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Nanotechnology is an emerging technology and day to day expanding its roots of knowledge to various branches of Science and fulfilling human conveniences. To manage vector populations, new tools have been emerging through nanotechnology. Nanoparticles possess peculiar toxicity mechanisms due to surface volume ratio, and this may actively contribute to their excellent larvicidal potential against Aedes aegypti mosquito. Dengue is a mosquito borne disease and making major public health issue worldwide. Aedes (Stegomyia) aegypti (Linnaeus, 1762) prefers to bread in artificial containers, and anti-larval measures with Ximenia americana L. (Olacaceae) leaf mediated silver nanoparticles (AgNPs) proves to be a potential substitute for the existing organophosphorus insecticides like temephos, malathion and fenthion etc., for mosquito control programme. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 hours. From the results, it was found that plant extracts showed moderate larvicidal effects (LC50 at 179.87 and LC90 at 376.77 ppm) but, the synthesized silver nanoparticles had found to be toxic to larvae at LC50 (0.63 ppm) and LC90 (1.20 ppm). This research highlighted that, the Ximenia americana leaf mediated AgNPs are an efficient and eco-friendly agents against Ae. aegypti mosquito, though the laboratory studies have shown the promising results, yet their efficacy in the field is to be tested for effective mosquito larval control.

Susceptibility status of Aedes albopictus (Skuse) sampled from residential areas in Interior, Sandakan and Tawau divisions of Sabah, Malaysia, was evaluated based on the WHOrecommended doses of organochlorine and organophosphate larvicides. To determine susceptibility status, larval bioassays were carried out and post 24-hour mortalities based on WHO resistance classifications were adopted. The results demonstrated that Ae. albopictus larvae were resistant toward 5 out of the 8 larvicides tested. Larvae from all populations were resistant against bromophos, fenitrothion, malathion, temephos and dichlorodiphenyltrichloroethane (DDT), with mortalities ranging from 0.00 to 89.33%. Dieldrin, on the other hand, could induce 100.00% mortalities in all populations, followed by fenthion and chlorpyrifos, with mortalities ranging from 97.33 to 100.00% and 81.33 to 100.00% respectively. Despite most populations exhibiting similitude in their resistance status, larvae from Sandakan exhibited the highest resistance level whereas the lowest level was observed in Keningau. In view of the inadequacy of some larvicides in controlling Ae. albopictus in this study, integrated management such as insecticide rotation or combination of interventions is warranted.

Aedes albopictus larvae obtained from different types of agricultural and non-agricultural localities in Peninsular Malaysia were subjected to several larvicides at World Health Organization (WHO) recommended dosages. Upon 24 h of WHO larval bioassay using two organochlorines and six organophosphates, high resistance against dichlorodiphenyltrichloroethane (DDT), temephos, chlorpyrifos and bromophos were demonstrated among all larval populations. Aedes albopictus larvae from both paddy growing areas (92.33% mortality) and rubber estates (97.00% mortality) were moderately resistant to dieldrin while only Ae. albopictus larvae from dengue prone residential areas (89.00% mortality) showed high resistance against dieldrin. All Ae. albopictus larval populations also developed either incipient or high resistance to both malathion (33.67%–95.33% mortality) and fenitrothion (73.00%–92.67% mortality). Only Ae. albopictus larvae from fogging-free residential areas that were tolerant to fenthion (97.33% mortality), whereas Ae. albopictus larvae from dengue prone residential areas were highly resistant to the same organophosphate (88.33% mortality). Cross resistance between intraclass and interclass larvicides of organochlorines and organophosphates were also exhibited in this study. The present study provided baseline data on various susceptibility levels of Ae. albopictus larval populations from different types of agricultural and non-agricultural localities against organochlorines and organophosphates at WHO recommended dosages. Nevertheless, further susceptibility investigations are suggested using revised doses of larvicides established from the local reference strain of Ae. albopictus to prevent the underestimation or overestimation of insecticide resistance level among Ae. albopictus field strains of larvae.

The production of Nile tilapia (Oreochromis niloticus) in Brazil exhibits the highest growth rate in the world and represents approximately 45% of the total fish production. The objective of the present study was to assess the risk for human health due the consumption of tilapia farmed in net cages in eight aquaculture parks in Brazil. The concentrations of pesticides (40 compounds), metals (Mn, Ni, Zn, Cd, Pb, and Sn), arsenic, and cyanotoxins (microcystins) were evaluated in 16 fish from each park. Among analyzed pesticides, pyraclostrobin (0.18–0.32 mg/kg) and fenthion (0.0026–0.0037 mg/kg) exhibited values above the limit of quantification in the tilapia from Aracoiaba, Castanhao, and Ilha Solteira. The highest concentrations of As (0.44 μg/g) in fish tissues were found in Juara, Mn (0.21 μg/g) in Castanhao, and Zi (11.5 μg/g) were found in Tres Marias. Furnas and Linhares exhibited the lowest metal concentrations. The estimated daily intake of muscle by the average Brazilian with 70 kg body weight is below the reference dose for all studied metals in all parks. Total free microcystins showed an accumulation pattern (muscle < gill < liver). The highest concentration in muscle was found in Castanhao (1043 μg/kg) samples. The results showed that fish exhibited metal, As, and pesticide tolerable daily intake (TDI) below the limit and pose low risk for human consumption. Otherwise, TDI for microcystins in fish of all studied parks was above the maximum level recommended by the World Health Organization, indicating that there exists a toxicity risk of fish consumption.

Out of the five isoforms of human flavin-containing monooxygenase (hFMO), FMO1 and FMO3 are the most relevant to Phase I drug metabolism. They are involved in the oxygenation of xenobiotics including drugs and pesticides using NADPH and FAD as cofactors. Majority of the characterization of these enzymes has involved hFMO3, where intermediates of its catalytic cycle have been described. On the other hand, research efforts have so far failed in capturing the same key intermediate that is responsible for the monooxygenation activity of hFMO1. In this work we demonstrate spectrophotometrically the formation of a highly stable C4a-hydroperoxyflavin intermediate of hFMO1 upon reduction by NADPH and in the presence of O2. The measured half-life of this flavin intermediate revealed it to be stable and not fully re-oxidized even after 30 min at 15 °C in the absence of substrate, the highest stability ever observed for a human FMO. In addition, the uncoupling reactions of hFMO1 show that this enzyme is

Following the loss of two key pesticides, dimethoate and fenthion, producers and regulators need to develop new fruit fly management options. A systems approach is a likely measure in the post dimethoate and fenthion era. The risk of fruit fly can be mitigated at the regional, district and farm level. Some measures such as awareness and exclusion are common across all three levels. Pest control measures will be based on an understanding of climate, biology and pesticides. In this present paper, 28 different risk mitigation options that can be used in a systems approach in Australia are discussed.

This study was conducted to monitor the susceptibility status of Aedes aegypti (Linnaeus) larvae in the Sunda Islands of Indonesia against various organophosphates and organochlorines. Larval bioassay was performed in accordance with the World Health Organization standard protocol. Field-collected and reference strains of Ae. aegypti larvae were tested against diagnostic doses of eight larvicides belonging to organophosphates and organochlorines, namely bromophos (0.050 mg/liter), chlopyrifos (0.002 mg/liter), fenitrothion (0.020 mg/liter), fenthion (0.025 mg/liter), malathion (0.125 mg/liter), temephos (0.012 mg/liter), DDT (0.012 mg/liter), and dieldrin (0.025 mg/liter). Mortality rates of larvae were recorded at 24-h posttreatment. This study showed that Ae. aegypti larvae from Padang, Samarinda, Manggarai Barat, and South Central Timor were susceptible to both fenitrothion and dieldrin (mortality rates ≥ 98%). About 6 out of 10 field strains of Ae. aegypti larvae were resistant (

The aim of this study was to investigate reported cases of honeybee mortality incidents and the potential association to pesticide exposure and to their metabolites. The same honeybee samples were also assessed for Varroa mites, and Nosema microsporidia provoked infections to provide an integrated picture of all observable stressors that may impact bees' survival. Thus, honeybee samples from different areas of Greece (2014–2018) were analyzed for the presence of pesticide residues and metabolites. In this context, an existing LC-ESI-QqQ-MS multiresidue method of analytes of different chemical classes such as neonicotinoids, organophosphates, triazoles, carbamates, was enriched with additional active substances, developed and validated. A complementary GC-EI-QqQ-MS method was also exploited for the same scope covering pyrethroid compounds. Both methods monitored more than 150 active substances and metabolites and presented acceptable linearity over the ranges assayed. The calculated recoveries ranged from 65 to 120% for the three concentration levels, while the precision (RSD%) values ranged between 4 and 15%. Therefore, this approach proved sufficient to act as a monitoring tool for the determination of pesticide residues in cases of suspected honeybee poisoning incidents. From the analysis of 320 samples, the presence of 70 active substances and metabolites was confirmed with concentrations varying from 1.4 ng/g to 166 μg/g. Predominant detections were the acaricide coumaphos, several neonicotinoids exemplified by clothianidin, organophosporous compounds dimethoate and chlorpyrifos, and some pyrethroids. Metabolites of imidacloprid, chlorpyrifos, coumaphos, acetamiprid, fenthion and amitraz were also identified. Concerning Nosema and Varroa they were identified in 27 and 22% of samples examined, respectively, verifying their prevalence and coexistence with pesticides and their metabolites in honeybees.

Protein carbonylation is an irreversible oxidative modification that has been associated with a decrease in the quality and nutritional value of products of animal origin. Generally, the carbonylation is attributed to processes of slaughter, processing, and cold storage of products. However, in vitro studies have shown that fluoroquinolone and organophosphate pesticides residues at their maximum residue limits (MRL) can promote carbonylation of animal proteins. Though, this effect on in vivo conditions has not yet been evaluated. Thus, Eisenia fetida was chosen as a model to assay their oxidant effect. For this, adult earthworms were exposed to artificial soil contaminated with ciprofloxacin, danofloxacin, fenthion, and diazinon at three concentrations (0.5, 1.0, and 1.5 MRL) for 28 days. Then, these were purged and sacrificed to obtain the muscle region between the anus and preclitellum. The muscle samples were cold macerated to obtain muscle proteins, which were used for protein quantification, determination of carbonyl levels, and carbonyl protein profiles employing Bradford, Dot-blot, and Western blot assays, respectively. The results showed that at each concentration assayed, all pollutants induced significant carbonylation respect to control (p 0.05). Additionally, mass spectrometry-based analysis (MALDI-TOF/TOF) identified actin as the protein most susceptible to carbonylation promoted by these substances. Therefore, these findings show for the first time the oxidant power of fluoroquinolones and organophosphates pesticides at MRLs concentrations on muscle proteins under in vivo conditions. Fact causes concern due to the homology of muscle proteins in eukaryotes, which allow to hypothesize that this effect could also be experienced by proteins from food-producing animals in the same way that observed in in vitro studies.

Short-term biomarkers of toxicity have an increasingly important role in the screening and prioritization of new chemicals. In this study, we examined early indicators of liver toxicity for three reference organophosphate (OP) chemicals, which are among the most widely used insecticides in the world. The OP methidathion was previously shown to increase the incidence of liver toxicity, including hepatocellular tumors, in male mice. To provide insights into the adverse outcome pathway (AOP) that underlies these tumors, effects of methidathion in the male mouse liver were examined after 7 and 28 day exposures and compared to those of two other OPs that either do not increase (fenthion) or possibly suppress liver cancer (parathion) in mice. None of the chemicals caused increases in liver weight/body weight or histopathological changes in the liver. Parathion decreased liver cell proliferation after 7 and 28 days while the other chemicals had no effects. There was no evidence for hepatotoxicity in any of the treatment groups. Full-genome microarray analysis of the livers from the 7 and 28 day treatments demonstrated that methidathion and fenthion regulated a large number of overlapping genes, while parathion regulated a unique set of genes. Examination of cytochrome P450 enzyme activities and use of predictive gene expression biomarkers found no consistent evidence for activation of AhR, CAR, PXR, or PPARα. Parathion suppressed the male-specific gene expression pattern through STAT5b, similar to genetic and dietary conditions that decrease liver tumor incidence in mice. Overall, these findings indicate that methidathion causes liver cancer by a mechanism that does not involve common mechanisms of liver cancer induction.

WOS: 000446380100003 PubMed: 30012025 Purpose: Today, the long-term effects of partial exposure of cholinesterase on the kidney continue to be a research topic. in this study, we aimed to histopathologically investigate the possible effect of acute toxicity due to fenthion, an organophosphate (OP) compound, on the kidneys. Methods: in all, 21 rats were randomly divided into three groups. Experimental group was each administered intraperitoneal 0.8 g/kg fenthion within physiologic serum. Sham group was only administered intraperitoneal physiologic serum. the control group continued normal nutrition with no procedure performed. After 24 h, all rats were sacrificed by cervical dislocation. Half of the recipient kidney tissues were examined histopathologically and the other half biochemically. Results: No histopathological findings were found in the control group. Rats in the experimental group were observed to have epithelial cell disorganization in tubules, moderate epithelial cell loss, and degeneration. Again, expansion of tubules, vacuolization of tubular epithelial cells, and tubular structure approaching atrophy were observed, with cells approaching apoptosis and common hemorrhage noted although rats in the sham group were observed to have mild tubular degeneration. Conclusions: It should not be forgotten that one of the causes of systemic complaints linked to acute toxicity exposed to the OP compound of fenthion may be cellular injury to glomerular and tubular structures in the kidneys.

This work aimed to evaluate the persistence (duration of harmful activity) of five insecticides used for pest control in peach orchards, on larvae and adults of the predator Chrysoperla externa. The insecticides were sprayed on cv. Bordô vine plants using the maximum dosage recommended for peach orchards. Weekly, at 3, 10, 17, 24 and 31 days after spraying, larvae and adults of the predator were exposed to treated leaves in order to assess the residual effect of insecticides on mortality and possible effects on reproduction. Given the toxicity observed along the weekly bioassays, the insecticides were classified into persistence categories established by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). High persistence was obtained for the organophosphorus insecticides (% of active ingredient) phosmet (0.100) and malathion (0.200), and both were considered persistent (> 30 days of harmful activity) to larvae and adults of C. externa. Similarly, the benzoylurea insecticide lufenuron (0.005), which acts exclusively on immature stages of insects, was persistent to larvae. Differences concerning the persistence for both development stages evaluated were observed for the pyrethroid insecticide deltamethrin (0.001), that was persistent to larvae but moderately persistent (16 – 30 days of harmful activity) to adults; and for the organophosphate fenthion (0.050) which was considered moderately persistent to larvae and short-lived (< 5 days of harmful activity) to adults of C. externa. RESUMO Este trabalho teve como objetivo avaliar a persistência (duração da atividade nociva) de cinco inseticidas utilizados no controle de pragas em pessegueiro, em larvas e adultos do predador Chrysoperla externa. Os inseticidas foram pulverizados em plantas de videira cv. Bordô utilizando-se a máxima dosagem recomendada para o pessegueiro. Semanalmente, aos 3, 10, 17, 24 e 31 dias após a pulverização, larvas e adultos do predador foram expostos a folhas pulverizadas para determinação do efeito residual dos inseticidas na mortalidade e possíveis efeitos na reprodução. Em função da toxicidade observada ao longo dos bioensaios semanais, os inseticidas foram classificados conforme a escala de persistência da International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). Alta persistência foi obtida para os inseticidas (% de ingrediente ativo) fosmete (0,100) e malationa (0,200), sendo ambos considerados persistentes (> 30 dias de ação nociva) para larvas e adultos de C. externa. De forma semelhante, o inseticida do grupo das benzoilureias, lufenurom (0,005), que age exclusivamente sobre estágios imaturos de insetos, foi persistente para larvas. Diferenças quanto a persistência para ambos os estágios avaliados foi observada para o inseticida piretroide deltametrina (0,001), que se mostrou persistente para larvas, porém mode-radamente persistente (16 – 30 dias de ação nociva) para adultos; e para o organofosforado fentiona (0,050), que foi considerado moderadamente persistente para larvas e de vida curta (< 5 dias de ação nociva) para adultos de C. externa.

The present study aims to investigate the susceptibility status of Aedes albopictus (Skuse) collected from residential areas in Sabah, Malaysia towards eight WHO-recommended dosages of larvicides representing the classes of organophosphates and organochlorines. Field and reference strains of Ae. albopictus larvae were bioassayed in accordance to WHO standard methods using diagnostic dosages of bromophos, malathion, fenthion, fenitrothion, temephos, chlorpyrifos, dichlorodiphenyltrichloroethane (DDT), and dieldrin. The results revealed that Ae. albopictus was resistant (mortality < 90%) towards malathion, temephos, and DDT. In addition, most of the Ae. albopictus strains exhibited a wide range of susceptibilities against bromophos, with mortality ranged from 49.33 to 93.33%. On the contrary, only dieldrin was able to induce 100% mortality against all strains of Ae. albopictus. Tolerance to fenitrothion, fenthion, and chlorpyrifos, with mortality ranging from 81.33 to 97.33%, was also observed in this study.

The endocrine-disrupting activities of various environmental chemicals are metabolically activated. For example, diphenyls, styrene oligomers, chalcones, trans-stilbene and 2-nitrofluorene are not estrogens, but after incubation with liver microsomes, their metabolites show estrogenic activities. Thus, these chemicals are estrogenically activated by the cytochrome P450 system. In contrast, the antiandrogenic activity of fenthion, an organophosphorus insecticide, is abolished after metabolism to sulfoxide and sulfone derivatives. Structural requirements of twenty bisphenol A related compounds, as well as various benzophenones, for estrogenic and antiandrogenic activities have been investigated. The estrogenic and antiandrogenic activities of Benzophenone 3, a representative UV absorbant, are activated by oxidative metabolism. Parabens (used as antimicrobial agents) exhibit estrogenic activity, and their potency shows a bell-shaped curve between C1 (methylparaben) and C12 (dodecylparaben) parabens. The AhR ligand activity of indirubin is decreased by metabolism. Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDE) are activated by hydroxylation to show estrogenic and thyroid hormone-disrupting activities. Halogen adjacent to a hydroxyl group is essential for thyroid hormone-disrupting activity. Tetrabromobisphenol A, tetrachlorobisphenol A and tetramethylbisphenol A also exhibit thyroid hormone-disrupting activity. Amphibian metamorphosis of tadpoles to frogs is affected by hydroxylated PCB, hydroxylated PBDE and bisphenol A derivatives. These chemicals suppress thyroid hormone-dependent metamorphosis, acting as antagonists of thyroid hormone. Thus, metabolic modification can have a dramatic impact on the endocrine-disrupting activities of environmental chemicals.

Foi avaliada a eficácia de produtos ectoparasiticidas contra larvas de Aedes aegypti. Os princípios ativos fluazuron 2,5 g, cipermetrina 150 g, flumetrina 1 g, propoxur 1 g, deltametrina 25 g, clorpirifós 30 g, cipermetrina 15 g, fenthion 15 g, diazinon técnico estabilizado 40 g, fipronil 2,5%, triclorfone 97 g, coumafós 3 g, propoxur 2 g, fentione 15 g e amitraz 12,5% foram adquiridos comercialmente e preparados conforme recomendações dos fabricantes. Os produtos foram distribuídos em recipientes individuais contendo larvas de A. aegypti em ambiente controlado. A inspeção da viabilidade larval foi verificada durante 24 horas. Os produtos foram aplicados nos locais de coleta das larvas (criadouros dos mosquitos), vistoriados diariamente por um mês. Foi observado que 100% das larvas morreram em até 60 minutos, tanto nos recipientes monitorados em laboratório como no meio ambiente. Nas áreas em que foi realizada a pulverização com os inseticidas supramencionados, não foi verificada a presença de larvas por um período de até 30 dias. Concluiu-se que produtos comumente utilizados em animais como ectoparasiticidas foram eficazes contra larvas de A. aegypti, podendo ser utilizados para o controle desse importante vetor, caso tal utilização seja analisada e regulamentada pelos órgãos oficiais do país.

The objective of this study was to evaluate the capability of the bacteria Bacillus safensis strain FO-36bT isolated from pesticide-polluted soil in degrading fenthion and temphos in mineral salt media (MSM). Fenthion and temphos were incubated with the isolated bacteria. Samples were drawn at 0, 3, 7, 14, and 30 days to analyze residual fenthion and temphos content with gas chromatography (GC) and high-performance liquid chromatography (HPLC), respectively. The loss of the initial pesticide concentration (400 mg/L) over time was determined and used to compute the half-lives using a biphasic model. Gas chromatography-mass spectrometry (GC-MS) was used to identify the major metabolites as well as to re-confirm the identity of starting material (fenthion). The results showed that the bacterium was still viable at the end of each incubation period. The biodegradation of fenthion and temphos followed a biphasic model. The half-lives of fenthion in the first and in the second phase were 0.29 and 3.69 days, respectively, whereas the corresponding values for temphos were 0.11 and 1.15 days. Only one metabolite "iso-fenthion" (O, S-dimethyl O-[3-methyl-4-(methylthio)phenyl] phosphorothioate) was detected in fenthion culture, while no metabolites were detected in temphos culture. Based on the half-lives, this bacterium was able to degrade temphos at a faster rate than fenthion. Key words: Biodegradation, fenthion, temphos, bacteria, pesticides-contaminated soil, Sudan.

This study aimed to describe the relationship between viral infection in Nilaparvata lugens (Stal), the brown planthopper (BPH), and different insecticide susceptibilities. BPH-resistant strains were selected using fenthion (an organophosphate) or etofenprox (a pyrethroid); a susceptible strain was used as the baseline colony before insecticide selection. All strains were infected with rice ragged stunt virus (RRSV) or rice grassy stunt virus (RGSV), after which the activities of three detoxification enzymes, cytochrome-P450-monooxygenase (P450), glutathione S-transferase (GST), and carboxylesterase (CE), were compared. Males of the strains selected for both insecticides showed high P450 and GST-CDNB activities. The activity of all enzymes was higher in males than in females, as a whole. However, males of the susceptible strain infected with RRSV showed decreased CE and GST-CDNB activities. BPH with low susceptibility to etofenprox showed a marked increase in P450 activity after RRSV infection; the GST-CDNB activity of females in the insecticide-resistant strain increased. RGSV infection induced high CE and P450 activities in etofenprox-selected females. The RRSV infection rate, but not the RGSV, decreased in etofenprox-selected strains.

Development of an acute oral toxicity test with a terrestrial-phase amphibian was considered necessary to remove the uncertainty within the field of agrochemical risk assessments. The bullfrog (Lithobates catesbeianus) was selected for use as it is a representative of the family Ranidae and historically this species has been used as an amphibian test model species. Prior to definitive study, oral gavage methods were developed with fenthion and tetraethyl pyrophosphate. Dimethoate and malathion were subsequently tested with both male and female juvenile bullfrogs in comprehensive acute oral median lethal dose (LD50) studies. Juvenile bullfrogs were administered a single dose of the test article via oral gavage of a single gelatin capsule of dimethoate technical (dimethoate) or neat liquid Fyfanon® Technical (synonym malathion), returned to their respective aquaria, and monitored for survival for 14 d. The primary endpoint was mortality, whereas behavioral responses, food consumption, body weight, and snout-vent length (SVL) were used to evaluate indications of sublethal toxicity (secondary endpoints). Acute oral LD50 values (95% fiducial interval) for dimethoate were 1459 (1176-1810, males) and 1528 (1275-1831, females), and for malathion they were 1829 (1480-2259, males) and 1672 (1280-2183, females) mg active substance/kg body weight, respectively. Based on the results of these studies, the methodology for the acute oral gavage administration of test items to terrestrial-phase amphibians was demonstrated as being a practical method of providing data for risk assessments. Environ Toxicol Chem 2018;37:436-450. © 2017 SETAC.

The susceptibility values for field-collected (BG-BG) and laboratory (KS-BG) strains of German cockroaches (BS-BG), Blattella germanica (L.) to five synthetic pyrethroid and three organophosphate insecticides were assessed by topical application. Both KS-BG and BS-BG strains demonstrated the highest levels of susceptibility to deltamethrin with LD50 values of 0.0035 μg/female and 1.5744 μg/female, respectively. The KS-BG strain demonstrated the lowest susceptibility level to fenthion with an LD50 value of 0.0698 μg/female, while the BS-BG field population showed the lowest susceptibility to bifenthrin with 4.6811 μg/female. The BS-BG field population showed resistance levels of 50 to 640 fold higher against the eight pesticides evaluated compared to the KS-BG strain. The resistance ratios (RR) of the eight pesticides were compared using populations of B. germanica that were collected from the same locality during 2007 and 2014. The field population of B. germanica collected during 2014 demonstrated significantly high resistance to an organophosphates and all pyrethroids when compared with those collected during 2007, but RR values were

Fenthion (organophosphate) was used in Australia to target adults, eggs and larvae of Mediterranean fruit fly (Medfly), Ceratitis capitata Wiedmann (Diptera: Tephritidae) in deciduous fruits. With its removal from use in 2015, clothianidin and thiacloprid (neonicotinoids) were evaluated for any adulticide, ovicide or larvicide (eggs, larvae) activity against Medfly in a series of laboratory and field-cage experiments in peach and nectarine. We included fenthion in all experiments as a positive control. As an adulticide, fenthion had the greatest residual toxicity on fruit, with 7 d old residues killing 44% of adults within 48 h compared to thiacloprid (17%) and clothianidin (30%). When applied as a larvicide to naturally infested peaches, none of the insecticides was 100% effective, though fewest pupae (1.18 ± 0.19 pupae/fruit) (indirect measurement of larval survival) were produced when treated with fenthion, followed by clothianidin (3.40 ± 0.33 pupae/fruit) and thiacloprid (6.88 ± 0.34 pupae/fruit); with 11.35 ± 0.30 pupae/fruit in control (water). In peaches treated 48 h post-infestation, fenthion was most effective in reducing numbers of pupae and adult emergence and with higher percentage of deformed adults, with thiacloprid=clothianidin. In nectarines treated 48 h post-infestation, fenthion was most effective in reducing numbers of pupae and adult emergence as well as with higher percentage of deformed adults, followed by clothianidin. Insecticides were least effective when applied as a preventative 24 h or 7 d prior to infestation, with fenthion more effective than clothianidin. Whilst our study shows that neither clothianidin nor thiacloprid are equivalent to fenthion, they are acceptable substitutes to growers for use for Medfly in deciduous fruits given that fenthion is no longer available to growers in Australia. We recommend that growers incorporate other controls to target the adult stage rather than rely only on new insecticides.

The present study aims at evaluating potential genotoxic and cytotoxic effects caused by the occupational exposure of farmers to pesticide mixtures in the Aitoloakarnania Prefecture (Greece). The aforementioned assessment was conducted through in vivo Cytokinesis Block Micronucleus assay (CBMN assay) in peripheral blood lymphocytes, in relation to chemical analysis of pesticide residues in blood samples. The exposure of the farmers' population studied to different combinations of pesticides induced significant differences in the frequencies of micronuclei (MN) compared to those of the control group. Furthermore, our results indicated a possible clastogenic and aneugenic effect of pesticides on the genetic material of the farmers exposed. Five pesticides (trifluralin, chlorpyriphos methyl, metolachlor, fenthion and dimethoate) and three metabolites (fenthion sulfone, fenthion sulfoxide and 4,4′ DDE) were detected in the 62.5% of blood samples, with mean concentrations ranging from 0.4 ng/ml to 48 ng/ml. Since the farmers studied probably exhibit detectable levels of systematic exposure to the pesticides applied, continuous educational programs focused on the rational and safe use of pesticides, together with implementation of risk communication strategies among farmers are highly recommended.

The red-billed quelea (Quelea quelea) is the most important avian pest of small grain crops in semi-arid zones of Africa. Fenthion, an organophosphate, is the main avicide used for controlling the pest but it is highly toxic to non-target organisms. The only readily available pesticide that could replace fenthion is cyanophos, but this chemical is also highly toxic to non-target organisms, although less so than fenthion, and may be more expensive; however, more research on its environmental impacts is needed. Apart from chemical avicides, the only rapid technique to reduce the numbers of quelea substantially is the use of explosives combined with fuel to create fire-bombs but these also have negative effects on the environment, can be dangerous and have associated security issues. The technique is labour intensive and in practice can only be deployed against small (

An in vivo uptake and elimination tracing study based on solid phase microextraction (SPME) was conducted to investigate the accumulation, persistence and distribution of organochloride pesticides (OCPs) and organophosphorus pesticides (OPPs) in malabar spinach (Basella alba L.) plants. Uptake and elimination of the pesticides were traced in leaves, stems and roots of living malabar spinach plants. Root concentration factor (RCF), distribution concentration factor (DCF) and transpiration stream concentration factor (TSCF) were calculated based on the in vivo tracing data. The tracing data showed that the OCPs were much more accumulative and persistent than the OPPs in roots, while they were similarly accumulative and persistent in leaves and stems. RCF values of the OPPs or OCPs were likely to increase with the increase in LogKow values except fenthion. Obtained DCF values indicated that OPPs and OCPs were more accumulative in the organs containing more lipids. TSCF values showed that the translocation of OPPs and OCPs from roots to foliage was firstly dependent on the hydrophobicity of the compounds, but also significantly affected by the water solubility. This is the first study of generating RCF, DCF and TSCF data in living plants by in vivo sampling method, which provides a foundation to promote the application of in vivo SPME and improve understanding of contaminant behaviors in living plants.

In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography-mass spectrometry (GC-MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC-MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production.

Attract-and-kill is a possible alternative to the conventional control of Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann (Diptera: Tephritidae) with bait or cover sprays of organophosphate insecticides. In this study, we determined if an attract-and-kill device (MagMED ® ) could be applied alone at the recommended rate (80 devices/ha), or needed to be combined with other conventional control tactics to suppress medfly in deciduous fruit orchards (apple, nectarine, peach, pear, plum). We also determined if attract-and-kill had any detrimental effects on naturally occurring beneficial insects. Based on an acceptable level of crop loss of 2–5% (the level of crop loss growers can tolerate), attract-and-kill suppressed medfly and reduced crop loss below the acceptable level in orchards with additional controls. Attract-and-kill was most effective when combined with either bait spraying, cover spraying or both. Combining attract-and-kill with cover sprays of fenthion resulted in a drop in crop loss of apples from 2.5% to 0.5%. By combining attract-and-kill with weekly bait sprays and two cover spray applications, crop loss fell from 13.7% to 4.3% in peaches, from 6.3% to 5% in nectarines and from 6.3% to 3.7% in pears. Twice weekly bait spraying was the most effective technique at suppressing medfly, providing acceptable control when applied alone, which further improved by combining with attract-and-kill. By combining attract-and-kill with twice weekly bait spraying crop loss fell from 2% to 1% in nectarines and from 4% to 2% in apples. In laboratory trials, attract-and-kill devices killed 100% of brown lacewings ( Micromus tasmaniae Walker) and 94% of transverse ladybeetles ( Coccinella transversalis Fabricius) 24 h after contact. However, orchard samples suggest that it may not pose any significant negative impact on naturally occurring beneficials such as Neuroptera, Hymenoptera, Coleoptera, Thysanoptera and Syrphidae in the field.

Queensland fruit flies Bactrocera tryoni and B. neohumeralis are considered major quarantine pests of tomato, a major crop in the horticultural production district around Bowen, North Queensland, Australia. Preharvest and/or postharvest treatments are required to meet the market access requirements of both domestic and international trading partners. The suspension from use of dimethoate and fenthion, the two insecticides used for fruit fly control, has resulted in the loss of both pre and postharvest uses in fresh tomato. Research undertaken quantitatively at Bowen evaluated the effectiveness of pre-harvest production systems without specific fruit fly controls and postharvest mitigation measures in reducing the risk of fruit fly infestation in tomato. A district-wide trapping using cue-lure baited traps was undertaken to determine fruit fly seasonal patterns in relation to the cropping seasons. A total of 17,626 field-harvested and 11,755 pack-house tomatoes were sampled from ten farms over three cropping seasons (2006-2009). The fruit were incubated and examined for fruit fly infestation. No fruit fly infested fruit were recorded over the three seasons in either the field or the pack-house samples. Statistical analyses showed that upper infestation levels were extremely low (between 0.025 and 0.062%) at the 95% confidence level. The trap catches showed a seasonal pattern in fruit fly activity, with low numbers during the autumn and winter months, rising slightly in spring and peaking in summer. This seasonal pattern was similar over the four seasons. The main two species of fruit fly caught were B. tryoni and B. neohumeralis. Based on the results, it is clear that the risk of fruit fly infestation is extremely low under the current production systems in the Bowen region.

Management of cucumber fly (Bactrocera cucumis) has relied heavily on cover sprays of broad spectrum insecticides such as dimethoate and fenthion. Long term access to these insecticides is uncertain, and their use can disrupt integrated pest management programs for other pests such as whitefly, aphids and mites. Application of a protein bait spray for fruit fly control is common practice in tree crops. However, vegetable crops present different challenges as fruit flies are thought to enter these crops only to oviposit, spending the majority of their time in roosting sites outside of the cropping area. Perimeter baiting of non-crop vegetation was developed overseas as a technique for control of melon fly (B. cucurbitae) in cucurbits in Hawaii. More recent work has refined the technique further, with certain types of perimeter vegetation proving more attractive to melon fly than the sorghum or corn crops which are commonly utilised. Trials were performed to investigate the potential of developing a similar system for cucumber fly. Commercially available fruit fly baits were compared for attractiveness to cucumber fly. Eight plant species were evaluated for their relative attractiveness to cucumber flies as roosting sites. Differences were observed in the number of flies feeding at protein bait applied to each of the plants. Results are discussed in the context of the development of a perimeter baiting system for cucumber fly in cucurbit crops.

Queensland fruit fly (Bactrocera tryoni) is a significant quarantine pest of stonefruit. To access domestic markets within Australia stonefruit require treatment to ensure they are free of fruit flies. Due to the recent restriction of the organophosphate pesticides, fenthion and dimethoate, the stonefruit industry now faces a significant challenge to control fruit flies. In this field trial we quantified the level of control achieved by a 'best case' systems approach that relied on currently available and registered control measures. This system included protein bait sprays, Male Annihilation Technique, insecticide cover sprays of trichlorfon, maldison and spinetoram and inspection and culling of damaged fruit. We found that in two out of the three trial orchards, packed fruit samples from Gatton (QLD) and Bangalow (NSW) had low levels of fruit fly infestation; 1.47 and 2.97% respectively. However, at the third property located at Alstonville (NSW) a high level of infestation (51.63%) was found in packed nectarines, which was likely attributed to the late implementation of the systems approach. This trial has demonstrated the potential for fruit fly control without relying on fenthion, however further modification of the system is needed to refine and increase efficacy.

In Japan, Hirschmanniella diversa is an important pest in lotus cultivation in paddy fields and only lime nitrogen is registered for its control. Therefore, additional nematicides are required to control the nematode. The objective of this study was to screen for an effective nematicide. Fourth-stage juveniles and adults of H. diversa sampled from a lotus field were tested in in vitro solution experiments against 37 pesticides that are registered for the pest control of crops in Japan. Carbamate-based benfuracarb, organophosphate-based fenthion, nereistoxin-based cartap hydrochloride and cyanamide showed nematicidal effects against H. diversa. Benfuracarb at 1 &mu, g/mL showed a nematostatic effect on H. diversa in an agar plate assay. Further, H. diversa treated with benfuracarb did not resume activity 7 days post nematicide treatment when transferred to distilled water. Benfuracarb was tested in micro-field experiments, in which H. diversa density and lotus tuber damage levels were monitored. Results showed that benfuracarb reduced H. diversa densities in the roots during the cultivation period in 2012 and consistently reduced damage levels during a five year study period. Thus, benfuracarb is recommended as an effective nematicide to be used for H. diversa control in lotus cultivation.

A 25-year study has been made of the development and loss of resistance to chemicals and, in particular, of the inheritance of resistance in the cattle tick, Boophilus microplus. Various biological effects of pesticidal and other chemicals on ticks have also been investigated. This research is described in 26 papers. Seven supporting publications are appended and a list of six other publications included. These 13 publications deal with other aspects of tick toxicology and with toxic or other oral secretions of ticks.The first 19 papers represent three phases of research into resistance in B. microplus. In the first phase, methodology was developed which permitted detection and quantification of resistance to the organochlorine compounds. Resistance to toxaphene (Beaudesert strain), dieldrin (Mt. Gravatt strain) and DDT (Rockhampton strain) was detected. No cross resistance to diazinon occurred in the Mt. Gravatt or Rockhampton strains or to dieldrin or toxaphene in the Rockhampton strain. A DDT-resistant strain from Glen Geddes subsequently developed resistance to dieldrin but no cross resistance to coumaphos. However, DDT-resistance could not be detected among 14 strains of B. microplus from quarantine areas of New South Wales at the conclusion of the unsuccessful 1956-7 eradication campaign in which DDT was employed. Parthenogenetic reproduction was demonstrated for the first time in B. microplus by a form of thelytoky which was associated with extended life cycle. A new, simple bioassay method for detecting resistance in ticks, the "packet" method, was developed and later proved to be much more sensitive and convenient than previous methods. It permitted more reliable documentation of resistance and made possible subsequent genetic studies. The method was subsequently adopted by FAO as its standard method for international surveillance of resistance in ticks.In the second phase, the genetics of resistance to the organochlorine compounds, DDT and dieldrin, was investigated. DDT resistance was due to a single, incompletely recessive autosomal gene; resistance was associated with delayed moulting of nymphs and delayed detachment of engorged females. Dieldrin resistance was due to a single dominant autosomal gene. In dieldrin-free and DDT-free laboratory cultures, the proportion of dieldrin-resistant ticks in one strain declined to an undetectable level after 24 generations while the proportion of DDT-resistant ticks in another strain declined to 55% homozygotes after 13 generations. However, in the DDT-resistant strain, an equilibrium was established, there being no further change for at least another 10 generations, a possible example of "balanced polymorphism".In the third and most important phase of the study, the inheritance of resistance to the organophosphorus compounds was investigated in some depth. As an aid to this, the assessment of dominance of resistance was placed on a more rational quantitative basis by the development of a formula for the calculation of degree of dominance. Resistance to formothion in the Ridgelands (R) strain, to diazinon and fenthion in the Biarra (B) strain and to dimethoate in the Mackay (M) strain was shown to be due to a single, semidominant autosomal gene in each strain. Dimethoate resistance occurred in the three strains and was almost certainly controlled by a series of closely-linked genes or alleles. Resistance in each strain was shown to be associated with decreased levels of acetylcholinesterase (AChE) activity in the synganglion and both inherited characters were almost certainly pleiotropic effects of the same series of multiple alleles. The biochemical resistance mechanism, decreased AChE sensitivity to inhibitors, is controlled by a single, incompletely dominant autosomal gene. No overdominance of resistance could be demonstrated when strains R, B and M were crossed in all possible ways. The field importance of this finding is discussed. Resistance to chlorpyrifos in the Mt. Afford (A) strain and to diazinon in the Gracemere (G) strain is incompletely dominant and is controlled by two unlinked genes. One of these is almost certainly responsible for the B strain type resistance mechanism of decreased AChE sensitivity and the other for increased detoxication. The genes are complementary in strain A and probably so in strain G.A fourth area of research was related to more general aspects of pesticidal effects on arthropods. It -was shown that (a) fenthion resistance in larvae of the tropical house mosquito Culex pipiens fatigans was due to decreased absorption coupled with increased detoxification to water soluble metabolites; (b) using a simple laboratory method of evaluation, the N-monomethyl formamidines were the most effective of a group of 19 formamidine and related non-formamidine compounds in causing detachment of B. microplus adults from mice. Monoamine oxidase inhibitors also caused detachment possibly through action on monoaminergic neurones in B. microplus; (c) monoaminergic neurones were present in the synganglion of B. microplus; noradrenaline was identified by microspectrofluorometry as the principal monoamine in an isolated neurone. This was the first record of the presence of noradrenaline in an individual neurone of a invertebrate; (d) aggregation pheromones occur in two Australian ticks, the Australian paralysis tick Ixodes holocyclus and the echidna tick Aponomma concolor.

28 p.-4 fig.-3 tab., The ubiquity of pollutants, such as agrochemicals and heavy metals, constitute a serious risk to human health. To evaluate the induction of DNA damage and programmed cell death (PCD), root cells of Allium cepa and Vicia faba were treated with two organophosphate insecticides (OI), fenthion and malathion, and with two heavy metal (HM) salts, nickel nitrate and potassium dichromate. An alkaline variant of the comet assay was performed to identify DNA breaks; the results showed comets in a dose-dependent manner, while higher concentrations induced clouds following exposure to OIs and HMs. Similarly, treatments with higher concentrations of OIs and HMs were analyzed by immunocytochemistry, and several structural characteristics of PCD were observed, including chromatin condensation, cytoplasmic vacuolization, nuclear shrinkage, condensation of the protoplast away from the cell wall, and nuclei fragmentation with apoptotic-like corpse formation. Abiotic stress also caused other features associated with PCD, such as an increase of active caspase-3-like protein, changes in the location of cytochrome C (Cyt C) toward the cytoplasm, and decreases in extracellular signal-regulated protein kinase (ERK) expression. Genotoxicity results setting out an oxidative via of DNA damage and evidence the role of the high affinity of HM and OI by DNA molecule as underlying cause of genotoxic effect. The PCD features observed in root cells of A. cepa and V. faba suggest that PCD takes place through a process that involves ERK inactivation, culminating in Cyt C release and caspase-3-like activation. The sensitivity of both plant models to abiotic stress was clearly demonstrated, validating their role as good biosensors of DNA breakage and PCD induced by environmental stressors., The authors appreciate to Ministerio de Educación y Ciencia de España supports program by fellow shift to Josefina Cortés Eslava for search stay in sabbatical year (SAB 2003-0229) and to Programa de Intercambio Académico de la Universidad Nacional Autónoma de México-Consejo Superior de Investigaciones Científicas de España (UNAM-CSIC). We also thank to Claudio Amescua for his editing assistance and to Pietro Villalobos for the figures editing. Work partially supported by project AGL2017-82447-R, funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund.

FAPESP, Brazil [2008/50588-6, 2014/23858-3] CNPq, Brazil CAPES, Brazil In this work a direct, simple, fast and sensitive method to determine Fenthion was developed using a Boron-Doped Diamond Electrode and Square Wave Voltammetry. The method was applied into Passiflora alata herbal medicinal tinctures derivate from passion fruits. None previous treatment such as derivation or pre-concentration of the analyte was done. Cyclic Voltammetry results showed well defined irreversible oxidation peaks at around 1.27 V into the pH range of 2.0 to 8.0. Square Wave Voltammetry was used to analytical determination and the analysis parameters, such as frequency, amplitude and pH from support electrolyte were optimized. A calibration curve was obtained, and it was observed a sensitivity of 0.38 A/mol L-1 and linearity of 0.995. The limits of detection and quantification were 8.0x10(-8) mol L-1 (21 mu g L-1) and 2.5x10(-7) mol L-1 (70 mu g L-1), respectively. Recovery studies were applied using Passiflora alata samples fortified with Fenthion in concentrations of 2.5 mu mol L-1 and 4.0 mu mol L-1, followed by the standard addition of the pesticide aliquots. It was observed that the complex matrix does not interferes in the method. The recovery results were about 98.4 and 112.0%, reinforcing that the method is suitable to determine the analyte in target complexes samples, such as Herbal Medicinal Plants. Univ Camilo Castelo Branco, Estr Dr Altino Bondesan 500, BR-1224716 Sao Jose Dos Campos, SP, Brazil UNIFESP, Inst Environm Chem & Pharmaceut Sci, Dept Chem, DQ, Rua Prof Artur Riedel 275, BR-09972270 Diadema, SP, Brazil UNIFESP, IMAR, Inst Marine Sci, Rua Carvalho de Mendonca 144, BR-11070100 Santos, SP, Brazil UNISEPE, Fac Sao Lourenco, BR-90374700 Sao Lourenco, MG, Brazil UNIFESP, Inst Environm Chem & Pharmaceut Sci, Dept Chem, DQ, Rua Prof Artur Riedel 275, BR-09972270 Diadema, SP, Brazil UNIFESP, IMAR, Inst Marine Sci, Rua Carvalho de Mendonca 144, BR-11070100 Santos, SP, Brazil FAPESP: 2008/50588-6, 2014/23858-3 Web of Science

Dengue and chikungunya are important arboviral infections in the Andaman Islands. Competent vectors viz. Aedes aegypti and Aedes albopictus are widely prevalent. The most effective proven method for interrupting the transmission of these arboviruses is vector control, mediated through insecticides. Currently, DDT and temephos are the insecticides used for vector control in these islands. Lack of information on susceptibility necessitated assessing the susceptibility profile of A. aegypti and A. albopictus. F1 generation of adult and larvae were assayed, and LT50 and LT90 values were interpreted following the World Health Organization (WHO) protocol. Adults were found resistant to DDT-4 % while susceptible to dieldrin-0.4 %. Against organophosphates, both showed resistance to fenitrothion but susceptible to malathion-5 %. Both species showed resistance to carbamate and bendiocarb-0.1 % while susceptible to propoxur-0.1 %. Of the four synthetic pyrethroids, both were susceptible to deltamethrin-0.05 %, while resistant to permethrin-0.75 %, lambdacyhalothrin-0.05 % and cyfluthrin-0.15 %. Larvae of both species showed resistance to temephos at 0.02 mg/L but susceptible to malathion at 1 mg/L and fenthion at 0.05 mg/L. Currently, there is no prescribed WHO dose for adult-insecticide susceptibility testing. The emergence of resistance to DDT and temephos in the vector population poses a challenge to the on-going vector control measures. The results highlight the need for monitoring resistance to insecticides in the vector population. Impetus for source reduction and alternative choices of control measures are discussed for tackling future threat of arboviral infections in these islands.

Fenthion is an organophosphate pesticide commonly used in agriculture and public health for the control of insect pests. The present study investigated the toxic effect of fenthion and the histopathological alterations in the gill tissue of African catfish Clarias gariepinus. The 96 h LC 50 value of fenthion in C. gariepinus determined by probit analysis was found to be 39.97 mg/L. Fish exposed to different fenthion concentrations showed clinical signs such as erratic swimming, attempt to jump out of water, increased opercula frequencies, air gasping, mucus secretion followed by exhaustion and death. To evaluate the histopathological changes in the gill tissue, fish were exposed to 2.0, 4.0 and 8.0 mg/L corresponding to 1/20, 1/10 and 1/5 th , respectively of 96 h LC 50 of fenthion for 21 days and 7 days recovery. Gill disorder and fusion of the secondary lamellar were pronounced in all treatments. Alterations in gill structure exposed to the highest concentration were oedema, lifting of lamellar epithelia, destruction of gill architecture and lamellar fusion. From the findings, it can be deduced that fenthion-induced alterations are irreversible and therefore should be applied with caution in the environment so as to reduce its damage to aquatic organisms. Keywords: Clarias gariepinus , fenthion, lethal concentration, histopathology.

Made available in DSpace on 2015-10-22T06:19:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-15 This study aimed to compare three different methodologies (Adult Immersion Tests, field trials with naturally infected animals, and a Stall Test using artificially infested cattle) to evaluate the efficacy of two topical formulations that we administered as whole body sprays (15% Cypermethrin + 30% Chlorpyriphos + 15% Fenthion-Colosso (R) FC 30, Ouro Fino Agronegocios; and 60% Dichlorvos + 20% Chlorpyriphos-Ectofos (R), Vallee Saude Animal Ltd.), against a susceptible strain of Rhipicephalus (Boophilus) microplus. To achieve this objective, two natural infestation trials were conducted, as well as two artificial infestation trials (Stall Tests) and two Adult Immersion Tests (AIT). The AIT results showed that both spray formulations achieved 100% efficacy against R. (B.) micro plus fully engorged females. However, when observing results obtained by field trials (natural infestations) and Stall Tests, none of these topically applied compounds reached 100% efficacy or affected the reproductive capacity of the fully engorged female ticks. Additional studies must be conducted to compare these in vivo methodologies with different in vitro techniques, such as the Larval Packet Test. However, based on results obtained here, we can conclude that depending on the spray formulations used, the AIT can overestimate acaricidal efficacy and values of reproductive efficiency of such compounds against R (B.) micro plus. Specifically, when dealing with spray formulations in the Stall Tests, the period of residual action can increase because these animals are sheltered from contact with environmental factors that might interfere with the efficacy of the products tested. It may be necessary to take in vivo trial results into consideration (such as field trials with naturally infested animals or Stall Tests) to standardize a specific in vitro assay, such as the Adult Immersion Test. (C) 2014 Elsevier B.V. All rights reserved. Universidade Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, São Paulo, Brasil|Universidade Federal de Goiás, Regional de Jataí, Goiás, Brasil Universidade Camilo Castelo Branco (UNICASTELO), Descalvado, São Paulo, Brasil Universidade Estadual Paulista (UNESP) - Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, São Paulo, Brasil

This study evaluated the acaricidal efficiency of synthetic pyrethroids (SP) associated with organophosphates (OP) against Rhipicephalus (Boophilus) microplus populations in the state of Rio Grande do Sul, Southern Brazil. Ticks were collected in 54 cattle farms and tested using in vitro adult immersion test against four commercially available acaricide mixtures of SP and OP. Only one of four acaricides, comprising a mixture of cypermethrin, chlorpyrifos, and fenthion, had a mean efficiency higher than 95%, and was effective in 94.44% (51/54) of the cattle farms tested. The acaricide with a mixture of cypermethrin, chlorpyrifos, and citronelall had the lowest mean efficiency (62.11%), and was effective in 29.62% (16/54) of cattle farms tested. Furthermore, R. (B.) microplus in Southern Brazil exhibited differing degrees of resistance to SP and OP mixtures. The results suggest that the presence of fenthion contributes to the higher efficiency of the formulation with this active principle. This is possibly due to its recent commercial availability, as tick populations have been lower challenged with this product. Monitoring the resistance of ticks to carrapaticides is essential to maximize the efficiency of these products in the control of R. (B.) microplus. Resumo Este estudo avaliou a eficiência acaricida de piretroides sintéticos (SP) associados a organofosforados (OP) sobre populações de Rhipicephalus (Boophilus) microplus no estado do Rio Grande do Sul, Brasil. Carrapatos foram coletados em 54 fazendas de bovinos, testados in vitro pelo teste de imersão de teleóginas, contra quatro associações acaricidas comercialmente disponíveis de SP e OP. Apenas um dos quatro acaricidas, constituído por associação de cipermetrina, clorpirifós e fenthion, teve eficiência média superior a 95%, sendo eficaz em 94,44% (51/54) das fazendas testadas. O acaricida com associação de cipermetrina, clorpirifós e citronelal teve menor eficiência média (62,11%), sendo efetivo em 29,62% (16/54) das fazendas testadas. Além disso, o R. (B.) microplus no sul do Brasil, apresentou diferentes graus de resistência às associações de SP e OP. Os resultados sugerem que a presença do fenthion contribui para a maior eficiência da formulação com esse princípio ativo. Possivelmente, isso ocorre em função da sua recente introdução no mercado, já que as populações de carrapatos foram pouco desafiadas com este produto. Monitorar a resistência dos carrapatos aos carrapaticidas é fundamental para maximizar a eficiência desses produtos no controle de R. (B.) microplus.

Background:Dengue is rapidly becoming established in north-east India and spreading, on account of rapid urbanization and population movement, with reported morbidity and attributable death cases. This study aims to determine the seasonal abundance of Aedes (Stegomyia) albopictus and Aedes (Stegomyia) aegypti in Guwahati metropolis and suburban settlements; to characterize the breeding resources for these mosquitoes; and to ascertain the status of their susceptibility to adulticides and larvicides. Methods:Mosquito larval surveys were carried out in different localities in both Guwahati city and adjoining suburbs from January to December 2013, to determine the seasonal abundance of disease vectors and their breeding preferences. The insecticide susceptibility status of mosquito adults and larval populations of both Aedes aegypti and Aedes albopictus was ascertained, using World Health Organization standard diagnostic concentrations and test procedures. Results:The study revealed that both Aedes aegypti and Aedes albopictus are widely abundant in Guwahati city and suburbs, and breeding in a wide variety of resources. Aedes albopictus, however, was the predominant mosquito species in suburbs, breeding preferentially in flower vases, cut-bamboo stumps and leaf axils. Aedes aegypti was the most common in the city, breeding predominantly in discarded tyres, cement tanks and used battery boxes. Both Aedes aegypti and Aedes albopictus were resistant to dichlorodiphenyltrichloroethane (DDT; 4%), but susceptible to malathion (5%), and exhibited a varied response to pyrethroids. However, larval populations of both these mosquito species were susceptible to larvicides, including malathion (1.0 mg/L), temephos (0.02 mg/L) and fenthion (0.05 mg/L), at much lower dosages than diagnostic concentrations. Conclusion:Given the seasonal abundance and case incidence in city areas, it is highly probable that Aedes aegypti is the predominant mosquito vector transmitting dengue virus. The study results have direct relevance for the state dengue-control programme, for targeting interventions and averting outbreaks and spread of disease.

Background The yellow fever mosquito, Aedes aegypti, and the common house mosquito, Culex pipiens pallens, transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity of the three lignans (–)-asarinin, sesamin and (+)-xanthoxylol-γ,γ-dimethylallylether (XDA), and the alkaloid pellitorine from Zanthoxylum piperitum (Rutaceae) bark to third-instar larvae from insecticide-susceptible C. pipiens pallens and Ae. aegypti as well as wild C. pipiens pallens resistant to deltamethrin, cyfluthrin, fenthion, and temephos. Methods The toxicities of all isolates were compared with those of mosquito larvicide temephos. LC50 values for each species and their treatments were significantly different from one another when their 95% confidence intervals did not overlap. Results XDA was isolated from Z. piperitum as a new larvicidal principle. XDA (LC50, 0.27 and 0.24 mg/l) was 4, 53, and 144 times and 4, 100, and 117 times more toxic than pellitorine, sesamin, and asarinin toward larvae from susceptible C. pipiens pallens and Ae. aegypti, respectively. Overall, all the isolates were less toxic than temephos (LC50, 0.006 and 0.009 mg/l). These constituents did not differ in toxicity to larvae from the two Culex strains. The present finding indicates that the lignans and alkaloid and the insecticides do not share a common mode of larvicidal action or elicit cross-resistance. Conclusion Naturally occurring Z. piperitum bark-derived compounds, particularly XDA, merit further study as potential mosquito larval control agents or as lead compounds for the control of insecticide-resistant mosquito populations. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2154-0) contains supplementary material, which is available to authorized users.

The blood of fresh water, edible fish, Cyprinus carpio was exposed to sub lethal concentration of fenthion for 24, 48, 72 and 96 h to evaluate alterations in the levels of minerals i.e., sodium, potassium, chloride, calcium and magnesium . The increased mineral sodium and potassium play an important role in neuromuscular excitability, acid-base balance and increased osmotic pressure of the fish. The decreased calcium is of great importance in blood coagulation, muscle contraction and nerve transmission of the fish. The increased magnesium participates in principal metabolic activities, in formation of bones and teeth. Reduction in Chloride ion contents may be due to blockage of chloride ion from gut into serum due to Fenthion stress.

The frequent cases of dengue incidences are leading cause of illness and death in urban areas and Aedes albopictus (Skuse) is a primary vector for Dengue transmission in India. Synthesis of leaf mediated silver nanoparticles especially with Pongamia pinnata is a potential substitute for the existing organophosphorus insecticides like Tenophos, malathion and fenthion etc., for mosquito control programme. The nanoparticles were characterized by UV-visible absorption spectrum, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). Analysis of TEM showed that the synthesized silver nanoparticles are in spherical shape with average size of 20 nm. Further the XRD analysis confirms the nano-crystalline phase of silver with face centred cubic (FCC) crystal structure. GC-MS analysis elucidated the presence of two active ingredients, such as 9-Octadecenoic acid (Z) and n-hexadecanoic acid, which are the prominent substances considered as larvicide. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 hours. From the results, it is found that plant extracts showed moderate larvicidal effects but, the synthesized silver nanoparticles had found to be toxic to larvae at LC50 (0.25 ppm) and LC90 (1 ppm).

The selectivity of five insecticides, regularly used in peach farming, was assessed for larvae of the predator Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) by means of bioassay in semi-field conditions. The bioassay was based on the counting of captured larvae after release in peach trees treated with the insecticides (% of active ingredient in spray liquid): deltamethrin (0.001), fenthion (0.050), phosmet (0.100), lufenuron (0.005) and malathion (0.200). Bait-cards with eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) were used to capture larvae from treated plants; five of them were fixed in plant canopy and five others left on the soil around stem. A protective barrier made up of galvanized steel sheet was used for each plant to avoid loss of larvae. The number of larvae feeding on the bait-cards was measured for four days. According to the number of captured larvae, each insecticide effect was estimated and classified into toxicity categories as stated by the International Organization for Biological and Integratec Control of Noxious Animals and Plants (IOBC). Based on observations, the insect growth regulator lufenuron was harmless, while the neurotoxins deltamethrin and malathion were slightly harmful; and lastly, fenthion and phosmet were moderately harmful to C. externa larvae in semi-field conditions. Thus, lufenuron should be recommended for integrated pest management, since it would preserve this predator species in peach orchards. A seletividade de cinco inseticidas utilizados em pomares de pessegueiro foi avaliada sobre larvas do predador Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) por meio de bioensaio conduzido em semicampo. O bioensaio baseou-se na contagem do número de larvas capturadas após liberação em plantas de pessegueiro tratadas com os inseticidas (% de ingrediente ativo na calda) deltametrina (0,001), fentiona (0,050), fosmete (0,100), lufenurom (0,005) e malationa (0,200). Para captura das larvas nas plantas tratadas foram utilizados dez cartões-isca contendo ovos de Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae), sendo cinco fixados na copa e cinco fixados no solo ao redor do caule. Uma barreira de proteção composta por chapa de aço galvanizado foi utilizada em cada planta para evitar a perda de larvas. O número de larvas alimentando-se nos cartões foi mensurado durante quatro dias. Em função do número de larvas capturadas, o efeito de cada inseticida foi calculado e classificado nas categorias de toxicidade segundo a “International Organization for Biological and Integrated Control of Noxious Animals and Plants” (IOBC). Baseado no efeito observado, o regulador de crescimento lufenurom foi inofensivo, enquanto os neurotóxicos deltametrina e malationa foram pouco tóxicos, e fentiona e fosmete foram moderadamente tóxicos a larvas de C. externa em condições de semicampo. Desta forma, lufenurom deve ser recomendado no manejo integrado de pragas a fim de se preservar esta espécie de predador em pomares de pessegueiro.

WOS: 000486357600008 PubMed: 31152871 Background: The most commonly used insecticides and pesticides worldwide are organophosphate compounds, chemicals that irreversibly inhibit the cholinesterase enzyme. Acute intoxication with cholinesterase inhibitors is known to cause permanent effects on both the human and rat brains. Aim: To investigate the effect of acute organophosphate intoxication on hippocampus morphology, biochemistry, and pyramidal neuron numbers in female rats. Methods: Twenty-one rats were randomly divided into three groups. The control group received normal nutrition and underwent no procedures. The sham group received intraperitoneal physiological serum, while the experimental group received intraperitoneal 0.8 g/kg fenthion. Rats were sacrificed 24 h after these procedures. The brains were removed and divided in two halves medially, with one side being kept in 10% neutral formalin. After fixation procedures, tissues were embedded in blocks, sliced, and stained. A neuron count was then performed for the hippocampus. The other hippocampus was homogenized and used for biochemical procedures. Results: Hippocampus sections from rats in the experimental group exhibited swelling and loss of shape in pyramidal cells, while no changes were observed in the control or sham groups. The number of neurons in the experimental group was lower than in the control and sham groups. Biochemical analysis revealed higher MDA and GSH values in the experimental group compared to the control and sham groups. Conclusion: Our results show increased apoptotic neurodegeneration of cells in the cornu ammonis region of the hippocampus and changes in biochemical values in rats with acute organophosphate exposure. Ordu University Scientific Research Coordination Office [AP 1703] This study was supported by the Ordu University Scientific Research Coordination Office under project number AP 1703.

For several decades, control of fruit fly pests in Australia has depended to a large degree on dimethoate, a broad-spectrum organophosphate insecticide that has been widely used on many different crops as well as on ornamental plants. However, many dimethoate use patterns were withdrawn in 2011 following a review by regulatory authorities. This manuscript places dimethoate in context as the latest in a long line of pre-harvest pesticides such as the arsenics, tartar emetic, sodium fluosilicate, nicotine sulphate, the organochlorines, and organophosphates, that have been lost from the fruit fly control toolkit over the past century. The succession of postharvest treatments such as fumigants, dips and sprays is also examined. Dimethoate and fenthion have offered relatively easy and cost effective pest control solutions since the 1960s, but in the absence of equivalent alternatives it is now necessary to develop “systems approaches” based on multiple control strategies and risk assessment. Such approaches represent a fundamental shift in pest management strategy, and will require improved understanding of fruit fly biology to prevent infestation in the field, combined with postharvest surveillance and non-chemical treatments. Some options are briefly discussed.

The relative toxicity of different concentrations of temephos and fenthion with petroleum ether root extract of Solanum xanthocarpum (Schrader) at 1 : 1, 1 : 2 and 1 : 4 ratios was evaluated against Anopheles stephensi (Liston) larvae. All combinations exhibited antagonism at concentrations lower than LC50 values and synergism at concentrations higher than their LC90 values. A 1 : 1 product ratio was the most effective.

The toxicity of Pinus densiflora (red pine) hydrodistillate, its 19 constituents and 28 structurally related compounds against early third-instar larvae of Aedes albopictus (Ae. albopictus), Aedes aegypti (Ae. aegypti) and Culex pipiens palles (Cx. p. pallens) was examined using direct-contact bioassays. The efficacy of active compounds was further evaluated in semi-field bioassays using field-collected larval Cx. p. pallens. Results were compared with those of two synthetic larvicides, temephos and fenthion. In laboratory bioassays, Pinus densiflora hydrodistillate was found to have 24 h LC50 values of 20.33, 21.01 and 22.36 mg/L against larval Ae. albopictus, Ae. aegypti and Cx. p. pallens respectively. Among the identified compounds, thymol, δ-3-carene and (+)-limonene exhibited the highest toxicity against all three mosquito species. These active compounds were found to be nearly equally effective in field trials as well. In vitro bioassays were conducted to examine the acetylcholinesterase (AChE) inhibitory activity of 10 selected compounds. Results showed that there is a noticeable correlation between larvicidal activity and AChE inhibitory activity. In light of global efforts to find alternatives for currently used insecticides against disease vector mosquitoes, Pinus densiflora hydrodistillate and its constituents merit further research as potential mosquito larvicides.

Objectives Over 20% of all malaria cases reported annually in the Republic of Korea (ROK) occur in Paju, Gyeonggi Province. Vector control for malaria management is essential, but the insecticide resistance of the vector, Anopheles mosquitoes, has been a major obstacle in implementing effective control. In this study, the insecticide resistance of the vector mosquitoes was evaluated and compared with that of vector mosquitoes collected from the same locality in 2001 and 2009. Methods The insecticide resistance of Anopheles sinensis s.s. collected from Paju, Gyeonggi Province in the ROK was evaluated under laboratory conditions with a micro-application method using 13 insecticides currently used by local public health centers and pest control operators in the ROK. Results Based on median lethal dose (LC 50 ) values, An . sinensis s.s. were most susceptible to the insecticides bifenthrin, cyfluthrin, and etofenprox in that order, and least susceptible to permethrin. An. sinensis showed higher susceptibility to pyrethroids than organophosphates, except for fenthion and permethrin. In a comparative resistance test, the resistance ratios (RRs) of An. sinensis collected in 2012 (AS12) to the 13 insecticides were compared to the RRs of two strains of An . sinensis collected from the same locality in 2001 (AS01) and 2008 (AS08). With some exceptions, AS12 demonstrated higher resistance to all tested insecticides compared to AS01 and AS08, and less resistance to bifenthrin, cyfluthrin, and cypermethrin compared to AS01. Conclusion These results indicate that careful selection and rotation of these insecticides may result in continued satisfactory control of field populations of An . sinensis s.s. for effective malaria management in Paju.

In this study, African Catfish (also known as Sharptooth Catfish) Clarias gariepinus were exposed to sublethal concentrations of fenthion of 2.0, 4.0, and 8.0 mg/L for 21 d and allowed to recover for 7 d to investigate the potential for hematological changes. Whole blood was sampled on days 1, 7, 14, and 21 postexposure and after a 7-d recovery period. During exposure, fenthion caused a reduction in red blood cell counts, hemoglobin concentration, and packed cell volume. There was an increase in white blood cell counts but no significant difference in mean corpuscular hemoglobin concentration, mean corpuscular volume, and mean corpuscular hemoglobin. Both increases and decreases were observed in white blood cell differentials. After the 7-d recovery period, both increases and decreases were observed in the hematological parameters. These results reveal that sublethal concentrations of fenthion can cause hematological alterations in African Catfish and that the substance should be used with caution. Received October 20, 2015; accepted May 4, 2016.

Fenthion is one of the most widely used organophosphate insecticides for the control of many varieties of pests in Nigeria. The genotoxic effect of the pesticide was evaluated in the blood erythrocytes of Clarias gariepinus using the micronucleus (MN) test. The oxidative stress parameters were also studied in the liver and gill tissues. Fish were exposed to 2.0, 4.0, and 8.0 mgL-1 of fenthion and sampling was done on days 1, 7, 14, 21 and after 7-day recovery. Micronuclei induction was highest (7.55) on day 14 at all concentrations in the peripheral blood cells. Oxidative stress was evidenced by increased lipid peroxidation (LPO). Maximum LPO values of 62.47% and 71.17% were observed in the gill and liver tissues respectively in C. gariepinus exposed to 8.0 mgL-1 concentration of fenthion. There were alterations in the values of reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) during the exposure and recovery periods. The 7-day recovery period was not adequate to eliminate fenthion-induced changes as LPO, CAT, and GR activity remain elevated. However, MN frequency and activity of SOD, GSH, and GPx (except at 8.0 mgL-1) recovered. The present findings give further credence on the integrated use of MN test and oxidative stress parameters in risk assessment of pollutants in aquatic ecosystem.