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The impact of eight pesticides on the transmission of Tomato leaf curl virus (ToLCV) by the whitefly, Bemisia tabaci Gennadius to tomato, Lycopersicon esculentum (Miller), was studied in the field using a randomized block design. Differences in performance were anticipated because these eight insecticides comprise distinct mechanism of action including both contact and systemic. Increased insecticide efficacy is necessary, particularly in regions with conducive weather conditions that support a healthy whitefly population, to effectively manage the population. There is a need to vary the insecticides used in order to reduce the emergence of resistance in the whitefly population due to the extensive usage of a single mechanism of action for whitefly control. The foliar spray of insecticides was done when first incidence of whitefly was noticed in the field with 15 days of interval. The studies on effect of different insecticides in the management of ToLCV disease through the controlling whitefly population, we evaluated that Chlorantraniliprole 8.8% + Thiomethaxam 17.5% SC was effective in sustaining the yield by reducing the incidence of disease and whitefly population during both the years followed by Spirotetramat 11.01% + Imidacloprid 11.01% SC, Thiamethoxam 12.6% + Lambda cyhalothrin 9.5% ZC and Cyantraniliprole 10.26% OD, respectively. [ABSTRACT FROM AUTHOR]

Glutathione S‐transferases (GSTs) were reported to participate in insecticide resistance by metabolic and antioxidant activities. In our previous study, an ε class gene of GSTs, SlGSTe8 in Spodoptera litura, was screened out to be upregulated in a population resistant to pyrethroids and organophosphates. SlGSTe8 was highly expressed in the larvae stage, and the digestive tissue, foregut, midgut and hindgut, while the relative expression level was low in the pupae stage and other tissues. To further explore its role in the resistance to pyrethroids and organophosphates, the metabolic activity to insecticides by its recombinant protein was determined by Ultra Performance Liquid Chromatography, and its antioxidant enzyme activity was evaluated by disc diffusion assay. The recombinant protein showed significant metabolic activity to phoxim and chlorpyrifos, but not to fenvalerate, cyhalothrin or β‐cypermethrin. After incubation, the depletion rate of chlorpyrifos is 85.3%, higher than that of phoxim (17.5%). Also, the inhibition zone around filter discs decreased significantly after exposure to cumene hydroperoxide in recombinant plasmid than vector only, suggesting significant antioxidant activity of SlGSTE8. Further modelling and docking analysis indicated that the 3D structure of SlGSTE8 was well shaped for phoxim and chlorpyrifos, with the binding energy −5.58 and −5.15 kcal/mol, respectively. Our work provides evidence that SlGSTe8 in S. litura plays important roles in phoxim and chlorpyrifos resistance. [ABSTRACT FROM AUTHOR]

A combination of modified quick easy cheap effective rugged and safe extraction approach with carbon nano–onions–based dispersive solid‐phase extraction and dispersive liquid–liquid microextraction was developed for the extraction of several pesticides (diazinon, chlorpyrifos, tebuconazole, deltamethrin, permethrin, haloxyfop–methyl, penconazole, and cyhalothrin) from grape before their analysis by gas chromatography–flame ionization detection. In the extraction approach, an aliquot of grape sample is chopped and after separating its juice, the pesticides that remained in the refuse are extracted by the quick, easy, cheap, effective, rugged, and safe extraction method. The obtained acetonitrile phase is mixed with juice and the analytes are extracted by the carbon nano‐onions‐based dispersive solid‐phase extraction. The analytes are concentrated using the microextraction procedure to obtain high enrichment factors. The results showed low limits of detection (0.5–1.6 ng/g) and quantification (1.8–5.4 ng/g) with satisfactory linearity of the calibration curves (determination coefficient, r2 ≥ 0.994). The precision of the developed method expressed as relative standard deviations was good (≤7.2%). The method provided high enrichment factors (350–410) and extraction recoveries (70–82%). Finally, seven grape samples were analyzed successfully. [ABSTRACT FROM AUTHOR]

Forage sorghum (Sorghum bicolor L.) grown for silage production is frequently infested by the sugarcane aphid (SCA; Melanaphis sacchari [Zehntner] [Hemiptera: Aphididae]). The objective of this study was to establish first-time action thresholds for SCA infestation, leaf feeding, honeydew, and/or dead leaves. In this 2-yr Texas High Plains study, we quantified the impact of varying densities of SCA and subsequent damage beginning at boot stage to yields and silage nutritive value of a susceptible forage sorghum hybrid (Pioneer 841F) by using untreated controls and different insecticide treatments (lambda cyhalothrin, chlorpyrifos, malathion, and flupyradifurone). Aphid damage occurred from boot to flowering growth stages. Damaging infestations continued until harvest in 2017, but SCA densities declined sharply after peaking at the beginning milk growth stage (BMS) in 2019. Damage levels were significantly correlated to increases in aphid densities at BMS (R² = .91) in 2017 and at 50% bloom (R² = .83) and BMS (R² = .86) in 2019. Yield losses increased with increasing damage at the BMS in 2017 (R² = .82) and 2019 (R² = .42). Reductions in nutritive value were correlated to yield reductions. Results indicate that SCA infestations should be controlled when ≥20% of the leaf area is infested and damaged at BMS to prevent yield and nutritive value losses in the fresh and ensiled forage. Based on this work, an action threshold for forage sorghums to minimize losses to yield, nutritive value, and economic returns is presented. [ABSTRACT FROM AUTHOR]

This study determined the resistance to five different insecticides, and assessed the change in enzymes in three Myzus persicae populations in Liuyang, Guiyang, and Longshan tobacco (Nicotiana tabacum L.)-growing areas in Hunan province, China. The activities of the detoxification, protective, and digestive enzymes were determined using biochemical analysis. Results indicated that the Liuyang population had high resistance to Imidacloprid, and moderate resistance to Aacetamiprid and Cyhalothrin. The Longshan population showed low resistance to Phoxim, while the Liuyang and Guiyang populations both exhibited reduced susceptibility. All three populations exhibited reduced susceptibility to Methomyl. Field populations exhibited higher activity of detoxification enzymes [acetylcholinesterase (AchE), carboxylesterase (CarE), glutathione-S-transferase (GST), and mixed-function oxidase (MFO)], protective enzymes (superoxide dismutase [SOD], catalase [CAT], and peroxidase [POD]), and digestive enzymes (amylase [AMS]) than the susceptible population. The Liuyang population showed the highest detoxification, protective, and digestive enzyme activity of all aphid populations. The AchE activity and resistance level to acetamiprid was significantly, positively correlated. The CarE, CAT, and AMS activity and resistance to Imidacloprid were also significantly, positively correlated. The correlation between enzyme activity and resistance to methomyl was negative, except for AchE. When CarE, CAT, and AMS activity was up to 60, aphids exhibited low resistance to Imidacloprid, and when AchE activity was up to 90, aphids exhibited medium resistance to Imidacloprid. These results provide the theoretical basis for predicting regional resistance of M. persicae to Imidacloprid and Acetamiprid, which can be used to delay evolution of resistance of M. persicae to insecticides in the field. [ABSTRACT FROM AUTHOR]

The European Food Safety Authority (EFSA) was asked by the European Commission to provide scientific assistance with respect to the risk assessment for an active substance in light of confirmatory data requested following approval in accordance with Article 6(1) of Directive 91/414/EEC and Article 6(f) of Regulation (EC)No 1107/2009. In this context EFSA's scientific views on the specific points raised during the commenting phase conducted with Member States, the applicant and EFSA on the confirmatory data and their use in the risk assessment for lambda‐cyhalothrin are presented. The current report summarises the outcome of the consultation process organised by the rapporteur Member State Sweden and presents EFSA's scientific viewsand conclusions on the individual comments received. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pesticide is an important agricultural necessity to control plant diseases and pests, ensuring safe production of food. However, the low efficacy, large dosage and high‐frequency use of conventional pesticide formulation seriously induced food safety and ecological environment issues. In this research, lambda‐cyhalothrin solid nanodispersion (LCSND) was developed by a self‐dispersing method. RESULTS: The mean particle size of the lambda‐cyhalothrin solid nanodispersion was 32.7 ± 1.1 nm. It exhibited excellent dispersibility, wettability and stability, especially the improved bioavailability compared to the commercial formulations. Notably, the solid nanodisperison had a small particle size and large specific surface area. The solid nanodispersion without organic solvents can minimize the environment pollution and overcome the instability characteristic of the liquid formulations. CONCLUSION: Therefore, lambda‐cyhalothrin solid nanodispersion has broad application prospects in agricultural production and environmental protection. © 2018 Society of Chemical Industry The LCSND showed good performance in dispersion, wettability, stability and bioavailability. [ABSTRACT FROM AUTHOR]

Microcarriers containing pesticide have been designed to improve drug stability and increase release efficiency, which is favourable to the environment and agriculture development. In this work, biodegradable poly(butylene succinate) microspheres containing pesticide, λ-cyhalothrin, as an active agent are prepared by the solvent evaporation induced phase separation method. The microspheres show a uniform morphology and a narrow particle size distribution. The pesticide content is measured by high-performance liquid chromatography. The prepared microcarriers demonstrate high-loading capacity, encapsulation efficiency and long release time, which may find potential applications as new pesticide formulations. [ABSTRACT FROM AUTHOR]

BACKGROUND Although Leptoglossus zonatus is considered a secondary pest of maize grown for grain, when grown for seed, this pest can cause significant economic damage. There are no records of management recommendations for this pest. The objectives of this work were to quantify losses caused by L. zonatus to different genotypes used for seed maize production and to estimate the acute toxicity of selected insecticides to L. zonatus using different application technologies. The ultimate goal was to calculate economic injury levels (EILs) and develop economic thresholds (ETs) for L. zonatus infesting seed maize. RESULTS EILs and ETs varied, respectively, from 3 to 8 and from 2 to 6 adults per 1000 plants, depending on the genotype, insecticide and application technology. Effective control was obtained by using aerial or ground application of λ-cyhalothrin (10.6%) + thiametoxan (14.1%) or permethrin (38.4%) at the rates of 1.48 mL ha-1 and 27.10 mL ha-1, respectively, or ground application of methomyl (21.5%) at the rate of 244.06 mL ha-1. CONCLUSION Maize grown for seed is susceptible to L. zonatus damage during reproductive stages, and the pest densities requiring management vary with genotype, insecticide, and application technology. These results contribute significantly to integrated pest management (IPM) for seed maize. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND An increase in the spread of pyrethroid resistance in the pollen beetle has been documented in many European countries. Pyrethroid resistance in the pollen beetle in the Czech Republic has been detected using a topical application bioassay. Resistance monitoring has been carried out during the implementation of insect resistance management. RESULTS The susceptibilities of nine pollen beetle populations to four pyrethroids in 2009 − 2015 in the Czech Republic are presented in this paper. The highest resistance ratio (RR) values [based on the lethal dose for 50% of the population (LD50)] obtained for deltamethrin, lambda-cyhalothrin, tau-fluvalinate and etofenprox were 500, 299, 108 and 66.9, respectively. Pollen beetle mortality after application of deltamethrin or lambda-cyhalothrin gradually decreased from 2009 to 2013. High cross-resistance between lambda-cyhalothrin and deltamethrin and low cross-resistance between lambda-cyhalothrin and etofenprox were demonstrated. A kdr mutation known to cause resistance in the pollen beetle was not detected. CONCLUSION A high level of resistance was recorded in most of the nine populations of the pollen beetle in 2013. In the following 2 years, a decrease in resistance associated with a population density decrease of the pollen beetle was observed in all nine populations as a result of insect resistance management based on pyrethroid reduction in winter oilseed rape. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Euschistus heros (Fabricius, 1798) is one of the most harmful insect pests damaging Brazilian soybean crops and has become a major problem due to its high population density and resistance to insecticides. Currently, there are no data on whether alterations of testicular morphology and chromosomal behavior are associated with the resistance mechanisms related to the action of insecticides. This study integrated analyses of the testicular morphology, meiocyte cell division, and chromosomal structure and behavior in the process of spermatogenesis in E. heros. We compared these features among wild-caught individuals, insecticide-susceptible and -resistant strains. The resistant strain was established through a selection experiment exposing the bugs to insecticides (thiamethoxam + lambda-cyhalothrin) for 15 generations. No differences were detected in the examined features among the three groups of experimental individuals: the testis comprised six lobes, with the fifth lobe thinner than the others; the karyotype was 2n = 14 (12 +XY), with no evident changes in chromosomal breakage, rearrangement or behavior in the meiosis; and abundant spermatozoa were observed in all testicular lobes. Thus, any effects of the long-term (15 generations) experimental selection by exposure to the insecticides were not detected on the male germinal tissue and chromosomes, suggesting the irrelevancy of the examined features to insecticide-resistance mechanisms in E. heros. [ABSTRACT FROM AUTHOR]

A novel 2-tiered analytical approach was used to characterize and quantify interactions between type I and type II pyrethroids in Hyalella azteca using standardized water column toxicity tests. Bifenthrin, permethrin, cyfluthrin, and lambda-cyhalothrin were tested in all possible binary combinations across 6 experiments. All mixtures were analyzed for 4-d lethality, and 2 of the 6 mixtures (permethrin-bifenthrin and permethrin-cyfluthrin) were tested for subchronic 10-d lethality and sublethal effects on swimming motility and growth. Mixtures were initially analyzed for interactions using regression analyses, and subsequently compared with the additive models of concentration addition and independent action to further characterize mixture responses. Negative interactions (antagonistic) were significant in 2 of the 6 mixtures tested, including cyfluthrin-bifenthrin and cyfluthrin-permethrin, but only on the acute 4-d lethality endpoint. In both cases mixture responses fell between the additive models of concentration addition and independent action. All other mixtures were additive across 4-d lethality, and bifenthrin-permethrin and cyfluthrin-permethrin were also additive in terms of subchronic 10-d lethality and sublethal responses. Environ Toxicol Chem 2016;35:2542-2549. © 2016 SETAC [ABSTRACT FROM AUTHOR]

A novel supramolecular solvent-based microextraction followed by high-performance liquid chromatography with ultraviolet detection method has been developed for the extraction and determination of two pyrethroid analytes, cyhalothrin and fenvalerate, in water and soil samples. The liquid-liquid-phase separation of surfactants has been used in analytical extraction. The surfactant-rich phase is a nano-structured liquid, recently named as a supramolecular solvent, generated from the amphiphiles. The alkyl carboxylic acid based supramolecular solvents were introduced before. Coacervates made up of gemini surfactant, consisting of two amphiphilic moieties, were first used as solvent. The effective parameters on extraction (i.e., type of organic solvent, the amount of surfactant and volume of tetrahydrofuran, sample solution pH, salt addition, ultrasonic and centrifugation time) were investigated and optimized. Under the optimum conditions, preconcentration factors of 110 and 145 were obtained for the analytes. The linearity was 0.5-200.0 μg/L with the correlation of determination of ( R2) ≥ 0.9984. The limit of detection of the method was (S/N = 3) 0.2 μg/L, and precisions in the range of 6.3-10.3% (RSDs, n = 5) were obtained. This method has been successfully applied to analyze real samples, and good recoveries in the range of 101.2-108.8% were obtained. [ABSTRACT FROM AUTHOR]

BACKGROUND A 2 year study was conducted to evaluate the efficacy of biological control with optimally timed Trichogramma brassicae releases as an integrated pest management tool against the European corn borer ( ECB), Ostrinia nubilalis (Hübner), in on-farm experiments (i.e. real field conditions) in three European regions with dissimilar geoclimatic conditions and ECB pressure and conventional management (i.e. insecticide treated and untreated). RESULTS Biological control with Trichogramma (1) provided ECB protection comparable with conventional management, (2) in all cases maintained mycotoxin levels below the EU threshold for maize raw materials destined for food products, (3) was economically sustainable in southern France and northern Italy, but not in Slovenia where it resulted in a significant decrease in gross margin, mainly owing to the cost of Trichogramma product, and (4) enabled avoidance of detrimental environmental effects of lambda-cyhalothrin use in northern Italy. CONCLUSION Optimally timed mass release of T. brassicae could be considered a sustainable tool for IPM programmes against ECB in southern France and northern Italy. Better involvement of regional advisory services is needed for the successful dissemination and implementation of biological control. Subsidy schemes could also motivate farmers to adopt this IPM tool and compensate for high costs of Trichogramma product. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Pyrethroids are one of the most widespread and commonly used classes of insecticide and are used in multiple roles, including protecting potato crops from virus vector aphids. Resistance in some genotypes of a few species is now widespread, but most species remain susceptible. The rate of virus transmission by two genotypes of the peach potato aphid, Myzus persicae, fed on potato virus Y ( PVY)-infected leaves of potato treated with the pyrethroid λ-cyhalothrin was evaluated. RESULTS The susceptible genotype, type J, was significantly inhibited from transmitting virus to uninfected seedlings. A genotype containing the M918L super knockdown resistance mutation conferring resistance to pyrethroids, type O, showed no inhibition of transmission. However, when survival of the aphids after exposure was compared, the pyrethroid had not killed the type J aphids. CONCLUSIONS λ-Cyhalothrin in a commercial formulation disrupts PVY transmission by disorienting aphid vectors for a sufficient time for the virus to lose its transmissibility. However, M. persicae genotypes carrying the M918L mutation are not prevented from transmitting. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND The withdrawal of malathion in the European Union in 2009 resulted in a large increase in lambda-cyhalothrin applications for the control of the Mediterranean fruit fly, Ceratitis capitata, in Spanish citrus crops. RESULTS Spanish field populations of C. capitata have developed resistance to lambda-cyhalothrin (6-14-fold), achieving LC50 values (129-287 ppm) higher than the recommended concentration for field treatments (125 ppm). These results contrast with the high susceptibility to lambda-cyhalothrin found in three Tunisian field populations. We have studied the mechanism of resistance in the laboratory-selected resistant strain W- 1K λ (205-fold resistance). Bioassays with synergists showed that resistance was almost completely suppressed by the P450 inhibitor PBO. The study of the expression of 53 P450 genes belonging to the CYP4, CYP6, CYP9 and CYP12 families in C. capitata revealed that CYP6A51 was overexpressed (13-18-fold) in the resistant strain. The W- 1K λ strain also showed high levels of cross-resistance to etofenprox (240-fold) and deltamethrin (150-fold). CONCLUSION Field-evolved resistance to lambda-cyhalothrin has been found in C. capitata. Metabolic resistance mediated by P450 appears to be the main resistance mechanism in the resistant strain W- 1K λ. The levels of cross-resistance found may compromise the effectiveness of other pyrethroids for the control of this species. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: The objective was to assess the effect of two contact insecticides, lambda-cyhalothrin and flonicamid, and three systemic insecticides, pymetrozine, dimethoate and imidacloprid, on the behavior and potato virus Y (PVY) acquisition of three aphid species, Macrosiphum euphorbiae (Thomas), Rhopalosiphum padi L. and Aphis fabae (Scopoli). RESULTS: At 1-4 days after application, contact insecticides strongly modified aphid behavior and intoxicated them. Dimethoate sprayed on potato plants did not change the behavior of the three tested aphid species, while imidacloprid slightly reduced the probing behavior of M. euphorbiae and intoxicated several R. padi. The residual effect of the insecticides (10-21 days after application)was almost non-existent. No intoxication was found, and only slight changes in the behavior of R. padi and A. fabae were observed. The acquisition of PVY by R. padi was reduced on lambda-cyhalothrin- and dimethoate-treated plants that were sprayed a few days before the test. CONCLUSION: One systemic and two contact insecticides were effective at intoxicating aphids and reducing probing behavior soon after application. Some insecticides might sporadically reduce the spread of PVY either by modifying the behavior or reducing PVY acquisition, but their action is likely limited to a short period of time after application. [ABSTRACT FROM AUTHOR]

For the first time, combination of liquid-liquid extraction and dispersive liquid-liquid microextraction (LLE-DLLME) is reported in this study. The method is efficient and was applied to the analysis of pyrethroid pesticides (fenpropathrin, sumithrin, cyhalothrin, permethrin, and deltamethrin) in fruit juices and fresh grape using gas chromatographic techniques with flame ionization detection system and mass spectrometric detection system. Five milliliter n-hexane was used for the traditional liquid-liquid extraction of target analytes from 50 mL aqueous samples. After manual shaking, the supernatant phase ( n-hexane) was transferred into a test tube to which 0.75 mL dimethylformamide (DMF) was added then and the tube was shaken manually. After centrifugation, 0.6 mL of DMF was removed and used in a following DLLME procedure in which the extraction solvent was 20 μL of 1,1,2-trichloroethane. Extraction with the optimized conditions resulted in linear analytical signals within the range 0.5-1200 μg L−1 and the limits of detection and quantification were in the ranges of 0.1-15 and 0.4-50 μg L−1, respectively. The method also showed high enrichment factors (2570-6835) and relatively good extraction recoveries (26-68%). Finally, the method was successfully applied to determination of analytes in tap water, strawberry juice, apricot juice, and fresh grape. [ABSTRACT FROM AUTHOR]

The objective of this research was to investigate the neurotoxic effects of pyrethroid pesticide lambda-cyhalothrin by the modulation of cytochrome P450 with piperonyl butoxide in the brain of juvenile Oreochromis niloticus. The fish were exposed to 0.48 μg L−1 (1/6 of the 96-h LC50) lambda-cyhalothrin and 10 μg L−1 piperonyl butoxide for 96 h and 15 days. tGSH, GSSG, TBARS contents, GPx, GR, GST, and AChE enzymes activities were determined by spectrophotometrical methods and Hsp70 content was analyzed by ELISA technique. Lambda-cyhalothrin had no significant effect on the components of GSH redox system, lipid peroxidation and Hsp70 levels but inhibited AChE activity. In the presence of piperonyl butoxide, lambda-cyhalothrin caused increases in tGSH, GSSG, TBARS and Hsp70 contents, GST activity, and decrease in AChE activity. Present results showed that in the presence of piperonyl butoxide, lambda-cyhalothrin caused neurotoxic effects by increasing oxidative stress. Adaptation to its oxidative stress effects may be supplied by GSH-related antioxidant system. Piperonyl butoxide revealed neurotoxic effect of lambda-cyhalothrin. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1275-1282, 2014. [ABSTRACT FROM AUTHOR]

Lambda-cyhalothrin (LCT) is a widely used broad-spectrum pyrethroid insecticide. Oral LCT administration to adult male mice at 3 doses (0.2, 0.4, and 0.8 mg/kg/day) for 6 weeks caused a significant reduction in the weight of the seminal vesicles. The epididymal sperm count was lower in mice that received at the highest dose than in control mice. However, the proportions of live and motile spermatozoa were reduced at both the medium and the high doses compared with control mice. All doses induced an increase in the number of morphologically abnormal spermatozoa. Histopathological observations of the testes, liver, kidneys, and spleen showed dose-related degenerative damage in LCT-treated mice. The results indicate that LCT has reproductive toxicity, hepatotoxicity, nephrotoxicity, and splenotoxicity in male mice at the tested doses. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 750-762, 2014. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the possible protective effects of Quercetin (Qe) against oxidative stress induced by λ cyhalothrin (LTC) in reproductive system. Thirty-two male rats were divided into four groups. First group was allocated as the control group. Second group was given a Qe alone while the third group received a LTC alone. Animals in the fourth group were given a Qe with LTC. Caudae epididymis was removed for sperm analysis. Lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and reduced glutathione (GSH) were determined in the testis. Additionally, the different histopathologic changes were observed in the testis of animals. LTC exposure significantly increased the abnormal morphology and LPO. On the contrary, sperm motility, viability and count, levels of GSH, and activities of SOD, CAT, GPx, and GST were significantly decreased compared to controls. Qe with LTC offset the decrease in functional sperm parameters, antioxidants enzymatic activities, and nonenzymatic antioxidant levels when compared with LTC-treated rats. Furthermore, LTC showed irregular seminiferous tubules containing only Sertoli cells and Qe with LTC caused regular seminiferous tubules showing spermatogenesis at level of spermatocytes. We conclude that LTC-induced oxidative stress and functional sperm parameters in male rats, and dietary of Qe attenuates the reproductive toxicity of LTC to restore the antioxidant system and sperm parameters in male rats. © 2011 Wiley Periodicals, Inc. Environ Toxicol 28: 673-680, 2013. [ABSTRACT FROM AUTHOR]

Poly(2-hydroxyethyl methacrylate)- co-polylactide (PHEMA- co-PLA) and its corresponding cyhalothrin-loaded ultrafine particles were successfully synthesized and prepared, respectively. The chemical structures of the copolymers have been confirmed by Fourier transform infrared spectroscopy (FTIR), 1H-nuclear magnetic resonance (1H-NMR), 13C-nuclear magnetic resonance (13C-NMR), and thermogravimetric analysis (TGA). Furthermore, the particle size, the cyhalothrin loading content (LC), and the cyhalothrin release behavior were investigated. PHEMA- co-PLA proved to be a good material for the preparation of ultrafine particles for lipophilic pesticide delivery. The developed cyhalothrin-loaded PHEMA- co-PLA ultrafine particles showed good dispersity in water and sustained release behavior. In addition, it is easy to be prepared by both nanoprecipitation method and emulsion/solvent evaporation method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

The European Union's directive for sustainable use of pesticides requires implementing risk mitigation measures at streams threatened by pesticide entries. The need for mitigation measures was investigated at 10 stream sites within an intensively used arable region in central Germany by characterizing pesticide exposure following edge-of-field runoff and effects on the aquatic macroinvertebrates. Moreover, the influence of riparian buffer strip width (as a mitigation measure) at the sampling sites was considered. Generally, invertebrate fauna was dominated by pesticide-tolerant species, suggesting a high pesticide exposure at almost all sites. This result is also reflected by the elevated levels of suspended particle contamination in terms of toxic units (logTUMax > −2), corresponding to one-hundredth of the median lethal concentration (LC50) to Daphnia magna. At two sites that received high aqueous-phase entries of the pyrethroid lambda-cyhalothrin (logTUMax > −0.6), the abundance and number of sensitive species in terms of the species at risk index decreased during the pesticide application period. In contrast, no acute significant negative effects on macroinvertebrates were observed at sites characterised by low water-phase toxicity (logTUMax < -3.5). An influence of riparian buffer strip width on pesticide exposure was not observed, supposedly because of the presence of erosion rills and ephemeral ditches. In conclusion, results show that mitigation measures (such as the improvement of currently present riparian buffer strips) are needed in the study area. Environ Toxicol Chem 2013;32:1254-1263. © 2013 SETAC [ABSTRACT FROM AUTHOR]

The present study assessed the fitness of a lambda-cyhalothrin-resistant population of Eriopis connexa (Germar) with respect to development, reproduction, survival under prey scarcity and prey consumption., Nontreated resistant females (R0) and females recovered after the topical application of 0.05, 0.10 and 0.25 mg active ingredient/mL of lambda-cyhalothrin (R0.05, R0.10 and R0.25) produced, on average, 50% less eggs than susceptible females (S0), irrespective of the applied dose. All of the other traits evaluated remained similar. With respect to developmental characteristics, the larval viability and weight of adult male R0.25 progeny were statistically lower compared with the R0 and S0 progenies. Prey scarcity between days 3 and 13 of adulthood did not affect R0 and R0.25 survival, although egg production was significantly lower for R0 females, followed by R0.25 females, compared with S0 females., The mean consumption of cotton aphids Aphis gossypii Glover over 5 consecutive days was significantly higher for S0, followed by R0 and R0.25, up to day 3 of observation. However, after day 4, prey consumption was similar among the three populations., The results obtained in the present study show that resistant females have a lower reproductive output than susceptible females and that this is not related to the knockdown effect; however, the costs of recovering from knockdown interfere with the survival of offspring and also slightly with prey consumption. Thus, we conclude that the lambda-cyhalothrin-resistant E. connexa population exhibits an egg production disadvantage relative to the susceptible population and that this is increased when the population is subjected to prey scarcity. [ABSTRACT FROM AUTHOR]

Synthetic pyrethroids are widely used in both agricultural and urban environments for insect control. Lambda-cyhalothrin (LCT) is one of the most common pyrethroids and is used mainly for controlling mosquitoes, fleas, cockroaches, flies, and ants around households. Previous studies have addressed the environmental behaviors and acute toxicities of LCT, but little is known about its chronic toxicity, such as estrogen-like activity. In the present study, the estrogenic potential of LCT was evaluated using the MCF-7 human breast carcinoma cell line. The in vitro E-screen assay showed that 10-7 M LCT could significantly promote MCF-7 cell proliferation, with a relative proliferative effect ratio of 45%. The cell proliferation induced by LCT could be blocked completely, however, by the addition of 10-9 M of the estrogen receptor (ER)-antagonist ICI 182,780. The semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) results showed that the Trefoil factor 1 (pS2) and progesterone receptor gene expression were up-regulated by 10-7 M LCT for 2- and 1.5-fold, respectively. On the other hand, RT-PCR, Western blot analysis, and immunofluorescent assay demonstrated that LCT significantly repressed the mRNA and protein expression levels of ERα and ERβ. These observations indicate that LCT possesses estrogenic properties and may function as a xenoestrogen, likely via a mechanism similar to that of 17β-estradiol. The endocrine-disruption potential of LCT should be considered when assessing the safety of this compound in sensitive environmental compartments. [ABSTRACT FROM AUTHOR]

Pertussis toxin (PTX) inhibits the activation of the α-subunit of the inhibitory heterotrimeric G-proteins (Gαi./o) and modulates voltage-gated sodium channels, which may be one of the primary targets of pyrethroids. To investigate the potential mechanisms of agricultural pests resistance to pyrethroid insecticides, we examined the modulations by PTX on sodium channels in the central neurons of the 3rd—4th instar larvae of cyhalothrin-resistant (Cy-R) and cyhalothrin-susceptible (Cy-S) Helicoverpa armigera by the whole-cell patch-clamp technique. The isolated neurons were cultured for 12—16 h in an improved L15 insect culture medium with or without PTX (400 ng/mL). The results showed that both the Cy-R and Cy-S sodium channels exhibited fast kinetics and tetrodotoxin (TTX) sensitivity. The Cy-R sodium channels exhibited not only altered gating properties, including a 8.88-mV right shift in voltage-dependent activation ( V0.5act) and a 6.54-mV right shift in voltage-dependent inactivation ( V0.5inact), but also a reduced peak in sodium channel density ( Idensity) (55.2% of that in Cy-S neurons). Cy-R sodium channels also showed low excitability, as evidenced by right shift of activation potential ( Vacti) by 5—10 mV and peak potential ( Vpeak) by 20 mV. PTX exerted significant effects on Cy-S sodium channels, reducing sodium channel density by 70.04%, right shifting V0.5act by 14.41 mV and V0.5inact by 9. 38 mV. It did not cause any significant changes of the parameters mentioned above in the Cy-R sodium channels. The activation time ( Tpeak) from latency to peak at peak voltage and the fast inactivation time constant (τinact) in both Cy-S and Cy-R neurons were not affected. The results suggest that cotton bollworm resistant to pyrethroid insecticides involves not only mutations and allosteric alterations of voltage-gated sodium channels, but also might implicate perturbation of PTX-sensitive Gαi./o-coupled signaling transduction pathways. [ABSTRACT FROM AUTHOR]

The effects of cyhalothrin on the transient outward potassium current in central neurons of Helicoverpa armigera were studied by using the patch clamp techniques. The results showed that before using cyhalothrin (10−5 mmol/L), activation potential was approximately -40 mV, after application of the drug, the activation potential shifted roughly 10 mV to the negative potential direction, so channels can be activated more easily. Before and after cyhalothrin application, the change of current amplitude was insignificant. The value of V1/2 and k of activation curves did not change significantly, however, the V1/2 of the inactivation curves changed significantly. Inactivation curves significantly shifted to a negative direction, so that inactivation of the channels was hastened. It is indicated that there may exit a primary way in which cyhalothrin provides neurotoxicity to the nervous system through the regulation of activation potentials and inactivation state of IA channels. [ABSTRACT FROM AUTHOR]

The European Food Safety Authority (EFSA) was asked by the European Commission to provide scientific assistance with respect to the risk assessment for an active substance in light of confirmatory data requested following approval in accordance with Article 6(1) of Directive 91/414/EEC and Article 6(f) of Regulation (EC) No 1107/2009. In this context EFSA's scientific views on the specific points raised during the commenting phase conducted with Member States, the applicant and EFSA on the confirmatory data and their use in the risk assessment for gamma‐cyhalothrin are presented. The current report summarises the outcome of the consultation process organised by the rapporteur Member State the United Kingdom and presents EFSA's scientific views and conclusions on the individual comments received. [ABSTRACT FROM AUTHOR]