius, Harpalus latus, Limodromus assimilis, Philonthus decorus, Tachinus signatus, Ponera coarctata, Carabus convexus, Philonthus coprophilus, Philonthus laevicollis, Platydracus latebricola, Labia minor, and Carabus granulatus (LC50 for those species ranged from 6 to 12 mg/m2). The greatest sensitivity to pirimiphos-methyl was observed in Hister fenestus, Drusilla canaliculata, Bisnius fimetarius, Oxytelus sculptus, Lasius niger, and Lasius flavus (LC50 ranged from 0.4 to 6 mg/m2). We found a relationship between the parameters of bodies of invertebrates (the average body length and dry body mass) and sensitivity to pirimiphos-methyl. With an increase in body sizes of invertebrates, the tolerance to the insecticide increased (per each mm of body length, LC50 increased by 0.82 mg/m2 on average). We identified no relationship between the trophic specialization and sensitivity to the insecticide. [ABSTRACT FROM AUTHOR]

Exogenous, well‐established antioxidant N‐acetylcysteine can reduce or prevent the deleterious effects of pesticides. In this study, utilizing a mouse model of daily single dose of N‐acetylcysteine administration, we investigated the impact of this adjuvant on the treatment with atropine and/or obidoxime as well as oxidative stress response in pyrimiphos‐methyl‐induced toxicity. We found that N‐acetylcysteine significantly reduces the oxidative stress generated by pyrimiphos‐methyl. The therapy consisting of atropine and/or obidoxime routinely used in organophosphorous insecticide poisonings, including pyrimiphos‐methyl, had no effect on the antioxidant properties of N‐acetylcysteine. Adjunctive treatment offered by N‐acetylcysteine fills therapeutic gap and may provide the full potential against pyrimiphos‐methyl‐induced toxicity. [ABSTRACT FROM AUTHOR]

The bioefficacy of several inert materials, such as Diatomaceous earth (DE), bentonite, and biochar enhanced with pirimiphos-methyl against Sitophilus oryzae, was used to evaluate the insecticidal activity of three new formulations using the technique of mixing with grain. DE was the most effective material (LC50 3.198 g/kg), followed by biochar LC50 3.709 g/kg, whereas bentonite was the least effective (LC50 3. 979 g/kg). The three materials were loaded with pirimiphos-methyl (0.5%). The formula of Pirimiphos-methyl with DE reported the highest significant effect compared to the other two formulations, with an LC50 value of 0.082 g/kg. DE formula had a co-toxicity coefficient value that was 6.46 times greater than pirimiphos-methyl, followed by the biochar formula, which was 1.74 times more effective, and the bentonite formula, which had a 0.69-fold increase in activity. In the laboratory examination of the wheat's free and compact bulk densities after being treated with LC50s of each dust material, DE slightly affected wheat-free bulk density. Still, both bentonite and biochar reduced the free bulk density. However, all the tested materials decreased in compact bulk density. The germination percentages of wheat treated with LC50 values of DE and bentonite and biochar after 10 days of storage revealed no significant difference between treated and untreated seeds after 7 days of germination. [ABSTRACT FROM AUTHOR]

Abstract Background The residual activity of a clothianidin + deltamethrin mixture and clothianidin alone in IRS covered more than the period of malaria transmission in northern Benin. The aim of this study was to show whether the prolonged residual efficacy of clothianidin-based products resulted in a greater reduction in vector populations and subsequent malaria transmission compared with the shorter residual efficacy of pirimiphos-methyl. Methods Human bait mosquito collections by local volunteers and pyrethrum spray collections were used in 6 communes under IRS monitoring and evaluation from 2019 to 2021. ELISA/CSP and species PCR tests were performed on Anopheles gambiae sensu lato (s.l.) to determine the infectivity rate and subspecies by commune and year. The decrease in biting rate, entomological inoculation rate, incidence, inhibition of blood feeding, resting density of An. gambiae s.l. were studied and compared between insecticides per commune. Results The An. gambiae complex was the major vector throughout the study area, acounting for 98.71% (19,660/19,917) of all Anopheles mosquitoes collected. Anopheles gambiae s.l. collected was lower inside treated houses (45.19%: 4,630/10,245) than outside (54.73%: 5,607/10,245) after IRS (p

Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The residual activity of a clothianidin + deltamethrin mixture and clothianidin alone in IRS covered more than the period of malaria transmission in northern Benin. The aim of this study was to show whether the prolonged residual efficacy of clothianidin-based products resulted in a greater reduction in vector populations and subsequent malaria transmission compared with the shorter residual efficacy of pirimiphos-methyl. Methods: Human bait mosquito collections by local volunteers and pyrethrum spray collections were used in 6 communes under IRS monitoring and evaluation from 2019 to 2021. ELISA/CSP and species PCR tests were performed on Anopheles gambiae sensu lato (s.l.) to determine the infectivity rate and subspecies by commune and year. The decrease in biting rate, entomological inoculation rate, incidence, inhibition of blood feeding, resting density of An. gambiae s.l. were studied and compared between insecticides per commune. Results: The An. gambiae complex was the major vector throughout the study area, acounting for 98.71% (19,660/19,917) of all Anopheles mosquitoes collected. Anopheles gambiae s.l. collected was lower inside treated houses (45.19%: 4,630/10,245) than outside (54.73%: 5,607/10,245) after IRS (p < 0.001). A significant decrease (p < 0.001) in the biting rate was observed after IRS in all departments except Donga in 2021 after IRS with clothianidin 50 WG. The impact of insecticides on EIR reduction was most noticeable with pirimiphos-methyl 300 CS, followed by the clothianidin + deltamethrin mixture and finally clothianidin 50 WG. A reduction in new cases of malaria was observed in 2020, the year of mass distribution of LLINs and IRS, as well as individual and collective protection measures linked to COVID-19. Anopheles gambiae s.l. blood-feeding rates and parous were high and similar for all insecticides in treated houses. Conclusion: To achieve the goal of zero malaria, the optimal choice of vector control tools plays an important role. Compared with pirimiphos-methyl, clothianidin-based insecticides induced a lower reductions in entomological indicators of malaria transmission. [ABSTRACT FROM AUTHOR]

The effects of pirimiphos-methyl have previously been assessed on blood-sucking insect species, pollinating insects, and target crop pest species. The sensitivity of non-target zoophagous and saprophage species to this insecticide remains largely unstudied. In laboratory conditions, we assessed the susceptibility of 43 species of invertebrates to pirimiphos-methyl. The most tolerant species to this insecticide were Pyrrhocoris apterus (LC50 measured over 60 mg/m2), Cylindroiulus truncorum, Pterostichus niger, Harpalus rufipes, Lithobius forficatus, and Carabus hortensis (LC50 ranged from 25 to 50 mg/m2). Average tolerance to pirimiphos-methyl was displayed by Ophonus rufibarbis, Teuchestes fossor, Silpha carinata, Badister sodalis, Rugilus rufipes, Phosphuga atrata, Porcellio laevis, Pterostichus oblongopunctatus, Aphodius foetens, Lasius fuliginosus, Oxypselaphus obscurus, Platydracus fulvipes, Myrmica ruginodis, Xantholinus tricolor, and Megaphyllum sp. (LC50 for those species ranged from 12 to 24 mg/m2). Higher sensitivity to this insecticide was seen for Amara nitida, Leistus ferrugineus, Harpalus xanthopus winkleri, Philonthus nitidus, Pterostichus melanarius, Harpalus latus, Limodromus assimilis, Philonthus decorus, Tachinus signatus, Ponera coarctata, Carabus convexus, Philonthus coprophilus, Philonthus laevicollis, Platydracus latebricola, Labia minor, and Carabus granulatus (LC50 for those species ranged from 6 to 12 mg/m2). The greatest sensitivity to pirimiphos-methyl was observed in Hister fenestus, Drusilla canaliculata, Bisnius fimetarius, Oxytelus sculptus, Lasius niger, and Lasius flavus (LC50 ranged from 0.4 to 6 mg/m2). We found a relationship between the parameters of bodies of invertebrates (the average body length and dry body mass) and sensitivity to pirimiphos-methyl. With an increase in body sizes of invertebrates, the tolerance to the insecticide increased (per each mm of body length, LC50 increased by 0.82 mg/m2 on average). We identified no relationship between the trophic specialization and sensitivity to the insecticide.

The prevalent use of pesticides, including pirimiphos-methyl (PPM) and bifenthrin (BF), poses a serious health risk, particularly to workers who encounter these chemicals daily. Despite the recognized hepatotoxic effects, the specific molecular mechanisms, especially those involving miRNAs in liver damage caused by PPM and BF, are not fully elucidated. Prior studies have not exhaustively analyzed the hepatic miRNA-target gene dynamics following exposure to these pesticides; thus, this research aims to fill that gap through an extensive miRNA analysis to discern their regulation in PPM or BF-induced hepatic toxicity. In this study, male Sprague-Dawley rats were exposed to BF or PPM for 28 days through oral gavage, simulating the chronic exposure faced by humans. We conducted a thorough assessment of the hepatotoxicity induced by PPM and BF, employing multiple evaluation levels, including histological analysis, liver enzyme measurements, and real-time PCR to detect changes in hepatic miRNA-target gene expressions. Additionally, we utilized DIANA-miRPath prediction tools to delineate the functional implications of these hepatic miRNA target genes. Our findings reveal a significant modulation in the expression of rno-miR-155–5p and rno-miR-122–5p, along with their target genes, following PPM and BF treatment. In contrast, rno-miR-21–5p levels remained unaltered. These observations suggest potential utility of these specific hepatic miRNAs as biomarkers for liver injury resulting from pesticide exposure. Subsequent GO enrichment analysis linked target genes to functions like molecular activity, protein binding, and cellular processes. Additionally, KEGG pathway analysis showed these genes, influenced by varied miRNA expressions, play significant roles in metabolic and signaling pathways In conclusion, this study enhances our comprehension of the biological roles of miRNAs in hepatic toxicity induced by PPM and BF. The insights gained here not only shed light on molecular mechanisms but also open avenues for considering these miRNAs as potential diagnostic biomarkers in conditions of pesticide-induced hepatotoxicity, thereby guiding future therapeutic strategies.

Exposure to Pirimiphos-methyl (POM) has been reported to adversely affect sperm functions, leading to male infertility. This study seeks to investigate the effect of resveratrol on POM induced male reproductive dysfunction. Twenty-four male Sprague-Dawley rats weighing between 165g - 200g were randomly divided into four groups of control, the POM group (received 62.5mg/kg POM/b. w), POM + RES (received 62.5mg/kg POM and 20mg/kg body weight of resveratrol, and the RES group (received 20mg/kg body weight resveratrol) for 65 days. The results showed a significant decrease in body weight gain in the POM group, POM +RES group compared to the control. The relative liver weight of the POM group was also significantly increased compared with the control (p<0.05). RES + POM significantly increased the epididymal sperm count, motility, morphology, and testosterone level compared to the POM group. POM increased MDA and reduced SOD, GSH, and catalase activities, while POM + RES only reversed this trend in the MDA, catalase, and SOD levels. There was a significant increase in the cholesterol concentration of the POM group compared to the control while there were no significant differences in the HDL, LDL, and triglyceride levels across all the groups. There was distortion in the POM group's cytoarchitecture of the liver and testes compared to the control and RES groups. In conclusion, the results showed that POM disrupts sperm functions and caused hepatotoxicity in rats' livers. This study also shows that RES improves sperm parameters impaired by POM. [ABSTRACT FROM AUTHOR]

Simple Summary: The house fly is a worldwide public health pest associated with humans and livestock. The use of insecticides is still the main method of house fly management. The extensive use of insecticides is the main reason for the development of resistance in many insect species. The development of resistance in house flies was documented for numerous insecticides. Pirimiphos-methyl is used for house fly control in Saudi Arabia. This study was conducted to evaluate the resistance of M. domestica field populations against pirimiphos-methyl. The field-collected populations of M. domestica displayed different levels of resistance. The samples collected from Riyadh city exhibited the highest resistance, followed by populations from Jeddah and Taif. We investigated the genetic mutations of the acetylcholinesterase (Ace) gene in field-collected flies and the survivors after exposure to pirimiphos-methyl. The outcomes of the present study provide valuable information that may help in house fly management in Saudi Arabia. The house fly Musca domestica L. (Diptera: Muscidae) is a worldwide medical and veterinary pest, causing great economic losses. Organophosphate insecticides have been widely used to control house fly populations. The main objectives of the present study were to evaluate the resistance levels of M. domestica slaughterhouse populations, collected from Riyadh, Jeddah, and Taif, against the organophosphate insecticide pirimiphos-methyl and investigate the genetic mutations of the Ace gene associated with pirimiphos-methyl resistance. The obtained data showed that there were significant differences among pirimiphos-methyl LC50 values of the studied populations, where the highest LC50 was recorded for the Riyadh population (8.44 mM), followed by Jeddah and Taif populations (2.45 mM and 1.63 mM, respectively). Seven nonsynonymous SNPs were detected in the studied house flies. The Ile239Val and Glu243Lys mutations are reported for the first time, whereas Val260Leu, Ala316Ser, Gly342Ala, Gly342Val, and Phe407Tyr were previously reported in M. domestica field populations from other countries. Considering three mutations associated with insecticide resistance, at amino acid positions 260, 342, and 407 of acetylcholinesterase polypeptide, 17 combinations were recovered in this study. Three out of these seventeen combinations were frequently found both worldwide and in the three Saudi house fly field populations, as well as their pirimiphos-methyl-surviving flies. Overall, the single and combined Ace mutations are apparently associated with pirimiphos-methyl resistance, and the obtained data can be useful in managing house fly field populations in Saudi Arabia. [ABSTRACT FROM AUTHOR]

During storage, soybean kernels can be attacked by insects, which are preventively controlled with insecticides. Information on the dissipation of insecticide residues is crucial to know their final concentrations in food and establish the waiting periods necessary for consumption without health risks, and to determine the minimum waiting period necessary to comply with national and international standards. The aims of this study were to quantify the residue levels of organophosphorus insecticides (dichlorvos, chlorpyrifos-methyl and pirimiphos-methyl) in stored soybean, establish the effect during the storage period, and model the dissipation dynamics. Insecticide residues in soybeans were analyzed at 2, 30, 60, 90 and 120 days after application. An analytical method based on QuEChERS extraction followed by gas chromatography mass spectrometry (GC-MS/MS) determination was validated, with mean recoveries of 82-105%, depending on the spiking levels. Residues decreased below 80% of the initial concentration at 60 days after application and below quantifiable levels at 120 days. Residues followed a pseudo-first-order dissipation dynamics [Ct = C0×exp(-k.t)], with the dissipation constant (k) and half-lives being 0.538 and 1.3 days for dichlorvos, 0.018 and 38.8 days for chlorpyrifos-methyl, and 0.023 and 30.1 days for pirimiphos-methyl, respectively. These results allow concluding that, at the recommended dosage, these insecticides are safe for use on soybean grains stored under standard conditions commonly nowadays used in Argentina. [ABSTRACT FROM AUTHOR]

A number of characteristics make fish excellent experimental models in toxicological research, especially for the contamination of aquatic systems. The main aim of the present study was to investigate the negative effects of different classes of pesticides (insecticide, herbicide and fungicide), based on their LC50 on the gills histological architecture of common carp (Cyprinus carpio Linnaeus, 1758). The effects of the tested pesticides on fish gills were expressed with histopathological alterations, such as proliferative, degenerative and changes in the circulatory system. Based on our results, the test insecticide showed higher toxicity with more severe irreversible necrotic changes in common carp gills compared to the herbicide and fungicide exposure. The identified histopathological changes in the fish gills can be successfully applied as reliable biomarkers for monitoring the degree of negative effects on the organisms due to the pesticide toxicity. The results from such experiments could be applied in the legislation in order to protect the water bodies from pesticide contamination, in areas with intensive application of plant protection products used in agricultural practices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of Tb-In-MOF-EBA via post-synthetic modification was investigated. • The structure of Tb-In-MOF-EBA was explored by NMR, FTIR and SEM. • Tb-In-MOF-EBA was used in optically detection of organophosphorus insecticides. • Tb-In-MOF-EBA shows higher sensitivity toward chlorpyrifos and Primiphos-methyl. Metal-organic frameworks (MOFs) are represented ideal candidate materials for chemical sensing of different kinds of species because they contain optically active sites may be in organic linker or ions node, moreover, MOFs have high porosity that capture different types of guests. Lanthanide MOFs (Ln-MOFs) was very common in sensing chemical species due to identical light emission characteristics. The problem of Ln-MOFs was the difficulty of its preparation; therefore, post-synthetic modification (PSM) technique was excellent for incorporation of lanthanide site in the network. Unlike other MOFs, In-MOF can be post-synthesized because of its free amino group in the network, therefore, it was chosen in the current work. Here, Tb-In-MOF-EBA was generated by PSM of In-MOF in two steps: (1) formation of the amide by the reaction of In-MOF with ethyl benzoyl acetate; (2) chelation of Tb3+ cations by the diketone fragment. The main challenge of present work is not to give another luminescent MOF based sensor rather than using decorative technique based PSM route to tune optically active sensors for organophosphorus (OP) insecticides (dimethoate, chlorpyrifos, and pirimiphos-methyl) identification quantitatively and qualitatively. The emission intensity of Tb-In-MOF-EBA were reduced with 8 %, 50 %, and 81 %, after adding dimethoate, chlorpyrifos, and pirimiphos-methyl for the parent compounds, respectively. Tb-In-MOF-EBA showed interesting selectivity toward dimethoate, chlorpyrifos, pirimiphos-methyl, therefore, it can be used in measuring the concentration of OP insecticide with high accuracy. [ABSTRACT FROM AUTHOR]

IntroductionTo interrupt malaria transmission, strategies must target the parasite reservoir in both humans and mosquitos. Testing of community members linked to an index case, termed reactive case detection (RACD), is commonly implemented in low transmission areas, though its impact may be limited by the sensitivity of current diagnostics. Indoor residual spraying (IRS) before malaria season is a cornerstone of vector control efforts. Despite their implementation in Namibia, a country approaching elimination, these methods have been met with recent plateaus in transmission reduction. This study evaluates the effectiveness and feasibility of two new targeted strategies, reactive focal mass drug administration (rfMDA) and reactive focal vector control (RAVC) in Namibia.Methods and analysisThis is an open-label cluster randomised controlled trial with 2×2 factorial design. The interventions include: rfMDA (presumptive treatment with artemether-lumefantrine (AL)) versus RACD (rapid diagnostic testing and treatment using AL) and RAVC (IRS with Acellic 300CS) versus no RAVC. Factorial design also enables comparison of the combined rfMDA+RAVC intervention to RACD. Participants living in 56 enumeration areas will be randomised to one of four arms: rfMDA, rfMDA+RAVC, RACD or RACD+RAVC. These interventions, triggered by index cases detected at health facilities, will be targeted to individuals residing within 500 m of an index. The primary outcome is cumulative incidence of locally acquired malaria detected at health facilities over 1 year. Secondary outcomes include seroprevalence, infection prevalence, intervention coverage, safety, acceptability, adherence, cost and cost-effectiveness.Ethics and disseminationFindings will be reported on clinicaltrials.gov, in peer-reviewed publications and through stakeholder meetings with MoHSS and community leaders in Namibia.Trial registration numberNCT02610400; Pre-results.

Background: Malaria is a major cause of morbidity and mortality globally, especially in sub-Saharan Africa. Widespread resistance to pyrethroids threatens the gains achieved by vector control. To counter resistance to pyrethroids, third-generation indoor residual spraying (3GIRS) products have been developed. This study details the results of a multi-country cost and cost-effectiveness analysis of indoor residual spraying (IRS) programmes using Actellic®300CS, a 3GIRS product with pirimiphos-methyl, in sub-Saharan Africa in 2017 added to standard malaria control interventions including insecticide-treated bed nets versus standard malaria control interventions alone. Methods: An economic evaluation of 3GIRS using Actellic®300CS in a broad range of sub-Saharan African settings was conducted using a variety of primary data collection and evidence synthesis methods. Four IRS programmes in Ghana, Mali, Uganda, and Zambia were included in the effectiveness analysis. Cost data come from six IRS programmes: one in each of the four countries where effect was measured plus Mozambique and a separate programme conducted by AngloGold Ashanti Malaria Control in Ghana. Financial and economic costs were quantified and valued. The main indicator for the cost was cost per person targeted. Country-specific case incidence rate ratios (IRRs), estimated by comparing IRS study districts to adjacent non-IRS study districts or facilities, were used to calculate cases averted in each study area. A deterministic analysis and sensitivity analysis were conducted in each of the four countries for which effectiveness evaluations were available. Probabilistic sensitivity analysis was used to generate plausibility bounds around the incremental cost-effectiveness ratio estimates for adding IRS to other standard interventions in each study setting as well as jointly utilizing data on effect and cost across all settings. Results: Overall, IRRs from each country indicated that adding IRS with Actellic®300CS to the local standard intervention package was protective compared to the standard intervention package alone (IRR 0.67, [95% CI 0.50–0.91]). Results indicate that Actellic®300CS is expected to be a cost-effective (> 60% probability of being cost-effective in all settings) or highly cost-effective intervention across a range of transmission settings in sub-Saharan Africa. Discussion: Variations in the incremental costs and cost-effectiveness likely result from several sources including: variation in the sprayed wall surfaces and house size relative to household population, the underlying malaria burden in the communities sprayed, the effectiveness of 3GIRS in different settings, and insecticide price. Programmes should be aware that current recommendations to rotate can mean variation and uncertainty in budgets; programmes should consider this in their insecticide-resistance management strategies. Conclusions: The optimal combination of 3GIRS delivery with other malaria control interventions will be highly context specific. 3GIRS using Actellic®300CS is expected to deliver acceptable value for money in a broad range of sub-Saharan African malaria transmission settings. [ABSTRACT FROM AUTHOR]

Simple Summary: A key tool in the fight against mosquitoes, which transmit malaria, is the application of insecticidal indoor residual spray (IRS) to the internal walls of buildings where mosquitoes alight and rest to digest their blood-meals. When evaluating the effectiveness of IRS formulations for killing mosquitoes when applied to a wall, it is important that the insecticide is applied evenly at the target dose. Traditionally, IRS is applied using a hand-held pump, but this study showed that an automated track sprayer delivered the desired dose to wall surfaces more accurately and more evenly. This was first shown using a fluorescent tracer to measure spray deposit on the wall of a laboratory, and then by spraying different IRS formulations onto the walls of an experimental hut. Indoor residual spraying (IRS) has changed little since its introduction in the 1940s. Manual spraying is still prone to variation in insecticide dose. To improve the application of IRS in experimental hut trials, an automated track sprayer was developed, which regulates the speed of application and the distance of the nozzle from the wall, two key sources of variation. The automated track sprayer was compared to manual spraying, firstly using fluorescein solution in controlled indoor settings, and secondly in experimental huts in Tanzania using several IRS products. Manual spraying produced greater variation with both fluorescein and insecticide applications. Both manual and automated spray methods under-dosed the actual dose sprayed compared to the target dose. Overall, the track sprayer treats surfaces more consistently, offering a potential improvement over manual spraying for experimental hut evaluation of new IRS formulations. [ABSTRACT FROM AUTHOR]

Abstract Background Indoor Residual Spray (IRS) against vector mosquitoes is a primary means for combating malaria transmission. To combat increased patterns of resistance to chemicals against mosquito vectors, alternative candidate insecticide formulations should be screened. With mortality as the primary endpoint, the persistence of residual efficacy of a polymer-enhanced pyrethroid suspension concentrate containing deltamethrin (K-Othrine® PolyZone—KOPZ) applied at 25 mg active ingredient (ai)/m2 was compared with a microencapsulated organophosphate suspension formulation of pirimiphos-methyl (Actellic® 300CS—ACS) applied at 1 g ai/m2. Methods Following standard spray application, periodic contact bioassays were conducted for at least 38 weeks on four types of wall surfaces (unbaked clay, baked clay, cement, and painted cement) sprayed with either KOPZ or ACS in simulated semi-field conditions. Similarly, two types of existing walls in occupied houses (painted cement and baked clay) were sprayed and examined. A colonized strain of female Anopheles arabiensis mosquitoes were exposed to treated or untreated surfaces (controls) for 30 min. For each wall surface test period, 40 treatment mosquitoes (4 cones × 10) in semi-field and 90 (9 cones × 10) in ‘natural’ house conditions were used per wall. 30 mosquitoes (3 cones × 10) on a matching unsprayed surface served as the control. Insecticide, wall material, and sprayed location on wall (in houses) were compared by final mortality at 24 h. Results Insecticide, wall material, and sprayed location on wall surface produced significant difference for mean final mortality over time. In semi-field conditions, KOPZ produced a 72% mean mortality over a 38-week period, while ACS gave 65% (p

Copyright of Journal of Henan University of Technology Natural Science Edition is the property of Henan University of Technology Journal Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Vector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk. Methods WHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate. Results Annual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n = 4,403 IRS sites, 58%, n = 2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto in unsprayed sites (20.4%, n = 858) than in sprayed sites (7.9%, n = 595) and fewer Anopheles parensis (2%, n = 85 unsprayed, 7.8%, n = 591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10–12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI 1.4–2.9) in unsprayed sites compared to 0.8% (95% CI 0.5–1.3) in sprayed sites (p = 0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. Conclusion This study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

Pesticides kill organisms harmful for the human organism, sometimes also harming beneficial ones. After treatment, pesticides remain on the soil surface in agrocenoses and adjacent plots for decades. For the laboratory experiment, we selected Rossiulus kessleri (Lochmander, 1927) – a species which lives 5–6 years on the soil surface and can dig in to soil to a depth of 30–40 cm. During a 20-day experiment we used herbicides (Roundup, Urahan Forte), insecticides (Omite, BI 58, Biotlin, Actellic, Nurelle D) and fungicides (Ridomil Gold, Thiovit Jet, Penncozeb 80 WP, Falcon, Tilt, Horus) which are often used in agrocenosises of Ukraine. Under the impact of Roundup and Urahan, body weight of R. kessleri reliably did not change, but food consumption and production of excrement increased. Pesticide-treated litter did not digest in the intestine of millipedes, but they survived to the end of the experiment (20 days). In the conditions of treating litter with insecticides Omite, BI 58, Biotlin, Actellic and Nurelle D, the amount of consumed food and body weight reliably did not change; most of these insecticides slowed the formation of feces in the millipedes. The highest studied concentrations of Actellic and Nurelle D preparations caused death to R. kessleri. Depending on the concentration in the litter, the studied fungicides Ridomil Gold, Thiovit Jet, Penncozeb, Falcon, Tilt, Horus had a varying effect on food consumption, body weight and the amount of excrement of R. kessleri. Thus, in agrocenoses and forest ecosystems adjacent to them (windbreaks, ravine and flood plain forests), R. kessleri can be significantly affected by the manufacturer-recommended doses of pesticides, as well as more than ten-fold lower doses.

55% pirimiphos-methyl EC mixed ultrapure water by proportion of 1∶2, was sprayed to the surface and the upper space of grain in large warehouse by Ultra-low-volume sprayer. Our study was performed twice at the end of April 2019 and the end of July 2019 respectively. Stored-grain pest protection layer was formed on the surface of grain bulk to continuously prevent the grain from suffering pest infringement. At the same time, the temperature controlled by air conditioner of warehouse was lower than 25 ℃. In this way, we can maximize the effect of pirimiphos-methyl protective layer on insect pests. By using pirimiphos-methyl will significantly reduce the amount of aluminium phosphide used in large warehouse and the intensity of labor. Because of the low toxicity, residue, cost and environmental friendly of pirimiphos-methyl, we concentrate on replacing aluminium phosphide with pirimiphos-methyl to achieve the goal of warehouse fumigation-free all year round.

The house fly Musca domestica L. (Diptera: Muscidae) is a worldwide medical and veterinary pest, causing great economic losses. Organophosphate insecticides have been widely used to control house fly populations. The main objectives of the present study were to evaluate the resistance levels of M. domestica slaughterhouse populations, collected from Riyadh, Jeddah, and Taif, against the organophosphate insecticide pirimiphos-methyl and investigate the genetic mutations of the Ace gene associated with pirimiphos-methyl resistance. The obtained data showed that there were significant differences among pirimiphos-methyl LC50 values of the studied populations, where the highest LC50 was recorded for the Riyadh population (8.44 mM), followed by Jeddah and Taif populations (2.45 mM and 1.63 mM, respectively). Seven nonsynonymous SNPs were detected in the studied house flies. The Ile239Val and Glu243Lys mutations are reported for the first time, whereas Val260Leu, Ala316Ser, Gly342Ala, Gly342Val, and Phe407Tyr were previously reported in M. domestica field populations from other countries. Considering three mutations associated with insecticide resistance, at amino acid positions 260, 342, and 407 of acetylcholinesterase polypeptide, 17 combinations were recovered in this study. Three out of these seventeen combinations were frequently found both worldwide and in the three Saudi house fly field populations, as well as their pirimiphos-methyl-surviving flies. Overall, the single and combined Ace mutations are apparently associated with pirimiphos-methyl resistance, and the obtained data can be useful in managing house fly field populations in Saudi Arabia.

Copyright of Journal of Plant Protection & Pathology is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Indoor Residual Spray (IRS) against vector mosquitoes is a primary means for combating malaria transmission. To combat increased patterns of resistance to chemicals against mosquito vectors, alternative candidate insecticide formulations should be screened. With mortality as the primary endpoint, the persistence of residual efficacy of a polymer-enhanced pyrethroid suspension concentrate containing deltamethrin (K-Othrine® PolyZone—KOPZ) applied at 25 mg active ingredient (ai)/m2 was compared with a microencapsulated organophosphate suspension formulation of pirimiphos-methyl (Actellic® 300CS—ACS) applied at 1 g ai/m2. Methods: Following standard spray application, periodic contact bioassays were conducted for at least 38 weeks on four types of wall surfaces (unbaked clay, baked clay, cement, and painted cement) sprayed with either KOPZ or ACS in simulated semi-field conditions. Similarly, two types of existing walls in occupied houses (painted cement and baked clay) were sprayed and examined. A colonized strain of female Anopheles arabiensis mosquitoes were exposed to treated or untreated surfaces (controls) for 30 min. For each wall surface test period, 40 treatment mosquitoes (4 cones × 10) in semi-field and 90 (9 cones × 10) in 'natural' house conditions were used per wall. 30 mosquitoes (3 cones × 10) on a matching unsprayed surface served as the control. Insecticide, wall material, and sprayed location on wall (in houses) were compared by final mortality at 24 h. Results: Insecticide, wall material, and sprayed location on wall surface produced significant difference for mean final mortality over time. In semi-field conditions, KOPZ produced a 72% mean mortality over a 38-week period, while ACS gave 65% (p < 0.001). Painted cement wall performed better than other wall surfaces throughout the study period (73% mean mortality). In the two occupied houses, KOPZ provided a mean mortality of 88%, significantly higher than ACS (p < 0.001). KOPZ provided an effective residual life (≥ 80% mortality) between 7.3 and 14 weeks on experimental walls and between 18.3 and 47.2 weeks in houses, while ACS persisted between 3 and 7.6 weeks under semi-field conditions and between 7.1 and 17.3 weeks in houses. Household painted cement walls provided a longer effective residual activity compared to baked clay for both formulations. Greater mortality was recorded at the top and middle sections of sprayed wall compared to the bottom portion near the floor. Conclusion: KOPZ provided longer residual activity on all surfaces compared to ACS. Painted cement walls provided better residual longevity for both insecticides compared to other surfaces. Insecticides also performed better in an occupied house environment compared to semi-field constructed walls. This study illustrates the importance of collecting field-based observations to determine appropriate product active ingredient formulations and timing for recurring IRS cycles. [ABSTRACT FROM AUTHOR]

Copyright of Agriscientia is the property of Revista AgriScientia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, we evaluated the insecticidal efficacy of diatomaceous earth (DE) and pirimiphos-methyl for the control of phosphine-susceptible and phosphine-resistant populations of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.). Insecticides were applied on wheat or rice at two doses: DE was applied at 1000 and 2000 ppm and pirimiphos-methyl at 1 and 5 ppm. Adult mortality was measured after 7, 14, and 21 days of exposure, and progeny production capacity on the treated substrates was evaluated 65 days later. For T. castaneum, we found that DE, at 2000 ppm, was able to provide 100% control of two of the three populations tested, while for the third population mortality reached only 84%. Similarly, there were differences in mortality levels after exposure to DE-treated grains between the two S. oryzae populations tested. At 1 ppm, pirimiphos-methyl was not effective for any of the T. castaneum populations tested, but complete mortality was recorded for all populations at 5 ppm. In general, populations of S. oryzae were more susceptible than those of T. castaneum, for both commodities. Our data indicate that both insecticides can be used with success in phosphine resistance management programs, but there are populations of a given species that may be less susceptible, which constitutes a preliminary screening essential. [ABSTRACT FROM AUTHOR]

[Display omitted] The prevalent use of pesticides, including pirimiphos-methyl (PPM) and bifenthrin (BF), poses a serious health risk, particularly to workers who encounter these chemicals daily. Despite the recognized hepatotoxic effects, the specific molecular mechanisms, especially those involving miRNAs in liver damage caused by PPM and BF, are not fully elucidated. Prior studies have not exhaustively analyzed the hepatic miRNA-target gene dynamics following exposure to these pesticides; thus, this research aims to fill that gap through an extensive miRNA analysis to discern their regulation in PPM or BF-induced hepatic toxicity. In this study, male Sprague-Dawley rats were exposed to BF or PPM for 28 days through oral gavage, simulating the chronic exposure faced by humans. We conducted a thorough assessment of the hepatotoxicity induced by PPM and BF, employing multiple evaluation levels, including histological analysis, liver enzyme measurements, and real-time PCR to detect changes in hepatic miRNA-target gene expressions. Additionally, we utilized DIANA-miRPath prediction tools to delineate the functional implications of these hepatic miRNA target genes. Our findings reveal a significant modulation in the expression of rno-miR-155–5p and rno-miR-122–5p, along with their target genes, following PPM and BF treatment. In contrast, rno-miR-21–5p levels remained unaltered. These observations suggest potential utility of these specific hepatic miRNAs as biomarkers for liver injury resulting from pesticide exposure. Subsequent GO enrichment analysis linked target genes to functions like molecular activity, protein binding, and cellular processes. Additionally, KEGG pathway analysis showed these genes, influenced by varied miRNA expressions, play significant roles in metabolic and signaling pathways In conclusion, this study enhances our comprehension of the biological roles of miRNAs in hepatic toxicity induced by PPM and BF. The insights gained here not only shed light on molecular mechanisms but also open avenues for considering these miRNAs as potential diagnostic biomarkers in conditions of pesticide-induced hepatotoxicity, thereby guiding future therapeutic strategies. • Pesticide exposures significantly affect hepatic miRNA expression. • rno-miR-155–5p upregulation alters genes target expression. • Modulation of rno-miR-122–5p expression results in changes in its targets. • Functional enrichment analysis associates these miRNAs with metabolic processes. [ABSTRACT FROM AUTHOR]

Objective. This study was designed to investigate the effect of sublethal doses (10, 60, and 120 mg/kg of pirimiphos-methyl on implantation and pregnancy in female Sprague-Dawley rats. Pirimiphos-methyl is a pesticide widely used worldwide, especially in Africa to protect food against pests and has gained widespread acceptance.

he efficiency and biochemical effects of certain insecticides belonging to different groups namely: flubendiamide (diamide), pyridalyl (phenoxy-pyridaloxy), clothianidin (neonicotinoide), fipronil (phenylpyrazole) and spirotetramat (tetramic acid) and pirimiphos-methyl (Ops) were tested against 2nd larval instar of Spodoptera littoralis laboratory strain using dipping technique. The efficacy of the tested insecticides are arranged as follows to LC50 values. The results showed that flubendiamide was the superior toxicant insecticides ( LC50 1.03 ppm) followed by pyridalyl (2.13 ppm) then fipronil (7.42 ppm), clothianidin (26.87ppm), pirimiphos-methyl (76.31 ppm) and spirotetramat (431.91 ppm). Biochemical effects of the tested insecticides on acetylcholine esterase (AChE), glutathione-s-transferases (GST), adenosinetriphosphatase (ATPase), phenoloxidase, total calcium, and total protein were determined in the treated larvae. Data showed highest significant increase at AChE activity in treatment of fipronil by change% (70.59), while treatment with pirimiphosmethyl recorded highest significant decrease by change% (-56.41). Whereas, all treatments recorded increase in GST activity except pirimiphosmethyl recorded non significant decrease. All insecticides treatments were showed a decrease in phenoloxidase activity the highest decrease recorded by pirimiphos-methyl treatment by change % (- 53.06). Regarding change percentage of ATPase, activity data recorded significant increase with pirimiphos-methyl treatment by (72.91%). However, total protein in all treatments showed a significant decrease. On the other hand, treatment with pirimiphos-methyl recorded a significant decrease in total calcium and the corresponding change % was (- 6.0%). Previous data confirmed the mode of action of the novel tested insecticides.

Indoor residual spraying (IRS) has changed little since its introduction in the 1940s. Manual spraying is still prone to variation in insecticide dose. To improve the application of IRS in experimental hut trials, an automated track sprayer was developed, which regulates the speed of application and the distance of the nozzle from the wall, two key sources of variation. The automated track sprayer was compared to manual spraying, firstly using fluorescein solution in controlled indoor settings, and secondly in experimental huts in Tanzania using several IRS products. Manual spraying produced greater variation with both fluorescein and insecticide applications. Both manual and automated spray methods under-dosed the actual dose sprayed compared to the target dose. Overall, the track sprayer treats surfaces more consistently, offering a potential improvement over manual spraying for experimental hut evaluation of new IRS formulations.

The aim of this work was to analyze the dissipation dynamics of the insecticides pirimiphos- methyl and dichlorvos in maize (Zea mays L.) grains after post-harvest spray applications. The recommendations for their use for Argentina and the Maximum Residue Limits (MRLs) established by local and international pesticide regulations were considered. Supervised experimental trials were conducted in stored maize grains treated with 10 cc.t-1 of pirimiphos-methyl and 20 cc.t-1 of dichlorvos. Samples were monitored 2, 30, 60, 90 and 120 days after application. The pesticides were extracted from the maize grains using the QuEChERS technique and the residues were determined using high-resolution gas chromatography with mass detector. Residue dissipation percentages and daily dissipation rates differed between active ingredients. At 48 hours after application, pirimiphos-methyl residues were 5.1±0.42 µg.g-1, i.e. below the MRLs established by the Argentine Service for Agrifood Health and Quality (10 µg.g-1), the USA (8 µg.g-1) and the Codex Alimentarius (7 µg.g-1), and close to the MRLs established by the EU (5 µg.g-1). Dichlorvos residues reached 2.97±0.27 µg.g-1, and required at least a 90-day withholding period to be lower than the MRLs of the EU. Highligths Pirimiphos-methyl residues had high dissipation in stored maize grains. Dichlorvos insecticides in stored maize required more time withholding period than Pirimiphos-metyl to be lower than de MRLs of the EU. Organophosphorus insecticide residues were below the MRL of the Codex Alimentarius.

Insecticidal treatment is a common practice for the control of stored-product insect pests. Most studies are focused on the direct effects of insecticides on target insects, while there are no data on the indirect effects on adults in terms of progeny fitness. This study deals with the effect of pirimiphos-methyl on adults of Tribolium castaneum (Coleoptera: Tenebrionidae), investigating their exposure time cost to progeny fitness. For this purpose, females of T. castaneum were exposed for 1, 3, 8, 16, 24, and 72 h to pirimiphos-methyl and progeny birth or death rates were calculated. The fecundity, as well as the survival of progeny, was affected by the parental exposure to the insecticide. When females were exposed for 1 and 3 h to pirimiphos-methyl, the net reproductive rate of the progeny was 4.1 and 4.3 females/female, respectively, which did not statistically differ with the progeny in control treatment (6.3 females/female). Further exposure time to pirimiphos-methyl affected significantly the progeny net reproductive rate, where the lowest value was observed at the 72-h exposure time (0.97 females/female). The intrinsic rate of increase, as well as the finite rate of increase, did not differ between the progeny of the control treatment (0.029 females/female/day and 1.029, respectively) and the progeny of exposed females at 1 h (0.021 females/female/day and 1.021, respectively) or 3 h (0.023 females/female/day and 1.023, respectively). By increasing the time of exposure to pirimiphos-methyl, a detrimental effect to progeny fitness was revealed based on the values of the intrinsic and finite rate of increase. The lowest values of these parameters were observed at the 72-h exposure time (0.001 females/female/day and 1.000, respectively). The same trend was observed in the values of the doubling time. In contrast, the mean generation time did not statistically differ between control and all insecticide treatments. The fact that the exposure of parental females of T. castaneum to pirimiphos-methyl negatively affects the demographic parameters of their offspring production should be seriously taken into account when management strategies are applied against this notorious stored-product insect species since it could reduce the repeatedly insecticidal applications in storage facilities. [ABSTRACT FROM AUTHOR]

In this study, polyurethane microcapsules loaded with pirimiphos-methyl were prepared by an interfacial polymerization method using modified poly-isocyanate as the precursor and triethanolamine as a curing agent. The microcapsules were fully characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and so on. The results showed that the microcapsules had good morphology, excellent encapsulation efficiency (90.88%) and loading ability (about 50%) for pirimiphos-methyl. Furthermore, the microcapsules exhibited an excellent sustained release property (above 8 days) in 50% isopropanol aqueous solution(v/v). The biological activity on Musca domestica showed that the microcapsules persistence period was above 90 days, which was longer than emulsifiable concentrate formulation. [ABSTRACT FROM AUTHOR]

The effects of the insecticides chlorpyrifos-methyl and pirimiphos-methyl in combination with low temperature treatment at 5°C were tested in the laboratory to improve the existing pest management programs for S. oryzae control. Adults were released into wheat grain pretreated with three insecticide doses: 0.08, 0.12 and 0.16 mg/kg of chlorpyrifos-methyl, and 0.125, 0.19 and 0.25 mg/kg of pirimiphos-methyl, and exposed to 5°C temperature over intervals of 5, 6, 7 and 8 days. Mortality after low temperature only, insecticides only, and their combinations, was assessed after 1, 2, 7 and 14 days of recovery at 25±1°C and 60±5% r.h., as well as their impact on F1 progeny production/reduction (PR) after 8 weeks. The combined application of 0.16 mg/kg chlorpyrifosmethyl and 5°C temperature (5-7 days of exposure) caused a significantly higher mortality of S. oryzae after 1, 2, 7 and 14 days of recovery than the activity of low temperature alone, as well as the combined application of 0.12 mg/kg chlorpyrifos-methyl and 5°C after 7 and 14 days of recovery. Adults mortality and progeny reduction of S. oryzae was =92% after 14 days of recovery from an interaction of 0.16 mg/kg dose of chlorpyrifos-methyl and exposure for 6 days to 5°C, as well as all doses in combination with 7 days exposure to 5°C. Combined application of 0.25 mg/kg pirimiphos-methyl and 5, 6 and 7 days of exposure to 5°C caused a significantly higher mortality of S. oryzae after 7, 2 and 1 day of recovery, respectively, compared to temperature-only exposure. High mortality (91-95%) and progeny reduction >92% were caused by the same pirimiphos-methyl rate in combination with 6 and 7 days of exposure to 5°C after 7 days of recovery as the combination of 5, 6 and 7 days of exposure to 5°C after 14 days of recovery.

Abstract Background Scaling-up of effective anti-malarial control strategies in Central-West region of Senegal has resulted in the sharp decline in malaria prevalence in this area. However, despite these strategies, residual malaria transmission has been observed in some villages (hot spots). The objective of this study was to assess the impact of indoor residual spraying (IRS) with pirimiphos-methyl on malaria transmission in hot spot areas. Methods The malaria vector population dynamics were monitored in each of the six selected villages (4 of which used IRS, 2 were unsprayed control areas) using overnight human landing catches (HLC) and pyrethrum spray catches (PSC). The host source of blood meals from freshly fed females collected using PSC was identified using the direct ELISA method. Females caught through HLC were tested by ELISA for the detection of Plasmodium falciparum circumsporozoite protein and Anopheles gambiae complex was identified using PCR. Results Preliminary data shown that the densities of Anopheles populations were significantly lower in the sprayed areas (179/702) compared to the control. Overall, malaria transmission risk was 14 times lower in the intervention zone (0.94) compared to the control zone (12.7). In the control areas, three Anopheles species belonging to the Gambiae complex (Anopheles arabiensis, Anopheles coluzzii and Anopheles melas) maintained the transmission, while only An. coluzzii was infective in the sprayed areas. Conclusion The preliminary data from this pilot study showed that IRS with the CS formulation of pirimiphos-methyl is likely very effective in reducing malaria transmission risk. However, additional studies including further longitudinal entomological surveys as well as ecological and ethological and genetical characterization of vectors species and their populations are needed to better characterize the entomological impact of indoor residual spraying with pirimiphos-methyl in the residual transmission areas of Senegal.

Background & objectives: There is an urgent need of introducing new insecticide molecules with novel modes of action to counter the ever growing insecticide-resistance in mosquito vectors. In the present study, a new insecticide molecule, SumiShield 50 WG (clothianidin 50%, w/w) was investigated for its efficacy as an indoor residual spray along with its residual action in comparison to deltamethrin, pirimiphos-methyl and bendiocarb. Methods: The study area included three villages in Almatti Dam catchment area in Bagalkot district, Karnataka, India. Spraying was done using Hudson sprayers with the following dosages—Clothianidin, 300 mg AI/m2; deltamethrin, 25 mg AI/m2; bendiocarb, 400 mg AI/m2; and pirimiphos-methyl, 1 g AI/m2. Cone bioassays were conducted on cement and mud plastered surfaces at fortnightly intervals to assess the bioefficacy and residual activity. Mosquito densities in the sprayed houses were recorded at regular intervals for assessment of the insecticidal efficacy. Filter paper samples collected from the sprayed houses were analyzed for insecticide content sprayed on different wall surfaces at the Walloon Agricultural Research Institute, Gembloux, Belgium. Results: Chemical content analysis of filter paper samples revealed that the applied to target ratios were in the acceptable range (1 + 0.5) for all the treatment types. Duration of persistence of effectiveness of bendiocarb (≥80% mortality in cone bioassays) was 19 to 21 wk on cement plastered surfaces and 15 to 19 wk on mud plastered surfaces. Duration of persistence of effectiveness of deltamethrin was 17 to 21 wk on both mud and cement plastered surfaces and that of pirimiphos-methyl was 15 to 19 wk. For SumiShield, it was 17 to 25 wk on both types of surfaces, indicating slow action of SumiShield. The densities of Anopheles culicifacies were lower in bendiocarb sprayed houses throughout the observation period, followed by pirimiphos methyl, deltamethrin and clothianidin sprayed houses. In case of other mosquitoes also, similar trend was observed. Interpretation & conclusion: Considering the persistence of effectiveness of SumiShield on sprayed surfaces, effectiveness in reducing the density of mosquitoes, operational feasibility, safety and community acceptance, the formulation of clothianidin is a better option for IRS for the control of insecticide-resistant mosquito vectors.

Processing Factors (PFs) reflect the concentration or dilution of pesticide residues resulting from food processing. PFs are key elements to demonstrate the compliance of processed foods with Maximum residue levels (MRLs) as set by Regulation 396/2005. While efforts have been made by the European Food Safety Authority (EFSA) and by national authorities to compile PFs from processing studies, such PFs are not available for all pesticides/processed product combinations. The EU vegetable oil and proteinmeal industry association (FEDIOL) has therefore developed a theoretical approach to approximate MRLs in crude vegetable oils and fats, based on the partition coefficient (log Pow) of the pesticides and on the oil content of the raw materials. To substantiate this approach, a pilot-scale processing study was initiated with rapeseeds spiked with selected pesticides and the experimental PFs for these pesticides determined. The aims of this study were (i) to study the reliability of pilot-scale conditions for PF determination and (ii) to assess the experimental PFs obtained in comparison to the theoretical PFs proposed by FEDIOL. This study demonstrated that production yields obtained for crude oil and meal in this processing study are similar to those in industrial processes even if differences were observed in the individual production steps (mechanical or solvent extraction steps). The experimental PFs obtained confirmed that the chosen fat-soluble pesticides did concentrate in the oil fraction. For metalaxyl-M having a log Pow lower than 3, a partitioning between the oil and the meal was observed, as expected. By comparing the experimental PFs and theoretical PFs, it can be concluded that the FEDIOL approach can be recommended as a suitable tool when PFs derived from specific processing studies are missing. Similar studies on pesticides with wider ranges of log Pow are required in order to complete our conclusions on default PFs for vegetable oils. [ABSTRACT FROM AUTHOR]

The aim of this work was to analyze the dissipation dynamics of the insecticides pirimiphos- methyl and dichlorvos in maize (Zea mays L.) grains after post-harvest spray applications. The recommendations for their use for Argentina and the Maximum Residue Limits (MRLs) established by local and international pesticide regulations were considered. Supervised experimental trials were conducted in stored maize grains treated with 10 cc.t-1 of pirimiphos-methyl and 20 cc.t-1 of dichlorvos. Samples were monitored 2, 30, 60, 90 and 120 days after application. The pesticides were extracted from the maize grains using the QuEChERS technique and the residues were determined using high-resolution gas chromatography with mass detector. Residue dissipation percentages and daily dissipation rates differed between active ingredients. At 48 hours after application, pirimiphos-methyl residues were 5.1±0.42 µg.g-1, i.e. below the MRLs established by the Argentine Service for Agrifood Health and Quality (10 µg.g-1), the USA (8 µg.g-1) and the Codex Alimentarius (7 µg.g-1), and close to the MRLs established by the EU (5 µg.g-1). Dichlorvos residues reached 2.97±0.27 µg.g-1, and required at least a 90-day withholding period to be lower than the MRLs of the EU. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of pirimiphos-methyl using silica-functionalized graphene oxide (GO)/ ZnO incorporated with fiberglass (silica-GO/ZnO) was evaluated. The effect of different variables including the initial concentration of pirimiphos-methyl, temperature, contact time, and hydrogen peroxide concentration was tested on the photocatalytic degradation. Moreover, the effect of co-existing organic compounds (folic acid, citric acid, oxalate, phenol, and ethylenediaminetetraacetic acid) and different purging gases (oxygen and nitrogen) was explored. The maximum removal efficiency was achieved at a neutral medium, in other words at acidic and alkaline conditions the catalyst corrosion occurred which resulted in a decrease in efficiency. By increasing the temperature, the photocatalytic removal efficiency using silica-GO/ZnO increased, because of the catalyst expansion and therefore, greater availability of functional groups. With an increase in the concentration of pollutant from 5 to 60 mg/L, the kobs values decreased from 0.050 to 0.005, while the electrical energy per order (EE0) increased from 95.81 to 923.12 kWh/m³. The removal efficiency of pirimiphos-methyl in the absence of hydrogen peroxide under the optimal conditions of other factors was obtained by ≈98%. However, as the concentration of hydrogen peroxide increased from 3 to 45 mM, the removal efficiency decreased from 86.74% to 81.61%, respectively. The presence of organic compounds acted as a scavenger and resulted in reduced removal efficiency. The findings of this study also suggested that purging of oxygen gas provided greater photocatalytic activity compared to nitrogen and ambient air for the degradation of the target contaminant. [ABSTRACT FROM AUTHOR]

Insecticidal applications may result to morphological deformations upon exposed insects or their offspring production. In the present study, we tested whether pirimiphos-methyl can induce deformities to wings of progeny production of the invasive khapra beetle, Trogoderma granarium (Coleoptera: Dermestidae) when its parental female adults have been treated with this organophosphorus active ingredient. For that purpose, we analysed both elytra and hindwings of both sexes of T. granarium progeny production by using the geometric morphometrics method. Our results showed that the wings of progeny of the pirimiphos-methyl-treated T. granarium parental female adult individuals suffered certain changes in their usual shape depending on size. Deformations occurred on both pairs of wings, but changes were more noticeable on the hindwings. A longer than 5-h exposure of parental female adults to pirimiphos-methyl, resulted in progeny with more deformed wings than in those individuals emerged after the exposure of their parental female adults in shorter periods on the toxicant. Generally, wings of both sexes were sensitive to pirimiphos-methyl, distinguishing the control group from the insecticidal treatments. The existence of deformed adults could be a useful indicator of earlier insecticidal applications as surface treatments and/or grain protectants in the storage facilities. [ABSTRACT FROM AUTHOR]

We evaluated the efficacy of bendiocarb (Ficam W® 80%) and pirimiphos-methyl (Actellic 300CS® 28.16%), applied to different surfaces potentially sprayable within houses during the application of a targeted indoor residual spraying (TIRS) against a field pyrethroid-resistant strain of Aedes aegypti. Bioassays with cones were performed on cement (walls), wood (doors), and textile (cloth) surfaces within typical houses in the Mexican city of Merida (n = 10). Optimal residual efficacy (>80% of mean mortality) of bendiocarb ranged from 3 months (cement) to 2 months (wood and textiles). Residual efficacy of pirimiphos-methyl ranged from 5 months (cement) to 2 months (wood and textiles). Both insecticides proved to be effective as adulticides against field Ae. aegypti and may be useful in mosquito control programs implementing TIRS with pyrethroid-resistant populations. [ABSTRACT FROM AUTHOR]

Consumers are constantly exposed to a variety of chemical mixtures as part of their everyday activities and lifestyle. Food, water and commercial products are only some examples of the possible ways people get exposed to these mixtures. However, following federal and local guidelines for risk assessment related to chemical exposure, risk analysis focuses on a single substance exposure scenario and not on a mixture, as in real life. Realizing the pronounced gap of this methodology, the real-life risk simulation scenario approach tries to address this problem by investigating the possible effect of long-term exposure to chemical mixtures closely resembling the actual circumstances of modern life. As part of this effort, this study aimed to identify the cumulative effects of pesticides belonging to different classes and commonly used commercial products on long-term exposure with realistic doses. Sprague Dawley rats were given a pesticide mix of active ingredients and formulation chemicals in a daily acceptable dose (ADI) and 10xADI for 90 days. Following thorough everyday documentation of possible side-effects, after 90 days all animals were sacrificed and their organs were examined. Exposure to pesticides particularly affects the miRNA levels at that point will provide us with more information about whether they can be potential biomarkers. [Display omitted] • Exposure to a mixture of pesticides at acceptable daily intakes induces degenerative changes in endocrine organs. • Increased miR-21 in pancreatic and mesentery tissue suggests that it may be linked to pesticide-mediated inflammatory process. • MiR-223 levels, which suppress proinflammatory cytokines, were significantly reduced in mesenteric tissue. • In pancreatic tissue, miR-146a expression was increased especially in the Mix-2 commercial group. [ABSTRACT FROM AUTHOR]

Abstract Background Indoor residual spraying is one of the key vector control interventions for malaria control in Ethiopia. As malaria transmission is seasonal in most parts of Ethiopia, a single round of spraying can usually provide effective protection against malaria, provided the insecticide remains effective over the entire malaria transmission season. This experiment was designed to evaluate the residual efficacy of bendiocarb, pirimiphos-methyl, and two doses of propoxur on four different wall surfaces (rough mud, smooth mud, dung, and paint). Filter papers affixed to wall surfaces prior to spraying were analyzed to determine the actual concentration applied. Cone bioassays using a susceptible Anopheles arabiensis strain were done monthly to determine the time for which insecticides were effective in killing mosquitoes. Results The mean insecticide dosage of bendiocarb applied to walls was 486 mg/m2 (target 400/mg). This treatment lasted 1 month or less on rough mud, smooth mud, and dung, but 4 months on painted surfaces. Pirimiphos-methyl was applied at 1854 mg/m2 (target 1000 mg/m2), and lasted between 4 and 6 months on all wall surfaces. Propoxur with a target dose of 1000 mg/m2 was applied at 320 mg/m2, and lasted 2 months or less on all surfaces, except painted surfaces (4 months). Propoxur with a target dose of 2000 mg/m2, was applied at 638 mg/m2, and lasted 3 months on rough mud, but considerably longer (5–7 months) on the other substrates. Conclusions It would appear that the higher dose of propoxur and pirimiphos-methyl correspond best to the Ethiopian transmission season, although interactions between insecticide and the substrate should be taken into account as well. However, the insecticide quantification revealed that the dosages actually applied differed considerably from the target dosages, even though care was taken in the mixing of insecticide formulations and spraying of the walls. It is unclear whether this variability is due to initial concentrations of insecticides, poor application, or other factors. Further work is needed to ensure that target doses are correctly applied, both operationally and in insecticide evaluations.

Abstract Background Malaria vector control in Tanzania is based on use of long-lasting insecticide treated nets (LLINs) and indoor residual spraying (IRS), which both rely on the use of chemical insecticides. The effectiveness of these control tools is endangered by the development of insecticide resistance in the major malaria vectors. This study was carried out to monitor the susceptibility status of major malaria vectors to insecticides used for IRS and LLINs in mainland Tanzania. Methods Mosquito larvae were collected in 20 sites of Tanzania mainland in 2015. Phenotypic resistance was determined using standard WHO susceptibility tests. Molecular assay were used to determine distribution of Anopheles gambiae sub-species. A microplate assay approach was used for identifying enzyme levels on single mosquitoes from each sites compared with a susceptible reference strain, An. gambiae sensu stricto (s.s.) Kisumu strain. Results Anopheles arabiensis was the dominant malaria specie in the country, accounting for 52% of the sibling species identified, while An. gambiae s.s. represented 48%. In Arumeru site, the dominant species was An. arabiensis, which was resistant to both pyrethroids (permethrin and deltamethrin), and pirimiphos-methyl, and had significant elevated levels of GSTs, non-specific esterases, and oxidase enzymes. An. arabiensis was also a dominant species in Kilombero and Kondoa sites, both were resistant to permethrin and deltamethrin with significant activity levels of oxidase enzymes. Resistance to bendiocarb was recorded in Ngara site where specie composition is evenly distributed between An. gambiae s.s. and An.arabiensis. Also bendiocarb resistance was recorded in Mbozi site, where An. gambiae s.s. is the dominant species. Conclusions Overall, this study confirmed resistance to all four insecticide classes in An. gambiae sensu lato in selected locations in Tanzania. Results are discussed in relation to resistance mechanisms and the optimization of resistance management strategies.

Residual efficacy of EC formulations of two insecticides: cypermethrin supplemented with the synergist piperonyl butoxide, and pirimiphos-methyl, against adults of the Angoumois grain moth, Sitotroga cerealella (Olivier), was investigated in the laboratory (at 25±1°C and 55-60% r.h.) by applying water solutions of products based either on cypermethrin (1.6 mg a.i./kg of wheat grain) or pirimiphos-methyl (4 mg a.i./kg of wheat grain) to wheat grain. Insect mortality on deposits of different age: 0, 7, 14, 30, 60, 90, 120, 150 and 180 days was estimated after 2, 7 and 14 days of insect exposure to treated wheat. After 2 day exposure, cypermethrin caused mortality of up to 46% on all deposits (age 0-180 days). After 7 days of exposure, high efficacy (94-100%) was found only on deposits that were up to 90 days old, while the mortality of S. cerealella adults on all deposits following 14 days of exposure was 98-100%, and it was probably additionally enhanced by natural mortality. Pirimiphos-methyl was 98-100% effective after 2 days of exposure to deposits that were up to 30 days old, while it achieved maximum efficacy (100%) after 7 days of insect exposure to deposits aging for up to 150 days, and 94% efficacy on 180 days old deposits. After 14 days of adult exposure to all deposit ages, there were no surviving insects (efficacy 100%). The results show that pirimiphos-methyl was more effective against S. cerealella adults and had a longer residual activity than cypermethrin.

The composition of Atlantic salmon feed has changed considerably over the last two decades from being marine-based (fishmeal and fish oil) to mainly containing plant ingredients. Consequently, concern related to traditional persistent contaminants typically associated with fish-based feed has been replaced by other potential contaminants not previously associated with salmon farming. This is the case for many pesticides, which are used worldwide to increase food production, and may be present in plant ingredients. Earlier studies have identified two organophosphorus pesticides, chlorpyrifos-methyl and pirimiphos-methyl, in plant ingredients used for aquafeed production. In the present study, we developed a reliable and sensitive analytical method, based on liquid chromatography coupled to tandem mass spectrometry, for the determination of these pesticides and their main metabolites in warm water (zebrafish) and cold water (Atlantic salmon) species, where possible differences in metabolites could be expected. The method was tested in whole zebrafish and in different salmon tissues, such as muscle, bile, kidney, fat, and liver. The final objective of this work was to assess kinetics of chlorpyrifos-methyl and pirimiphos-methyl and their main metabolites in fish tissue, in order to fill the knowledge gaps on these metabolites in fish tissues when fed over prolonged time. [ABSTRACT FROM AUTHOR]

Highlights • Quantitation of organophosphorus pesticide pirimiphos-methyl in maize grains. • Fluorescence enhancement by inclusion of the target analyte in surfactant micelles. • Development of a simple and efficient extraction procedure. • Chemometric strategy to overcome matrix effect. Abstract A novel method for the determination of pirimiphos-methyl (PMM) in maize grains by fluorescence spectroscopy and three-way calibration was developed. The formation of supramolecular complexes and their effect on the luminescence properties of PMM were studied. A solvent extraction step followed by solid phase extraction for sample clean-up was optimized. A chemometric approach consisting in PARAFAC as second-order data processing tool and piecewise direct standardization (PDS) for reducing the complexity of the calibration process was developed to overcome the matrix effect. This strategy allowed dealing with the matrix effect while reducing the number of samples to be processed and, consequently, the solvent consumption and the total analysis time. Finally, three-way calibration was applied to predict the PMM concentration in unknown samples. The mean recovery was 115% and the limits of detection and quantitation were in the order of the parts per trillion, i.e. 6 and 20 ng g−1, respectively. [ABSTRACT FROM AUTHOR]

The efficiency and biochemical effects of certain insecticides belonging to different groups namely: flubendiamide (diamide), pyridalyl (phenoxy- pyridaloxy), clothianidin (neonicotinoide), fipronil (phenylpyrazole) and spirotetramat (tetramic acid) and pirimiphos-methyl (Ops) were tested against 2nd larval instar of Spodoptera littoralis laboratory strain using dipping technique. The efficacy of the tested insecticides are arranged as follows to LC50 values. The results showed that flubendiamide was the superior toxicant insecticides ( LC50 1.03 ppm) followed by pyridalyl (2.13 ppm) then fipronil (7.42 ppm), clothianidin (26.87ppm), pirimiphos-methyl (76.31 ppm) and spirotetramat (431.91 ppm). Biochemical effects of the tested insecticides on acetylcholine esterase (AChE), glutathione-s-transferases (GST), adenosinetriphosphatase (ATPase), phenoloxidase, total calcium, and total protein were determined in the treated larvae. Data showed highest significant increase at AChE activity in treatment of fipronil by change% (70.59), while treatment with pirimiphosmethyl recorded highest significant decrease by change% (-56.41). Whereas, all treatments recorded increase in GST activity except pirimiphosmethyl recorded non significant decrease. All insecticides treatments were showed a decrease in phenoloxidase activity the highest decrease recorded by pirimiphos-methyl treatment by change % (- 53.06). Regarding change percentage of ATPase, activity data recorded significant increase with pirimiphos-methyl treatment by (72.91%). However, total protein in all treatments showed a significant decrease. On the other hand, treatment with pirimiphos-methyl recorded a significant decrease in total calcium and the corresponding change % was (- 6.0%). Previous data confirmed the mode of action of the novel tested insecticides. [ABSTRACT FROM AUTHOR]