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Cockroaches, ubiquitous pests known for significant reproduction and as potential vectors of diseases, are notorious for their adoptability to a variety of insecticides that cause substantial challenges in pest control. The present research evaluated the LC50 concentrations of imidacloprid (0.65 mg/L) and clothianidin (2.5 μg/L) for Blattella germanica using topical and bait methods. The cockroaches were exposed to one‐third concentration of LC50 at a regular interval of 1, 2, 4, 8, 12, 16 and 20 days. During exposure, the activity of P450 monooxygenase increased, whereas the activity of brain acetylcholinesterase decreased. Lactate dehydrogenase, alkaline and acid phosphatase activity were highest on day 4, with a slight recovery on day 20. The elevated activities for superoxide dismutase and catalase, as well as increased lipid peroxidation levels on day 4, followed by a significant recovery in activity on day 20. The glutathione‐S‐transferase activity was elevated while the glutathione content was reduced, and a significant restoration was observed at the end of the experiment. The biochemical mechanisms of the organisms such as P450, esterase enzymes and oxidative systems, are actively involved in the detoxification mechanism. The study elucidated that the insecticide defence mechanism triggers detoxification pathways that encompass the metabolism of endogenous insecticidal compounds, with clothianidin showing greater efficacy and lower detoxification compared with imidacloprid. [ABSTRACT FROM AUTHOR]

The potential of entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae was studied in combination with the commonly used insecticides, viz. clothianidin 50 WDG, imidacloprid 17.8 SL and chlorpyriphos 20 EC, against grubs of Brahmina coriacea (Hope) and Holotrichia longipennis (Blanchard). Clothianidin, imidacloprid and chlorpyriphos were applied at 50, 75 and 100 ppm respectively, and both the fungi were applied at 107 conidia/ml. Synergistic interactions were consistent across all the combinations and calculated values of χ² ranged from 4.2 to 5.73 in both the species of white grubs. The grubs of H. longipennis exhibited a higher degree of synergism than B. coriacea as observed from the mortality data. Among entomopathogenic fungi, M. anisopliae showed more synergism than B. bassiana against both species. This study will also help reduce insecticidal pollution and the cost of interventions for the management of white grubs in a sense that application rates of chemical insecticides and synergists will be reduced. This practice may be incorporated in integrated pest management, and further study of the synergistic interactions will guide how entomopathogenic fungi and insecticides can be combined to combat environmental pollution effectively. [ABSTRACT FROM AUTHOR]

Neonicotinoids are the most widely used class of insecticides in the United States (U.S.). and the world. Consistent with their high use and persistence, neonicotinoids are often found contaminating drinking water and food. They are also detected in human urine, breast milk, amniotic and cerebrospinal fluids, as well as the brains of treated rodents. Neonicotinoids were once thought to pose little neurotoxic risk to humans, but a growing body of research challenges that assumption. In this study we provide the first comprehensive assessment of unpublished rodent developmental neurotoxicity (DNT) studies on five neonicotinoids that were submitted to the U.S. Environmental Protection Agency (EPA) by neonicotinoid manufacturers. Groups of female rats were administered three different doses of a neonicotinoid during pregnancy and lactation, and their offspring subjected to various neurological tests and brain measurements. We identified nicotine-like effects such as reduced brain size, indicative of neuronal cell loss. Statistically significant shrinkage of brain tissue was observed in high-dose offspring for five neonicotinoids: acetamiprid, clothianidin, imidacloprid, thiacloprid, and thiamethoxam. Two brain regions reduced in the rodent studies-the corpus callosum and caudateputa mentend to be smaller in people diagnosed with attention-deficit hyperactivity disorder (ADHD), and in children of mothers who smoked during pregnancy, suggesting a possible link between perinatal neonicotinoid exposure and ADHD. A decreased auditory startle reflex was reported for acetamiprid at all doses and was statistically significant in the mid- and high-dose offspring, and for clothianidin in juvenile high-dose females. No mid- or low-dose brain morphometric data were submitted for acetamiprid, imidacloprid, or thiacloprid. Thiamethoxam mid- and low-dose brain morphometric data were provided to EPA upon request. Only partial mid-dose brain morphometry data were submitted for clothianidin, but no low-dose data. Yet despite this lack of data, EPA concluded that only the high-dose brain morphometric effects were treatment-related-setting the mid-dose as the study's No Observed Adverse Effect Level (NOAEL) or failing to find a definitive NOAEL for acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam. We found numerous deficiencies in EPA's regulatory oversight and data analyses. EPA dismissed statistically significant adverse effects, accepted substandard DNT studies despite lack of valid positive control data, and allowed neonicotinoid registrants to unduly influence agency decision-making. We conclude that perinatal exposure to neonicotinoids and their metabolites induces adverse, nicotine-like neurotoxic effects in rodent bioassays, and that the exposure limits set by EPA for human exposure are either not protective or not supported by available neurotoxicity data. We propose regulatory changes to empower EPA to better protect public health from developmental neurotoxins like neonicotinoids. [ABSTRACT FROM AUTHOR]

Worldwide, bird populations are declining dramatically. This is especially the case in intensely used agricultural areas where the application of neonicotinoid insecticides is thought to—unintendedly—cause a cascade of negative impacts throughout food webs. Additionally, there could be direct (sub‐) lethal impacts of neonicotinoids on birds, but to date there is no comprehensive quantitative assessment to confirm or rule out this possibility. Therefore, we use a meta‐analytical approach synthesising 1612 effect sizes from 49 studies and show that neonicotinoids consistently harm bird health, behaviour, reproduction, and survival. Thus, in addition to reduced food availability, the negative direct effects of exposure to neonicotinoids likely contribute to bird population declines globally. Our outcomes are pivotal to consider in future risk assessments and pesticide policy: despite localised bans, the metabolites and residues of neonicotinoids remain present in the environment and in birds and will thus have long‐lasting direct effects on both the individual and the population levels. [ABSTRACT FROM AUTHOR]

There is growing concern that sprayed neonicotinoid pesticides (neonics) persist in mixed forms in the environmental soil and water systems, and these concerns stem from reports of increase in both the detection frequency and concentration of these pollutants. To confirm the toxic effects of neonics, we conducted toxicity tests on two neonics, clothianidin (CLO) and imidacloprid (IMD), in embryos of zebrafish. Toxicity tests were performed with two different types of mixtures: potential mixture compounds and realistic mixture compounds. Potential mixtures of CLO and IMD exhibited synergistic effects, in a dose-dependent manner, in zebrafish embryonic toxicity. Realistic mixture toxicity tests that are reflecting the toxic effects of mixture in the aquatic environment were conducted with zebrafish embryos. The toxicity of the CLO and IMD mixture at environmentally-relevant concentrations was confirmed by the alteration of the transcriptional levels of target genes, such as cell damage linked to oxidative stress response and thyroid hormone synthesis related to zebrafish embryonic development. Consequently, the findings of this study can be considered a strategy for examining mixture toxicity in the range of detected environmental concentrations. In particular, our results will be useful in explaining the mode of toxic action of chemical mixtures following short-term exposure. Finally, the toxicity information of CLO and IMD mixtures will be applied for the agricultural environment, as a part of chemical regulation guideline for the use and production of pesticides. [ABSTRACT FROM AUTHOR]

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Neonicotinoids, a neuro-effective class of insecticides, are heavily applied in agricultural activities worldwide. Poultry can be exposed to neonicotinoids by several routes, but the knowledge of neonicotinoid's metabolism in poultry and its associated interspecies differences is highly limited. Hence, this study aims to investigate the species differences in metabolite formations, as well as cytochrome P450 (CYP)-dependent metabolism of four major neonicotinoid compounds, acetamiprid, imidacloprid, clothianidin, and thiamethoxam, in poultry. In vitro biotransformation assays using hepatic microsomes of chicken, ducks, geese, quails, and rats were conducted. Metabolites of neonicotinoids were then screened by LC/Q-TOF and quantified by LC/MS/MS. The results revealed an existence of interspecies differences in the formations of N-[(6-chloro-3-pyridyl) methyl] -N-methyl acetamidine (IM-1-5) of acetamiprid and dm-clothianidin of clothianidin between chicken and other species. In addition, the greatest CYP activities in the metabolism of most neonicotinoid substrates, such as acetamiprid to dm-acetamiprid, imidacloprid to hydroxylated-imidacloprid and imidacloprid-olefin, clothianidin to dm-clothianidin, and thiamethoxam to clothianidin, were found in chicken. These results suggested that the CYPs in chicken may have a greater capacity for metabolism of neonicotinoids compared to other poultry. This study further revealed that the maximum intrinsic clearance of dn-imidacloprid and dn-clothianidin in ducks may be superintended by CYP-mediated nitro-reductions of imidacloprid and clothianidin. Further studies employing CYP recombinant enzymes may be required to elucidate the specific CYP isoforms that may be involved in neonicotinoid metabolism in avian species. [ABSTRACT FROM AUTHOR]

Background: Neonicotinoids are a group of synthetic insecticides that are highly effective and have a wide range of insecticidal activities. This group includes acetamiprid, dinotefuran, clothianidin, imidacloprid, sulfoxaflor, nitenpyram, thiamethoxam, and thiacloprid. They are extensively used worldwide, both in rural and urban environments. However, the widespread use of neonicotinoids has led to their accumulation and biomagnification in the environment due to their long half-life. This has resulted in the emergence of toxicological and hazardous pollutants, posing significant risks to humans and non-target animals. Neonicotinoids are a type of insecticides that bind to neuronal nicotinic acetylcholine receptors (nAChRs). This mechanism allows them to effectively activate insect nAChRs while having minimal impact on vertebrate nAChRs. This reduces the risk of toxicity and makes them safer for non-target species. However, the presence of neonicotinoids in the environment can still increase the risk of toxicity and exposure. Although they have low affinity for mammalian nAChRs, concerns arise due to the abundance, diversity, and widespread presence of these receptors, as well as their various functions. These factors raise concerns about the potential impact of these pesticides on unintended species. Therefore, it is crucial to remove neonicotinoids from the environment in a sustainable and methodical manner. Various techniques can be employed to eliminate neonicotinoid residues in soil and aquatic habitats. These techniques include physiochemical remediation methods such as advanced oxidation processes, adsorption, oxidation, Fenton technology, photocatalysis, and activated persulfate-based oxidation. Additionally, microbial remediation techniques involving bacteria, fungi, and microalgae can also be utilized. This review aims to focus on the scientific foundation, advancements, and key topics related to microbial remediation technologies for neonicotinoids. Proper implementation of bioremediation techniques can significantly reduce the harmful effects of neonicotinoids on the environment and human health. Short conclusion: The main focus of this review is the new studies on the bioremediation of neonicotinoids by bacteria, fungi, and microalgae, and the role of their enzymes. This topic is gaining importance as pesticide bioremediation techniques become increasingly significant. [ABSTRACT FROM AUTHOR]

Neonicotinoids (NEOs), used as insecticides against aphids, whiteflies, lepidopterans, and beetles, have numerous detrimental impacts on human health, including chronic illnesses, cancer, infertility, and birth anomalies. Monitoring the residues in food products is necessary to guarantee public health and ecological balance. The present work validated a new method to measure seven neonicotinoid insecticides (acetamiprid ACT, clothianidin CLT, dinotefuran DNT, imidacloprid IMD, nitenpyram NTP, thiacloprid TCP, and thiamethoxan THT) in wheat. The analytical procedure was based on simple and fast wheat sample cleanup using solid-phase extraction (SPE) to remove interferents and enrich the NEOs, alongside the NEOs' separation and quantification by reverse-phase chromatography coupled with a diode array detector (DAD). The validation process was validated using the accuracy profile strategy, a straightforward decision tool based on the measure of the total error (bias plus standard deviation) of the method. Our results proved that, in the future, at least 95% of the results obtained with the proposed method would fall within the ±15% acceptance limits. The test's cost-effectiveness, rapidity, and simplicity suggest its use for determining the levels of acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam in routine analyses of wheat. [ABSTRACT FROM AUTHOR]

Neonicotinoids are insecticides widely used in the world. Although neonicotinoids are believed to be toxic only to insects, their developmental neurotoxicity in mammals is a concern. Therefore, we examined the effects of developmental exposure to neonicotinoids on immune system in the brain and post‐developmental behaviors in this study. Imidacloprid or clothianidin was orally administered to dams at a dosage of 0.1 mg/kg/day from embryonic day 11 to postnatal day 21. Imidacloprid decreased sociability, and both imidacloprid and clothianidin decreased locomotor activity and induced anxiety, depression and abnormal repetitive behaviors after the developmental period. There was no change in the number of neurons in the hippocampus of mice exposed to imidacloprid. However, the number and activity of microglia during development were significantly decreased by imidacloprid exposure. Imidacloprid also induced neural circuit dysfunction in the CA1 and CA3 regions of the hippocampus during the early postnatal period. Exposure to imidacloprid suppressed the expression of csf1r during development. Collectively, these results suggest that developmental exposure to imidacloprid decreases the number and activity of microglia, which can cause neural circuit dysfunction and abnormal behaviors after the developmental period. Care must be taken to avoid exposure to neonicotinoids, especially during development. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides (NNIs), as a new type of insecticide, are widely used in agriculture and daily life. Because of the low volatility of NNIs, few studies have evaluated them in atmospheric particulate matter. In this study, 101 outdoor PM2.5 samples were collected from the Wuhan urban area from 2019 to 2021, leading to the detection of seven NNIs and three of their metabolites. The detection frequencies of all 10 substances were more than 60%, with DIN (dinotefuran) and IMI (imidacloprid) reaching 100%. DIN (52.4 pg/m3) and IMI (43.0 pg/m3) had higher median concentrations than other substances. Concentration distributions of the four substances ACE (acetamiprid), DIN, IMI, and 5-OH-IMI (5-Hydro-Imidacloprid) exhibited statistically significant differences (P < 0.05) across the four seasons. Concentration levels of ACE, CLO (clothianidin), and IMI were statistically different between the three years (P < 0.05). The median concentration of imidacloprid-equivalent total neonicotinoids (IMIeq: generated by the relative potency factor method) was 256.1 pg/m3. Finally, the estimated daily intake (EDI) of NNIs via respiration was greater in infants and young children than in the rest of the population, suggesting that infants and young children were more likely to be exposed to the health effects of airborne residual PM2.5. [ABSTRACT FROM AUTHOR]

The persistence in the environment and possible harmful effects of neonicotinoid insecticides have raised some concerns, which have led to the proposal of various measures for their remediation. The aim of this work was to study the elimination of five neonicotinoids (thiamethoxam (THM), imidacloprid (IMI), clothianidin (CLO), thiacloprid (THC), and acetamiprid (ACE)) using ferrate (Fe(VI)) as the oxidizing agent. Firstly, second-order rate constants for the reactions of neonicotinoids with Fe(VI) were determined at different pHs. The most reactive compound was THC, with a rate constant of 400 ± 43 M−1 s−1 at pH 8 (the optimum pH considering the predominance of the most reactive species (HFeO4−) and the decreasing self-decomposition of Fe(VI) with pH), followed by CLO (10.7 ± 1.7 M−1 s−1), THM (9.7 ± 0.7 M−1 s−1), and IMI (2.5 ± 0.6 M−1 s−1). ACE did not significantly react with Fe(VI). The oxidation of the selected pollutants in secondary effluents by Fe(VI) was rather slow, and only THC could be efficiently removed. The presence of natural organic matter (NOM) exerted a negative influence on the removal of the neonicotinoids of moderate reactivity with Fe(VI) (CLO, THM, and IMI). The additional presence of peroxymonosulfate (Fe(VI)/PMS system) slightly increased the removal of neonicotinoids due to the formation of hydroxyl and sulfate radicals. Finally, the application of the Fe(VI)/sulfite system considerably increased the oxidation rate of the selected pollutants, with enhanced formation of hydroxyl and, especially, sulfate radicals. Overall, these results suggest that the Fe(VI)/sulfite system has significant potential to address environmental and health concerns associated with neonicotinoids in water sources with low NOM content. [ABSTRACT FROM AUTHOR]

The insecticide known as neonicotinoid has negative impacts on the ecosystem, human health, and the environment; specifically, its effects on the relationship between crop yields and the death rate of natural pollinators, such as bees, affect food security. The active ingredients in neonicotinoids include imidacloprid, clothianidin, thiamethoxam, acetamiprid, sulfoxaflor, and thiacloprid, which are sold under various trade names. For many of the components of these toxic insecticides, patents have been expired; however, farmers and consumers who continue to use these chemicals are unaware of the products' toxicity and the environmental effects they have. Thus, agricultural industries are required to consider diverse methods to minimize neonicotinoid use in farming operations and move away from the current prevailing methods. In this short review, the negative effects of neonicotinoid use; the toxic components, health effects, and environmental regulations of neonicotinoids; and sustainable methods to minimize their use are examined. [ABSTRACT FROM AUTHOR]

Pesticide exposure patterns tested in laboratory bioassays often do not match real-world pesticide exposure profiles in edge-of-field waterbodies. Toxicokinetic–toxicodynamic (TKTD) models are therefore increasingly used, as they allow for predictions of the toxic effects under actual time-variable field exposures. The TKTD models from the General Unified Threshold models of Survival (GUTS), for example, are considered ready for use by regulators for calculating the survival rates for any time-variable exposure profile. However, questions remain regarding their predictive power for compounds showing increased toxicity over time, such as neonicotinoid insecticides. The aim of the present study was therefore to compare the GUTS-predicted 28 d toxicity values of three neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) for the common New Zealand mayfly genus Deleatidium spp. with those observed in a previously published study. Overall, the GUTS modeling results underestimated the toxicity values derived experimentally. From the three neonicotinoids, clothianidin showed the best fit between the estimated and observed 28 d LC50 (median-lethal-concentration) values. Shortcomings of the modeling exercise, future research needs, and implications for the application of GUTS models in regulatory risk assessment are discussed. [ABSTRACT FROM AUTHOR]

The neurotoxic insecticide class of neonicotinoids has become one of the most widely used groups of pesticides globally. Their long half-lives and high water solubility increase their potential to linger and affect numerous organisms long after application. A prominent concern associated with residual contamination is the negative impact that neonicotinoids can have on beneficial arthropods such as bees and certain groups of beetles. Many studies have looked at the effects neonicotinoids have on arthropod communities in lab settings; however, comparatively few studies have looked at these groups in neonicotinoid-contaminated restored prairie habitats. These habitats are often restored from or located near agriculture and are almost ubiquitously contaminated with neonicotinoids. Our one-year manipulated field study compared native bee nesting rates and beetle community assemblages between paired clothianidin-contaminated and non-contaminated restored prairie plots. Native bee nesting probability and nesting abundance increased by 46% and 172%, respectively, in sites contaminated with clothianidin. Conversely, we observed no significant differences in beetle family assemblages, abundance, or richness between clothianidin-contaminated and control sites. These results suggest that neonicotinoid contamination of natural habitats can have numerous environmental consequences for arthropods and that these effects are not always consistent between taxa. Understanding how neonicotinoid contamination affects beneficial groups such as bees and arthropod community assemblages is crucial for characterizing the risks these chemicals pose to ecologically imperative taxa. [ABSTRACT FROM AUTHOR]

Neonicotinoid pesticides are utilized against an extensive range of insects. A growing body of evidence supports that these neuro-active insecticides are classified as toxicants in invertebrates. However, there is limited published data regarding their toxicity in vertebrates and mammals. the current systematic review is focused on the up-to-date knowledge available for several neonicotinoid pesticides and their non-acute toxicity on rodents and human physiology. Oral lethal dose 50 (LD50) of seven neonicotinoids (i.e. imidacloprid, acetamiprid, clothianidin, dinotefuran, thiamethoxam, thiacloprid, and nitenpyram) was initially identified. Subsequently, a screening of the literature was conducted to collect information about non-acute exposure to these insecticides. 99 studies were included and assessed for their risk of bias and level of evidence according to the Office of Health and Translation (OHAT) framework. All the 99 included papers indicate evidence of reproductive toxicity, hepatotoxicity, nephrotoxicity, neurotoxicity, immunotoxicity, and oxidative stress induction with a high level of evidence in the health effect of rodents and a moderate level of evidence for human health. The most studied type of these insecticides among 99 papers was imidacloprid (55 papers), followed by acetamiprid (22 papers), clothianidin (21 papers), and thiacloprid (11 papers). While 10 of 99 papers assessed the relationship between clothianidin, thiamethoxam, dinotefuran, and nitenpyram, showing evidence of liver injury, dysfunctions of oxidative stress markers in the reproductive system, and intestinal toxicity. This systematic review provides a comprehensive overview of the potential risks caused by neonicotinoid insecticides to humans and rodents with salient health effects. However, further research is needed to better emphasize and understand the patho-physiological mechanisms of these insecticides, taking into account various factors that can influence their toxicity. [ABSTRACT FROM AUTHOR]

Background: For decades, various agrochemicals have been successfully repurposed for mosquito control. However, preexisting resistance caused in larval and adult populations by unintentional pesticide exposure or other cross-resistance mechanisms poses a challenge to the efficacy of this strategy. A better understanding of larval adaptation to the lethal and sublethal effects of residual pesticides in aquatic habitats would provide vital information for assessing the efficacy of repurposed agrochemicals against mosquitoes. Methods: We reared field-collected mosquito larvae in water containing a concentration of agrochemical causing 100% mortality in susceptible mosquitoes after 24 h (lethal concentration). Using this experimental setup, we tested the effect of lethal concentrations of a pyrrole (chlorfenapyr, 0.10 mg/l), a pyrethroid (deltamethrin, 1.5 mg/l), and three neonicotinoids including imidacloprid (0.075 mg/l), acetamiprid (0.15 mg/l), and clothianidin (0.035 mg/l) on mortality rates, growth, and survival in third-instar larvae of the two sibling species Anopheles gambiae and Anopheles coluzzii collected from Yaoundé, Cameroon. Results: We found that An. gambiae and An. coluzzii larvae were susceptible to chlorfenapyr and were killed within 24 h by a nominal concentration of 0.10 mg/l. Consistent with strong resistance, deltamethrin induced low mortality in both species. Lethal concentrations of acetamiprid, imidacloprid, and clothianidin strongly inhibited survival, growth, and emergence in An. coluzzii larvae. By contrast, depending on the active ingredient and the population tested, 5–60% of immature stages of An. gambiae were able to grow and emerge in water containing a lethal concentration of neonicotinoids, suggesting cross-resistance to this class of insecticides. Conclusions: These findings corroborate susceptibility profiles observed in adults and suggest that unintentional pesticide exposure or other cross-resistance processes could contribute to the development of resistance to neonicotinoids in some Anopheles populations. [ABSTRACT FROM AUTHOR]

This study aimed (1) to assess the ability of collembolans Folsomia candida to avoid soils contaminated with three seed dressing insecticides imidacloprid, clothianidin, and fipronil; (2) to assess the effects of the insecticides on collembolans' locomotion behavior; (3) to check if changes in the locomotion behavior would explain the avoidance/preference responses; and (4) to evaluate the possibility to use locomotion behavior as toxicity biomarker of the tested insecticides. Avoidance and locomotion behavior assays with collembolans F. candida were performed with commercial seed dressing formulations of three insecticides (imidacloprid, clothianidin, and fipronil). Results showed no avoidance behavior at any concentration, while a "preference" was observed with increasing concentrations of the three tested insecticides. Significant reductions in the locomotion of exposed collembolans were observed at ≥ 1 mg kg−1 for imidacloprid (18–38%) and fipronil (29–58%) and ≥ 4 mg kg−1 for clothianidin (10–47%). At the higher insecticide concentrations, the collembolans had their trajectories restricted to smaller areas, with a tendency for circular movements. Our results confirm that the "preference" for contaminated soils with neurotoxic substances is likely due to locomotion inhibition impairing the ability of organisms to escape. This effect highlights that only avoidance assays may be not sufficient to assure the safety of some substances and confirm the potential of locomotion behavior as a sensitive toxicity biomarker for neurotoxic insecticides. [ABSTRACT FROM AUTHOR]

The honey bee, a crucial organism that provides ecological and economic value to humans, is currently facing threats from various environmental factors including pesticides. Numerous studies have been conducted to demonstrate the risks associated with neonicotinoid pesticides, but research on their occurrence in actual field conditions has not been identified. Therefore, in this study, we observed changes in honey bee (Apis mellifera) colonies located near rice cultivation areas as they progressed beyond the rice pesticide application period. Furthermore, we collected honey bees exposed to the clothianidin and analyzed their stress-related gene expression. The results showed that the foraging behavior of honey bee colonies located near rice cultivation areas did not exhibit significant differences between the treatment sites (Cheongyang and Gimje) and the control site (Wanju) during the experimental period. However, it was observed that the expression levels of stress-related genes in honey bees collected from the treatment group were significantly higher than those in the control. Most of the stress-related genes were associated with detoxification processes in response to pesticides. As a result, pesticide treatment in proximity to rice cultivation areas did not cause direct damage to honey bees but had an indirect impact, suggesting the potential for ongoing chronic damage. [ABSTRACT FROM AUTHOR]

In this study, the transfer rates of nine pesticides with different water solubility (imidaclothiz, acetamiprid, thiamethoxam, imidacloprid, clothianidin, carbendazim, pyraclostrobin, phoxim and etoxazole) from dry tea to infusion were carefully determined using the liquid-chromatography-tandem mass spectrometry (LC-MS/MS). The obtained results show that the transfer of each pesticide from tea spiked with the pesticides to the infusion ranged from 4.54% (etoxazole) to 58.0% (acetamiprid) under the traditional brewing condition in China, which indicates that transfer of pesticides was dependent on their water solubilities. Increases in infusion time resulted in increased transfer within 30 min. However, there was little influence of infusion time on transfer rates after 30 min. When the infusion temperature was between 50 and 100°C, the transfer rates of acetamiprid, thiamethoxam, imidacloprid, carbendazim, pyraclostrobin, phoxim and etoxazole increased with temperature, while transfer rates for imidaclothiz and clothianidin decreased with increasing temperature. After three infusions, the transfer rates of imidaclothiz, thiamethoxam, acetamiprid, and clothianidin were >70%. Our results provide a basis for the rational use of pesticides in tea gardens and a reasonable evaluation of dietary exposure levels of pesticide residues in brewed tea. [ABSTRACT FROM AUTHOR]

Numerous studies have documented the negative effects of neonicotinoids on bees; it remains crucial to examine how neonicotinoids affect other non‐target nectar‐feeding insects, such as the monarch butterfly, Danaus plexippus.Wildflowers growing near agricultural areas can be contaminated with neonicotinoids that affect survival or cause sublethal changes to behaviours of nectar‐feeding insects. Nectar residues of imidacloprid and clothianidin found in milkweeds and wildflowers adjacent to agricultural field range from 0 to 72.8 ng/mL.At field‐relevant doses, two neonicotinoids (imidacloprid and clothianidin) were studied for their effects on adult monarch survival, reproduction, flight and behaviour. First, we fed adult monarchs artificial nectar solutions ranging from 15 to 386 ng/mL of imidacloprid and 19 to 531 ng/mL of clothianidin. Neonicotinoid ingestion slightly reduced monarch reproduction but had no significant effects on survival, weight change, or activity levels.Second, we fed monarchs higher clothianidin doses (909 and 4030 ng/mL), that exceed field‐relevant levels by 22 and 99 times. These higher doses reduced monarch nectar consumption, survival, flight performance and reaction time in response to a drop test.Results show that adult monarchs tolerate field‐relevant doses as high as 54 ng/mL for imidacloprid and 75 ng/mL for clothianidin, with minimal lethal or sub‐lethal effects until much higher doses are supplied. We conclude that adult monarchs are more tolerant of ingested clothianidin and imidacloprid than indicated by previous research. [ABSTRACT FROM AUTHOR]

[Objectives] To determine the resistance of Aphis gossypii to different pesticides and identify those that are safer for Hippodamia variegata. [Methods] The number of A. gossypii and H. variegata larvae and adults in each plot after the application of 13 different pesticides from 8 different types was quantified using the five-point sampling and visual methods. The effect of each pesticide on A. gossypii, the corrected rate of decrease of larvae and adults of H. variegata, and the ratio of H. variegata to A. gossypii, were also measured. [Results] A. gossypii were more susceptible to sulfoxaflor, flonicamid and afidopyropen, which at 3, 7, 10 and 14 days after application had reduced numbers by 73.53%-97.46%, respectively. The ratio of H. variegata to A. gossypii was also higher in plots treated with these pesticides (0.0168-0.0927). With the exception of acetamiprid, dinotefuran and spirotetramat, the other 10 pesticides tested were relatively safer for H. variegata larvae. The effects of all 13 pesticides on H. variegata adults were low; the corrected decrease rate was 6.73%-32.61%. Among the pesticides tested, dinotefuran, clothianidin, thiamethoxam, nitenpyram and pymetrozine had the least effect on H. variegata adults (7.37%-31.00%). Except for imidacloprid (7 days after treatment), acetamipri (3 days after treatment) and dinotefuran (3, 7 and 14 days after treatment), there were no significant differences between the corrected decrease rates of H. variegata larvae and adults among the other pesticides. [Conclusion] Sulfoxaflor, flonicamid and afidopyropen are both more effective than the other pesticides tested for the control of A. gossypii, and safer for H. variegata. Alternating the application of these three pesticides could both reduce the development of resistance in A. gossypii and mortality of H. variegata. [ABSTRACT FROM AUTHOR]

Three insecticides viz., imidacloprid (Admire 70 WG), clothianidin (Dantotsu 50 WDG) and thiamethoxam (Actara 25 WG) were evaluated against termite, Odontotermes obesus and red ant, Dorylus orientalis by using dry film method. It was observed that all the tested insecticides were very effective against test insectpests but thiamethoxam was found to be the most superior insecticide. The mortality of termites and red ants increased gradually with increase in concentration as well as increase in exposure period. The order of toxicity to termite and ant, at 24 hours post exposure period, was recorded as thiamethoxam (2.6 ppm) > clothianidin (5.6 ppm) > imidacloprid (9.8 ppm) and thiamethoxam (8.5 ppm) > clothianidin (14.9 ppm) > imidacloprid (31.9 ppm), respectively. The median lethal time (LT50) values revealed that thiamethoxam was the most fast acting insecticide as compared to the other tested insecticides at the highest concentrations for both the test insects. [ABSTRACT FROM AUTHOR]

The field experiment was carried out to evaluate the efficacy of different insecticides against hoppers on rice. The result revealed that, pymetrozine 50 WG was the best in reducing the white backed plant hopper (WBPH) and green leaf hopper (GLH) with 2.95 and 2.89 hoppers per hill, respectively, which was followed by clothianidin 50 WDG (3.05 WBPH and 2.99 GLH per hill) and flonicamid 50 WG (3.45 WBPH and 3.33 GLH per hill). The treatments imidacloprid 70 WG (4.47 WBPH and 3.87 GLH per hill) and fipronil 5 SC (5.61 WBPH and 4.44 GLH per hill) were found moderately effective, while bifenthrin 10 EC (6.76 WPBH and 4.92 GLH per hill) and cartap hydrochloride 50 SP (7.07 WBPH and 5.45 GLH per hill) were found to be the least effective in managing the WBPH and GLH. In case of natural enemies' population, no detrimental impact of insecticides was observed on the population of spiders as the treatment differences were non-significant. Amongst the seven insecticides evaluated, pymetrozine 50 WG treated plots recorded the highest grain and straw yield. [ABSTRACT FROM AUTHOR]

Recently, the effects of exposure to clothianidin (CLO) on the thymus and gut microbiota have become clear, but no report has examined its next-generation impacts. Pregnant C57BL/6N mice were administered a no-observed-adverse-effect-level dose of CLO until weaning. We examined CLO's effects on the gut microbiota and immune organs of dams and their 3- and 10-week-old male offspring. CLO administration led to several alterations of the top 30 bacterial genera in the gut microbiota in dams and 3-week-old mice. Compared to controls, 10-week-old mice had more thymic Hassall's corpuscles, and both dams and 10-week-old mice had fewer macrophages. These results suggest that fetal and lactational CLO exposure may affect the immune system and gut microbiota of the next generation. [ABSTRACT FROM AUTHOR]

This paper presents studies performed for the monitoring of imidacloprid, clothianidin and thiamethoxam residues applied as seed treatment in rapeseed (Brassica napus ssp. oleifera), maize (Zea mays) and sunflower crops (Helianthus annuus). The experiments were located in representative areas of the mentioned crops. Residue levels were determined in plant samples at different phenological development stages, including flowers, as well as in bees and hive products (pollen, honeycomb, honey) by liquid chromatography/tandem mass spectroscopy (LC-MS/MS). The analyses were performed in ISO 17025-accredited laboratories, referring to the limit of quantification (LOQ), characteristic of the method used to determine the residues. In 2019, the percentage of samples that contained residues of the three substances, applied to the seed, was 16.39%, representing 20 samples out of the total of 122 analyzed samples. In 2020, 10 samples contained neonicotinoid residues above the LOQ, including 5 soil samples and 5 plant samples, representing 6.17% of the total samples. In 2021, from 149 samples with neonicotinoid applied as seed treatment, residues were identified in 12 soil samples and 11 plant samples, representing 15.43% of the total number of samples. In 2022, only 12 soil samples and 1 pasture sample contained residues above the LOQ. The results show that the highest percentage of samples with residues above the LOQ was recorded by the soil samples, while the flower and bee samples had the lowest percentages of samples with residues above the LOQ; no residues of the three neonicotinoid substances were identified in the honey samples. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the chronic toxicity of imidacloprid (IMI), clothianidin (CLO) and fipronil (FIP) as a single exposure, as well as binary mixtures of IMI with CLO or FIP toward collembolans Folsomia candida, which are fauna present in the soil. Chronic toxicity assays were performed following an ISO guideline in a Tropical Artificial Soil (TAS), and the influence on the number and growth of the juveniles produced were determined. The range of nominal concentrations used in the tests with the individual compounds was 0.08–1.28 mg/kg (IMI), 0.079–1.264 mg/kg (FIP) and 0.007–0.112 mg/kg (CLO), whereas the mixture assays were performed with half the value used in the tests with individual compounds. Based upon single exposures, IMI produced a similar impact of reducing reproduction by 50% (EC50 ranging from 0.74 to 0.85 mg/kg) compared to FIP (EC50 = 0.78 mg/kg), whereas CLO was the most toxic to F. candida (EC50 = 0.08 mg/kg). Their mixtures generally resulted in a diminished effect on reproduction, as evidenced by the higher EC50 values. In contrast, in the case of the IMI+FIP combination at high concentrations at the EC50 level, a synergistic effect on toxicity was observed. The single exposure to the three insecticides and the mixture of IMI-FIP also decreased the size of generated juveniles, which was evidenced by the reduction in the proportion of large juveniles and increased proportion of small juveniles. However, both binary mixtures (IMI-FIP and IMI-CLO) presented antagonistic effects as evidenced by less than expected reductions in growth. Data on the toxic effects of IMI in a mixture with other seed dressing insecticides to collembolans provides useful information to environmental risk assessors by diminishing the uncertainties on the ecological risk of exposure to pesticides, enabling soil management degradation by utilizing multiple insecticides. [ABSTRACT FROM AUTHOR]

Neonicotinoids are extensively used to prevent and control crop diseases and insect pests. Qilu Lake Basin is an important agricultural area in Southwest China, with huge consumption of neonicotinoids. However, the lack of data on neonicotinoid residues in Qilu Lake Basin challenges us with assessing the environmental contamination levels and the potential risks for the local aquatic ecosystem. Therefore, in this study, the occurrence and spatiotemporal distribution of three neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) in surface waters of Qilu Lake Basin were investigated. Their concentrations ranged from 0.65 ng/L (thiamethoxam in spring) to 1041.21 ng/L (imidacloprid in summer), which exhibited decreasing trends from the surrounding rivers to Qilu Lake. The highest concentrations were observed in summer, owing to the intensive application of pesticides and the heavy precipitation and surface runoff in this season. Imidacloprid and thiamethoxam presented relatively high ecological risks, and clothianidin was the most threatening compound, with high risk quotient values in every season owing to its low predicted no-effect concentration values and high toxicity. [ABSTRACT FROM AUTHOR]

Evaluation of sonication energy effect on in-situ synthesis of deep eutectic solvent-based liquid phase microextraction process was performed in fresh fruit samples for extraction of five neonicotinoids insecticide including clothianidin, imidacloprid, nitenpyram, acetamiprid, and thiacloprid. A suitable amount of choline chloride was dissolved in sample solution and it was poured into a glass narrow-bore tube. Then, a sodium chloride tablet was taken and a few microlitres of hexanoic acid were penetrated into the tablet and it was released into the tube. The narrow–bore tube was located into an ultrasonic bath at controlled frequency and power. The sodium chloride tablet started to dissolve and hexanoic acid was released into the solution and hydrogen bonding was correlated between the ChCl and hexanoic acid. The formed deep eutectic solvent went up through the sample solution and analytes were extracted into the ChCl: hexanoic acid DES. Validation parameters were calculated and low limits of detection (0.04–0.31 ng mL–1) and quantification (0.13–1.03 ng mL–1), high enrichment factors (1280–1780) and extraction recoveries (64–89%), and acceptable precision (RSD ≤7.2%) were obtained. Lastly, the procedure was done on some fresh fruit samples imidacloprid and acetamiprid were detected on some samples. [ABSTRACT FROM AUTHOR]

Abstract A method based on isotope dilution liquid chromatography/tandem mass spectrometry (ID-LC/MS/MS) was established as a candidate reference method for accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage. Their deuterated isotopes, imidacloprid-d 4, chlothianidin-d 3, and thiamethoxam-d 4 were used as internal standards. The combination of HLB and Carb solid-phase extraction (SPE) cartridges was used to clean-up kimchi cabbage extracts. The ID-LC/MS/MS conditions were optimized with fortified kimchi cabbage samples for validation. Imidacloprid in the ERM-BC403 cucumber sample (0.627 ± 0.026) mg/kg was analyzed with the developed method, and the measured value (0.604 ± 0.028) mg/kg agreed within their uncertainties. The developed method was employed for the certification of kimchi cabbage reference materials prepared in this laboratory. The measured values of imidacloprid, clothianidin, and thiamethoxam are (0.860 ± 0.020) mg/kg, (0.524 ± 0.012) mg/kg, (0.787 ± 0.014) mg/kg, respectively. The standard deviation of the measured values for ten bottles was

Zinc oxide nanoparticles were synthesized through green chemistry using lemon extract as reducing agent. The sensitivity of the synthesized nanoparticles against pesticide residues in water was determined. The nanoparticles were characterized based on the absorbance. Characteristic peaks were observed at 281nm and 328nm attributed to the exciton absorption peak and maximum absorbance that confirmed the size of the product. The nanoparticles were mixed with different concentration of pesticides in water at varying ratio. The color change was observed in relation to its sensitivity to the solutions. Evident change in color from pale yellow to colorless were observed for both 400ppb of clothianidin and imidacloprid mixed with ZnO nanoparticles at 1:1 ratio. Absorbance spectra revealed that there is a difference in the interaction of the two pesticides with ZnO nanoparticles. However, same visual color change were observed for both pesticides from pale yellow to colorless. This suggests that the ZnO nanoparticles were not selective as colorimetric detector for clothianidin and imidacloprid. [ABSTRACT FROM AUTHOR]

Neonicotinoids are the most commonly used insecticides due to their effectiveness. However, non-targeted insects, especially bees, are also affected by neonicotinoids. Therefore, neonicotinoid application can contribute to the declining bee populations worldwide. The presented study describes the development of novel competitive, fluorescent microsphere-based suspension immunoassays for neonicotinoid profiling and their application to bees and essential bee-related matrices, using the Multi-Analyte Profiling (xMAP) technology. For the construction of these neonicotinoid microsphere immunoassays (nMIAs), neonicotinoid–ovalbumin conjugates were coupled to unique fluorescent, paramagnetic microspheres, which competed with the free neonicotinoids that were present in test samples for interacting with the corresponding, specific antibodies. In total, five independent nMIA's were developed for the detection of imidacloprid, acetamiprid, clothianidin, thiacloprid, thiamethoxam, dinotefuran, nitenpyram and imidaclothiz with the limits of detection being for 0.01 ng/mL, 0.01 ng/mL, 0.02 ng/mL, 0.02 ng/mL, 0.003 ng/mL, 2.95 ng/mL, 0.09 ng/mL and 0.04 ng/mL, respectively. The developed nMIAs were applied to fortified matrices including surface water, pollen, honey and honeybees. All of the neonicotinoids, except dinotefuran, could be sensitively detected in all of the tested environmental matrices and bees, with there being sensitivities of 1 ng/mL in water and 10 ng/g in solid materials. These nMIAs provide a rapid profiling method for all of the common neonicotinoids, including those that are banned by the European Union for outdoor use. The developed method can contribute to healthy and sustainable beekeeping, globally, via its application in the apiary environment. [ABSTRACT FROM AUTHOR]

Residues of neonicotinoid pesticides have potential risks to food, environmental and biological safety. In this study, the hapten toward imidacloprid was adopted to gain antibodies. After molecular modeling, the electrostatic potentials of eight commonly-used neonicotinoid pesticides were individually calculated to analyze the structural similarity. Two representative compounds (imidacloprid and acetamiprid) with moderate similarity were rationally selected for hybridoma screening. Using this strategy, four clones of broad-specific monoclonal antibodies (mAbs) against multiple neonicotinoids were obtained, and the clone 6F11 exhibited the broadest spectrum to six neonicotinoid pesticides and two metabolites, with half-maximal inhibitory concentrations (IC50) ranging from 0.20 to 5.92 ng/mL. Then, the novel antibody gene was sequenced and successfully expressed in full-length IgG form using mammalian cells. Based on the sensitive recombinant antibody, a gold lateral-flow immunosensing strip assay was developed and it was qualified for rapid detection of imidacloprid, clothianidin or imidaclothiz residues in food samples. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides (NNIs) have been widely used to control insect pests, while their environmental residues and associated hazardous impacts on human and ecosystem health have attracted increasing attention worldwide. In this study, we examined the current levels and associated spatial and temporal patterns of NNIs in multiple environmental media across China. Concentrations of NNIs in surface water, sediment, and soil were in the range of 9.94–755 ng·L−1, 0.07–8.30 ng·g−1 DW, and 0.009–356 ng·g−1 DW, respectively. The high levels of NNIs in surface water, such as in Yangtze River (755 ng·L−1), North River (539 ng·L−1), Nandu River (519 ng·L−1), and Minjiang River (514 ng·L−1), were dominated by imidacloprid, thiamethoxam, and acetamiprid due to their extensive use. The levels of NNIs in sediments were relatively low, and the highest concentration (8.30 ng·g−1 DW) was observed in Dongguan ditch. Sediment–water exchange calculated from fugacity fraction indicated that NNIs in sediment can be released back into the water due to their high solubility and low KOW. Soils from agricultural zones contained the largest residual NNIs, with imidacloprid concentrations in cultivated soil reaching 119 ng·g−1 DW. The calculated leaching potential showed that clothianidin has the highest migration potential to deep soil or groundwater. The monitored data of NNIs presented a decreasing trend from 2016 to 2018, which might be caused by the implementation of relevant control policies for NNI applications. The high levels of NNIs mainly occurred in southern China due to frequent agricultural activities and warm and humid meteorological conditions. The results from this study improve our understanding of the pollution levels and environmental behavior of NNIs in different environmental media across China and provide new knowledge that is needed for making future control policies for NNIs production and application. [ABSTRACT FROM AUTHOR]

Recently, the high toxicity of neonicotinoids to the survival and reproduction of adult earthworms has become apparent in standard 56‐day toxicity tests. The persistence of some neonicotinoids and/or their repeated application may lead to long‐term exposure, possibly also affecting other parts of the life cycle of earthworms. The present study aimed at providing insight into the sublethal effects of imidacloprid, thiacloprid, and clothianidin on juvenile Eisenia andrei exposed for 16 weeks in Lufa 2.2 soil. Significant effects on growth and maturation were observed for all compounds. Exposure to 0.125 mg imidacloprid/kg dry soil and 0.03125 and 0.0625 mg thiacloprid/kg dry soil significantly affected the growth of the earthworms, while significant maturation effects were observed at 0.03125 mg/kg dry soil for imidacloprid and thiacloprid and 0.25 mg clothianidin/kg dry soil. The 16‐week no‐observed‐effect concentrations (NOECs) found in the present study were lower than previously reported NOECs for effects on earthworm reproduction. Predicted environmental concentrations after a single application exceeded the observed NOECs for effects on earthworm maturation in the case of imidacloprid and thiacloprid and for effects on earthworm growth in the case of thiacloprid and clothianidin. Environ Toxicol Chem 2022;41:1686–1695. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

The extensive use of neonicotinoids (NEOs) in agricultural production has led to their pervasive presence in various environmental matrices, including human samples. Given the central role of fruits and vegetables in daily human diets, it is crucial to evaluate the levels of NEOs residues and their potential health risks. In this study, 3104 vegetable samples and 1567 fruit samples from the Shenzhen city were analyzed. Using the relative potency factor (RPF) method, the residue levels of six representative neonicotinoids, including imidacloprid (IMI), acetamiprid (ACE), thiamethoxam (THM), dinotefuran (DIN), clothianidin (CLO), thiacloprid (THI), were systematically evaluated. The estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) for both children and adults were calculated to gauge the prevalence and potential health risks of NEOs in fruits and vegetables. Acetamiprid (ACE) was the most frequently detected NEO in vegetables (69.4%) and fruits (73.9%), making it the predominant contributor to total residues. Further analyses indicated notably higher levels of imidacloprid-equivalent total neonicotinoids (IMI RPF) in root and tuber vegetables (3025 μg/kg) and other fruits (243 μg/kg). A significant strong positive correlation (r = 0.748, P < 0.05) was observed between thiamethoxam (THM) and clothianidin (CLO), possibly due to their shared metabolic pathways. Although the mean HI values for adults and children from daily fruit (adults: 0.02, children: 0.01) and vegetable (adults: 0.02, children: 0.03) intake were generally below safety thresholds, some maximum HI values exceeded these limits, indicating that the potential health risks associated with NEOs exposure should not be overlooked. [Display omitted] • ACE is the most commonly detected neonicotinoid, dominating residue levels. • CLO and THM show a strong positive correlation. • The health risk from fruit and vegetable intake is low for both children and adults. [ABSTRACT FROM AUTHOR]

Neonicotinoids, sometimes abbreviated as neonics, represent a class of neuro-active insecticides with chemical similarities to nicotine. Neonicotinoids are the most widely adopted group of insecticides globally since their discovery in the late 1980s. Their physiochemical properties surpass those of previously established insecticides, contributing to their popularity in various sectors such as agriculture and wood treatment. The environmental impact of neonicotinoids, often overlooked, underscores the urgency to develop tools for their detection and understanding of their behavior. Conventional methods for pesticide detection have limitations. Chromatographic techniques are sensitive but expensive, generate waste, and require complex sample preparation. Bioassays lack specificity and accuracy, making them suitable as preliminary tests in conjunction with instrumental methods. Aptamer-based biosensor is recognized as an advantageous tool for neonicotinoids detection due to its rapid response, user-friendly nature, cost-effectiveness, and suitability for on-site detection. This comprehensive review represents the inaugural in-depth analysis of advancements in aptamer-based biosensors targeting neonicotinoids such as imidacloprid, thiamethoxam, clothianidin, acetamiprid, thiacloprid, nitenpyram, and dinotefuran. Additionally, the review offers valuable insights into the critical challenges requiring prompt attention for the successful transition from research to practical field applications. [Display omitted] • The review investigates strategies for selecting and applying aptamers against common neonicotinoid in biosensors. • Various aptasensors are examined, with a focus on enhancing sensitivity through nanomaterial surface modifications. • The fundamental working principles and mechanisms underlying aptasensing strategies were discussed. • A comparison of different aptasensing strategies was highlighted. [ABSTRACT FROM AUTHOR]

Simple Summary: The Colorado potato beetle is an insect pest that can significantly harm potato crops. Various approaches are available to mitigate its damages including the use of insecticides. Unfortunately, its ability to develop resistance towards these compounds is substantial, and understanding the basis of this process is of utmost importance to design strategies to limit the impact of this insect. This work thus aims at quantifying the expression of key transcripts coding for proteins associated with insecticide resistance in Colorado potato beetles exposed to four insecticides. Significant variations were observed, notably in insects exposed to the insecticide clothianidin. Interestingly, subsequent reduction of endogenous levels of selected targets modulated by clothianidin was associated with increased insect susceptibility to this neonicotinoid. These results further highlight molecular players with potential relevance for insecticide resistance, and introduce novel targets that underlie clothianidin resistance in the Colorado potato beetle. The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is known for its capacity to cause significant damages to potato crops worldwide. Multiple approaches have been considered to limit its spread including the use of a diverse arsenal of insecticides. Unfortunately, this insect frequently develops resistance towards these compounds. Investigating the molecular bases underlying the response of L. decemlineata against insecticides is of strong interest to ultimately devise novel and targeted approaches aimed at this pest. This work aimed to characterize, via qRT-PCR, the expression status of targets with relevance to insecticide response, including ones coding for cytochrome P450s, glutathione s-transferases, and cuticular proteins, in L. decemlineata exposed to four insecticides; chlorantraniliprole, clothianidin, imidacloprid, and spinosad. Modulation of levels associated with transcripts coding for selected cytochrome P450s was reported in insects treated with three of the four insecticides studied. Clothianidin treatment yielded the most variations in transcript levels, leading to significant changes in transcripts coding for CYP4c1, CYP4g15, CYP6a13, CYP9e2, GST, and GST-1-Like. Injection of dsRNA targeting CYP4c1 and CYP9e2 was associated with a substantial decrease in expression levels and was, in the case of the latter target, linked to a greater susceptibility of L. decemlineata towards this neonicotinoid, supporting a potential role for this target in clothianidin response. Overall, this data further highlights the differential expression of transcripts with potential relevance in insecticide response, as well as generating specific targets that warrant investigation as novel dsRNA-based approaches are developed against this insect pest. [ABSTRACT FROM AUTHOR]

Under the excitation of a 980 nm excitation light, the fluorescence signals of the synthesized core-shell NaYF4:Yb@NaYF4:Ho and monolayer NaYF4:Yb,Tm upconversion nanoparticles (UCNPs) were simultaneously detected at 656 and 696 nm, respectively. The two upconversion materials were coupled with anti-clothianidin and anti-imidacloprid monoclonal antibodies by the glutaraldehyde cross-linking method as signal probes. Imidacloprid (IMI) and clothianidin (CLO) could compete with antigen-conjugated amino Fe3O4 magnetic nanomaterials for binding to signaling probes, thus establishing a rapid and sensitive fluorescent immunoassay for the simultaneous detection of IMI and CLO. Under optimal conditions, the limits of detection (LOD, IC10) and sensitivity (IC50) of IMI and CLO were (0.032, 0.028) and (4.7, 2.1) ng/mL, respectively, and the linear assay ranges were at 0.032–285.75 ng/mL and 0.028–200 ng/mL, respectively. Immunoassay did not cross-react significantly with other analogs. In fruits and vegetables such as apples, oranges, peaches, cucumbers, tomatoes and peppers, the mean recoveries of IMI and CLO ranged from 83.33% to 115.02% with relative standard deviations (RSDs) of 1.9% to 9.2% and 1.2% to 9.0%, respectively. Furthermore, the results of the immunoassay correlate well with the high-performance liquid chromatography method used to detect the actual samples. [ABSTRACT FROM AUTHOR]

Organism tolerance thresholds for emerging contaminants are vital to the development of water quality criteria. Acute (96-h) and chronic (10-day) effects thresholds for neonicotinoid pesticides clothianidin and thiamethoxam, and the carbamate pesticide methomyl were developed for the midge Chironomus dilutus to support criteria development using the UC Davis Method. Median lethal concentrations (LC50s) were calculated for acute and chronic exposures, and the 25% inhibition concentrations (IC25) were calculated for the chronic exposures based on confirmed chemical concentrations. Clothianidin effect concentrations were 4.89 µg/L, 2.11 µg/L and 1.15 µg/L for 96-h LC50, 10-day LC50 and 10-day IC25, respectively. Similarly, thiamethoxam concentrations were 56.4 µg/L, 32.3 µg/L and 19.6 µg/L, and methomyl concentrations were 244 µg/L, 266 µg/L and 92.1 µg/L. Neonicotinoid effect concentrations compared favorably to previously published 96-h and 14-day LC50 concentrations, and methomyl effect concentrations were within the acute survival range reported for Chironomus species and other organisms. [ABSTRACT FROM AUTHOR]

BACKGROUND: The corn leafhopper, Dalbulus maidis (Hemiptera: Cicadellidae), spreads maize stunt pathogens and requires timely and effective crop protection. We determined the interaction between maize phenology and the vector feeding/infection period by stunt pathogens with the residual efficacy of neonicotinoid insecticidal seed treatments. Greenhouse‐ and field‐grown maize plants, seed‐treated with clothianidin or imidacloprid insecticides, were infested during seven growth stages with corn leafhoppers reared under controlled conditions on maize plants displaying infection symptoms by both spiroplasma (corn stunt spiroplasma, Spiroplasma kunkelii) and phytoplasma (maize bushy phytoplasma) pathogens. RESULTS: In the greenhouse and field settings, seed treatment reduced the stunt disease symptoms and corn yield loss during the VE–V4 maize growth stages and caused no phytotoxicity. The neonicotinoid seed treatment reduced 20–60% of the yield losses from the corn stunt disease until the V4 growth stage. Infestation by infective corn leafhoppers in the V12 maize growth stage caused a 25–30% yield loss irrespective of seed treatment, yet no stunt disease symptom was evident. Nonetheless, corn yield losses and visual stunt symptoms as rated by a nine‐category ordinal scale were strongly correlated (r = 0.79, P < 0.01). CONCLUSION: These results reinforce that maize plants are more susceptible to leafhopper stunt disease during the VE–V4 growth stages (emergence to the fourth‐leaf stage). Seed treatment helps reduce the damage in the early growth stages (VE–V2), although supplemental control measures depending on leafhopper population density may be needed from VE–V12 to protect yield losses from the maize stunt condition. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A method based on isotope dilution liquid chromatography/tandem mass spectrometry (ID-LC/MS/MS) was established as a candidate reference method for accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage. Their deuterated isotopes, imidacloprid-d4, chlothianidin-d3, and thiamethoxam-d4 were used as internal standards. The combination of HLB and Carb solid-phase extraction (SPE) cartridges was used to clean-up kimchi cabbage extracts. The ID-LC/MS/MS conditions were optimized with fortified kimchi cabbage samples for validation. Imidacloprid in the ERM-BC403 cucumber sample (0.627 ± 0.026) mg/kg was analyzed with the developed method, and the measured value (0.604 ± 0.028) mg/kg agreed within their uncertainties. The developed method was employed for the certification of kimchi cabbage reference materials prepared in this laboratory. The measured values of imidacloprid, clothianidin, and thiamethoxam are (0.860 ± 0.020) mg/kg, (0.524 ± 0.012) mg/kg, (0.787 ± 0.014) mg/kg, respectively. The standard deviation of the measured values for ten bottles was < 1%, and the measured values after one year agreed with their first measurements indicating reliable repeatability and reproducibility of the developed method. [ABSTRACT FROM AUTHOR]

The European honey bee, Apis mellifera, is the most common and important pollinator of crops worldwide. Honey bees are damaged by destructive parasitic mites, but they also have evolved a behavioral immune system to remove them. Exposures to neonicotinoids, however, can cause significant behavioral effects because these compounds alter the central role of nicotinic acetylcholine receptor in insect brains. In this study, we assessed the effects of three neonicotinoids that have a high toxicity to bees—imidacloprid, thiamethoxam, and clothianidin—on the behavioral immune system of honey bees. We used A. mellifera and the endoparasitic mite Acarapis woodi as a behavioral immune system model because A. mellifera can effectively remove the mite by autogrooming. Our results did not demonstrate an effect of neonicotinoid application on whether bees show autogrooming or on mite removal, but the time to initial autogrooming became shorter and the number of autogrooming attempts increased. As opposed to previous studies, our findings indicate that the honey bee response to parasitic mites becomes more sensitive after exposure to neonicotinoids. Clinical Trials Registration: Not applicable [ABSTRACT FROM AUTHOR]

The present study evaluated the relative susceptibility of insecticides viz., imidacloprid, thiamethoxam, thiacloprid, flonicamid, clothianidin, diafenthiuron, spiromesifen, thiodicarb and chlorpyriphos against field collected population of Amrasca (S.) biguttula. Out of nine insecticides, maximum susceptibility was observed with thiamethoxam. The descending order of susceptibility was observed as thiamethoxam> thiacloprid> diafenthiuron> spiromesifen> imidacloprid> clothianidin> flonicamid> thiodicarb> chlorpyriphos. Based on the relative toxicity value it was observed that the insecticides such as chlorpyriphos, thiodicarb, flonicamid and clothianidin were 14.04, 12.01, 9.43 and 9.41x, respectively less toxic as compared to thiamethoxam. The detoxification enzyme assay revealed that the activity of esterase was high in thiamethoxam and thiacloprid exposed leafhopper, while cytochrome p450 activity was high in spiromesifen, thiamethoxam and thiacloprid exposed ones. Elevated level of esterase and cytochrome p450 in the insecticide exposed leafhoppers indicates the probability of insecticide resistance development. [ABSTRACT FROM AUTHOR]

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Polar organic chemical integrative sampler (POCIS) devices have been suggested for measuring time‐weighted averages (TWAs) of contaminant concentrations resulting from chemical leak accidents in aquatic environments. However, the response of the POCIS device in the emergency condition in natural water remains unclear. The response of the POCIS device to contaminant fluctuation was investigated using a chamber test with tap water and a channel test with natural water. The fluctuation in the chamber and the channel simulated the condition of river water under a chemical leak scenario (maximum concentration: 1–10 μg L–1, half‐life: 1 day). The target chemicals were neonicotinoid pesticides (dinotefuran, clothianidin, thiamethoxam, imidacloprid, acetamiprid, and thiacloprid) and bisphenol A. The ratio of the POCIS measured value to the TWA values of grab samplings (POCIS/TWA) for the channel test (temperature: 15 °C, flow velocity: 15 cm s–1) ranged from 61% (clothianidin) to 133% (thiacloprid). The results indicated that the POCIS device could be effectively used as a monitoring device in an aquatic environment under the chemical leak scenario over a time period of more than14 days. In addition, the POCIS/TWA ratios obtained from the chamber test and the channel test were in the range of 50–150%. Thus, the chamber test could be used to evaluate the POCIS device at a low cost. Environ Toxicol Chem 2021;40:3010–3018. © 2021 SETAC [ABSTRACT FROM AUTHOR]

BACKGROUND Uridine diphosphate‐glycosyltransferases (UGTs) are phase II metabolic enzymes involved in metabolism of toxins and resistance to insecticides in insect pests. Reactive oxygen species (ROS) induced by xenobiotics are important for activation of detoxification pathways. However, relationships between ROS and UGTs involved in toxin metabolism and insecticide resistance remain unclear. RESULTS: Here, involvement of dual oxidase (Duox)‐dependent ROS in regulating UGT expression‐mediated insecticide resistance in the brown planthopper (Nilaparvata lugens) was investigated. The overexpression of NlUGT386F2 contributed to the resistance of N. lugens to clothianidin. Furthermore, the ROS inhibitor (N‐acetylcysteine) significantly reduced the expression of NlUGT386F2 and increased the susceptibility of N. lugens to clothianidin. Silencing the ROS producer Duox significantly increased the susceptibility of N. lugens to clothianidin through the down‐regulation of NlUGT386F2 expression. CONCLUSION: NlDuox‐dependent ROS regulates NlUGT386F2 expression‐mediated clothianidin resistance in brown planthopper. These observations further our understanding of the metabolism of toxins and of insecticide‐resistance in insect pests. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides (NNIs) are now popular in many agricultural systems across Africa; however, the extent of human exposures to NNIs in African countries is scarcely reported. The present study evaluates neonicotinoid exposures in the consumer population of Kumasi, a cosmopolitan city in Ghana. A total of 75 human urine samples were collected from healthy volunteers (nonfarmers, aged 13–80 yr) and analyzed with a liquid chromatography electrospray ionization tandem mass spectrometry system. Seven NNIs and 3 NNI metabolites were detected in the following pattern (frequency, median concentration, maximum concentration): N‐dm‐acetamiprid (94.7%, 0.41 µg/L, 8.79 µg/L) > imidacloprid (70.7%, 0.15 µg/L, 211.62 µg/L) > N‐(6‐chloro‐3‐pyridylmethyl)‐N‐ethyl‐N′‐methylformamidine (62.2%, 0.43 µg/L, 53.85 µg/L) > 2‐[N‐(6‐chloro‐3‐pyridylmethyl)‐N‐ethylamino]‐2‐(methylimino)acetic acid (56.8%, 0.10 µg/L, 3.53 µg/L) > clothianidin (40%, >limit of quantification [LOQ], 0.45 µg/L) > nitenpyram (18.7%, >LOQ, 0.14 µg/L) ≈ thiamethoxam (18.7%, >LOQ, 0.21 µg/L) > dinotefuran (12.0%, >LOQ, 1.01 µg/L) > acetamiprid (2.7%, >LOQ, 0.08 µg/L) ≈ thiacloprid (2.7%, >LOQ, 0.14 µg/L). Approximately 92% of the subjects were found to be exposed to multiple neonicotinoids simultaneously. The mean, median, and maximum imidacloprid equivalent of the relative potency factor of NNIs were found to be 1.6, 0.5, and 22.52, respectively. The median estimated daily intakes of acetamiprid, imidacloprid, and nitenpyram were 0.47, 1.27, and 0.02 µg/kg/d for females and 0.91, 0.66, and 0.08 µg/kg/d for males, respectively. The maximum daily intakes of all the NNIs were <1% of their chronic reference doses (cRfDs), except for imidacloprid and thiacloprid which recorded maximum daily intakes corresponding to 17.97 and 8.28% of cRfDs, respectively. To the best of our knowledge, the present study is the first biomonitoring report on neonicotinoid insecticides in Africa. Environ Toxicol Chem 2021;40:2306–2318. © 2021 SETAC [ABSTRACT FROM AUTHOR]