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Simple Summary: This work investigates the olfactory mechanism of aphids with varying preferences for TMX-coated and uncoated wheat plants. This study utilized the olfactory localization preferences of aphids to identify the volatile metabolites of both TMX-coated and uncoated wheat. The differential metabolites were then used to assess the olfactory behavior of aphids. The results indicated that four compounds had repellent activity towards aphids, while two compounds demonstrated attracting activity towards aphids. These findings highlight the potential of using TMX-induced VOCs to manage aphid behavior and develop environmentally friendly pest control strategies. Pesticides can induce target plants to release odors that are attractive or repellent to their herbivore insects. But, to date, the activity of volatile organic compounds (VOCs), singly or as mixtures, which play a crucial role in the olfactory behavior of herbivore insects, remains unclear. The objective of our research was to investigate the impact of thiamethoxam (TMX), a pesticide, on the emission of odors by wheat plants, and how these odors influence the behavior of grain aphids (Sitobion miscanthi). S. miscanthi showed a greater repellent response to the volatiles emitted by Thx-induced plants compared to those emitted by uncoated plants. Using gas chromatography–mass spectrometry (GCMS), we discovered that TMX greatly induced the release of VOCs in wheat plants. For instance, the levels of Bornyl acetate, 2-Oxepanone, Methyl acrylate, Cyclohexene, α-Pinene, and 1-Nonanol in coated wheat plants were significantly higher as compared to uncoated wheat plants. Moreover, varying concentrations also had an impact on the olfactory behavior of S. miscanthi. For instance, Cyclohexene exhibited clear attractiveness to aphids at concentrations of 100 μL/mL, whereas it displayed evident repellent properties at concentrations of 1 μL/mL and 10 μL/mL. These new findings demonstrate how TMX-induced VOCs affect the behavior of S. miscanthi and could help in developing innovative approaches to manage aphids by manipulating the emission of plant volatiles. Furthermore, these findings can also be utilized to evaluate substances that either attract or repel aphids, with the aim of implementing early monitoring and environmentally friendly methods to manage aphids, while simultaneously impeding the spread of viruses. [ABSTRACT FROM AUTHOR]

In the tea-planting process, insecticides are commonly combined, potentially prolonging the pre-harvest interval and heightening the risk of dietary exposure. This study focused on three frequently used insecticides in tea cultivation: thiamethoxam, bifenthrin, and dinotefuran, aiming to investigate their dissipation behaviors and associated dietary risks upon individual and simultaneous application. The dissipation kinetics of thiamethoxam, bifenthrin, and dinotefuran were successfully characterized by first-order kinetics, yielding respective half-lives of 5.44, 9.81, and 10.16 days. Upon joint application, the dissipation half-lives of thiamethoxam and bifenthrin were notably prolonged compared with their individual applications, resulting in final concentrations after 28 days that were correspondingly elevated by 1.41 and 1.29 times. Assessment of the dietary intake risk revealed that the chronic and acute risk quotients associated with thiamethoxam and bifenthrin escalated by 1.44–1.59 times following their combined application. Although dietary risks associated with Tianmuhu white tea, as determined by the exposure assessment model, were deemed acceptable, the cumulative risks stemming from pesticide mixtures across various dietary sources warrant attention. Molecular docking analyses further unveiled that thiamethoxam and bifenthrin competitively bound to glutathione S-transferase (GST) at amino acid residues, notably at the 76th GLU and the 25th PHE, pivotal in the metabolism and absorption of exogenous substances. Moreover, the interactions between P-glycoprotein and pesticides during transport and absorption were likely to influence dissipation behaviors post-joint application. This research offers valuable insights and data support for optimizing joint pesticide application strategies and assessing risks associated with typical pesticides used in tea cultivation. [ABSTRACT FROM AUTHOR]

Simple Summary: Previous studies have documented regional susceptibility of the silverleaf whitefly (Bemisia tabaci) to common insecticide active ingredients among populations with different bacterial endosymbionts. Here, we tested the efficacy of 11 different insecticides on three populations of silverleaf whitefly found in Brazil with varying bacterial communities. Significant differences among population responses were measured for four of the tested active ingredients, two of which were neonicotinoids. DNA sequencing detected two types of bacteria in the population more susceptible to insecticides, showing a linkage of host, symbiote, and insecticide resistance. The silverleaf whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), is a significant agricultural pest worldwide, impacting a variety of crop yields. Since the introduction of B. tabaci Mediterranean (MED) species in Brazil, limited research has measured the relative efficacy of the primary insecticides used in whitefly management. This study evaluated the susceptibility of three distinct B. tabaci MED populations to 11 insecticide active ingredients and characterized the bacterial endosymbionts within each population. The insecticides tested were acetamiprid, bifenthrin, cyantraniliprole, diafenthiuron, spiromesifen, imidacloprid, pymetrozine, pyriproxyfen, sulfoxaflor, and thiamethoxam. Results showed varying LC50 and LC90 values among tested insecticides and populations. Notably, populations varied in response to imidacloprid and thiamethoxam with some populations having a 6× higher tolerance. Sequencing data of endosymbionts revealed that individuals from the most susceptible B. tabaci population harbored Rickettsia and Arsenophonus, whereas these bacteria were not detected in the resistant populations. These findings highlight the need for frequent insecticide toxicity bioassays of distinct B. tabaci populations and the adoption of integrated pest management strategies to preserve the efficacy of insecticides for B. tabaci control. Additionally, the role of infection by endosymbionts to alter susceptibility should be further explored. [ABSTRACT FROM AUTHOR]

Simple Summary: Several differentially expressed genes encoding cytochrome P450 monooxygenases (P450s) and UDP-glycosyltransferases (UGTs), namely, CYP9Z140, CYP9AY1, and UGT321AP1, were screened and verified between thiamethoxam-susceptible and resistant populations of Leptinotarsa decemlineata (Say). The expression of the three genes was significantly enhanced after exposure to thiamethoxam. RNA interference of three genes increased mortality of test adults following thiamethoxam treatment. The findings reveal that the three genes have roles in the thiamethoxam resistance of L. decemlineata. Cytochrome P450 monooxygenases (P450s) and UDP-glycosyltransferases (UGTs) are involved in the evolution of insecticide resistance. Leptinotarsa decemlineata (Say), the Colorado potato beetle (CPB), is a notorious insect that has developed resistance to various insecticides including neonicotinoids. This study investigated whether the differentially expressed P450 genes CYP9Z140 and CYP9AY1 and UGT gene UGT321AP1, found in our transcriptome results, conferred resistance to thiamethoxam in L. decemlineata. Resistance monitoring showed that the sampled field populations of L. decemlineata adults collected from Urumqi City and Qapqal, Jimsar, and Mulei Counties of Xinjiang in 2021–2023 developed low levels of resistance to thiamethoxam with resistance ratios ranging from 6.66- to 9.52-fold. Expression analyses indicated that CYP9Z140, CYP9AY1, and UGT321AP1 were significantly upregulated in thiamethoxam-resistant populations compared with susceptible populations. The expression of all three genes also increased significantly after thiamethoxam treatment compared with the control. Spatiotemporal expression patterns showed that the highest expression of CYP9Z140 and CYP9AY1 occurred in pupae and the midgut, whereas UGT321AP1 was highly expressed in adults and Malpighian tubules. Knocking down all three genes individually or simultaneously using RNA interference increased the sensitivity of adult L. decemlineata to thiamethoxam. These results suggest that overexpression of CYP9Z140, CYP9AY1, and UGT321AP1 contributes to the development of thiamethoxam resistance in L. decemlineata and provides a scientific basis for improving new resistance management of CPB. [ABSTRACT FROM AUTHOR]

Repeated pesticide residue detection in chili peppers in the Republic of Korea has become a serious health concern. Thus, monitoring domestically grown and imported chili peppers for pesticide residues is of great significance. Here, we investigated pesticide residues detected in imported and domestically grown chili peppers using global pesticide residue monitoring data. Our analysis involved organizing inspection and detection data from different sources. Global pesticide residue monitoring data for chili peppers revealed 139 pesticide types, 43,532 inspections, and 3966 detections (detection rate, 9.11%). Peppers from Mexico were sampled the most (39,927 inspections) and showed the highest number of detected cases (2998 cases). Globally, the top 10 most frequently detected pesticides were clothianidin, imidacloprid, thiamethoxam, chlorpyrifos, thiacloprid, metalaxyl, myclobutanil, azoxystrobin, carbendazim, and cyhalothrin, with detection rates in the range of 10.52–28.66%. Furthermore, domestic chili pepper pesticide residue monitoring revealed 73 pesticide types, 3535 inspections, and 332 detected cases (detection rate, 9.39%), and the top 10 most frequently detected pesticides were chlorfenapyr, tebuconazole, flonicamid, dinotefuran, boscalid, pyraclostrobin, fluxametamide, thiamethoxam, pyridaben, and azoxystrobin, with detection rates in the range of 13.89–32.58%. These findings may serve as fundamental data for safety management related to chili pepper pesticide residues in the Republic of Korea. [ABSTRACT FROM AUTHOR]

The stink bug, Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), is a highly destructive pest that significantly damages legume crops in East and South Asia. Neonicotinoid insecticides containing thiamethoxam are widely used to control R. pedestris in soybean fields. However, the current knowledge on the impact of different thiamethoxam concentrations on R. pedestris growth and reproduction is lacking and insufficient. The present study investigated the effects of thiamethoxam on the biological traits of R. pedestris after treatment with LC10 (19.8 mg/L), LC20 (31.6 mg/L), LC30 (44.2 mg/L), LC40 (58.9 mg/L), and LC50 (77.0 mg/L) concentrations. These five thiamethoxam concentrations (LC10~LC50) reduced adult longevity and fecundity in the F1 generation females. Thiamethoxam treatment also significantly decreased the population trend index, intrinsic rate of increase, net reproductive rate, gross reproductive rate, and finite rate of increase and increased the mean generation time. These results show that thiamethoxam hinders and suppresses the development and growth of the F1 population of R. pedestris. Thiamethoxam is recommended for spray control during peak adult emergence, as it not only has a controlling effect on the parental generation but also a negative impact on the F1 generations. [ABSTRACT FROM AUTHOR]

Simple Summary: Bemisia tabaci (Gennadius) is a worldwide agricultural pest and is one of the most harmful invasive insect pests in the world. The overuse of insecticides has caused B. tabaci to develop high resistance against multiple insecticidal chemicals. It is well recognized that over-expression of cytochrome P450s involved in insecticide detoxification is one common and major mechanism of resistance to various classes of insecticides in insects. In addition to gene duplication and amplification, up-regulation of P450s at the transcriptional level is a common and important mechanism for P450-mediated insecticide resistance. Here, two new CYP450 genes from B. tabaci MEAM1 were cloned, and their expression patterns were studied in response to two different insecticides, high temperature, and their combined effects. The results showed that the insecticide tolerance could be reduced by high temperatures; under combined stress, the mortality of B. tabaci MEAM1 increased. This study is an important addition to the research on insecticide tolerance in B. tabaci and may help to reduce the overreliance on insecticides for B. tabaci control. Bemisia tabaci (Gennadius) is one of the most important invasive species in China, with strong insecticide resistance and thermotolerance. In this study, we investigated the effects of elevated temperature on the tolerance of B. tabaci MEMA1 to abamectin (AB) and thianethixam (TH) insecticides. We firstly cloned two new CYP450 genes from B. tabaci MEAM1, including one CYP6 family gene (BtCYP6k1) and one CYP305 family gene (BtCYP305a1). The expression patterns of the two BtCYP450 genes were compared in response to high-temperature stress and insecticide exposure, and RNAi was then used to demonstrate the role that these two genes play in insecticide tolerance. The results showed that expression of the two BtCYP450 genes could be induced by exposure to elevated temperature or insecticide, but this gene expression could be inhibited to a certain extent when insects were exposed to the combined effects of high temperature and insecticide treatment. For AB treatment, the expression of the two BtCYP450 genes reached the lowest level when insects were exposed to a temperature of 41 °C and treated with AB (combined effects of temperature and insecticide). In contrast, TH treatment showed a general decrease in the expression of the two BtCYP450 genes with exposure to elevated temperatures. These findings suggest that insecticide tolerance in B. tabaci MEAM1 could be mediated by high temperatures. This study provides a prospective method for the more effective application of insecticides for the control of B. tabaci in the field. [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]

Pesticides ensure greater productivity in less time; however, they spread beyond the perimeters to which they are applied to reach non-target organisms, thereby affecting plant, animal, and human health. Thiamethoxam (TMX) is considered to be one of the main agents responsible for poisoning bees and potentially contaminating surface and groundwater. Conventional water-treatment protocols are unable to degrade thiamethoxam; therefore, electrochemically advanced oxidative processes (EAOPs) have become promising alternatives owing to their ease of operation and cost-effectiveness. Herein, we examined the use of EAOPs to oxidize thiamethoxam in commercial Actara® and analyzed treatment efficiencies through phytotoxicity studies using cucumber and maize seeds as bioindicators. In addition, the cost of each process was analyzed based on the resulting current efficiency. The treated solutions were used to germinate seeds that were analyzed for total protein, hydrogen peroxide, lipid peroxidation (MDA), superoxide dismutase (SOD), and catalase (CAT) activities. EAOPs were found to effectively oxidize TMX, with more than 50% degraded and 80% COD removed under all treatment conditions, even when the commercial product was used. The photoelectro-Fenton process using 10 mg L−1 FeSO4 and 100 mg L−1 H2O2 exhibited the best results, with 79% of the TMX degraded and 83% of the COD removed, additionally exhibiting the lowest estimated operating cost (USD 1.01 dm−3). Higher enzymatic SOD and CAT activities, total protein content, and H2O2 concentration were observed; however, no significant changes in MDA were recorded. This treatment protocol effectively oxidizes TMX and reduces its phytotoxicity in maize and cucumber seedlings. [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 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]

Plant growth and physiology can be affected by environmental and chemical factors that have the potential to influence yields. Among the factors that influence plant growth, neonicotinoid seed treatments have shown significant effects on plant growth, particularly in cotton. The dual benefits seen from neonicotinoids on plant growth and insect control show promise in improving cotton yields but little is known about how different seed treatments affect seedling physiology. A greenhouse experiment was undertaken to investigate how three neonicotinoid seed treatments (clothianidin, thiamethoxam, and imidacloprid) affect the physiology and growth of cotton seedlings in controlled environmental conditions. A randomized complete block design was used to examine seed treatments and an untreated control. Cotton seeds were treated, grown, and evaluated for physiological changes until the fifth true leaf-stage and measurements were taken at each of these stages. Data were collected on plant height, shoot fresh weight, leaf area, root length, and root biomass. In addition, chlorophyll pigments and nutrient analysis were performed on cotton seedlings. The seedlings of imidacloprid treated seeds had greater height, shoot fresh mass, leaf area, and relative growth rate by the fifth true leaf stage compared to other treated plants; however, clothianidin showed comparative performance at earlier stages in plant development that equilibrated over time. While all neonicotinoid seed treatments showed positive effects, imidacloprid showed the most potential as a bioactivator on plant growth. [ABSTRACT FROM AUTHOR]

Thiamethoxam is a second-generation neonicotinoid pesticide that is used worldwide. In this study, a three-dimensional electrode-enhanced ozone catalytic oxidation system (3DE-GAC-O3) was constructed to pretreat thiamethoxam wastewater, with granular active carbon as the particle electrode. The effects of catalytic oxidation time, current density, ozone concentration, initial thiamethoxam concentration, pH, and particle electrode dosage on thiamethoxam degradation were investigated. A response surface method based on the Box–Behnken design was employed to optimize the 3DE-GAC-O3 process. The results revealed that the 3DE-GAC-O3 system exhibited higher efficiency compared with the 3D electrode method, ozone catalytic oxidation, or 2DE-O3. The optimal operating conditions included a particle electrode dosage, ozone concentration, current density, solution pH, catalytic oxidation time, and initial thiamethoxam concentration of 18 g/dm3, 12 g/h, 25 A/m2, 7, 300 min, and 500 mg/dm3, respectively. The corresponding chemical oxygen demand removal rate reached 93.86 ± 0.95%. Thiamethoxam degradation followed a second-order reaction kinetics equation, and the rate constant decreased with increasing the initial thiamethoxam concentration. Free-radical quenching experiments indicated that both O2∙− and ∙OH were present within the 3DE-GAC-O3 system, with ∙OH being the predominant species. A GC-MS analysis revealed the formation of several intermediate products, which were characterized based on the mass fragmentation pattern. Additionally, a probable degradation pathway for thiamethoxam was proposed. Therefore, 3DE-GAC-O3 is an efficient method for the pretreatment of thiamethoxam wastewater. [ABSTRACT FROM AUTHOR]

Coconut cultivation faces serious challenges caused by pests and diseases, whose targets are often not reached by conventional application methods such as spraying and soil application. New control strategies, such as vegetative endotherapy, have emerged, but knowledge gaps persist regarding many aspects, especially in pesticide translocation within palm trees, which is crucial for an efficient practical field application. This study investigated the translocation of a mixture of commercial insecticides and fungicides—difenoconazole, imidacloprid, thiabendazole, cyproconazole, thiamethoxam, spirodiclofen, and carbosulfan—applied via pressurized and nonpressurized endotherapeutic methods to coconut stems. This assessment aimed to quantify the concentrations of pesticide translocation through the stem, from the application site to the plant canopy. Due to the difficulty of applying the solution to the instrument used for pressurized endotherapy, the solution had to be diluted and used at a lower volume. In experimental field conditions, stem samples were assessed at 50 and 100 cm above the application point following endotherapy treatments conducted over a period ranging from 2 to 45 days. The analyses were performed using LC-MS/MS. In the pressurized method, the highest concentrations were observed for difenoconazole (1684 µg kg−1), imidacloprid (1278 µg kg−1), and thiabendazole (781 µg kg−1). Conversely, in the nonpressurized method, the highest concentrations were recorded for imidacloprid (5803 µg kg−1), followed by difenoconazole (3660 µg kg−1) and thiabendazole (2598 µg kg−1). To address the issue with formulation conditions in the pressurized method and to allow a comparison between the two application methods, we simulated extrapolated results for comparison with the nonpressurized method. This evaluation aimed to evaluate both methods under similar formulation conditions (volume and concentration). The results predicted that if the solution had not been diluted, the pressurized method would present the best translocations, mainly near the plant canopy, except for carbofuran. All pesticides were translocated independently of their physical–chemical properties or formulation. No pesticide residues were detected in the coconut water and pulp up to 120 days after the endotherapy application. [ABSTRACT FROM AUTHOR]

Thiamethoxam, a second-generation neonicotinoid insecticide is widely used for controlling sap-sucking insect pests including Rhopalosiphum padi. The current study aimed to investigate the life-history parameters and feeding behavior of R. padi following treatments with sublethal concentrations of thiamethoxam. The lethal concentration 50 (LC50) value of thiamethoxam against adult R. padi was 11.458 mg L−1 after 48 h exposure. The sublethal concentrations of thiamethoxam (LC5 and LC10) significantly decreased the adult longevity, fecundity, and reproductive days in the directly exposed aphids (F0 generation). In the progeny R. padi (F1), the developmental durations and total prereproductive period (TPRP) were decreased while the adult longevity, fecundity, and reproductive days (RPd) were increased at both thiamethoxam concentrations. The demographic parameters including the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were prolonged only at the LC5 of thiamethoxam. The EPG results indicated that the sublethal concentrations of thiamethoxam increases the total duration of non-probing (Np) while reducing the total duration of E2 in directly exposed aphids (F0). Interestingly, the E2 were significantly increased in the progeny generation (F1) descending from previously exposed parental aphids (F0). Overall, this study showed that thiamethoxam exhibited high toxicity against directly exposed individuals (F0), while inducing intergenerational hormetic effects on the progeny generation (F1) of R. padi. These findings provided crucial details about thiamethoxam-induced hormetic effects that might be useful in managing resurgences of this key pest. [ABSTRACT FROM AUTHOR]

Simple Summary: The Colorado potato beetle is known for its ability to cause significant damage to potato crops worldwide. Unfortunately, this insect is also capable of developing substantial resistance against different compounds deployed to regulate its spread. A better understanding of the molecular basis underlying this resistance is key in order to develop novel strategies aimed at this potato pest. The goal of the current study was, thus, to characterize the expression of transcripts with likely relevance for insecticide resistance in Colorado potato beetles treated with two compounds of interest. Changes were observed for several transcripts in response to either low- or high-dose exposure, as well as for different time durations. The modulation of one transcript using RNAi was also associated with the increased susceptibility of insects treated with the insecticide cyantraniliprole. Overall, this information highlights potentially relevant targets for insecticide resistance in the Colorado potato beetle and reveals a transcript of interest for investigating further within the context of cyantraniliprole response in this pest. The Colorado potato beetle (Leptinotarsa decemlineata (Say)) can cause extensive damage to agricultural crops worldwide and is a significant insect pest. This insect is notorious for its ability to evade various strategies deployed to control its spread and is known for its relative ease in developing resistance against different insecticides. Various molecular levers are leveraged by L. decemlineata for this resistance to occur, and a complete picture of the genes involved in this process is lacking. While small non-coding RNAs, including miRNAs, are differentially expressed in insects exposed to insecticides, levels of transcript coding for proteins underlying their synthesis remain to be characterized fully. The overarching objective of this work aims to fill that gap by assessing the expression of such targets in L. decemlineata exposed to cyantraniliprole and thiamethoxam. The expression status of Ago1, Ago2, Ago3, Dcr2a, Dcr2b, Expo-5, Siwi-1 and Siwi-2 transcripts were quantified via qRT-PCR in adult L. decemlineata treated with low and high doses of these compounds for different lengths of time. Variation in Ago1 and Dcr2b expression was notably observed in L. decemlineata exposed to cyantraniliprole, while thiamethoxam exposure was associated with the modulation of Dcr2a and Siwi-1 transcript levels. The down-regulation of Ago1 expression in L. decemlineata using dsRNA, followed by cyantraniliprole treatment, was associated with a reduction in the survival of insects with reduced Ago1 transcript expression. Overall, this work presents the insecticide-mediated modulation of transcripts associated with small non-coding RNA processing and showcases Ago1 as a target to further investigate its relevance in cyantraniliprole response. [ABSTRACT FROM AUTHOR]

Insecticide resistance has long been a problem in crop pest control. Bactericera gobica is a major pest on the well-known medicinal plants Lycium barbarum L. Investigating insecticide resistance mechanisms of B. gobica will help to identify pesticide reduction strategies to control the pest. Gene expression normalization by RT-qPCR requires the selection and validation of appropriate reference genes (RGs). Here, 15 candidate RGs were selected from transcriptome data of B. gobica. Their expression stability was evaluated with five algorithms (Delta Ct, GeNorm, Normfinder, BestKeeper and RefFinder) for sample types differing in response to five insecticide stresses and in four other experimental conditions. Our results indicated that the RGs RPL10 + RPS15 for Imidacloprid and Abamectin; RPL10 + AK for Thiamethoxam; RPL32 + RPL10 for λ-cyhalothrin; RPL10 + RPL8 for Matrine; and EF2 + RPL32 under different insecticide stresses were the most suitable RGs for RT-qPCR normalization. EF1α + RPL8, EF1α + β-actin, β-actin + EF2 and β-actin + RPS15 were the optimal combination of RGs under odor stimulation, temperature, developmental stages and both sexes, respectively. Overall, EF2 and RPL8 were the two most stable RGs in all conditions, while α-TUB and RPL32 were the least stable RGs. The corresponding suitable RGs and one unstable RG were used to normalize a target cytochrome P450 CYP6a1 gene between adult and nymph stages and under imidacloprid stress. The results of CYP6a1 expression were consistent with transcriptome data. This study is the first research on the most stable RG selection in B. gobica nymphs exposed to different insecticides, which will contribute to further research on insecticide resistance mechanisms in B. gobica. [ABSTRACT FROM AUTHOR]

(1) Background: Potato is the most important tuber crop in the world that can contribute to food security. However, the crop has been shown to be sensitive to drought and its yields decline significantly during successive periods of stress. Drought triggers a number of responses in potato, ranging from physiological changes to fluctuations in growth rates and yields. In light of global climate change, it is important to understand the effects of thiamethoxam on potato growth and yield under drought conditions. (2) Methods: The objective was to evaluate the impact of thiamethoxam on improving drought resistance and yield of potato under drought conditions. The drought-tolerant and sensitive-genotypes Qingshu No. 9 and Atlantic were used for a two–year pot experiment. Potato seeds were coated with 70% thiamethoxam before sowing (treatment group (T)), with a control group without treatment (NT). Two experimental treatments were applied: normal irrigation (ND) and drought stress (D). (3) Results: The results showed that root length, plant yield, chlorophyll content and superoxide dismutase (SOD) activity significantly increased under both genotypes, while malondialdehyde (MDA) and proline (Pro) content were reduced under thiamethoxam under drought stress. The best indicators were obtained in the comprehensive evaluation for the T–D treatment, suggesting that the application of thiamethoxam under drought stress was more effective than normal irrigation. (4) Conclusions: Our results suggest that the application of thiamethoxam improves potato growth, thereby increasing drought tolerance and potato yield. However, thiamethoxam is a neonicotinoid pesticide, and the limitation of this study is that it did not explore the ecological effects of thiamethoxam, which need to be systematically studied in the future. Moreover, considering the potential risks of thiamethoxam to the environment, specific agronomic measures to effectively degrade thiamethoxam residue should be taken when it is applied in agricultural production. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) has been introduced to detect pesticides at low concentrations and in complex matrices to help developing countries monitor pesticides to keep their concentrations at safe levels in food and the environment. SERS is a surface-sensitive technique that enhances the Raman signal of molecules absorbed on metal nanostructure surfaces and provides vibrational information for sample identification and quantitation. In this work, we report the use of silver nanostars (AgNs) as SERS-active elements to detect four neonicotinoid pesticides (thiacloprid, imidacloprid, thiamethoxam and nitenpyram). The SERS substrates were prepared with multiple depositions of the nanostars using a self-assembly approach to give a dense coverage of the AgNs on a glass surface, which ultimately increased the availability of the spikes needed for SERS activity. The SERS substrates developed in this work show very high sensitivity and excellent reproducibility. Our research opens an avenue for the development of portable, field-based pesticide sensors, which will be critical for the effective monitoring of these important but potentially dangerous chemicals. [ABSTRACT FROM AUTHOR]

Simple Summary: Acetamiprid, which is a neonicotinoid, is a cyano-substituted insecticide. It is commonly used due to its rapid insecticidal activity. Acetamiprid has been described as a partial agonist of nicotinic acetylcholine receptors expressed on the thoracic and dorsal neurons of the American cockroach. However, previous electrophysiological studies have demonstrated that not all neonicotinoids display the same modes of action on insects. In this study, we analysed the effect of acetamiprid on the locomotor activity of the American cockroach and compared our results with previously published data for thiamethoxam and clothianidin, which are nitro-substituted neonicotinoid insecticides. We demonstrated that the three neonicotinoids had different effects on the locomotor activity. Overall, these data add to the understanding of the mode of action of neonicotinoid insecticides. Toxicological studies have shown that the American cockroach Periplaneta americana (Linnaeus) is a classical model for studying the mode of action of commonly used insecticides. In a previous study, we demonstrated that thiamethoxam and clothianidin decreased locomotor activity in an open-field-like apparatus. Here, we tested the effect of the neonicotinoid acetamiprid when applied orally, topically, or injected into the haemolymph. We found that acetamiprid was also able to impair locomotor activity in the open-field-like apparatus. When treated with acetamiprid, a strong alteration in locomotor activity was observed 1 h, 24 h, and 48 h after haemolymph and topical applications. Oral application induced an impairment of locomotor activity at 24 h and 48 h. A comparison of the present data with our previously published results showed that neonicotinoids were more active when injected into the haemolymph compared to oral and topical applications. These findings increased our understanding of the effect of neonicotinoid insecticides on insect locomotor activity, and demonstrated that the cyano-substituted neonicotinoid, acetamiprid, was able to alter cockroach locomotor activity. [ABSTRACT FROM AUTHOR]

The honey bee Apis mellifera is exposed to a variety of biotic and abiotic stressors, such as the highly prevalent microsporidian parasite Nosema (Vairimorpha) ceranae and neonicotinoid insecticides. Both can affect honey bee physiology and microbial gut communities, eventually reducing its lifespan. They can also have a combined effect on the insect's survival. The use of bacterial probiotics has been proposed to improve honey bee health, but their beneficial effect remains an open question. In the present study, western honey bees were experimentally infected with N. ceranae spores, chronically exposed to the neonicotinoid thiamethoxam, and/or supplied daily with the homofermentative bacterium Pediococcus acidilactici MA18/5M thought to improve the honey bees' tolerance to the parasite. Deep shotgun metagenomic sequencing allowed the response of the gut microbiota to be investigated with a taxonomic resolution at the species level. All treatments induced significant changes in honey bee gut bacterial communities. Nosema ceranae infection increased the abundance of Proteus mirabilis, Frischella perrara, and Gilliamella apicola and reduced the abundance of Bifidobacterium asteroides, Fructobacillus fructosus, and Lactobacillus spp. Supplementation with P. acidilactici overturned some of these alterations, bringing back the abundance of some altered species close to the relative abundance found in the controls. Surprisingly, the exposure to thiamethoxam also restored the relative abundance of some species modulated by N. ceranae. This study shows that stressors and probiotics may have an antagonistic impact on honey bee gut bacterial communities and that P. acidilactici may have a protective effect against the dysbiosis induced by an infection with N. ceranae. [ABSTRACT FROM AUTHOR]

The bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) is one of the most economically important pests of wheat crops worldwide. Thiamethoxam, bifenthrin, and flonicamid are extensively used insecticides for controlling this key pest. However, the indiscriminate use of chemical insecticides has led to the development of resistance in insects. In this study, we assessed the development of selection-induced resistance to bifenthrin, flonicamid, and thiamethoxam under controlled laboratory conditions. Additionally, we employed the age-stage, two-sex life table method to examine the fitness of R. padi. After ten generations of selection, bifenthrin-, flonicamid-, and thiamethoxam-resistant strains of R. padi were developed with resistance levels of 34.46, 31.97, and 26.46-fold, respectively. The life table analysis revealed a significant decrease in adult longevity and fecundity in these resistant strains compared to susceptible strain. Furthermore, the key demographic parameters such as net reproductive rate (R0) and reproductive days exhibited a significant reduction in all resistant strains, while the intrinsic rate of increase (r) and finite rate of increase (λ) were decreased only in resistant strains to bifenthrin and thiamethoxam. Taken together, these findings provide a comprehensive understanding of laboratory-induced insecticide resistance evolution and the associated fitness costs in R. padi. This knowledge could help to design resistance management strategies against this particular pest of wheat. [ABSTRACT FROM AUTHOR]

In this study, the fate of two pesticides commonly used on cowpeas, thiamethoxam and pyraclostrobin, during the preparation of home-made pickled cowpeas was investigated using an improved QuEChERS method combined with UHPLC-MS/MS. Although pesticide residues were primarily distributed on cowpea samples, some were transferred to brine. The dissipation half-life of thiamethoxam on cowpea samples was significantly shorter than that of pyraclostrobin due to thiamethoxam's higher water solubility. Thiamethoxam demonstrated a half-life of 5.12 ± 0.66 days, whereas pyraclostrobin exhibited a longer half-life of 71.46 ± 7.87 days. In addition, the degradation half-lives of these two pesticides in the whole system (cowpea and brine) were 45.01 ± 4.99 and 70.51 ± 5.91 days, respectively. This result indicates that the pickling did not effectively promote the degradation of thiamethoxam and pyraclostrobin. The metabolite clothianidin of thiamethoxam was not produced throughout the pickling process, but the metabolite BF 500-3 of pyraclostrobin was detected in cowpea samples. The detection rates for thiamethoxam, pyraclostrobin, and BF 500-3 in the 20 market samples were 10%, 70%, and 45%, respectively. However, the risk quotient analysis indicated that the risk of dietary intake of thiamethoxam and pyraclostrobin in pickled cowpeas by Chinese consumers was negligible. [ABSTRACT FROM AUTHOR]

The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is an economically devastating crop pest worldwide. The M. persicae (SEF-R) population of a cabbage field in China was tested for susceptibilities to 13 insecticides. Compared with the susceptible population (FFJ-S), extremely high and high resistance to beta-cypermethrin (324-fold) and imidacloprid (106.9-fold) was detected in SEF-R. More importantly, this is the first report of resistance in the field M. persicae population to sulfoxaflor (32.4-fold), flupyradifurone (9.5-fold), pymetrozine (34.8-fold), spirotetramat (8.1-fold), flonicamid (5.8-fold), and broflanilide (15.8-fold) in China when compared with FFJ-S. The resistance factor decayed to a low level to sulfoxaflor and pymetrozine after 15 generations without any selection pressure. The resistance-related mutations (R81T and kdr) detected in SEF indicated target-site resistance to neonicotinoids and pyrethroids, respectively. Biochemical assays revealed the involvement of monooxygenase, carboxylesterase, superoxide dismutase, and peroxidase in a multi-insecticide resistance mechanism. The overexpression of P450s, esterases, and a UDP-glycosyltransferase might be responsible for the multi-insecticide resistance in SEF-R. The knockdown of CYP6CY3 in SEF-R increased its susceptibility to imidacloprid, thiacloprid, and thiamethoxam, which verified that P450s play vital roles in neonicotinoid metabolism. Our findings provide guidance for the rational use of insecticides to delay resistance development in GPA. [ABSTRACT FROM AUTHOR]

Accurate identification of the rational and standardized use of pesticides is important for the sustainable development of agriculture while maintaining a high quality. The insecticides thiamethoxam and fenvalerate and the vegetables spinach, cabbage, and lettuce were used here as study objects. Descriptive analysis and primary reaction kinetic equations were used to analyze the changes in metabolic residues of the two insecticides after different numbers of application in three vegetables. The effects of pesticide residue levels on the δ13C, δ15N, δ2H, and δ18O values of vegetables were analyzed by one-way analysis of variance and correlation analysis. Partial least squares discriminant analysis (PLS-DA) was applied to build discrimination models of the vegetables with different pesticide residues based on stable isotopes. The results showed that the first degradation residues of thiamethoxam and fenvalerate in spinach, cabbage, and lettuce conformed to primary reaction kinetic equations, but the degradation half-lives were long, and accumulation occurred in the second application. The differences in the four stable isotope ratios in the control group of the three vegetables were statistically significant, and two-thirds of the stable isotope ratios in the three vegetables with different numbers of pesticide applications were significantly different. The δ13C and δ15N values of spinach, the δ13C, δ15N, and δ2H values of cabbage, and the δ13C, δ15N, δ2H, and δ18O values of lettuce were significantly correlated with different residues of thiamethoxam and/or fenvalerate applications. The control groups of the three vegetables, spinach-thiamethoxam-first, spinach-thiamethoxam-second, cabbage-thiamethoxam-second, cabbage-fenvalerate-first, and lettuce-thiamethoxam-first, were fully identified by PLS-DA models, while the identification models of other vegetables containing pesticide residues still need to be further improved. The results provide technical support for identifying the rational use of pesticides in vegetables and provide a reference method for guaranteeing the authenticity of green and organic vegetables. [ABSTRACT FROM AUTHOR]

Simple Summary: Among pests threatening stored food, Rhyzopertha dominica, Tribolium castaneum, Trogoderma granarium, and Sitophilus oryzae are highly dangerous because they cause considerable losses around the world. Taking into account that there is a narrow available spectrum of contact insecticides for the management of stored-grain insects, a laboratory study was conducted to evaluate an insecticidal formulation containing two active ingredients, i.e., thiamethoxam plus chlorantraniliprole, when applied on grains and different surfaces against adults of the aforementioned species. Complete mortality was observed for S. oryzae on all three commodities, for R. dominica on wheat and rice, and for T. castaneum on wheat, 14 days post-initial exposure at the highest dose. At the end of the 90-day storage period, S. oryzae showed the maximum mortality, whereas T. granarium showed the lowest. Bioassays on surfaces revealed that thiamethoxam plus chlorantraniliprole applied on metal killed more adult individuals of all species than on cement, ceramic, or wood. Sitophilus oryzae was found to be the most sensitive on metal, followed by R. dominica, T. castaneum, and T. granarium. An insecticide containing the neonicotinoid thiamethoxam + the diamide chlorantraniliprole was evaluated against adults of Rhyzopertha dominica, Tribolium castaneum, Trogoderma granarium, and Sitophilus oryzae under laboratory bioassays both on freshly treated grain as well as on treated grain stored over 90 days for its persistence in efficacy. In laboratory bioassays, the insecticide was applied on wheat, maize, or rice at four doses, while in persistence bioassays on wheat at the same doses. Mortality and progeny were assessed in both laboratory and persistence bioassays. After 14 days of exposure, S. oryzae exhibited 100% mortality on all three commodities at the highest dose, while R. dominica showed complete mortality on wheat or rice and T. castaneum on wheat. For a period of 90 days, S. oryzae exhibited 42.69% mortality, followed by R. dominica (35.26%), T. castaneum (27.08%), and T. granarium (18.63%) at the highest dose. Progeny was successfully suppressed in all cases of complete mortality in laboratory bioassays and for S. oryzae for 90 days in persistence bioassays. Laboratory trials were also performed on plywood, concrete, ceramic tile, and steel at one dose. The highest mortality was observed on steel, followed by concrete, ceramic tile, and plywood for all insect species tested. This study demonstrates that thiamethoxam + chlorantraniliprole is effective against the tested species depending on exposure, storage period, surface, commodity, and dose. [ABSTRACT FROM AUTHOR]

In order to acquire scientific evidence for the application of thiamethoxam (TMX) in Agaricus bisporus cultivation, residue and dissipation experiments for field trials were performed with the application of TMX in compost and casing soil, respectively. An effective QuEChERS method was established to analyze TMX and its two metabolites, clothianidin (CLO) and thiamethoxam-urea (TMX-urea), in compost, casing soil, and fruiting bodies. The results indicated that the TMX dissipation half-lives (t1/2) at dosages of 10 and 50 mg kg−1 were 19.74 d (day) and 28.87 d in compost and 33.54 d and 42.59 d in casing soil, individually. TMX, CLO, and TMX-urea were observed after TMX application in compost and casing soil. For TMX applied to the casing soil, only TMX residues were detected in fruiting bodies with bioconcentration factors (BCFs) of 0.0003~0.0009. In addition, both the chronic risk quotient (RQ) and acute risk quotient (HQ) values of TMX in fruiting bodies were far less than 1, which means the dietary health risks to humans were acceptable. However, in the TMX application to the compost, these analytes were not detected in the fruiting bodies. This suggested that the application of TMX in compost was safer than in casing soil during A. bisporus cultivation. [ABSTRACT FROM AUTHOR]

Neonicotinoid seed treatments are commonly used in agricultural production even though their benefit to crop yield and their impact on pollinators, particularly wild bees, remains unclear. Using an on-farm matched pair design in which half of each field was sown with thiamethoxam treated seed and half without, we assessed honey bee and wild bee exposure to pesticides in sunflower fields by analyzing pesticide residues in field soil, sunflower pollen and nectar, pollen-foraging and nectar-foraging honey bees, and a sunflower specialist wild bee (Melissodes agilis). We also quantified the effects of thiamethoxam-treated seed on wild bee biodiversity and crop yield. M. agilis abundance was significantly lower with thiamethoxam treatment and overall wild bee abundance trending lower but was not significantly different. Furthermore, crop yield was significantly lower in plots with thiamethoxam treatment, even though thiamethoxam was only detected at low concentrations in one soil sample (and its primary metabolite, clothianidin, was never detected). Conversely, wild bee richness was significantly higher and diversity was marginally higher with thiamethoxam treatment. Nectar volumes harvested from the nectar-foraging honey bees were also significantly higher with thiamethoxam treatment. Several pesticides that were not used in the sunflower fields were detected in our samples, some of which are known to be deleterious to bee health, highlighting the importance of the landscape scale in the assessment of pesticide exposure for bees. Overall, our results suggest that thiamethoxam seed treatments may negatively impact wild bee pollination services in sunflower. Importantly, this study highlights the advantages of the inclusion of other metrics, such as biodiversity or behavior, in pesticide risk analysis, as pesticide residue analysis, as an independent metric, may erroneously miss the impacts of field realistic pesticide exposure on bees. [ABSTRACT FROM AUTHOR]

Pesticides are used on fruit and vegetable crops to obtain greater yield and quality. Residues can be detected in these crops or their products if applied pesticides do not degrade naturally. Therefore, this study aimed to estimate pesticide residues in some strawberry and tomato-based products available in the market for human consumption and associated dietary risks. Contamination with 3–15 pesticides in the tested samples was found. The total number of pesticides detected in the tested samples was 20, belonging to the group of insecticides (84%) and fungicides (16%). Pesticides of cypermethrin, thiamethoxam, chlorpyrifos, and lambda-cyhalothrin appeared at 100% in a number of samples, where the most detected was cypermethrin followed by thiamethoxam. The average values of pesticide residues detected in the tested samples ranged from 0.006 to 0.568 mg kg−1, where it was found that cypermethrin had the highest residue value and appeared in strawberry jam obtained from the market. The recovery rate of pesticides from fortified samples with pyrethroids ranged from 47.5% (fenvalerate) to 127% (lambda-cyhalothrin). Home processing of fortified tomato and strawberry samples had a significant effect on reducing residues in tomato sauce and strawberry jam, where the reduction reached 100%. The results of acute and chronic risk assessment showed that their values were much lower than 100%, indicating minimal risk of dietary intake. [ABSTRACT FROM AUTHOR]

Simple Summary: Huanglongbing (HLB), a disease associated with the bacteria Candidatus Liberibacter spp. and transmitted by the Asian citrus psyllid (ACP) Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the primary and most destructive disease that affects citrus crops. The disease management tactics can target both the causal agent and the insect vector. Studies have demonstrated the potential of the curry leaf tree (Bergera koenigii L.) as a trap plant for D. citri, as it is more attractive than commercial citrus plants, in addition to being immune to the bacteria that cause HLB. The use of the trap plant technique, combined with systemic insecticides, creating an attract-and-kill system, can significantly increase the effectiveness of disease and pest management. The systemic insecticides thiamethoxam, thiamethoxam + chlorantraniliprole, and imidacloprid, frequently used in citriculture, were tested on adults of D. citri in the curry leaf tree by the drench method. The results demonstrated efficacy in controlling D. citri, showing the high mortality (>90%) of adults and a prolonged effect of biological activity after application in field and protected cultivation experiments. Low concentrations of insecticides affected D. citri oviposition. The results indicate that it is possible to combine the use of the curry leaf tree as a trap plant with systemic insecticides in citrus, increasing control efficacy and reducing the application of insecticides used in commercial groves. Huanglongbing (HLB), the most serious disease in citriculture, is caused by the bacteria Candidatus Liberibacter spp., which is transmitted by the Asian citrus psyllid (ACP) Diaphorina citri. HLB is mainly controlled with insecticides, necessitating the development of alternative methods, e.g., the use of trap plants such as curry leaf Bergera koenigii, which is highly attractive to the ACP. We evaluated the effects of the main systemic insecticides used by citrus growers, applied via drench to adults of D. citri on the curry leaf tree. We tested the persistence of three pesticides: thiamethoxam, thiamethoxam + chlorantraniliprole, and imidacloprid in protected cultivation and the field condition at 7, 14, 28, 42, 56, 70, 98, and 154 days after the application. Different concentrations of insecticides containing the active ingredient thiamethoxam were tested on adults to determine the LC10 and LC50. Finally, we assessed the sublethal effects on the oviposition and development of D. citri. The insecticides controlled the adults for long periods. However, in the field experiment, from 42 days after application there was a decrease in mortality caused by pesticides applied via drench, while in the protected cultivation, mortality did not decline until the last day of evaluation. The median lethal concentration (LC50) for thiamethoxam was 0.031 g of active ingredient per plant, and for thiamethoxam in a mixture, the LC50 was 0.028 g a.i. per plant. In the experiment with sublethal doses, D. citri did not oviposit on the treated plants. Our findings suggest that the attract-and-kill system using the curry leaf tree and systemic insecticides is effective for the control of D. citri and contributes to the integrated management of HLB. [ABSTRACT FROM AUTHOR]

Honey bees (Apis mellifera L.) are affected by different biotic and abiotic stressors, such as the fungus Nosema ceranae and neonicotinoid insecticides, that negatively impact their health. However, most studies so far conducted have focused on the effect of these stressors separately and in European honey bees. Therefore, this study was conducted to analyze the impact of both stressors, singly and in combination, on honey bees of African descent that have demonstrated resistance to parasites and pesticides. Africanized honey bees (AHBs, Apis mellifera scutellata Lepeletier) were inoculated with N. ceranae (1 × 105 spores/bee) and/or chronically exposed for 18 days to a sublethal dose of thiamethoxam (0.025 ng/bee) to evaluate their single and combined effects on food consumption, survivorship, N. ceranae infection, and immunity at the cellular and humoral levels. No significant effects by any of the stressors were found for food consumption. However, thiamethoxam was the main stressor associated to a significant decrease in AHB survivorship, whereas N. ceranae was the main stressor affecting their humoral immune response by upregulating the expression of the gene AmHym-1. Additionally, both stressors, separately and combined, significantly decreased the concentration of haemocytes in the haemolymph of the bees. These findings indicate that N. ceranae and thiamethoxam differentially affect the lifespan and immunity of AHBs and do not seem to have synergistic effects when AHBs are simultaneously exposed to both stressors. [ABSTRACT FROM AUTHOR]

Silkworm Bombyx mori (L.) (Lepidoptera: Bombycidae) is a critical insect for silk producers, but the inappropriate application of insecticides negatively affects the physiology and behavior of silkworms. This study found that the effects of neonicotinoid insecticides applied using two spraying methods on the growth and development of silkworms were different: the median lethal concentration (LC50) values of two pesticides applied using the leaf-dipping method were 0.33 and 0.83 mg L−1 and those of two pesticides applied using the quantitative spraying method were 0.91 and 1.23 mg kg−1. The concentration of pesticides on the mulberry leaves did not decrease after their application using the quantitative spraying method, and a uniform spraying density was observed after the mulberry leaves were air-dried (no liquid) under realistic conditions. We then treated silkworms with the quantitative spraying method and leaf-dipping method. The treatment of silkworm larvae with imidacloprid and thiamethoxam at sublethal concentrations significantly prolonged the development time and significantly decreased the weight and pupation rate, as well as economic indicators of enamel layers and sputum production. Thiamethoxam treatment significantly increased the activities of carboxylesterase (CarE) and glutathione-S-transferase (GST). The activity of CarE and GST increased, decreased, and then increased, and the highest activity was detected on the 10th and 12th days. Thiamethoxam exposure significantly elevated the transcription levels of CarE-11, GSTe3 and GSTz2 and induced DNA damage in hemocytes. This study confirmed that the quantitative spray method is more stable than the leaf-dipping method. Moreover, imidacloprid and thiamethoxam treatment affected the economy and indexes of silkworms and induced changes in detoxification enzymes and DNA damage in silkworms. These results provide a basis for understanding the mechanism of the sublethal effects of insecticides on silkworms. [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]

Simple Summary: Lepidoptera caterpillars are important pests around the world that decrease crop production, including that of soybeans. The use of insecticides and bioinsecticides is the main control strategy for these pests. Biological control with parasitoids, in combination with insecticides, is widely used as an alternative. However, the use of insecticides with parasitoids depends on tests to assess the survival/mortality of these natural enemies for each insecticide. Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae) is a polyphagous pupal parasitoid that mainly comprises defoliating lepidopterans. This study evaluated the mortality of T. diatraeae from seven insecticides (acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin). The insecticides were sprayed on soybean leaves, which were left to dry and placed in cages with 10 T. diatraeae females. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival; deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity; and acephate was highly toxic, causing 100% mortality in this parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae. Selectivity is an important aspect of modern insecticides to be able to target pests whilst maintaining beneficial entomofauna in the crop. The present objective was to assess the selectivity of different insecticides for the pupal parasitoid of soybean caterpillars, i.e., Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae). Acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin at the highest recommended concentrations for the soybean looper Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae), as well as water in the control, were used against the pupal parasitoid T. diatraeae. The insecticides and the control were sprayed on the soybean leaves, which were left to dry naturally and placed in cages with T. diatraeae females in each one. Survival data were submitted to analysis of variance (ANOVA) and the means were compared using Tukey's HSD test (α = 0.05). Survival curves were plotted according to the Kaplan–Meier method, and the pairs of curves were compared using the log-rank test at 5% probability. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival, while deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity and acephate was highly toxic, causing 100% mortality in the parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae and could be used in IPM programs. [ABSTRACT FROM AUTHOR]

Pesticide residues, when present in agricultural wastewater, constitute a potential risk for the environment and human health. Hence, focused actions for their abatement are of high priority for both the industrial sectors and national authorities. This work evaluates the effectiveness of the photocatalytic process to decompose two frequently detected pesticides in the water effluents of the fruit industry: thiamethoxam-a neonicotinoid compound and flonicamid-a pyridine derivative. Their photocatalytic degradation and mineralization were evaluated in a lab-scale photocatalytic batch reactor under UV-A illumination with the commercial photocatalyst Evonik P25 TiO2 by employing different experimental conditions. The complete degradation of thiamethoxam was achieved after 90 min, when the medium was adjusted to natural or alkaline pH. Flonicamid was proven to be a more recalcitrant substance and the removal efficiency reached ~50% at the same conditions, although the degradation overpassed 75% in the acidic pH medium. Overall, the pesticides' degradation follows the photocatalytic reduction pathways, where positive charged holes and hydroxyl radicals dominate as reactive species, with complete mineralization taking place after 4 h, regardless of the pH medium. Moreover, it was deduced that the pesticides' degradation kinetics followed the Langmuir-Hinshelwood (L-H) model, and the apparent rate constant, the initial degradation rate, as well as the L-H model parameters, were determined for both pesticides. [ABSTRACT FROM AUTHOR]

Pesticide exposure has been cited as a key threat to insect pollinators. Notably, a diverse range of potential sublethal effects have been reported in bee species, with a particular focus on effects due to exposure to neonicotinoid insecticides. Here, a purpose-built thermal–visual arena was used in a series of pilot experiments to assess the potential impact of approximate sublethal concentrations of the next generation sulfoximine insecticide sulfoxaflor (5 and 50 ppb) and the neonicotinoid insecticides thiacloprid (500 ppb) and thiamethoxam (10 ppb), on the walking trajectory, navigation and learning abilities of the buff-tailed bumblebee (Bombus terrestris audax) when subjected to an aversive conditioning task. The results suggest that only thiamethoxam prevents forager bees from improving in key training parameters (speed and distanced travelled) within the thermal visual arena. Power law analyses further revealed that a speed–curvature power law, previously reported as being present in the walking trajectories of bumblebees, is potentially disrupted under thiamethoxam (10 ppb) exposure, but not under sulfoxaflor or thiacloprid exposure. The pilot assay described provides a novel tool with which to identify subtle sublethal pesticide impacts, and their potential causes, on forager bees, that current ecotoxicological tests are not designed to assess. [ABSTRACT FROM AUTHOR]

Simple Summary: The sugarcane weevil Sphenophorus levis is a soil pest that causes extensive damage in sugarcane. The association of poor insect control by available pest management tools with the current incomprehension of the insect's behavior favors the expansion of S. levis infestations to several sugarcane farming regions. In this study, we evaluated the behavioral aspect of S. levis in terms of reaction to one recommended insecticide dose to assess if its application would either attract or repel S. levis adults. We also evaluated the hourly activity and location pattern of S. levis adult insects through the day by simulating their natural habitat with sugarcane plants and soil. The results indicate that S. levis adults were not attracted nor repelled by the recommended insecticide dose; therefore, its behavior should not lead to any positive or negative effects for the tested insecticide dose performance. S. levis activity results showed that insects are primarily nocturnal with most activities (walking, digging and mating) starting and finishing at night. Most insects remained hidden under the soil surface during the day and night; however, insects were exposed (out of the soil) up to four times more during the evening than throughout the day, suggesting that nocturnal insecticide applications could potentially improve S. levis control. Sphenophorus levis Vaurie, 1978 (Coleoptera: Curculionidae). is a difficult to control pest in sugarcane that causes great damage to the subterranean part of the plant. Low insect control is the result of the pesticide application technology adopted but also a consequence of the lack of studies regarding the pest's behavior. This research aimed to examine the attractiveness and repellency of one labelled insecticide dose to S. levis adults and to evaluate the activity and location behavior of S. levis adults under hourly observations over 24 h. Repellency and attractiveness studies were conducted in free-choice tests with treated soil with an insecticide product composed of lambda-cyhalothrin + thiamethoxam active ingredients and untreated soil. Insect activity and location behavior studies were assessed by conducting hourly observations of S. levis adults in containers with soil and sugarcane plant. The results indicate that S. levis adults are not repelled nor attracted to soil treated with the labelled dose of lambda-cyhalothrin + thiamethoxam in sugarcane. Additionally, insects presented nocturnal behavior for most activities (walking, digging and mating) starting at 6:00 p.m. until 2:00 a.m. An average of 21% of insects were out of the soil at night while the majority, 79%, remained inside the soil. During the day, most insects, 95%, remained hidden in the soil. Exposed insects were primarily located on the soil surface. According to these results, nocturnal insecticide applications may improve S. levis adult control due to greater insect activity and exposure at night. [ABSTRACT FROM AUTHOR]

Thiamethoxam, a nicotinic pesticide used worldwide, can cause great harm to the environment and even to human health, and aptamers, known as chemical antibodies, have high affinity and specificity for the target, as well as great potential in detecting small molecules such as pesticides. In this paper, we report a highly sensitive biosensor system for thiamethoxam residue detection based on aptamer technology. After 15 rounds of screening with the pressurized GO-SELEX technology, we found that the aptamer libraries of the 5th and 9th rounds showed high affinity by the capture method. Four candidate aptamers were obtained by high-throughput sequencing and secondary structure prediction. Among them, the aptamer named Thi-5R-18 from the 5th round was demonstrated to possess the highest affinity by isothermal titration calorimetry, with a dissociation constant (Kd) of 4.935 × 10−5 M. The results of molecular docking showed that thiamethoxam and Thi-5R-18 were combined with bases G-15, A-19, and T-71 through hydrogen bonding and π–π interaction.Thi-5R-18 was used as a recognition element to construct a AuNPs colorimetric aptasensor, achieving an ultralow detection limit of 0.37 nM. More importantly, this colorimetric aptasensor can be used for quantitative detection of thiamethoxam on tea leaves, with a recovery of 96.94%~105.86%. This study provides a highly sensitive biosensor for detection of thiamethoxam residue. [ABSTRACT FROM AUTHOR]

Thiamethoxam (TMX) is an effective neonicotinoid insecticide. However, its widespread use is detrimental to non-targeted organisms and water systems. This study investigates the biodegradation of this insecticide by Labrys portucalensis F11. After 30 days of incubation in mineral salt medium, L. portucalensis F11 was able to remove 41%, 35% and 100% of a supplied amount of TMX (10.8 mg L−1) provided as the sole carbon and nitrogen source, the sole carbon and sulfur source and as the sole carbon source, respectively. Periodic feeding with sodium acetate as the supplementary carbon source resulted in faster degradation of TMX (10.8 mg L−1); more than 90% was removed in 3 days. The detection and identification of biodegradation intermediates was performed by UPLC-QTOF/MS/MS. The chemical structure of 12 metabolites is proposed. Nitro reduction, oxadiazine ring cleavage and dechlorination are the main degradation pathways proposed. After biodegradation, toxicity was removed as indicated using Aliivibrio fischeri and by assessing the synthesis of an inducible β-galactosidase by an E. coli mutant (Toxi-Chromo test). L. portucalensis F11 was able to degrade TMX under different conditions and could be effective in bioremediation strategies. [ABSTRACT FROM AUTHOR]

The white-backed planthopper Sogatella furcifera (Horváth) is an important pest on rice plants throughout Asia. The application of chemical insecticides is still the main approach to suppressing the field population of S. furcifera. However, misuse of chemical insecticides has promoted the development of insecticide resistance in this insect pest. Thus, in the present study, dose responses of 58 field populations of S. furcifera to 7 insecticides were analyzed by rice-stem dipping from 2011 to 2021 in Central China. The results indicated that field populations of S. furcifera showed moderate levels of resistance to nitenpyram (RR = 1.7–17.8-fold), thiamethoxam (RR = 1.4–25.8-fold), dinotefuran (RR = 1.5–25.3-fold), clothianidin (RR = 2.1–12.5-fold), chlorpyrifos (RR = 1.1–56.6-fold), etofenprox (RR = 1.1–14.8-fold) and isoprocarb (RR = 1.4–11.5-fold). The results presented here will be beneficial to improve our ability to identify and predict insecticide resistance, make better control recommendations and prevent further insecticide resistance development. [ABSTRACT FROM AUTHOR]

Neonicotinoids are pesticides widely used for pest control in agriculture with undesirable effects on pollinators. However, other beneficial insects are exposed to insecticides that are not lethal to them but may accumulate and affect their vital characteristics. The objective of this study was to determine neonicotinoid residues in two types of beneficial soil organisms. The first group includes ground beetles (family: Carabidae, order: Coleoptera). They are important in the food web within existing ecosystems, especially in agricultural areas. The second group includes earthworms (family: Lumbricidae, order: Opisthopora) as humifiers, important members of the soil fauna. Fauna was collected at two sugar beet growing areas in Croatia under intensive sugar beet management. Ground beetles were collected from six plots of sugar beet fields treated with imidacloprid and thiamethoxam or left untreated with neonicotinoids. Earthworms were collected from the eight fields involved in four-year sugar beet crop rotation (sugar beet, maize, soybean, oilseed rape). Detection of neonicotinoid residues was performed by LC-MS/MS, SPE-QuEChERS method. The limit of quantification (LOQ) was 0.001 mg/kg. In ground beetles, the highest concentration of imidacloprid was detected at 0.027 mg/kg, while the residues of thiamethoxam and clothianidin were below LOQ. The highest concentration of imidacloprid in earthworms was 0.2141 mg/kg, while residues of thiamethoxam did not exceed 0.0008 mg/kg. This is the first study of this kind on Croatian territory and provides a valuable first insight into the ecotoxicological status of beneficial soil fauna. More comprehensive studies are needed to assess the extent of accumulation in and to take further steps regarding conservation programs for beneficial soil organisms. [ABSTRACT FROM AUTHOR]

Sublethal doses of insecticides have many impacts on pest control and agroecosystems. Insects that survive a sublethal dose of insecticide could adapt their physiological and behavioral functions and resist this environmental stress, which contributes to the challenge of pest management. In this study, the sublethal effects of thiamethoxam on gene expression were measured through RNA sequencing in the melon aphid Aphis gossypii. Genes regulating energy production were downregulated, while genes related to neural function were upregulated. To further address the function of genes related to neurotransmission, RNA interference (RNAi) was implemented by transdermal delivery of dsRNA targeting synapsin (syn), a gene regulating presynaptic vesicle clustering. The gene expression of synapsin was knocked down and the mortality of aphids was increased significantly over the duration of the assay. Co-delivery of syn-dsRNA and thiamethoxam reversed the upregulation of synapsin caused by low-dose thiamethoxam and resulted in lethality to melon aphids, suggesting that the decreased presynaptic function may contribute to this synergistic lethal effect. In addition, the nanocarrier star polycation, which could bind both dsRNA and thiamethoxam, greatly improved the efficacy of lethality. These results increase our knowledge of the gene regulation induced by sublethal exposure to neonicotinoids and indicated that synapsin could be a potential RNAi target for resistance management of the melon aphid. [ABSTRACT FROM AUTHOR]

Simple Summary: Honey bees are key pollinators in agricultural crops. Today, honey bee colonies in decline are a global concern as a result of various stressors, including pesticides, pathogens, honey bee health, and parasites. A healthy honey bee colony refers to colonies that are not exposed to biotic and abiotic stressors. In this study, we examine how thiamethoxam (pesticide) and deformed wing virus type A (DWV-A) interact in effects on honey bee health. The results revealed that the honey bees were infected with DWV-A and were additionally exposed to thiamethoxam, showing effects that increased the mortality rate, and crippled wings in newly emerged adult honey bees. Moreover, the exposure to thiamethoxam and DWV-A injection resulted in induced expression of immune genes (hymenoptaecin gene) while downregulation of two apoptosis genes (caspase8-like, caspase9-like genes). The impact interaction of pesticide and DWV-A have on the expression of apoptosis genes can directly affect viral susceptibility in the honey bee host. Honey bees are economically important insects for crop pollination. They play a significant role as pollinators of wild plants and agricultural crops and produce economical products, such as honey, royal jelly, wax, pollen, propolis, and venom. Despite their ecological and economical importance, the global honey bee population is in decline due to factors including pathogens, parasites, intensive agriculture, and pesticides. Moreover, these factors may be interlinked and exacerbate the loss of honey bees. This study aimed to investigate the interaction between a pesticide, thiamethoxam, and deformed wing virus type A (DWV-A) to honey bees and the effects on survival rate, wing characteristics, and expression of immune and apoptosis genes in Apis mellifera. We described the potential interaction between thiamethoxam and DWV-A on honey bee wing characteristics, DWV-A loads, and the expressions of immune (defensin, abaecin, and hymenoptaecin) and apoptosis genes (buffy, apaf1, caspase3-like, caspase8-like, and caspase9-like). Honey bee larvae were fed with three different thiamethoxam doses (0.001, 1.4, and 14.3 ng/µL of the diet). Then, thiamethoxam-treated white-eyed pupae were injected with 107 copy numbers/honey bee of the DWV-A genome. The interaction between thiamethoxam and DWV-A caused a high mortality rate, crippled wings in newly emerged adult honey bees (100%), and resulted in induced expression of hymenoptaecin gene compared to the control group, while downregulation of caspase8-like, caspase9-like genes compared to the DWV injection group. Therefore, the potential interaction between thiamethoxam and DWV-A might have a deleterious effect on honey bee lifespan. The results from this study could be used as a tool to combat DWV-A infection and mitigate pesticide usage to alleviate the decrease in the honey bee population. [ABSTRACT FROM AUTHOR]

Thiamethoxam and its metabolite clothianidin residues pose a potential threat to human health. This study aims to investigate the residue behavior and acute dietary risk assessment of thiamethoxam and clothianidin on spinach. Thiamethoxam and clothianidin were extracted using a quick, easy, cheap, effective, rugged, safe (QuEChERS) method and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). At spike levels from 0.01 to 5 mg kg−1, the average recoveries of both analytes were in the range of 94.5–105.5%, with relative standard deviations (RSDs) of 3.8–10.9%. The dissipation behavior of thiamethoxam followed first-order kinetics, with half-lives of ≤1.6 days. Clothianidin appeared readily as a plant metabolite with highest level exhibited during 3 to 5 days after application. Temperature and light may be two main factors for degradation of thiamethoxam. Besides, acute risk assessment of thiamethoxam and clothianidin was evaluated with risk quotients (RQs) <100%, which suggested a low health risk for all consumer groups of Chinese residents. [ABSTRACT FROM AUTHOR]

Simple Summary: The collapse of the honey bee colonies is a complex phenomenon in which different factors may participate in an interrelated manner (e.g., pathogen interactions, exposure to chemicals, beekeeping practices, climatology, etc.). In light of the current debate regarding the interpretation of field and monitoring studies in prospective risk assessments, here we studied how exposure to thiamethoxam affects honey bee colonies in Central Spain when applied as a seed treatment to winter oilseed rape, according to the good agricultural practice in place prior to the EU restrictions. Under the experimental conditions, exposure to thiamethoxam, alone or in combination with other stressors, did not generate and maintain sufficient chronic stress as to provoke honey bee colony collapse. The stress derived from exposure to thiamethoxam and honey bee pathogens was compensated by adjustments in the colony's dynamics, and by an increase in the worker bee population, a behavior known as hormesis. An analysis of the factors underlying this phenomenon should be incorporated into the prospective risk assessment of plant protection products in order to improve the future interpretation of field studies and management practices. To study the influence of thiamethoxam exposure on colony strength and pathogen prevalence, an apiary (5 colonies) was placed in front of a plot sown with winter oilseed rape (wOSR), just before the flowering phase. Before sowing, the seeds were treated with an equivalent application of 18 g thiamethoxam/ha. For comparison, a second apiary (5 colonies) was located in front of a separate 750 m plot sown with untreated wOSR. Dead foragers at the entrance of hives were assessed every 2–3 days throughout the exposure period, while the colony strength (number of combs covered with adult honey bees and brood) and pathogens were monitored each month until the following spring. Foraging on the wOSR crop was confirmed by melissopalynology determination of the corbicular pollen collected periodically, while the chemical analysis showed that exposure to thiamethoxam was mainly through nectar. There was an increase in the accumulation of dead bees in the apiary exposed to thiamethoxam relating with the control, which was coped with an increment of bee brood surface and adult bee population. However, we did not find statistically significant differences between apiaries (α = 0.05) in terms of the evolution of pathogens. We discuss these results under hormesis perspective. [ABSTRACT FROM AUTHOR]

Neonicotinoids (NEOs) are neurotoxic pesticides widely used in agriculture due to their high effectiveness against pest insects. Despite their widespread use, very little is known about their toxicity towards marine organisms, including sensitive and ecologically relevant taxa such as copepods. Thus, we investigated the toxicity of five widely used NEOs, including acetamiprid (ACE), clothianidin (CLO), imidacloprid (IMI), thiacloprid (THI), and thiamethoxam (TMX), to assess their ability to inhibit the larval development of the copepod Acartia tonsa. The more toxic NEOs were ACE (EC50 = 0.73 μg L−1), TMX (EC50 = 1.71 μg L−1) and CLO (EC50 = 1.90 μg L−1), while the less toxic compound was IMI (EC50 = 8.84 μg L−1). Early life-stage mortality was unaffected by NEOs at all of the tested concentrations. The calculated toxicity data indicated that significant effects due to ACE (EC20 = 0.12 μg L−1), THI (EC20 = 0.88 μg L−1) and TMX (EC20 = 0.18 μg L−1) are observed at concentrations lower than established chronic aquatic life benchmarks reported by USEPA for freshwater invertebrates. Nevertheless, since environmental concentrations of NEOs are generally lower than the threshold concentrations we calculated for A. tonsa, the effects may be currently of concern only in estuaries receiving wastewater discharges or experiencing intense runoff from agriculture. [ABSTRACT FROM AUTHOR]

The superfamily cytochrome P450s is involved in the evolution of insecticide resistance. However, whether CYP4G68, a differentially expressed gene identified from our transcriptomics analysis, confers resistance to the world's heavily used insecticide class neonicotinoids is unknown. Hence, we explored the role of CYP4G68 in conferring imidacloprid and thiamethoxam resistance in Bemisia tabaci. The species B. tabaci MED developed low-to-high resistance to imidacloprid and thiamethoxam. Exposure to imidacloprid and thiamethoxam significantly increased the expression of CYP4G68. Moreover, quantitative real-time PCR analysis demonstrated that CYP4G68 was remarkably overexpressed in imidacloprid-resistant and thiamethoxam-resistant strains compared to susceptible strains. Further correlation analysis showed that CYP4G68 expression was significantly positively correlated with the associated resistance level in various strains of B. tabaci. These results suggest that the enhanced expression of CYP4G68 appears to mediate imidacloprid and thiamethoxam resistance in B. tabaci. Additionally, silencing CYP4G68 via RNA interference strongly increased the susceptibility of B. tabaci MED to imidacloprid and thiamethoxam. Collectively, this work revealed that CYP4G68 plays a vital role in imidacloprid and thiamethoxam resistance in B. tabaci MED. These findings will not only advance our understanding of the role of P450s in insecticide resistance but also provide a great potential target for the sustainable control of destructive insect pests such as whiteflies. [ABSTRACT FROM AUTHOR]

Neonicotinoids are systemic insecticides commonly used for pest control in agriculture and veterinary applications. Due to their widespread use, neonicotinoid insecticides (neonics) are found in different environmental compartments, including water, soils, and biota, in which their high toxicity towards non-target organisms is a matter of great concern. Given their widespread use and high toxicity, the development of strategies to remove neonics, while avoiding further environmental contamination is of high priority. In this work, ionic-liquid-based materials, comprising silica modified with tetraalkylammonium cations and the chloride anion, were explored as alternative adsorbent materials to remove four neonics insecticides, namely imidacloprid, acetamiprid, thiacloprid, and thiamethoxam, from aqueous media. These materials or supported ionic liquids (SILs) were first synthesized and chemically characterized and further applied in adsorption studies. It was found that the equilibrium concentration of the adsorbate in the solid phase decreases with the decrease in the SIL cation alkyl chain length, reinforcing the relevance of hydrophobic interactions between ionic liquids (ILs) and insecticides. The best-identified SIL for the adsorption of the studied insecticides corresponds to silica modified with propyltrioctylammonium chloride ([Si][N3888]Cl). The saturation of SILs was reached in 5 min or less, showing their fast adsorption rate towards all insecticides, in contrast with activated carbon (benchmark) that requires 40 to 60 min. The best fitting of the experimental kinetic data was achieved with the Pseudo Second-Order model, meaning that the adsorption process is controlled at the solid-liquid interface. On the other hand, the best fitting of the experimental isotherm data is given by the Freundlich isotherm model, revealing that multiple layers of insecticides onto the SIL surface may occur. The continuous removal efficiency of the best SIL ([Si][N3888]Cl) by solid-phase extraction was finally appraised, with the maximum adsorption capacity decreasing in the following sequence: imidacloprid > thiacloprid > thiamethoxam > acetamiprid. Based on real reported values, under ideal conditions, 1 g of [Si][N3888]Cl is able to treat at least 106 m3 of wastewater and water from wetland contaminated with the studied neonics. In summary, the enhanced adsorption capacity of SILs for a broad diversity of neonics was demonstrated, reinforcing the usefulness of these materials for their removal from aqueous matrices and thus contributing to preventing their introduction into the ecosystems and reducing their detrimental effects in the environment and human health. [ABSTRACT FROM AUTHOR]

The toxic action of the Actara 25 WG insecticide (it contains 25% thiamethoxam as an active substance) in non-lethal doses was studied in two species of aquatic organisms—the Prussian carp (Carassius gibelio) and the marsh frog (Pelophylax ridibundus)—at two thermal levels, 6–8 °C (low temperature) and 18–20 °C (room temperature), respectively. In the Prussian carp, we recorded decreases in oxygen consumption and stimulation of the respiratory rhythm, changes that were more pronounced in the case of intoxicated fish and when the species were kept at room temperature. The histopathology of the lung in the frog illustrated the thickening of the conjunctival septum, an increase in the number of mucous cells, and an increase in the ratio between the diameter of the nucleus and the diameter of the pneumocyte. All of these changes were more pronounced in the animals kept at higher temperature. Our study looks at the extent to which temperature changes can influence the ability of poikilothermic organisms to withstand the presence of toxic substances in the environment as a result of the impact of the use of insecticides in agriculture. The two tested organisms are a common presence for the study area, which was affected in the last decade by climate change. [ABSTRACT FROM AUTHOR]

The amount of sludge produced in wastewater treatment plants (WWTPs) has increased over the years, and the methods used to reduce this waste, such as incineration, agricultural use, or disposal in landfills, cause problems of secondary pollution. For this reason, it is necessary to find sustainable and low-cost solutions to manage this waste. Additionally, emerging and priority pollutants are attracting attention from the scientific community as they can generate health problems due to inadequate removal in conventional WWTPs. In this work, a pharmaceutical industry sludge was used as a precursor in the synthesis of four activated carbons (ACs) using different activating agents (ZnCl2, FeCl3∙6H2O, Fe(NO3)3∙9H2O, and Fe(SO4)3∙H2O), to be used for the removal by adsorption of three neonicotinoid pesticides included in latest EU Watch List (Decision 2018/840): acetamiprid (ACT), thiamethoxam (THM), and imidacloprid (IMD). The prepared ACs showed micro–mesoporous properties, obtaining relatively slow adsorption kinetics to reach equilibrium, but despite this, high values of adsorption capacity (qe) were obtained. For example, for AC-ZnCl2 (SBET = 558 m2/g), high adsorption capacities of qe = 128.9, 126.8, and 166.1 mg/g for ACT, THM, and IMD, respectively, were found. In most cases, the adsorption isotherms showed a multilayer profile, indicating an important contribution of the mesoporosity of the activated carbons in the adsorption process. [ABSTRACT FROM AUTHOR]