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BACKGROUND Substantial honey bee colony losses have occurred periodically in the last decades. The drivers for these losses are not fully understood. The influence of pests and pathogens are beyond dispute, but in addition, chronic exposure to sublethal concentrations of pesticides has been suggested to affect the performance of honey bee colonies. This study aims to elucidate the potential effects of a chronic exposure to sublethal concentrations (one realistic worst-case concentration) of the neonicotinoid thiacloprid to honey bee colonies in a three year replicated colony feeding study. RESULTS Thiacloprid did not significantly affect the colony strength. No differences between treatment and control were observed for the mortality of bees, the infestation with the parasitic mite Varroa destructor and the infection levels of viruses. No colony losses occurred during the overwintering seasons. Furthermore, thiacloprid did not influence the constitutive expression of the immunity-related hymenoptaecin gene. However, upregulation of hymenoptaecin expression as a response to bacterial challenge was less pronounced in exposed bees than in control bees. CONCLUSION Under field conditions, bee colonies are not adversely affected by a long-lasting exposure to sublethal concentrations of thiacloprid. No indications were found that field-realistic and higher doses exerted a biologically significant effect on colony performance. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Neonicotinoid insecticides are under review owing to emerging toxicity to non-target species. Interest has focused on biological pollinators while their effects on other organisms that are key contributors to the ecosystem remain largely unknown. To advance this, we have tested the effects of representatives of three major classes of neonicotinoids, thiacloprid, clothianidin and nitenpyram, on the free-living nematode Caenorhabditis elegans ( C. elegans), as a representative of the Nematoda, an ecologically important phylum contributing to biomass. RESULTS Concentrations that are several-fold higher than those with effects against target species had limited impact on locomotor function. However, increased potency was observed in a mutant with a hyperpermeable cuticle, which shows that drug access limits the effects of the neonicotinoids in C. elegans. Thiacloprid was most potent ( EC50 714 μ m). In addition, it selectively delayed larval development in wild-type worms at 1 m m. CONCLUSION C. elegans is less susceptible to neonicotinoids than target species of pest insect. We discuss an approach in which this defined low sensitivity may be exploited by heterologous expression of insect nicotinic acetylcholine receptors from both pest and beneficial insects in transgenic C. elegans with increased cuticle permeability to provide a whole organism assay for species-dependent neonicotinoid effects. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

An analytical method was developed to quantify the residual levels of the neonicotinoid insecticides, acetamiprid and thiacloprid, in field-incurred butterbur samples using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Samples were extracted with acetonitrile and partitioned with dichloromethane. After partitioning, purification was conducted using a Florisil ® cartridge. Linearity of a matrix-matched calibration curve of the two compounds over a concentration range of 0.004–0.4 μg/g was excellent, with determination coefficients ( R 2 ) ≥ 0.9998. The limits of detection (LOD) and quantitation (LOQ) for both acetamiprid and thiacloprid were 0.0006 and 0.002 mg/kg, respectively. The average recoveries for acetamiprid and thiacloprid at two spiking levels (0.02 and 0.1 mg/kg, i.e. , 10 × LOQ and 50 × LOQ) were between 78.23 to 82.17%, with relative standard deviations (RSDs) ≤ 7.22%. The method was successfully applied to field-incurred samples treated with a commercial pesticide product, either once (zero or 7 days before harvest) or twice (0 and 7, 7 and 14, or 14 and 21 days before harvest). The highest and lowest residues were obtained for the 7 and 0 days’ treatment and the 21 and 14 days’ treatment, respectively. The developed method is simple and accurate and can be extrapolated to other leafy vegetables. [ABSTRACT FROM AUTHOR]

Free radical induced oxidation/reduction mechanisms of the hazardous water contaminant thiacloprid have been unravelled using pulse radiolysis techniques involving transient spectral analysis and redox titration experiments. The OH-induced oxidation of thiacloprid proceeds with appreciable rate, the reaction rate constant has been determined to be k OH = 4.8 × 10 9 mol −1 L s −1 . The OH attack leaves behind a rather complex free radical system consisting of ∼9% α-aminoalkyl radicals, ∼31% aminyl + aminium nitrogen centred radicals, ∼46% radicals at the sulfur and ∼14% hydroxycyclohexadienyl radical of the pyridyl moiety. Since ∼86% of radicals are formed on the key cyanoiminothiazolidine pharmacophore, OH is anticipated to be an appropriate candidate for inactivation of this biologically active pollutant. The one-electron reduction exerted by e aq − occurs at a diffusion controlled rate. As a result of the e aq − attack pyridinyl radical forms that takes part in subsequent protonation and dechlorination processes. The course of events is anticipated to lead to the destruction of another important part of the molecule in respect to insecticidal activity. [ABSTRACT FROM AUTHOR]

This study focuses on interactions between nanoparticles and a pesticide. The aim was to investigate how nano-sized aluminum oxide (410 nm) can alter the toxic effects of thiacloprid, even if no sorption between particles and the insecticide takes place. Thus, our study investigated a rather unexplored interaction. We conducted our research with larvae of Chironomus riparius and used thiacloprid as test substance as its toxicity to C. riparius is well described. The used nano-Al2O3 particles where chosen due to their suitable properties. For testing the acute effects of the interaction, we exposed larvae to thiacloprid (0.5, 1.0, 2.0, and 5.0 μg/L) and nano-Al2O3 (300 and 1000 mg/L), either solely or in binary mixtures. While thiacloprid resulted in elevated mortality, nano-Al2O3 solely did not exert any effects. Moreover, we observed an aggregation of nano-Al2O3 within the lumen of the intestinal tract of the larvae. Further results showed a significantly reduced mortality of fourth instar larvae when they were exposed to mixtures of nanoparticles and the pesticide, compared to thiacloprid alone. With increasing nano-Al2O3 concentration, this effect became gradually stronger. Additionally, chemical analyses of internal thiacloprid concentrations implicate reduced uptake of thiacloprid in animals exposed to mixtures. However, as larvae exposed to thiacloprid concentrations > 0.5 μg/L showed severe convulsions, independent of the presence or concentration of nano-Al2O3, we assume that nano-Al2O3 leads to a delay of mortality and does not entirely prevent it. As sorption measurements on pristine or defecated nano-Al2O3 did not reveal any sorptive interaction with thiacloprid, we can exclude sorption-based reduction of thiacloprid bioavailability as a mechanism behind our results. Even though we used test substances which might not co-occur in the environment in the tested concentrations, our study gives evidence for an interaction besides adsorption, which is important to generally understand how nanoparticles might affect biota. [ABSTRACT FROM AUTHOR]

The study was conducted to investigate matrix interferences using QuEChERS sample preparation to understand whether the dilution of matrix and/ or the grouping of commodities can eliminate the need for selective individual matrix-matched standards in LC with tandem MS (MS/MS) analysis, and whether the calibration graph based on only one matrix can be used for quantification in the other matrixes. Matrix effects (MEs) were studied by comparing the slopes of calibration curves of the matrix-matched standards (diluted with mobile phase) vis-à-vis the solvent-based standards. The present study showed that MEs were dependent on the nature of both the commodity and the analyte. Among the test matrixes, the highest variability in ME was recorded in capsicum. Most of the pesticides showed signal suppression in tomato, capsicum, and cumin matrixes. In brinjal matrix, the signal of most of the pesticides showed slight enhancement. Due to the similar nature of the MEs in tomato and capsicum, these two commodities can be grouped together. Considering analyte variability, acetamiprid, 3-hydroxy carbofuran, dichlorvos, dimethoate, and spinosyn A and D showed no significant ME (≤20%) in tomato. Very high MEs (2360.9 and 1250.8%) were observed for quizalofop-p-tefuryl and tebuconazole, respectively. To check the effect of dilution in minimizing the ME, cucumber and brinjal matrixes were diluted 10×, and calibration curves were drawn with five concentration levels. It was found that about 60% of the total analyzed pesticides showed MEs ≤20%. In cumin, MEs ranged from -5.3% for triazophos to 661% for thiacloprid. Most of the pesticides showed recoveries in the acceptable range of 70-130% with calibration curves from both matrixes. To compensate for MEs, it is suggested that (1) tomato and capsicum matrixes, which show similar trends, can be grouped together; and (2) cucumber matrix, when diluted 10×, can be used to prepare calibration curves for the quantification of pesticides in various fruiting and cucurbit vegetable matrixes by LC-MS/MS. [ABSTRACT FROM AUTHOR]

This study was undertaken to quantify the residue levels and propose the dissipation kinetics of thiacloprid formulated as suspension concentrate in field-incurred Asian pears grown under two different open-field conditions. Samples were extracted with 20% distilled water in acetonitrile; partitioned with brine water and dichloromethane; and purified with a Florisil solid phase extraction cartridge. The analyte was identified with an LC ultraviolet detector, and field-incurred samples were confirmed using LC-MS/MS. The calibration curve was linear over the range 0.05-5.0 mg/L with a satisfactory coefficient of determination ( R2 = 0.9994). The limits of detection and limits of quantification (LOQ) were 0.003 and 0.01 mg/kg, respectively. The recovery rate fortified to blank samples at LOQ, 10× LOQ, and the maximum residue limit (MRL) were between 73.7 and 86.2% with relative standard deviation ≤9.0%. The residual concentrations at both sites were considerably lower than the MRL (0.7 mg/kg) set by the Korean Ministry of Food Drug Safety, with biological half-lives of 5.0 and 7.4 days, for sites 1 and 2, respectively. From the pre-harvest residue limit curve, it was predicted that if the residues were <1.13 or 1.40 mg/kg 10 days before harvest, the residue level would be lower than the MRL during harvest. Risk assessment on day 0 showed an acceptable daily intake (%) of 13.0% and 11.0% for sites 1 and site 2, respectively, which indicates that the residual amounts are not hazardous to the Korean population. [ABSTRACT FROM AUTHOR]

Purpose: In mine soils, especially from arid or semiarid areas, the use of low-quality water for irrigation is a usual practice. Therefore to fill this gap, different experiments have been carried out to evaluate the effect of compost, pesticide and wastewater on the growth of tomato plants in a mine soil located at an iron extraction area. Materials and methods: Soils proceeded from Alquife mine wastes whose most outstanding characteristics are alkaline conditions, low organic matter and electrical conductivity and high As concentration. The compost of sewage sludge (CSL) used to amend this soil had a slightly acid pH (6.8), EC 3.0 ± 0.07 dS m (1/10 ratio, m/V) and 10 % organic carbon (OC) content. Irrigation was performed with distilled water (DW) or wastewater (WW) and two pesticides, the insecticide thiacloprid and the fungicide fenarimol, were applied to the soil. Tomato was grown directly from seeds on each pot. Four treatments with addition of pesticides were considered. For comparison purposes, two additional treatments without pesticides were also included. Results and discussion: Addition of compost of sewage sludge led to a significant and sustained increase of soil OC content and dehydrogenase activity, while irrigation with wastewater had a slight or negligible effect on both properties. The plant species responded negatively to wastewater irrigation when this practice was undertaken with the application of both pesticides. No detectable amounts of thiacloprid, a relatively unstable and polar insecticide, were found in soil. The concentration of fenarimol in soil was higher after amendment with compost, but was not modified by irrigation with wastewater. In tomato shoots, the amounts of both pesticides were inversely correlated with final soil organic carbon, indicating that this soil property is relevant for their plant uptake. Besides, fenarimol concentrations in the soil and the tomato shoots were inversely related ( r = −0.836). Conclusions: Tomato was not able to grow healthy in Alquife mine soil without compost addition. The irrigation with wastewater only reduced plant growth when used in combination with pesticides. Uptake of both pesticides by tomato plants was negligible according to the low bioaccumulation factor values, but was almost doubled for wastewater irrigation. Caution should be taken with the use of treated wastewater, because it may reduce plant growth in tomato that is a species sensitive to salinity. [ABSTRACT FROM AUTHOR]

Three advanced oxidation processes (AOPs), heterogeneous photocatalysis, vacuum ultraviolet (VUV) photolysis and γ radiolysis were used for the generation of reactive primary free radicals to induce the transformation of Z-thiacloprid in aqueous solution. The effects of dissolved oxygen and the initial concentration (from 10 −6 to 10 −4 mol L −1 ) were investigated. The initial reaction rates increased with the initial concentration of thiacloprid, both in oxygen saturated and oxygen free solutions. Dissolved oxygen had significant effect on the transformation rate only in case of heterogeneous photocatalysis. Three main intermediates and the E-thiachloprid were detected using all three methods. One of these intermediates could be related to the reaction with e aq − , while the other two could be related to the OH-initiated reactions. Heterogeneous photocatalysis showed the highest efficiency regarding the transformation of intermediates in presence of dissolved oxygen, while thiacloprid transformed with the highest initial reaction rate during VUV photolysis. However, according to the Electric energy per order ( E EO ) data γ radiolysis was found to be the economically most feasible method, requiring several orders of magnitude less energy than VUV photolysis and heterogeneous photocatalysis for reduction of the target compound concentration by one order of magnitude in a unit volume. [ABSTRACT FROM AUTHOR]

In a recent study, we showed that the springtail Folsomia candida was quite sensitive the neonicotinoid insecticides imidacloprid and thiacloprid. This study aimed at determining the toxicity of both compounds to F. candida following exposure over three generations, in natural LUFA 2.2 standard soil. In the first generation, imidacloprid was more toxic than thiacloprid, with LCs of 0.44 and 9.0 mg/kg dry soil, respectively and ECs of 0.29 and 1.5 mg/kg dry soil, respectively. The higher LC/EC ratio suggests that thiacloprid has more effects on reproduction, while imidacloprid shows lethal toxicity to the springtails. In the multigeneration tests, using soil spiked at the start of the first generation exposures, imidacloprid had a consistent effect on survival and reproduction in all three generations, with LCs and ECs of 0.21-0.44 and 0.12-0.29 mg/kg dry soil, respectively, while thiacloprid-exposed animals showed clear recovery in the second and third generations (LC and EC > 3.33 mg/kg dry soil). The latter finding is in agreement with the persistence of imidacloprid and the fast degradation of thiacloprid in the test soil. [ABSTRACT FROM AUTHOR]

Biochars can significantly sorb pesticides, and reduce their bioavailability in agricultural soils. In this study, the effects of a type of biochar (BC500) on the sorption, degradation, bioaccumulation and bioavailability of thiacloprid, which is a commonly used insecticide, were investigated. The thiacloprid sorption constant ( K f values) increased by 14 times after 2% BC500 application, and the degradation of the insecticide decreased with increasing amounts of the biochars in the soil. Coupled with the exhaustive extraction and single-point Tenax method, the bioavailability of thiacloprid was predicted in the presence of the biochar. In soils amended with BC500, the thiacloprid concentrations accumulated in Tenax correlated well with those observed in earthworms (R 2 = 0.887), whereas the concentrations extracted by exhaustive method followed a less significant relationship with those in earthworms (R 2 = 0.624). The results of Tenax extractions and earthworm bioassays indicate that biochar reduces the bioavailability of thiacloprid in soil, but the delayed degradation and increased earthworm accumulation in aged biochar-amended soil imply that the environmental risks of biochar application to earthworms remain. [ABSTRACT FROM AUTHOR]

We have tuned the applications of gold nanoparticles (Au NPs) with nitro and hydroxy benzylindole-dithiocarbamate derivatives for simple and selective colorimetric detection of terbufos and thiacloprid insecticides in environmental samples. The nitro and hydroxy benzylindole-dithiocarbamate (NBI- and HBI- DTC) derivatives are used as anchors on the surfaces of unmodified Au NPs and cause the aggregation of Au NPs induced by terbufos and thiacloprid insecticides, resulting in the red-to-blue color change and the appearance of new surface plasmon resonance peaks at 630 and 625 nm in the absorption spectrum of NBI- and HBI- DTC Au NPs. On this basis, the concentrations of terbufos and thiacloprid can be visualized through the red-to-blue color change of NBI- and HBI- DTC Au NPs and quantitatively determined by UV–vis spectroscopy. Under the optimized conditions, the colorimetric systems exhibit a linear range from 0.5 to 50 μM for terbufos and from 5.0 to 500 μM for thiacloprid using NBI- and HBI- DTC Au NPs as probes. The detection limits (3 σ/m ) of 7.3 × 10 −8 and 6.0 × 10 −7 M were achieved for terbufos and thiacloprid, respectively. Furthermore, we demonstrate the application of the approach for the analysis of terbufos and thiacloprid in environmental water and food samples, which suggests that the present method exhibits good recoveries (97.16–99.31%) and capable to identify individual terbufos and thiacloprid or mixtures of them in real samples. [ABSTRACT FROM AUTHOR]

The effect of a single chemical treatment against Ostrinia nubilalis (Hbn.) on thrips abundance on maize in south-eastern Poland was evaluated. Two insecticides: Karate Zeon 050 CS, containing lambda-cyhalothrin, and Proteus 110 OD, containing thiacloprid with deltamethrin, were tested. Maize was sprayed in the second ten days of July, during the abundant occurrence of O. nubilalis larvae, which coincided with the population peak of thrips on plants. The tested active substances showed high effectiveness against thrips, but a better effect, reflected in a decrease in thrips abundance, was found for the mixture of thiacloprid with deltamethrin. The tested insecticides significantly reduced the population of thrips for up to 14 days after treatment. [ABSTRACT FROM AUTHOR]

The codling moth, Cydia pomenella is considered as the most important pest of apple worldwide and it causes significant economic losses yearly in orchards where it is not controlled effectively. The purpose of this study was to determine the resistance ratios to thiacloprid and the detoxification enzymes of Cydia pomonella from apple orchards in Isparta, Turkey. Populations of codling moth were collected from six orchards in the region and the diapausing larvae were treated with thiacloprid and chlorpyrifos by topical application. The LD 50 values of field and a susceptible population were used to determine the resistance ratios to thiacloprid and chlorpyrifos. The corresponding LD 50 values of C. pomonella populations showed a low (5.5–6.7 fold) or medium resistance (11.2–16.5 fold) against thiacloprid but were susceptible to chlorpyrifos. In studies conducted with synergists, piperonyl butoxide (PBO) and S,S,S, tributyl phosphorotrithioate (DEF) had a significant synergistic effect on two populations (from Gelendost and Senirkent) that medium resistance to thiacloprid. The levels of detoxifying enzymes [esterase, glutathion –S– transferase (GST) and cytochrome P450 monooxygenase (P450)] were investigated using biochemical methods and differed depending on the population. Based on the results of the enzyme analyses, the P450 and esterase enzymes may play a role in the resistance in codling moths to thiacloprid. [ABSTRACT FROM AUTHOR]

Thiacloprid (TCL) is a neonicotinoid insecticide. Its widespread use has led to high levels of residue in fruits and vegetables. Hence, it is important to detect TCL rapidly, accurately, and sensitively in fruits and vegetables. Recombinant antibodies (rAbs) can be synthesized rapidly with little batch-to-batch variation. In this study, recombinant single-chain variable fragment (scFv) antibody and full-length recombinant antibody against TCL were produced using three different expression systems (E. coli , yeast, and mammalian cell). The results of SDS-PAGE and non - competitive enzyme-linked immunosorbent assay (ELISA) indicated that the full-length rAb exhibited promising characteristics, and the IC 50 value of indirect competitive ELISA (ic-ELISA) was 2.63 μg L−1. However, recombinant scFv antibody had little affinity for the antigen. To understand antibody recognition, the three-dimensional (3D) model of the variable fragment (Fv) was built via homologous modeling. The interaction between Fv and TCL was analyzed via molecular docking and the results of molecular docking showed that VAL-158, ALA-211, PHE-220, TRP-218, TRP-49, and ILE-100 were mainly responsible for antibody recognition. In addition, a time-resolved fluorescent microsphere-immunochromatographic test strip (TRFM-ICTS) was developed with a linear range and limit of detection of 0.01–10 ng mL−1 and 0.003 ng mL−1 within 15 min under optimal conditions. The IC 50 value was 4.268 ng mL−1, and the recovery ranged between 79.4% and 118.6%, which was consistent with HPLC-MS. The TRFM-ICTS has great advantages in sensitivity and applicability. [Display omitted] • Recombinant single-chain variable fragment antibody against thiacloprid was produced. • Recombinant antibody showed a good affinity, IC 50 was 2.63 μg L−1 in ic-ELISA. • VAL-158, ALA-211, PHE-220, TRP-218, TRP-49 and ILE-100 were predicted in docking. • The strip using Eu(III) as a fluorescent label had a limit of detection of 3 pg mL−1. [ABSTRACT FROM AUTHOR]

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is one of the most devastating agricultural pests worldwide. It is mainly controlled by chemical insecticides, however, the development of resistance against main chemical classes has made its control extremely difficult. We evaluated the effectiveness of and resistance levels against flupyradifurone, sulfoxaflor, cyantraniliprole, thiacloprid, thiamethoxam, pymetrozine and spiromesifen in B. tabaci populations collected from 2017 to 2021. Leaf -- dip bioassays both in adults and nymphs, under validated methods were used. Low resistance ratio (RR) to flupyradifurone (RR <18-fold) and to sulfoxaflor (RR <13-fold) was recorded in all cases suggesting absence of resistance to these compounds. For cyantraniliprole and thiamethoxam low RR (<6-, <23-fold respectively) was also detected, with one exception for each insecticide (RR: 39- and 398-fold respectively), indicating a single case of control failure likelihood. High resistance levels were identified in all cases for thiacloprid (RR: 56- >3000-fold) and pymetrozine (RR> 4000-fold). For spiromesifen insecticide, the initial low RRs (<9-fold) were gradually replaced by extremely high resistance levels (RR> 1500-fold) after 2018. The low resistance levels for the relatively new insecticides flupyradifurone and sulfoxaflor indicates the absence of cross-resistance with other insecticides. The findings of this study can be directly implemented in the design of efficient chemical control programmes within the frame of rational IPM schemes. [ABSTRACT FROM AUTHOR]

Resistance to pyrethroid insecticides has evolved in Bactrocera oleae populations in Greece, threatening the efficacy of control interventions based on this insecticide class. Here we report the collection of populations from Crete, with resistance levels reaching up to 132-folds, compared to susceptible laboratory strains and show that pyrethroid resistance is substantially suppressed by the PBO synergist, suggesting the involvement of detoxification enzymes. To identify specific candidate genes implicated in resistance, we performed comparative transcriptomic analysis, between the pyrethroid resistant populations from Crete and the susceptible laboratory strains, using both whole bodies and Malpighian tubules. Several genes were found differentially transcribed between resistant and susceptible flies in each comparison, with P450s being among the most highly over-expressed detoxification genes in pyrethroid resistant populations. Four of the over-expressed P450s (Cyp6A61, Cyp6G6, Cyp4P6 and Cyp6G28) were recombinantly expressed in Escherichia coli and in vitro metabolism assays revealed that CYP6A61 is capable of metabolizing alpha-cypermethrin, while CYP6G6 , CYP4P6 and CYP6G28 are capable of metabolizing deltamethrin. No metabolism of neonicotinoid insecticides was recorded. We further silenced CYP6G6 in vivo , via RNAi, which led to a small, but significant increase in deltamethrin toxicity. The study provides valuable information towards the development of molecular diagnostics and evidence-based insecticide resistance management strategies. [Display omitted] • Highly pyrethroid resistant populations of B. oleae were detected in Crete (Greece). • RNAseq on whole bodies and malpighian tubules associated resistance with overexpression of CYPs. • CYP6A61 metabolizes alpha-cypermethrin, while CYP6G6 , CYP4P6 and CYP6G28 metabolize deltamethrin. • Cyp6G6 silencing through RNAi increased the susceptibility to deltamethrin. • None of the above P450s was capable to metabolize thiacloprid and acetamiprid. [ABSTRACT FROM AUTHOR]

• All four neonicotinoids exhibit photo-enhanced toxicity to V. fischeri with different toxic responses because of diverse photolysis mechanism for different main structure. • ROSs play important roles in the photolysis process and photo-enhanced toxicity. • A developed theoretical equation can well explain the toxicity variations of four neonicotinoids. Neonicotinoids are widely used pesticides that contaminate aquatic environments. Although these chemicals can be photolyzed under sunlight radiation, it is unclear for the relationship between photolysis mechanism and toxicity change in aquatic organisms. This study aims to determine the photo-enhanced toxicity of four neonicotinoids with different main structures (acetamiprid, and thiacloprid for cyano-amidine structure, imidacloprid and imidaclothiz for nitroguanidine). To Achieve the goal, photolysis kinetics, effect of dissolved organic matter (DOM) and reactive oxygen species (ROSs) scavengers on photolysis rates, photoproducts, and photo-enhanced toxicity to Vibrio fischeri were investigated for four neonicotinoids. The results showed direct photolysis plays a key role in the photo-degradation of imidacloprid and imidaclothiz (photolysis rate constants are 7.85 × 10−3 and 6.48 × 10−3 min−1, respectively), while the photosensitization process of acetamiprid and thiacloprid was dominated by ·OH reactions and transformation (photolysis rate constants are 1.16 × 10−4 and 1.21 × 10−4 min−1, respectively). All four neonicotinoid insecticides exerted photo-enhanced toxicity to Vibrio fischeri , indicating photolytic product(s) posed greater toxicity than their parent compounds. The addition of DOM and ROS scavengers influenced photo-chemical transformation rates of parent compounds and their intermediates, leading to diverse effects on photolysis rates and photo-enhanced toxicity for the four insecticides as a result of different photo-chemical transformation processes. Based upon the detection of chemical structures of intermediates and Gaussian calculations, we observed different photo-enhanced toxicity mechanisms for the four neonicotinoid insecticides. Molecular docking was used to analyze the toxicity mechanism of parent compounds and photolytic products. A theoretical model was subsequently employed to describe the variability of toxicity response to each of the four neonicotinoids. [Display omitted] [ABSTRACT FROM AUTHOR]

Thiacloprid (TH) is a neonicotinoid insecticide employed in agriculture to protect fruits and vegetables against different insects. It showed different deleterious effects on the general health of non-target organisms including birds and animals, however, its developmental toxicity has yet to be fully elucidated. Chicoric (CA) and rosmarinic (RA) acids are polyphenolic compounds with a wide range of beneficial biological activities. In this study, the possible protective effects of CA and RA were investigated in chick embryos exposed in ovo to TH (1µg/egg) with or without CA (100 µg/egg) or RA (100 µg/egg) co-exposure. TH reduced the hatchling body weight, body weight/egg weight, and relative weight of bursa of Fabricius in the one-day-old hatchlings. Examination of the 7-day-old chicks revealed a decline in feed intake, daily weight gain, feed conversion ratio (FCR), and plasma levels of T3, T4, and growth hormone. Serum ALT, AST activities, and total cholesterol levels showed significant elevations. Hepatic MDA was increased with a reduction in SOD activity and GSH level and downregulation of the liver SOD and GST gene expression pattern. Serum IgG and IgM levels were reduced, and various histopathological alterations were noticed in the liver. Co-administration of CA or RA with TH mitigated the toxic effects on hatchlings. When both CA and RA are combined, they present a synergistic protective effect. CA and RA can be used as protective agents against TH toxicity as they improve growth performance and have hepatoprotective and immunostimulant effects in newly hatched chicks. [ABSTRACT FROM AUTHOR]

The nitrile-containing insecticides sulfoxaflor, flonicamid, thiacloprid, and acetamiprid are used widely in agriculture, polluting the environment and harming animals. The Co2+-dependent enzyme nitrile hydratase (NHase) is a powerful tool for the degradation of nitrile-containing insecticides. Here, the NHase activities of Escherichia coli pET28a- Ps NHase, harboring Pseudomonas stutzeri CGMCC 22915 (Ps) NHase gene, and E. coli pET28a- Ps NHase- Ps CbiM, harboring genes of Ps NHase and a cobalt transporter Ps CbiM, were compared. The presence of Ps CbiM promoted Ps NHase activity. E. coli pET28a- Ps NHase- Ps CbiM was immobilized using calcium alginate, which increased the tolerance of its NHase to acidic, alkaline, and high-temperature environments. Immobilized E. coli pET28a- Ps NHase- Ps CbiM was applied to degrade sulfoxaflor, flonicamid, thiacloprid, and acetamiprid. These insecticides were both substrates and inhibitors of immobilized E. coli pET28a- Ps NHase- Ps CbiM. Substrate inhibition model assays showed that the optimum initial concentrations of sulfoxaflor, flonicamid, thiacloprid, and acetamiprid for degradation by immobilized cells were 455.01, 195.50, 139.20, and 410.26 μmol/L, respectively. Degradation of nitrile-containing insecticides by immobilized engineered E. coli cells was reported here for the first time. This study provides a novel and excellent bioremediation agent for treatment of wastewater contaminated with nitrile-containing insecticides. [Display omitted] • Nitrile-containing insecticides were degraded by immobilized engineering E. coli. • The degradation activity of immobilized cells was inhibited by high concentrations of insecticides. • Cell immobilization increased the tolerance of its NHase to environmental stress. • Ps CbiM transport Co2+ to Ps NHase and promoted its activity. • Ps CbiM had less than 30 % amino acid sequence similarity to other Co2+ transporters. [ABSTRACT FROM AUTHOR]

In agricultural landscapes, bees are subjected to diminishing floral resources and exposure to pesticides. Potential interactions of nutritional stress and pesticide exposure on solitary bees are largely unknown. We investigated the development and survival of the solitary bee Osmia bicornis provisioned with different pollen nutrition and exposed to pesticides in a full-factorial design in the laboratory. We used three nutrition types characterized by a low pollen diversity and a mixture of these (higher pollen diversity). We investigated two field-realistic concentrations of the insecticides thiacloprid, sulfoxaflor and flupyradifurone, as well as of the fungicides azoxystrobin and tebuconazole. We explored whether a higher pollen diversity is beneficial for O. bicornis development and survival, how the pesticides affect various fitness measures and whether pesticide impacts are mitigated by the higher diversity pollen. We found that a more diverse pollen was beneficial for O. bicornis development time, cocoon weight, pollen efficacy and pollen consumption. Thiacloprid, sulfoxaflor and flupyradifurone elongated development time. Sulfoxaflor and flupyradifurone lowered cocoon weight and pollen efficacy, and sulfoxaflor reduced survival and pollen consumption. Our results do not support the hypothesis that a more diverse pollen mitigates negative pesticide effects, but highlight the importance of diverse floral resources for bee development and the need for further studies on the interactions of multiple stressors. [ABSTRACT FROM AUTHOR]

Due to their extensive use and high biological activity, insecticides largely contribute to loss of biodiversity and environmental pollution. The regulation of insecticides by authorities is mainly focused on lethal concentrations. However, sub-lethal effects such as alterations in behavior and neurodevelopment can significantly affect the fitness of individual fish and their population dynamics and therefore deserve consideration. Moreover, it is important to understand the impact of exposure timing during development, about which there is currently a lack of relevant knowledge. Here, we investigated whether there are periods during neurodevelopment of fish, which are particularly vulnerable to insecticide exposure. Therefore, we exposed zebrafish embryos to six different insecticides with cholinergic mode of action for 24 h during different periods of neurodevelopment and measured locomotor output using an age-matched behavior assay. We used the organophosphates diazinon and dimethoate, the carbamates pirimicarb and methomyl as well as the neonicotinoids thiacloprid and imidacloprid because they are abundant in the environment and cholinergic signaling plays a major role during key processes of neurodevelopment. We found that early embryonic motor behaviors, as measured by spontaneous tail coiling, increased upon exposure to most insecticides, while later movements, measured through touch-evoked response and a light-dark transition assay, rather decreased for the same insecticides and exposure duration. Moreover, the observed effects were more pronounced when exposure windows were temporally closer to the performing of the respective behavioral assay. However, the measured behavioral effects recovered after a short period, indicating that none of the exposure windows chosen here are particularly critical, but rather that insecticides acutely interfere with neuronal function at all stages as long as they are present. Overall, our results contribute to a better understanding of risks posed by cholinergic insecticides to fish and provide an important basis for the development of safe regulations to improve environmental health. [Display omitted] • Tail coiling, touch-evoked response, and locomotion were differently affected. • The outcome of a later behavioral endpoint cannot be inferred from an earlier phenotype. • Previously observed behavioral effects recovered in absence of the insecticides. • No particularly critical developmental window was identified. [ABSTRACT FROM AUTHOR]

The burden of neonicotinoid insecticides (neonics) in humans has attracted widespread attention in recent years due to the potential adverse effects. Nonetheless, information on the partitioning behavior and distribution in human blood is still limited. Herein, we obtained 115 adult whole blood and plasma specimens for analysis of eight neonics to better understand neonics' partitioning and distribution in human blood. At least one neonic was detected in 49.6% of the red blood cells and 55.7% of the plasma. In red blood cells, the highest detection rate and concentration was thiamethoxam (THI) with 19.1% and 3832 ng/L, respectively. Imidacloprid had the highest detection rate with 26.1% in the plasma. The mass fraction (Fp) of neonics detected indicates that thiacloprid, imidacloprid, and dinotefuran are mostly resided in plasma upon entering into human blood, while thiamethoxam is mostly present in red blood cells. The distribution of clothianidin and acetamiprid between plasma and red blood cells is similar. The mass fraction (Fp) values for THI were significantly different compared to other neonics, and the effect of age and gender on THI partitioning concluded that there may not be significant variability in the distribution of THI in the sampled population. Overall, this study was the first to investigate neonics residuals in red blood cells and provided fundamental information on the partitioning and distribution of neonics in human blood. [Display omitted] • Neonicotinoid residues were quantified the first time in human red blood cells. • Thiamethoxam was most frequently detected in red blood cells. • Thiacloprid, imidacloprid and Dinotefuran were mainly present in plasma. • Significant variations were observed for the mass fraction (Fp) of thiamethoxam. [ABSTRACT FROM AUTHOR]

Neonicotinoids are one of the newest groups of systemic pesticides, effective on a wide range of invertebrate pests. The success of neonicotinoids can be assessed according to the amount used, for example, in the Czech Republic, which now accounts for 1/3 of the insecticide market. The European Union (EU) has a relatively interesting attitude towards neonicotinoids. Three neonicotinoid substances (imidacloprid, clothianidin and thiamethoxam) were severely restricted in 2013. In 2019, imidacloprid and clothianidin were banned, while thiamethoxam and thiacloprid were banned in 2020. In 2022, another substance, sulfoxaflor, was banned. Therefore, only two neonicotinoid substances (acetamiprid and flupyradifurone) are approved for outdoor use in the EU. Neonicotinoids enter aquatic ecosystems in many ways. In European rivers, neonicotinoids usually occur in nanograms per litre. Due to the low toxicity of neonicotinoids to standard test species, they were not expected to significantly impact the aquatic ecosystem until later studies showed that aquatic invertebrates, especially insects, are much more sensitive to neonicotinoids. In addition to the lethal effects, many studies point to sublethal impacts - reduced reproductive capacity, initiation of downstream drift of organisms, reduced ability to eat, or a change in feeding strategies. Neonicotinoids can affect individuals, populations, and entire ecosystems., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2023 Strouhova et al.)

Two liquid chromatography–tandem mass spectrometric methods were developed and validated to determine spinosyn A and D, thiacloprid and pyridalyl in spring onions cultivated under Egyptian field conditions. The degradation rates, the pre-harvest interval (PHI) values and the half-life values of the three pesticides were estimated. QuEChERS was used for sample preparation and the separation was performed on an X-Bridge C18 column with ACN-formic acid 0.1% as the mobile phase. Linear range, method detection limits (MDLs), precision, recovery and matrix effects were estimated. The multi-residue MDLs ranged from 0.02 μg/kg (spinosyn A & D) to 0.05 μg/kg for pyridalyl. All the investigated pesticides showed high degradation rates. For spinosad the half-life value was 1.2 days, for thiacloprid it reached 2.2 days and for pyridalyl 4.4 days. Furthermore, the calculated PHI values, according to the maximum residue levels set by the EU, were 0 days for spinosad, 9.8 days for thiacloprid and 39.4 days for pyridalyl. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract In accordance with Article 6 of Regulation (EC) No 396/2005, the evaluating Member State (EMS), Germany, compiled an application to modify the existing maximum residue level (MRL) for the active substance thiacloprid in honey. Germany proposed to raise the existing MRL from the limit of quantification of 0.05 mg/kg to 0.2 mg/kg. No guidance document for the setting of MRL in honey is currently available at EU level and therefore, in addition to the EMS evaluation, EFSA proposed additional alternative MRL values based on monitoring data. An MRL proposal of 0.2 mg/kg was derived from field trials where honey was collected in hives positioned close to rapeseed plots treated with thiacloprid. In addition MRLs of 0.15 and 0.2 mg/kg were derived considering data from national monitoring programs and the approaches recommended by the Food and Agriculture Organization (FAO). EFSA proposes to risk managers to decide which approach should be taken into account for the setting of an MRL in honey. Adequate analytical enforcement methods are available to control the residues of thiacloprid in honey. Based on the risk assessment results, EFSA concludes that the proposed MRLs of 0.15 or 0.2 mg/kg in honey will not result in a consumer exposure exceeding the toxicological reference values and therefore is unlikely to pose a consumer health risk.