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Although malaria is endemic in coastal Côte d'Ivoire, updated data on the resistance profile of the main vector, Anopheles gambiae sensu lato (s.l.), are still lacking, thus compromising decision-making for an effective vector control intervention. This study investigated the complex members and the insecticide resistance in the Anopheles gambiae s.l. populations in coastal Côte d'Ivoire. Between 2018 and 2020, cross sectional survey bioassays were conducted on female An. gambiae s.l. mosquitoes in three coastal health districts (Aboisso, Jacqueville and San Pedro) of Côte d'Ivoire. Pyrethroids deltamethrin, permethrin and alphacypermethrin (1X, 5X and 10X), clothianidin and synergist piperonyl butoxide (PBO) combined with pyrethroid 1X were tested using WHO tube bioassays. Chlorfenapyr was evaluated using CDC bottle bioassays. An. gambiae complex members and kdr 995F, kdr 995S and Ace-1 280S mutations were identified using polymerase chain reaction (PCR) technique. Overall, An. gambiae s.l. populations were primarily composed of Anopheles coluzzii (88.24%, n = 312), followed by Anopheles gambiae sensu stricto (7.56%) and hybrids (4.17%). These populations displayed strong resistance to pyrethroids at standard diagnostic doses, with mortality remaining below 98% even at 10X doses, except for alphacypermethrin in Aboisso. Pre-exposure to PBO significantly increased mortality but did not induce susceptibility, except for alphacypermethrin in Jacqueville. Clothianidin induced full susceptibility in Jacqueville and San Pedro, while chlorfenapyr induced susceptibility in Aboisso at 100 μg ai/bottle and all three districts at 200 μg ai/bottle. kdr 995F mutation dominated, with frequencies varying from 71.2% to 79.3%. kdr 995S had low, rates with frequencies ranging from 2.3% to 5.7%. Ace-1 280S prevalence varied between 4.2% and 42.9%. Coastal Côte d'Ivoire's An. gambiae s.l. populations were mainly composed of An. coluzzii and showed high resistance to pyrethroids. Clothianidin, chlorfenapyr, and PBO with pyrethroids increased mortality, indicating their potential use as an alternative for malaria vector control. [ABSTRACT FROM AUTHOR]

Exposure to pesticides is one potential factor contributing to the recent loss of pollinators and pollinator diversity. Few studies have specifically focused on the relationship between pesticide management during ornamental plant production and contamination of nectar. We evaluated contamination of nectar in Salvia 'Indigo Spires' (Salvia longispicata M. Martens & Galeotti × S. farinacea Benth.) associated with applications of the systemic insecticide thiamethoxam, and the nonsystemic fungicides boscalid and pyraclostrobin. Applications were made at the labeled rates for the commercially available products, and we compared the influence of application method (drench vs. spray), timing (relative to flowering), and rate (low vs. high) for each pesticide. Nectar was sampled using 50‐µL microcapillary tubes and analyzed by liquid chromatography–tandem mass spectrometry. The results indicate that concentrations from the spray application resulted in the least contamination of nectar with the systemic thiamethoxam, with lower concentrations occurring when thiamethoxam was applied before blooming at the lowest rate. Concentrations of thiamethoxam and its metabolite clothianidin were detected in nectar in all treatments (regardless of the method, timing, or rate of application), and ranged from 3.6 ± 0.5 ng/mL (spray‐applied before blooming, low rate) to 1720.0 ± 80.9 ng/mL (drench‐applied after blooming, high rate). Residues of clothianidin in nectar ranged from below quantification limits (spray‐applied before blooming, low rate) to 81.2 ± 4.6 ng/mL (drench‐applied after blooming, high rate). Drench applications resulted in the highest levels of nectar contamination with thiamethoxam, and exceeded published median lethal concentrations (LC50s/median lethal doses for native bees and/or honeybees in all cases). Spray treatments resulted in nectar concentrations exceeding published LC50s for some bee species. In comparison, all nonsystemic treatments resulted in concentrations much lower than the published no‐observable‐effect doses and sublethal toxicity values, indicating low risks of toxicity. Environ Toxicol Chem 2024;43:2616–2627. © 2024 SETAC [ABSTRACT FROM AUTHOR]

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]

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]

Aprostocetus hagenowii (Ratzeburg) is a parasitoid wasp that parasitizes the oothecae of peridomestic pest cockroaches. A. hagenowii has been used in integrated pest management (IPM) programs for cockroach control but little is known about how this parasitoid responds to the insecticides commonly used for cockroach management. Five insecticidal gel bait products containing indoxacarb, clothianidin, fipronil, dinotefuran, or abamectin B1 were tested for their toxicity towards A. hagenowii and the American cockroach, Periplaneta americana (L.; Blattodea: Blattidae), a host of A. hagenowii and a common pest. All baits were tested as fresh and 1-d aged deposits. Indoxacarb was the only active ingredient that did not cause significant (P  < 0.05) A. hagenowii mortality compared to the control in both the fresh and aged gel experiments (Median survival time [MST]s: 168 h fresh, 72 h aged). Clothianidin caused the lowest A. hagenowii MSTs across experiments (24 h, fresh and aged). All baits caused significant P. americana mortality as fresh and 1-d aged deposits (P  < 0.05). Indoxacarb appears most compatible with A. hagenowii in cockroach IPM. [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]

Data from prior research indicate the prepupal stage of the monarch butterfly life cycle is more sensitive to clothianidin exposure than the larval stage. A set of experiments was conducted to determine if the dietary clothianidin exposures that cause prepupal mortality are environmentally relevant. Monarch larvae were raised from egg to pupae on clothianidin‐contaminated swamp milkweed plants (Asclepias incarnata). Larval growth as well as larval and prepupal survival were monitored throughout the experiments, in which the exposures ranged from 1.4 to 2793.1 ng/g leaf. Exposures of 5.4 to 46.9 ng/g leaf resulted primarily in prepupal mortality, whereas higher exposures of 1042.4 to 2793.1 ng/g leaf resulted exclusively in larval mortality, indicating the prepupal stage is more sensitive to clothianidin exposure than the larval stage. A median lethal concentration and a 10% lethal concentration of 37 and 6 ng/g leaf, respectively, were estimated for prepupal mortality. Both effect concentrations are within the range of clothianidin concentrations reported in leaves collected from wild milkweed plants, indicating prepupal mortality is an environmentally relevant effect. Environ Toxicol Chem 2024;43:2039–2044. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

There is growing concern that some managed and wild insect pollinator populations are in decline, potentially threatening biodiversity and sustainable food production on a global scale. In recent years, there has been increasing evidence that sub-lethal exposure to neurotoxic, neonicotinoid pesticides can negatively affect pollinator immunocompetence and could amplify the effects of diseases, likely contributing to pollinator declines. However, a direct pathway connecting neonicotinoids and immune functions remains elusive. In this study we show that haemocytes and non-neural tissues of the honeybee Apis mellifera express the building blocks of the nicotinic acetylcholine receptors that are the target of neonicotinoids. In addition, we demonstrate that the haemocytes, which form the cellular arm of the innate immune system, actively express choline acetyltransferase, a key enzyme necessary to synthesize acetylcholine. In a last step, we show that the expression of this key enzyme is affected by field-realistic doses of clothianidin, a widely used neonicotinoid. These results support a potential mechanistic framework to explain the effects of sub-lethal doses of neonicotinoids on the immune function of pollinators. [ABSTRACT FROM AUTHOR]

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

Neonicotinoid insecticide seed treatments are commonly used in rice (Oryza sativa) production to control rice water weevil (Lisorhoptrus oryzophilus). With the use of neonicotinoid seed treatments, there is potential that honey bees (Apis mellifera) could be exposed to neonicotinoids through translocation to the pollen. Studies were conducted in 2015 and 2016 to determine the level of neonicotinoids present in flag leaves, pollen, and grain of rice. Thiamethoxam was applied as a seed treatment and foliar prior to flooding. Clothianidin was applied as a seed treatment and as a foliar at a preflood and postflood timing. Subsamples of flag leaves, pollen, and grain were analyzed for positive neonicotinoid detections and abundance. Thiamethoxam was detected in 8.9% of samples and clothianidin was detected in 1.4% of samples. For both thiamethoxam and clothianidin, more positive samples were observed in flag leaf samples than in pollen or grain. An average of 4.30 ng/g of thiamethoxam was detected in flag leaves from seed-applied thiamethoxam. An average of 1.25 ng/g of clothianidin was found in flag leaves from a preflood application of clothianidin. A survey of honey bees present in rice fields was conducted in Mississippi and Arkansas to determine the abundance of honey bees present in rice fields based on the time of day. Honey bee densities were low in rice, with less than 5% and 3% positive detections observed in Mississippi and Arkansas, respectively. More positive detections and higher densities of honey bees were observed for mid-day sampling than for morning or evening sampling. [ABSTRACT FROM AUTHOR]

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]

The versatility of cytochrome P450 reductase (CPR) in transferring electrons to P450s from other closely related species has been extensively exploited, e.g., by using An. gambiae CPR (AgCPR), as a homologous surrogate, to validate the role of An. funestus P450s in insecticide resistance. However, genomic variation between the AgCPR and An. funestus CPR (AfCPR) suggests that the full metabolism spectrum of An. funestus P450s might be missed when using AgCPR. To test this hypothesis, we expressed AgCPR and AfCPR side-by-side with CYP6P9a and CYP6P9b and functionally validated their role in the detoxification of insecticides from five different classes. Major variations were observed within the FAD- and NADP-binding domains of AgCPR and AfCPR, e.g., the coordinates of the second FAD stacking residue AfCPR-Y456 differ from that of AgCPR-His456. While no significant differences were observed in the cytochrome c reductase activities, when co-expressed with their endogenous AfCPR, the P450s significantly metabolized higher amounts of permethrin and deltamethrin, with CYP6P9b-AfCPR membrane metabolizing α-cypermethrin as well. Only the CYP6P9a-AfCPR membrane significantly metabolized DDT (producing dicofol), bendiocarb, clothianidin, and chlorfenapyr (bioactivation into tralopyril). This demonstrates the broad substrate specificity of An. funestus CYP6P9a/-b, capturing their role in conferring cross-resistance towards unrelated insecticide classes, which can complicate resistance management. [ABSTRACT FROM AUTHOR]

Elevated resistance to pyrethroids in major malaria vectors has led to the introduction of novel insecticides including neonicotinoids. There is a fear that efficacy of these new insecticides could be impacted by cross-resistance mechanisms from metabolic resistance to pyrethroids. In this study, after evaluating the resistance to deltamethrin, clothianidin and mixture of clothianidin + deltamethrin in the lab using CDC bottle assays, the efficacy of the new IRS formulation Fludora® Fusion was tested in comparison to clothianidin and deltamethrin applied alone using experimental hut trials against wild free-flying pyrethroid-resistant Anopheles funestus from Elende and field An. gambiae collected from Nkolondom reared in the lab and released in the huts. Additionally, cone tests on the treated walls were performed each month for a period of twelve months to evaluate the residual efficacy of the sprayed products. Furthermore, the L1014F-kdr target-site mutation and the L119F-GSTe2 mediated metabolic resistance to pyrethroids were genotyped on a subset of mosquitoes from the EHT to assess the potential cross-resistance. All Anopheles species tested were fully susceptible to clothianidin and clothianidin + deltamethrin mixture in CDC bottle assay while resistance was noted to deltamethrin. Accordingly, Fludora® Fusion (62.83% vs 42.42%) and clothianidin (64.42% vs 42.42%) induced significantly higher mortality rates in EHT than deltamethrin (42.42%) against free flying An. funestus from Elende in month 1 (M1) and no significant difference in mortality was observed between the first (M1) and sixth (M6) months of the evaluation (P > 0.05). However, lower mortality rates were recorded against An. gambiae s.s from Nkolondom (mortality rates 50%, 45.56% and 26.68%). In-situ cone test on the wall showed a high residual efficacy of Fludora® Fusion and clothianidin on the susceptible strain KISUMU (> 12 months) and moderately on the highly pyrethroid-resistant An. gambiae strain from Nkolondom (6 months). Interestingly, no association was observed between the L119F-GSTe2 mutation and the ability of mosquitoes to survive exposure to Fludora® Fusion, whereas a trend was observed with the L1014F-kdr mutation. This study highlights that Fludora® Fusion, through its clothianidin component, has good potential of controlling pyrethroid-resistant mosquitoes with prolonged residual efficacy. This could be therefore an appropriate tool for vector control in several malaria endemic regions. [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]

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 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]

Simple Summary: Small hive beetles (Aethina tumida) are a honey bee pest with few reliable in-hive chemical treatments available for beekeepers to use in the United States. Gel roach baits have been used off-label by commercial beekeepers as an alternative way to reduce small hive beetle populations. The objective of this study was to determine the toxicity of the active ingredients in gel roach baits to small hive beetles and honey bees (Apis mellifera) through topical exposure. In addition, we exposed small hive beetles to the active ingredients orally through pollen. All the active ingredients tested were more toxic to honey bees than to small hive beetles, except for fipronil, which was only slightly less toxic to honey bees than small hive beetles. The results of this study imply that gel roach baits should not be used in honey bee hives as small hive beetle treatments due to their toxicity to honey bees. Beekeepers need new treatment options for controlling small hive beetles (Aethina tumida), a devastating honey bee (Apis mellifera) pest. For many years, commercial beekeepers in the U.S. have used gel roach baits off-label as a method for treating SHBs. Herein, we evaluated the acute toxicity of active ingredients commonly found in gel roach baits, including abamectin, clothianidin, hydramethylnon, fipronil, and indoxacarb through topical and oral routes of exposure against SHBs and honey bees. Additionally, coumaphos, the active ingredient of the only registered in-hive control treatment for SHBs, was evaluated to provide a comparison to the gel roach bait active ingredients. Fipronil was the most toxic compound to SHBs topically (LD50 = 0.23 ng/SHB) and through pollen (LC50 = 0.06 µg/g pollen). Fipronil (LD50 = 0.31 ng/honey bee) had a selectivity ratio of 1.3, suggesting that it is more toxic to SHBs than it is to honey bees, but only to a small degree. Abamectin, clothianidin, hydramethylnon, and indoxacarb had a higher toxicity to honey bees than to SHBs through topical exposure. Our results suggest that gel roach baits and their active ingredients are toxic to honey bees and pose a serious risk to colony safety if used as in-hive treatments. [ABSTRACT FROM AUTHOR]

The ubiquitous use of insecticides leads to detrimental effects on non)target organisms due to accidental exposure. Neonicotinoid insecticides are popularly used worldwide for their high affinity for arthropod nicotinic receptors which effectively kill insect pests. Low affinity towards vertebrate nicotinic receptors, make them safer as compared to traditional insecticides. Recent studies demonstrated that neonicotinoid exposure can cause some toxicity in vertebrates including humans. Zebrafish is one of the popular model organisms to study ecotoxicity. This is the first study on adult zebrafish to report the effect of novel neonicotinoid, Clothianidin on mortality, liver antioxidant stress profile, liver function profile and brain acetylcholinesterase (AChE). Observations were made over two treatment periods, 96 hours, and 21 days, in five groups exposed to varying concentrations of Clothianidin viz. 30mg/L, 50mg/L, 70mg/L, 90mg/L, 110mg/L and a control. Although no mortality was observed, Clothianidin exposure led to increased activity of superoxide dismutase (SOD) enzyme, lipid peroxidation and decreased catalase (CAT), glutathione-S-transferase (GST). Treated groups also showed increased concentrations of liver enzyme alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and acid phosphatase (ACP). These results indicate that Clothianidin causes disturbances in the hepatic function. A prominent decreasing trend observed in brain AChE shows that Clothianidin inhibits AChE in adult zebrafish. Further investigations on DNA damage and gene expression studies could be conducted to understand the exact mechanism of action of Clothianidin at molecular level. [ABSTRACT FROM AUTHOR]

Photocatalysis is a prominent alternative wastewater treatment technique that has the potential to completely degrade pesticides as well as other persistent organic pollutants, leading to detoxification of wastewater and thus paving the way for its efficient reuse. In addition to the more conventional photocatalysts (e.g., TiO2, ZnO, etc.) that utilize only UV light for activation, the interest of the scientific community has recently focused on the development and application of visible light-activated photocatalysts like g-C3N4. However, some disadvantages of g-C3N4, such as the high recombination rate of photogenerated charges, limit its utility. In this light, the present study focuses on the synthesis of WO3 fibers/g-C3N4 Z-scheme heterojunctions to improve the efficiency of g-C3N4 towards the photocatalytic removal of the widely used insecticide clothianidin. The effect of two different g-C3N4 precursors (urea and thiourea) and of WO3 fiber content on the properties of the synthesized composite materials was also investigated. All aforementioned materials were characterized by a number of techniques (XRD, SEM-EDS, ATR-FTIR, Raman spectroscopy, DRS, etc.). According to the results, mixing 6.5% W/W WO3 fibers with either urea or thiourea derived g-C3N4 significantly increased the photocatalytic activity of the resulting composites compared to the precursor materials. In order to further elucidate the effect of the most efficient composite photocatalyst in the degradation of clothianidin, the generated transformation products were tentatively identified through UHPLC tandem high-resolution mass spectroscopy. Finally, the detoxification effect of the most efficient process was also assessed by combining the results of an in-vitro methodology and the predictions of two in-silico tools. [ABSTRACT FROM AUTHOR]

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

Thiamethoxam, a systemic neonicotinoid insecticide, is widely accepted for use against various chewing and sucking insect pests. In this particular study, the authors examined the dissipation kinetics and metabolism of thiamethoxam in wheat using quick, easy, cheap, effective, rugged and safe (QuEChERS) methodology combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) over two years during the same cropping season. Residues of thiamethoxam and its metabolites in wheat plants were investigated following foliar spray of thiamethoxam at recommended dose (12.5 g a.i. ha−1) and four times the recommended dose (50.0 g a.i. ha−1) at earhead formation stage. Total residues of thiamethoxam and its metabolites in leaves at 0 day (2 h after spray) ranged from 3.69 to 14.36 mg kg−1 for the two doses over the two years. Clothianidin was the only metabolite detected in leaves at 0 day (2 h after spray); however at 7 days after spray nitroguanidine, N-desmethyl-thiamethoxam and 1-methyl-3-nitroguanidine were also detected. Total residues of thiamethoxam and its metabolites in soil at 0 day (2 h after spray) ranged from 0.23 to 0.84 mg kg−1. Thiamethoxam residue in leaves and soil followed first order kinetics with half-life ranging from 9.04 to 15.50 days for the two doses over the two study years. Residues of thiamethoxam and its metabolites in leaves, straw and grain at harvest time for both the doses were below their limit of quantification (0.01 mg kg−1). This information could be helpful for evaluating both regulatory and food safety decisions regarding use of neonicotinoids. [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]

Background: Anopheles mosquito resistance to insecticide remains a serious threat to malaria vector control affecting several sub-Sahara African countries, including Côte d'Ivoire, where high pyrethroid, carbamate and organophosphate resistance have been reported. Since 2017, new insecticides, namely neonicotinoids (e.g.; clothianidin) and pyrroles (e.g.; chlorfenapyr) have been pre-qualified by the World Health Organization (WHO) for use in public health to manage insecticide resistance for disease vector control. Methods: Clothianidin and chlorfenapyr were tested against the field-collected Anopheles gambiae populations from Gagnoa, Daloa and Abengourou using the WHO standard insecticide susceptibility biossays. Anopheles gambiae larvae were collected from several larval habitats, pooled and reared to adulthood in each site in July 2020. Non-blood-fed adult female mosquitoes aged 2 to 5 days were exposed to diagnostic concentration deltamethrin, permethrin, alpha-cypermethrin, bendiocarb, and pirimiphos-methyl. Clothianidin 2% treated papers were locally made and tested using WHO tube bioassay while chlorfenapyr (100 µg/bottle) was evaluated using WHO bottle assays. Furthermore, subsamples of exposed mosquitoes were identified to species and genotyped for insecticide resistance markers including the knock-down resistance (kdr) west and east, and acetylcholinesterase (Ace-1) using molecular techniques. Results: High pyrethroid resistance was recorded with diagnostic dose in Abengourou (1.1 to 3.4% mortality), in Daloa (15.5 to 33.8%) and in Gagnoa (10.3 to 41.6%). With bendiocarb, mortality rates ranged from 49.5 to 62.3%. Complete mortality (100% mortality) was recorded with clothianidin in Gagnoa, 94.9% in Daloa and 96.6% in Abengourou, while susceptibility (mortality > 98%) to chlorfenapyr 100 µg/bottle was recorded at all sites and to pirimiphos-methyl in Gagnoa and Abengourou. Kdr-west mutation was present at high frequency (0.58 to 0.73) in the three sites and Kdr-east mutation frequency was recorded at a very low frequency of 0.02 in both Abengourou and Daloa samples and absent in Gagnoa. The Ace-1 mutation was present at frequencies between 0.19 and 0.29 in these areas. Anopheles coluzzii represented 100% of mosquitoes collected in Daloa and Gagnoa, and 72% in Abengourou. Conclusions: This study showed that clothianidin and chlorfenapyr insecticides induce high mortality in the natural and pyrethroid-resistant An. gambiae populations in Côte d'Ivoire. These results could support a resistance management plan by proposing an insecticide rotation strategy for vector control interventions. [ABSTRACT FROM AUTHOR]

Nitro-substituted neonicotinoid insecticides have been widely used until recently to control a range of important agricultural pests. Growing concerns about thiamethoxam's toxicity to pollinators have led to its use being restricted or to it even being banned in some countries. Nevertheless, in Asia, Africa, Southeast Europe, and South America thiamethoxam is still used. Although thiamethoxam has been intensively studied all over the world, its dissipation dynamics have not been studied in depth. The subject of the present study was to (1) develop and validate a QuEChERS/LC-MS/MS protocol for the determination of thiamethoxam and its main metabolite clothianidin in samples of young oilseed rape plants with high chlorophyll content, and (2) make a comparison of the degradation behaviors of thiamethoxam and clothianidin in two crops of winter oilseed rape, cultivated on soils with different pH. For determination of thiamethoxam and clothianidin in plant material with high chlorophyll content, a QuEChERS/LC–MS/MS protocol enabling the detection of low levels of compound concentrations was developed. The proposed clean-up protocol provided recoveries within the range of 92–98% for the compounds under analysis. Precision, calculated as relative standard deviation, was below 20%. Satisfactory linearity of the method was obtained in the concentration range under analysis (0.001–1.0 mg kg−1). Differences in degradation of both insecticides, depending on the physico-chemical properties of the soil, were observed. Thiamethoxam and clothianidin residues disappeared in plants very quickly, and they were not detected below the limit of quantitation in oilseed rape at the flowering stage. [ABSTRACT FROM AUTHOR]

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

Highly stable and photoluminescent methylammonium lead halide perovskite quantum dots (MAPbBr3 PQDs) have been synthesized and applied for the fluorescence quenching detection of clothianidin in fruit and vegetable samples. Characterizations using different techniques, including photoluminescence (PL), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-resolved PL (TRPL), show that static quenching is the dominant fluorescence quenching mechanism of MAPbBr3 PQDs with clothianidin. Hydrogen bonds or van der Waals forces play major roles in the MAPbBr3 PQDs–clothianidin interaction. Under optimized conditions, the relative PL intensity of MAPbBr3 PQDs is linear to the concentration of clothianidin in the 0.0 and 20.0 mg/L range with a detection limit of 0.17 μg/kg. Excellent recoveries of 79.5–115.4% were acquired for radish and banana samples with a relative standard deviation below 9.4%. These results indicate that PQDs can be used for qualitative and quantitative identification of clothianidin, providing an effective detection method for risk prevention and control of neonicotinoid pesticide residues in agricultural products. [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]

The St. Lawrence River is an important North American waterway that is subject to anthropogenic pressures including intensive urbanization, and agricultural development. Pesticides are widely used for agricultural activities in fields surrounding the yellow perch (Perca flavescens) habitat in Lake St. Pierre (Quebec, Canada), a fluvial lake of the river where the perch population has collapsed. Clothianidin and chlorantraniliprole were two of the most detected insecticides in surface waters near perch spawning areas. The objectives of the present study were to evaluate the transcriptional and biochemical effects of these two pesticides on juvenile yellow perch exposed for 28d to environmental doses of each compound alone and in a mixture under laboratory/aquaria conditions. Hepatic mRNA-sequencing revealed an effect of chlorantraniliprole alone (37 genes) and combined with clothianidin (251 genes), but no effects of clothianidin alone were observed in perch. Dysregulated genes were mostly related to circadian rhythms and to Ca2+ signaling, the latter effect has been previously associated with chlorantraniliprole mode of action in insects. Moreover, chronic exposure to clothianidin increased the activity of acetylcholinesterase in the brain of exposed fish, suggesting a potential non-target effect of this insecticide. Further analyses of three clock genes by qRT-PCR suggested that part of the observed effects of chlorantraniliprole on the circadian gene regulation of juvenile perch could be the result of time-of-day of sacrifice. These results provide insight into biological effects of insecticides in juvenile perch and highlight the importance of considering the circadian rhythm in experimental design and results analyses. [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]

Background: Clothianidin-based indoor residual spraying (IRS) formulations have become available for malaria control as either solo formulations of clothianidin or a mixture of clothianidin with the pyrethroid deltamethrin. While both formulations have been successfully used for malaria control, studies investigating the effect of the pyrethroid in IRS mixtures may help improve our understanding for development of future IRS products. It has been speculated that the irritant effect of the pyrethroid in the mixture formulation may result in shorter mosquito contact times with the treated walls potentially leading to a lower impact. Methods: We compared contact irritancy expressed as the number of mosquito take-offs from cement surfaces treated with an IRS formulation containing clothianidin alone (SumiShield® 50WG) to clothianidin-deltamethrin mixture IRS formulations against pyrethroid-resistant Anopheles gambiae sensu lato under controlled laboratory conditions using a modified version of the World Health Organisation cone bioassay. To control for the pyrethroid, comparison was made with a deltamethrin-only formulation. Both commercial and generic non-commercial mixture formulations of clothianidin and deltamethrin were tested. Results: The clothianidin solo formulation did not show significant contact irritancy relative to the untreated control (3.5 take-offs vs. 3.1 take-offs, p = 0.614) while all deltamethrin-containing IRS induced significant irritant effects. The number of take-offs compared to the clothianidin solo formulation (3.5) was significantly higher with the commercial clothianidin-deltamethrin mixture (6.1, p = 0.001), generic clothianidin-deltamethrin mixture (7.0, p < 0.001), and deltamethrin-only (8.2, p < 0.001) formulations. The commercial clothianidin-deltamethrin mixture induced similar contact irritancy as the generic clothianidin-deltamethrin mixture (6.1 take-offs vs. 7.0 take-offs, p = 0.263) and deltamethrin-only IRS (6.1 take-offs vs. 8.2, p = 0.071), showing that the irritant effect in the mixture was attributable to its deltamethrin component. Conclusions: This study provides evidence that the enhanced contact irritancy of the pyrethroid in clothianidin-deltamethrin IRS mixtures can shorten mosquito contact times with treated walls compared to the clothianidin solo formulation. Further trials are needed to directly compare the efficacy of these formulation types under field conditions and establish the impact of this enhanced contact irritancy on the performance of IRS mixture formulations containing pyrethroids. [ABSTRACT FROM AUTHOR]

A novel molecularly imprinted nanomaterial (Eu (BTC)-MPS@MIP) was synthesized on the surface of silanized europium-based metal–organic frameworks (Eu (BTC)-MPS) using 1, 3, 5-benzotrioic acid (H3BTC) as a ligand. The resulting Eu (BTC)-MPS@MIP was applied to constructing a smartphone sensing platform for the sensitive and selective detection of clothianidin (CLT) in vegetables. The synthesized Eu (BTC)-MPS@MIP demonstrated the successful formation of a typical core–shell structure featuring a shell thickness of approximately 70 − 80 nm. The developed sensing platform based on Eu (BTC)-MPS@MIP exhibited sensitivity in CLT detection with a detection limit of 4 µg/L and a linear response in the range 0.01 − 10 mg/L at excitation and emission wavelengths of 365 nm and 617 nm, respectively. The fluorescence sensing platform displayed excellent specificity for CLT detection, as evidenced by a high imprinting factor of 3.1. This specificity is primarily attributed to the recognition sites in the molecularly imprinted polymer (MIP) layer. When applied to spiked vegetable samples, the recovery of CLT ranged from 78.9 to 102.0%, with relative standard deviation (RSD) values falling between 2.2 and 6.2%. The quenching mechanism of Eu (BTC)-MPS@MIP toward CLT can be attributed to the inner filter effect (IFE), resulting from the optimal spectral overlap between the absorption spectrum of CLT and the excitation spectra of Eu (BTC)-MPS@MIP. The proposed method has the potential for extension to the detection of other pesticides by replacing the MIP recognition probes. [ABSTRACT FROM AUTHOR]

Background: Indoor residual spraying (IRS) capitalizes on the natural behavior of mosquitoes because Aedes aegypti commonly seeks indoor resting sites after a blood meal. This behavior allows mosquitoes to be exposed to insecticide-treated surfaces and subsequently killed. Combinations of deltamethrin and clothianidin with different modes of action have shown promise in IRS, effectively targeting both susceptible and pyrethroid-resistant malaria vectors. However, the effects of this approach on Aedes mosquitoes remain unclear. The present study tested the effects of deltamethrin–clothianidin mixture treatment on behavioral responses and life history traits of Taiwanese and Indonesian populations of Ae. aegypti. Methods: We adopted an excito-repellent approach to explore the behavioral responses of pyrethroid-resistant Ae. aegypti populations from Indonesia and Taiwan to a deltamethrin–clothianidin mixture used in contact irritancy and non-contact repellency treatments. We further evaluated the life history traits of surviving mosquitoes (i.e., delayed mortality after 7-day post-treatment, longevity, fecundity, and egg hatching) and investigated the potential transgenerational hormetic effects of insecticide exposure (i.e., development rate and survival of immatures and adult mosquitos). Results: All tested field populations of Ae. aegypti displayed strong contact irritancy responses; the percentage of escape upon insecticide exposure ranged from 38.8% to 84.7%. However, repellent effects were limited, with the escape percentage ranging from 4.3% to 48.9%. We did not observe immediate knockdown or mortality after 24 h, and less than 15% of the mosquitoes exhibited delayed mortality after a 7-day exposure period. However, the carryover effects of insecticide exposure on the survival of immature mosquitoes resulted in approximately 25% higher immature mortality than that in the control. By contrast, we further documented stimulated survivor reproduction and accelerated transgenerational immature development resulting from the sublethal effects of the insecticide mixture. In particular, the number of eggs laid by treated (both treatments) female mosquitoes increased by at least 60% compared with that of eggs laid by control female mosquitoes. Conclusions: IRS with deltamethrin–clothianidin effectively deters Aedes mosquitoes from entering residential areas and thereby reduces mosquito bites. However, the application rate (deltamethrin: 25 mg/m2; clothianidin: 200 mg/m2) may be insufficient to effectively kill Aedes mosquitoes. Insecticide response appears to vary across mosquito species; their behavioral and physiological responses to sublethal doses have crucial implications for mosquito control programs. [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]

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

BACKGROUND: Understanding the trade‐offs between insecticide resistance and the associated fitness is of particular importance to sustainable pest control. One of the most devastating pest worldwide, the whitefly Bemisia tabaci, has developed resistance to various insecticides, especially the neonicotinoid group. Although neonicotinoid resistance often is conferred by P450s‐mediated metabolic resistance, the relationship between such resistance and the associated fitness phenotype remains largely elusive. By gene cloning, quantitative reverse transcription (qRT)‐PCR, RNA interference (RNAi), transgenic Drosophila melanogaster, metabolism capacity in vitro and 'two sex‐age stage' life table study, this study aims to explore the molecular role of a P450 gene CYP4CS5 in neonicotinoid resistance and to investigate whether such resistance mechanism carries fitness costs in the whitefly. RESULTS: Our bioassay tests showed that a total of 13 field‐collected populations of B. tabaci MED biotype displayed low‐to‐moderate resistance to thiamethoxam and clothianidin. Compared to the laboratory susceptible strain, we then found that an important P450 CYP4CS5 was remarkably upregulated in the field resistant populations. Such overexpression of CYP4CS5 had a good match with the resistance level among the whitefly samples. Further exposure to the two neonicotinoids resulted in an increase in CYP4CS5 expression. These results implicate that overexpression of CYP4CS5 is closely correlated with thiamethoxam and clothianidin resistance. RNAi knockdown of CYP4CS5 increased mortality of the resistant and susceptible populations after treatment with thiamethoxam and clothianidin in bioassay, but obtained an opposite result when using a transgenic line of D. melanogaster expressing CYP4CS5. Metabolic assays in vitro revealed that CYP4CS5 exhibited certain capacity of metabolizing thiamethoxam and clothianidin. These in vivo and in vitro assays indicate an essential role of CYP4CS5 in conferring thiamethoxam and clothianidin resistance in whitefly. Additionally, our life‐table analysis demonstrate that the field resistant whitefly exhibited a prolonged development time, shortened longevity and reduced fecundity compared to the susceptible, suggesting an existing fitness cost as a result of the resistance. CONCLUSION: Collectively, in addition to the important role of CYP4CS5 in conferring thiamethoxam and clothianidin resistance, this resistance mechanism is associated with fitness costs in the whitefly. These findings not only contribute to the development of neonicotinoids resistance management strategies, but also provide a new target for sustainable whitefly control. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Chronic exposure of mosquito larvae to pesticide residues and cross-resistance mechanisms are major drivers of tolerance to insecticides used for vector control. This presents a concern for the efficacy of clothianidin, an agricultural neonicotinoid prequalified for Indoor Residual Spraying (IRS). Methods: Using standard bioassays, we tested if reduced susceptibility to clothianidin can affect the efficacy of SumiShield® 50WG, one of four new IRS formulations containing clothianidin. We simultaneously monitored susceptibility to clothianidin and to SumiShield 50WG, testing adults of Anopheles gambiae, An. coluzzii and Culex sp sampled from urban, suburban and agricultural areas of Yaoundé, Cameroon. Results: We found that in this geographic area, the level of susceptibility to the active ingredient predicted the efficacy of SumiShield 50WG. This formulation was very potent against populations that reached 100% mortality within 72 h of exposure to a discriminating concentration of clothianidin. By contrast, mortality leveled off at 75.4 ± 3.5% within 7 days of exposure to SumiShield 50WG in An. gambiae adults collected from a farm where the spraying of the two neonicotinoids acetamiprid and imidacloprid for crop protection is likely driving resistance to clothianidin. Conclusions: Despite the relatively small geographic extend of the study, the findings suggest that cross-resistance may impact the efficacy of some new IRS formulations and that alternative compounds could be prioritized in areas where neonicotinoid resistance is emerging. [ABSTRACT FROM AUTHOR]

Background: Clothianidin, an insecticide with a novel mode of action, has been deployed in the annual indoor residual spraying programme in northern Ghana since March 2021. To inform pragmatic management strategies and guide future studies, baseline data on local Anopheles gambiae sensu lato (s.l.) susceptibility to the clothianidin insecticide were collected in Kpalsogu, a village in the Northern region, Ghana. Methods: Phenotypic susceptibility of An. gambiae mosquitoes to clothianidin was assessed using the World Health Organization (WHO) insecticide resistance monitoring bioassay. The WHO cone bioassays were conducted on mud and cement walls sprayed with Sumishield 50 wettable granules (WG) (with clothianidin active ingredient). Daily mortalities were recorded for up to 7 days to observe for delayed mortalities. Polymerase chain reaction (PCR) technique was used to differentiate the sibling species of the An. gambiae complex and also for the detection of knock down resistance genes (kdr) and the insensitive acetylcholinesterase mutation (ace-1). Results: The WHO susceptibility bioassay revealed a delayed killing effect of clothianidin. Mosquitoes exposed to the cone bioassays for 5 min died 120 h after exposure. Slightly higher mortalities were observed in mosquitoes exposed to clothianidin-treated cement wall surfaces than mosquitoes exposed to mud wall surfaces. The kdr target-site mutation L1014F occurred at very high frequencies (0.89–0.94) across all vector species identified whereas the ace-1 mutation occurred at moderate levels (0.32–0.44). Anopheles gambiae sensu stricto was the most abundant species observed at 63%, whereas Anopheles arabiensis was the least observed at 9%. Conclusions: Anopheles gambiae s.l. mosquitoes in northern Ghana were susceptible to clothianidin. They harboured kdr mutations at high frequencies. The ace-1 mutation occurred in moderation. The results of this study confirm that clothianidin is an effective active ingredient and should be utilized in malaria vector control interventions. [ABSTRACT FROM AUTHOR]

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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]

In this study, the aqueous photolytic degradation of the neonicotinoid pesticide clothianidin was studied in suspensions and aqueous extracts of hydrochar produced from olive kernels. A slight and nonsignificant decrease in the photodegradation rate of clothianidin in aqueous extracts of hydrochar (HCw) with an initial concentration of hydrochar ranged from 50 to 400 mg L−1 (rate constants ranged between k = 0.0034 and 0.0039 min−1) was observed in comparison to the respective rate in the bi-distilled water (k = 0.0040 min−1). On the contrary, in the presence of hydrochar suspensions (HCp), a significant decrease was observed for 50 mg L−1 hydrochar particle concentration (k = 0.020 min−1), while for higher concentrations (100 to 400 mg L−1), rate constants increased but with nonsignificant differences compared with the kinetics followed in the absence of them. Generally, the photodegradation rate of clothianidin, in the presence of HCw and HCp, is reduced compared to the photodegradation rate in bi-distilled aqueous solutions, except in the case of the aqueous suspension with an HCp concentration of 200 mg L−1. The transformation products (TPs) of clothianidin formed in the photolytic degradation processes were identified using ultrahigh-performance liquid chromatography coupled with accurate high-resolution mass spectrometry technique (UHPLC-LTQ-ORBITRAP). The formation profiles of TPs varied according to the matrix showing different degrees of participation of direct and indirect (photosensitized) phototransformation pathways. Photolytic degradation of clothianidin takes place mainly through denitration, hydroxylation and dechlorination pathways. Finally, the toxicity of the identified TPs was studied using the Vibrio fischeri bioassay. Toxicity was slightly reduced after 300 min of irradiation while maximum value was observed after 180–240 min of irradiation showing the formation of more toxic TPs along the photochemical degradation. [ABSTRACT FROM AUTHOR]

Neonicotinoids, systemic insecticides that are distributed into all plant tissues and protect against pests, have become a common part of crop production, but can unintentionally also affect non-target organisms, including pollinators. Such effects can be direct effects from insecticide exposure, but neonicotinoids can affect plant physiology, and effects could therefore also be indirectly mediated by changes in plant phenology, attractiveness and nutritional value. Under controlled greenhouse conditions, we tested if seed treatment with the neonicotinoid clothianidin affected oilseed rape's production of flower resources for bees and the content of the secondary plant products glucosinolates that provide defense against herbivores. Additionally, we tested if seed treatment affected the attractiveness of oilseed rape to flower visiting bumblebees, using outdoor mesocosms. Flowers and leaves of clothianidin-treated plants had different profiles of glucosinolates compared with untreated plants. Bumblebees in mesocosms foraged slightly more on untreated plants. Neither flower timing, flower size nor the production of pollen and nectar differed between treatments, and therefore cannot explain any preference for untreated oilseed rape. We instead propose that this small but significant preference for untreated plants was related to the altered glucosinolate profile caused by clothianidin. Thereby, this study contributes to the understanding of the complex relationships between neonicotinoid-treated crops and pollinator foraging choices, by suggesting a potential mechanistic link by which insecticide treatment can affect insect behavior. [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]

Xenobiotics, which include a wide range of synthetic chemicals and compounds, have become a significant threat to water quality and biodiversity. The need for innovative and sustainable solutions to mitigate the impact of pollutants on our ecosystems has become a hot topic of numerous discussions and research. One such solution lies in the potential application of simulated solar radiation and hydrogen peroxide to remove pesticides from aqueous solutions. In this paper, we investigated the possibility of removing selected pesticides (acetamiprid, clothianidin, and thiacloprid) under the influence of simulated solar radiation with and without the presence of hydrogen peroxide (H2O2). The influence of pH value and H2O2 concentration on removal and toxicity before and after photolytic removal was examined. The results showed that clothianidin is almost completely removed (94.80–96.35%) after 5 h under the influence of simulated solar radiation, while thiacloprid and acetamiprid confirm their persistence and resistance to photolytic degradation. The addition of H2O2 leads to the removal of all three pesticides and results in a significant acceleration of the degradation process itself and the removal of the individual pesticides already within 2 h. According to the data obtained, the k values obtained in the paper follow the following trend: clothianidin > thiacloprid > acetamiprid. [ABSTRACT FROM AUTHOR]

VECTRON™ T500 is a wettable powder IRS formulation of broflanilide, a newly discovered insecticide. We performed a two-arm non-inferiority community randomised evaluation of VECTRON™ T500, compared to Fludora® Fusion against pyrethroid-resistant Anopheles gambiae s.l. in an area of high coverage with pyrethroid-only nets in the Za-Kpota District of central Benin. One round of IRS was applied in all consenting households in the study area. Sixteen clusters were randomised (1:1) to receive VECTRON™ T500 (100 mg/m2 for broflanilide) or Fludora® Fusion (200 mg/m2 for clothianidin and 25 mg/m2 for deltamethrin). Surveys were performed to assess adverse events and the operational feasibility and acceptability of VECTRON™ T500 among spray operators and household inhabitants. Human landing catches were conducted in 6 households every 1–2 months for up to 18 months post-intervention to assess the impact on vector densities, sporozoite rates and entomological inoculation rates. Bottle bioassays were performed to monitor vector susceptibility to pyrethroids, broflanilide and clothianidin. Monthly wall cone bioassays were conducted for 24 months to assess the residual efficacy of the IRS formulations using susceptible and pyrethroid-resistant An. gambiae s.l. A total of 26,562 female mosquitoes were collected during the study, of which 40% were An. gambiae s.l., the main malaria vector in the study area. The vector population showed high intensity pyrethroid resistance but was susceptible to broflanilide (6 µg/bottle) and clothianidin (90 µg/bottle). Using a non-inferiority margin of 50%, vector density indicated by the human biting rate (bites/person/night) was non-inferior in the VECTRON™ T500 arm compared to the Fludora® Fusion arm both indoors (0.846 bites/p/n in Fludora® Fusion arm vs. 0.741 bites/p/n in VECTRON™ T500 arm, IRR 0.54, 95% CI 0.22–1.35, p = 0.150) and outdoors (0.691 bites/p/n in Fludora® Fusion arm vs. 0.590 bites/p/n in VECTRON™ T500 clusters, IRR 0.75, 95% CI 0.41–1.38, p = 0.297). Sporozoite rates and entomological inoculation rates did not differ significantly between study arms (sporozoite rate: 0.9% vs 1.1%, p = 0. 0.746, EIR: 0.008 vs 0.006 infective bites per person per night, p = 0.589). Cone bioassay mortality with both VECTRON™ T500 and Fludora® Fusion was 100% for 24 months post-IRS application on both cement and mud treated house walls with both susceptible and pyrethroid-resistant strains of An. gambiae s.l. Perceived adverse events reported by spray operators and householders were generally very low (< 6%) in both study arms. VECTRON™ T500 was non-inferior to Fludora® Fusion in reducing the risk of malaria transmission by pyrethroid resistant vectors when applied for IRS in communities in central Benin. The insecticide showed prolonged residual efficacy on house walls, lasting over 24 months and had a high acceptability with homeowners. Community application of VECTRON™ T500 for IRS provides improved and prolonged control of pyrethroid resistant malaria vectors and enhances our capacity to manage insecticide resistance. [ABSTRACT FROM AUTHOR]

For over a decade, beekeepers have experienced high losses of honey bee (Apis mellifera L.) colonies due to a variety of stressors including pesticide exposure. Some of these chemical stressors may residually remain in the colony comb and food resources (pollen and nectar) of failed colonies and be later re-used by beekeepers when splitting and building back new colonies. The practice of re-using comb from previously perished colonies (termed "deadout") is common in beekeeping practice, but its role in affecting colony health is not well understood. Here, we evaluate the impact of reused, pesticide-contaminated "deadout" combs on colony function during the process of replacing a queen bee. Queenless microcolonies were established to monitor queen rearing capacity in two treatment groups: (1) colonies given frames containing food resources from deadout colonies in control "clean" apiaries and, (2) colonies given frames containing "contaminated" resources from deadout colonies originating from apiaries experiencing chronic pesticide exposure from widespread systemic pesticide pollution (including neonicotinoid insecticides: clothianidin and thiamethoxam). Results indicate that colonies given pesticide-contaminated resources produced fewer queen cells per colony and had a lower proportion of colonies successfully raising a functional, diploid egg-laying queen. This research highlights the deleterious effects of re-using deadout combs from colonies previously lost due to pesticide contamination. [ABSTRACT FROM AUTHOR]