Anthranilic Diamide Insecticide Research Articles

Effects of anthranilic diamide insecticides on metamorphosis in the common toad Rhinella arenarum (Hensel, 1867) at concentrations found in aquatic environments

ABSTRACT Anthranilic diamides (AD) are a modern class of insecticides used as alternatives to pyrethroids and neonicotinoids, particularly against lepidopteran pests. Despite their widespread use and presence in surface waters, little is known regarding their effects on amphibians. The aim of this study was to examine the effects of environmentally-relevant concentrations of AD insecticides chlorantraniliprole (CHLO) and cyantraniliprole (CYAN) on metamorphosis of the toad Rhinella arenarum. Tadpoles were exposed to CHLO or CYAN at concentrations ranging from 5 and 5000 µg/L from stage 27 until metamorphosis completion. Both insecticides produced a non-monotonic acceleration of the time required for individuals to progress through development and a decrease in the proportion of individuals completing metamorphosis, although a delay in metamorphosis was also observed at 5 µg/L of CHLO. Snout-vent length and body weight of metamorphosed toads were not markedly affected by either insecticide. CHLO was more toxic than CYAN, with a lowest observed effect concentration (LOEC) for CHLO on time to metamorphosis defined as 5 µg/L compared to 5000 µg/L for CYAN. The LOEC for reduced metamorphic success defined as 50 µg/L for CHLO compared to 500 µg/L for CYAN. As most effects occurred after stage 39, when metamorphosis depends upon thyroid hormones, it is conceivable that that AD insecticides act as endocrine disruptors. These findings suggest that contamination of surface waters with CHLO and CYAN may disrupt amphibian development in the wild and warrant further research to investigate the possibility of endocrine-disruption by ADs.

Sublethal Effects of Chlorantraniliprole on the Mobility Patterns of Sitophilus spp.: Implications for Pest Management.

Chlorantraniliprole, an anthranilic diamide insecticide, has emerged as a promising solution for controlling agricultural pests because of its low mammalian toxicity and selectivity towards non-target organisms. This study investigated the sublethal effects of chlorantraniliprole on the mobility behavior of two significant stored-product pests, Sitophilus oryzae (L.) and Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). Contact toxicity assays revealed varying susceptibility levels between the two species, with S. zeamais showing higher sensitivity. Subsequent analysis of mobility behavior, both in the presence and absence of food, indicated significant differences between chlorantraniliprole-exposed and control groups. While S. oryzae exhibited altered locomotion patterns and a decreased number of food approaches at sublethal concentrations, S. zeamais displayed increased walking time and reduced immobility periods. These findings highlight the importance of considering sublethal effects in understanding the overall impact of chlorantraniliprole on stored-product pests. Further research into the long-term consequences of sublethal exposure is warranted to inform more effective pest management strategies in storage.

Lethal and Sublethal Effects of Cyantraniliprole on the Biology and Metabolic Enzyme Activities of Two Lepidopteran Pests, Spodoptera littoralis and Agrotis ipsilon, and A Generalist Predator, Chrysoperla carnea (Neuroptera: Chrysopidae).

Cyantraniliprole is a novel anthranilic diamide insecticide registered for controlling chewing and sucking insect pests. Here, the lethal and sublethal effects of this insecticide on two destructive lepidopteran pests, Spodoptera littoralis Boisduval and Agrotis ipsilon Hufnagel, were evaluated. Because the effects of novel insecticides on beneficial and non-target arthropods must be considered, the impact of cyantraniliprole on a generalist biological control agent, Chrysoperla carnea [Stephens 1836], were also examined. Overall, our study revealed that cyantraniliprole was more toxic to A. ipsilon than to S. littoralis. Moreover, the LC15 and LC50 of the insecticide significantly prolonged the duration of the larval and pupal stages and induced enzymatic detoxification activity in both species. Treatment of the second-instar larvae of C. carnea with the recommended concentration of cyantraniliprole (0.75 mg/L) doubled the mortality rates and resulted in a slight negative effect on the biology and detoxification enzymes of C. carnea. Our results indicate that both sublethal and lethal concentrations of cyantraniliprole can successfully suppress S. littoralis and A. ipsilon populations. They also suggest that C. carnea, as a generalist predator, is compatible with cyantraniliprole under the modelled realistic field conditions. In future investigations, insights into the effects of cyantraniliprole on S. littoralis, A. ipsilon, and C. carnea under field conditions will be required to appropriately validate our results.

Effect of Soil Application of Cyazypyr 20% SC, New Anthranilic Diamide Insecticide against Whitefly, Bemisia tabaci Genn. in Brinjal

Brinjal Solanum melongena L. is an herbaceous, tropical perennial plant, belongs to the family Solanaceae which is grown for its edible fruit. Among the different major insect pests infesting brinjal, whitefly, Bemicia tabaci (Genn.), is very important under West Bengal condition. The experiment was conducted during the 2013 and 2014 in the University farm at Kalyani, West Bengal state of India. Cv ‘Muktakeshi’ was grown in plots measuring 5 m×5 m, at spacing of 1 m x 0.75 m with three replication. The plots were set out in a randomized block design with six treatments including an untreated check. Five doses of cyazypyr 20% SC (4.5 MAT ,6.0 MAT, 7.5 MAT, 9.0 MAT and, 12 MAT in both year 2013 and 2014) were sprayed every year for their efficacy, After 50 days of treatment cyazypyr 20% SC @ 9.0 and 7.5 MAT (3.33 and 6.87 whiteflies / 5 leaves, respectively) maintained their superiority in controlling whiteflies, while @ 6.0 and 4.5 MAT (7.93 and 8.40 whiteflies / 5 leaves, respectively) and this treatment failed to show any significant difference from untreated control.

Non-targeted impact of cyantraniliprole residues on soil quality, mechanism of residue degradation, and isolation of potential bacteria for its bioremediation.

Cyantraniliprole (CY), an anthranilic diamide insecticide widely used in grape farming for controlling various sucking pests, poses ecological concerns, particularly when applied as soil drenching due to the formation of more toxic and persistent metabolites. This study established the dissipation and degradation mechanisms of CY in grape rhizosphere soil using high-resolution Orbitrap-LC/MS analysis. The persistence of CY residues beyond 60days was observed, with dissipation following biphasic first + first-order kinetics and a half-life of 15 to 21days. The degradation mechanism of CY in the soil was elucidated, with identified metabolites such as IN-J9Z38, IN-JCZ38, IN-N7B69, and IN-QKV54. Notably, CY was found to predominantly convert to the highly persistent metabolite IN-J9Z38, raising environmental concerns. The impact of CY residues on soil enzyme activity was investigated, revealing a negative effect on dehydrogenase, alkaline phosphatase, and acid phosphatase activity, indicating significant implications for phosphorous mineralization and soil health. Furthermore, bacterial isolates were obtained from CY-enriched soil, with five isolates (CY3, CY4, CY9, CY11, and CY20) demonstrating substantial degradation potential, ranging from 66 to 92% of CY residues. These results indicate that the identified bacteria hold potential for commercial use in addressing pesticide residue contamination in soil through bioremediation techniques.

Synthesis and Insecticidal Activity of Novel Anthranilic Diamide Insecticides Containing Indane and Its Analogs.

Diamide insecticides have always been a hot research topic in the field of pesticides. To further discover new compounds with high activity and safety, indane and its analogs were introduced into chlorantraniliprole, and a battery of chlorfenil derivatives, including indane and its analogs, were designed and prepared for biological testing. Their characterization and verification were carried out through nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). Biological detection showed that all the compounds exhibited good insecticidal activity against Mythimna separata. At 0.8 mg/L, the insecticidal activity of compound 8q against Mythimna separata was 80%, which was slightly better than that of chlorantraniliprole. The results of the structure-activity relationship (SAR) analysis indicated that the indane moiety had a significant effect on insecticidal activity, especially in the R-configuration. The results indicated that chlorantraniliprole derivatives containing indane groups could serve as pilot compounds for the further development of new insecticides.

Resistance Monitoring of Chilo suppressalis (Lepidoptera: Crambidae) to Chlorantraniliprole in Five Field Populations from Hunan China 2013–2020

Abstract Chlorantraniliprole, a new anthranilic diamide insecticide, has been commercialized in China since 2008 for controlling several lepidopterans, including rice stem borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae). Chemical control of this pest has become difficult because of its development of resistance to many conventional insecticides. To facilitate chlorantraniliprole resistance monitoring, seedling dip bioassays were conducted in 2013 and 2020 to assess the resistance of 5 field populations of C. suppressalis from Hunan provinces in China. The median lethal toxicity (LC50) of chlorantraniliprole against 3rd–4th instar larvae of field populations ranged from 14.799 to 103.587 mg active ingredient (a.i.)/L. The resistance of C. suppressalis to chlorantraniliprole is increasingly serious in most of the regions in Hunan. The levels of resistance of C. suppressalis to chlorantraniliprole ranged from 11.1-fold to 74.4-fold compared with a susceptible population, respectively. During the 8 years, the resistance level of C. suppressalis to chlorantraniliprole at five monitoring points showed a fluctuating upward trend. The resistance of C. suppressalis to chlorantraniliprole in Hengyang is highest in every year. These data are useful in future monitoring program for detecting any changes in resistance as a result of use of the insecticide.

New insights into chlorantraniliprole metabolic resistance mechanisms mediated by the striped rice borer cytochrome P450 monooxygenases: A case study of metabolic differences

The anthranilic diamide insecticide chlorantraniliprole has been extensively applied to control Lepidoptera pests. However, its overuse leads to the development of resistance and accumulation of residue in the environment. Four P450s (CYP6CV5, CYP9A68, CYP321F3, and CYP324A12) were first found to be constitutively overexpressed in an SSB CAP-resistant strain. It is imperative to further elucidate the molecular mechanisms underlying P450s-mediated CAP resistance for mitigating its environmental contamination. Here, we heterologously expressed these four P450s in insect cells and evaluated their abilities to metabolize CAP. Western blotting and reduced CO difference spectrum tests showed that these four P450 proteins had been successfully expressed in Sf9 cells, which are indicative of active functional enzymes. The recombinant proteins CYP6CV5, CYP9A68, CYP321F3, and CYP324A12 exhibited a preference for metabolizing the fluorescent P450 model probe substrates EC, BFC, EFC, and EC with enzyme activities of 0.54, 0.67, 0.57, and 0.46 pmol/min/pmol P450, respectively. In vitro metabolism revealed distinct CAP metabolic rates (0.97, 0.86, 0.75, and 0.55 pmol/min/pmol P450) and efficiencies (0.45, 0.37, 0.30, and 0.17) of the four recombinant P450 enzymes, thereby elucidating different protein catalytic activities. Furthermore, molecular model docking confirmed metabolic differences and efficiencies of these P450s and unveiled the hydroxylation reaction in generating N-demethylation and methylphenyl hydroxylation during CAP metabolism. Our findings not only first provide new insights into the mechanisms of P450s-mediated metabolic resistance to CAP at the protein level in SSB but also demonstrate significant differences in the capacities of multiple P450s for insecticide degradation and facilitate the evaluation and mitigation of toxic risks associated with CAP application in the environment.

Concise Approach to the Synthesis of First Generation Anthranilic Diamide Insecticide, Chlorantraniliprole

AbstractAn efficient and scalable process has been developed for the synthesis of anthranilic diamide insecticide i. e. chlorantraniliprole. The crucial step in this approach is the TiCl4‐mediated aza‐Fries rearrangement of aryl acetanilide to ortho‐aminoaryl ketone. Another key step is the nucleophilic substitution of tosylate into the corresponding bromide using NaBr in the presence of TBAB. All the steps in this synthesis are carried out effectively on a gram scale with excellent yields.

Risk assessment, fitness cost, cross-resistance, and mechanism of tetraniliprole resistance in the rice stem borer, Chilo suppressalis.

The rice stem borer (RSB), Chilo suppressalis, a notorious rice pest in China, has evolved a high resistance level to commonly used insecticides. Tetraniliprole, a new anthranilic diamide insecticide, effectively controls multiple pests, including RSB. However, the potential resistance risk of RSB to tetraniliprole is still unknown. In this study, the tetraniliprole-selection (Tet-R) strain was obtained through 10 continuous generations of selection with tetraniliprole 30% lethal concentration (LC30). The realized heritability (h2) of the Tet-R strain was 0.387, indicating that resistance of RSB to tetraniliprole developed rapidly under the continuous selection of tetraniliprole. The Tet-R strain had a high fitness cost (relative fitness=0.53). We established the susceptibility baseline of RSB to tetraniliprole (lethal concentration at LC50=0.727mg/L) and investigated the resistance level of 6 field populations to tetraniliprole. All tested strains that had resistance to chlorantraniliprole exhibited moderate- to high-level resistance to tetraniliprole (resistance ratio=27.7-806.8). Detection of ryanodine receptor (RyR) mutations showed that the Y4667C, Y4667D, I4758M, and Y4891F mutations were present in tested RSB field populations. RyR mutations were responsible for the cross-resistance between tetraniliprole and chlorantraniliprole. Further, the clustered regularly interspaced palindromic repeats (CRISPR) / CRISPR-associated protein 9-mediated genome-modified flies were used to study the contribution of RyR mutations to tetraniliprole resistance. The order of contribution of a single RyR mutation to tetraniliprole resistance was Y4667D>G4915E>Y4667C≈I4758M>Y4891F. In addition, the I4758M and Y4667C double mutations conferred higher tetraniliprole resistance than single Y4667C mutations. These results can guide resistance management practices for diamides in RSB and other arthropods.

Toxicity and effects on anuran tadpole metamorphosis of the anthranilic diamide insecticides chlorantraniliprole and cyantraniliprole

ABSTRACT The present study examined the acute and chronic toxicity attributed to commercial formulations of the anthranilic diamide insecticides chlorantraniliprole (CHLO) and cyantraniliprole (CYAN) on the neotropical amphibian species Rhinella arenarum, Rhinella fernandezae and Scinax granulatus. The median lethal concentrations obtained after 96 hr exposure (96 hr-LC50) were generally greater than 100 mg/L, except for stage 25 S. Granulatus, which were the most sensitive animals tested with a 96 hr-LC50 value of 46.78 mg/L. In subchronic exposures of R. arenarum, the 21day-LC50 were 151.4 mg/L for CHLO and >160 mg/L for CYAN, the weight gain of the tadpoles during this period not being markedly affected in both cases. Finally, when tadpoles of R. arenarum were exposed to CHLO throughout the metamorphic process, an inverted U-shaped non-monotonic dose-response relationship was observed between exposure concentrations and both % of individuals transiting between stage 39 and 42 and the time required to accomplish this. Data obtained raise the hypothesis of an effect of CHLO on the hypothalamic-pituitary-thyroid (HPT) axis, either directly or through an interaction with the stress-hormone system, as metamorphic progression from stage 39 to S42 occurs under the strict control of thyroid hormones. These observations are important as the anthranilic diamide insecticides are not currently known as endocrine disruptors. Further investigations are needed to clarify the pathways leading to these effects and examine whether environmentally-relevant aquatic concentrations of anthranilic diamides might be impacting amphibian populations in the wild.

The Selective Detection of Cyantraniliprole Insecticides Using Molecularly Imprinted Polymers Coupled with an Acetylcholinesterase Inhibition-Based Biosensor.

Cyantraniliprole is one of the anthranilic diamide insecticides widely used in the agriculture sector. Due to its low toxicity and relatively fast degradation, there is need for a sensitive determination method for its residues. Nowadays, there is growing interest in the development of enzyme-based biosensors. The major drawback is the non-specific binding of many insecticides to the enzyme. This work employs Molecularly imprinted polymers (MIPs) to increase enzyme specificity and eliminate the organic solvent effect on the enzyme activity. The synthesized Cyan-Molecularly imprinted polymers (Cyan-MIP) possesses high affinity and selectivity toward cyantraniliprole. Acetylcholinesterase assay characteristics including enzyme concentration, substrate concentration, DTNB concentration, and acetonitrile concentration were optimized. Under optimal experimental conditions, the developed MIP-Acetylcholinesterase (MIP-AchE) inhibition-based sensor provides better precision than the AchE inhibition-based sensor with a wide linear range (15-50 ppm), limit of detection (LOD) 4.1 ppm, and limit of quantitation (LOQ) 12.6 ppm. The sensor was successfully applied for cyantraniliprole determination in spiked melon, giving satisfactory recoveries.

Anthranilic Diamides Containing Monofluoroalkene Amide Linkers as Potential Insect RyR Activators: Design, Synthesis, Bio-evaluation, and Computational Study.

In order to develop anthranilic diamides with novel chemotypes, a series of anthranilic diamides with acrylamide linkers were designed and synthesized. The results of preliminary bioassays indicated that compounds with a monofluoroalkene amide linker (Z-isomer) exhibited good larvicidal activity against lepidopteran pests. The LC50 values of compound A23 against Mythimna separata and Plutella xylostella were 1.44 and 3.48 mg·L-1, respectively, while those of chlorantraniliprole were 0.08 and 0.06 mg·L-1, respectively. Compound A23 also exhibited the same level of lethal potency against resistant and susceptible strains of Spodoptera frugiperda at 50 mg·L-1. Compound A23 exhibited similar symptoms as chlorantraniliprole in test larvae. Comparative molecular field analysis was conducted to demonstrate the structure-activity relationship. Central neuron calcium imaging experiments indicated that monofluoroalkene compounds were potential ryanodine receptor (RyR) activators and activated calcium channels in both the endoplasmic reticulum and the cell membrane. Molecular docking suggested that A23 had a better binding potency to P. xylostella RyR than chlorantraniliprole. The MM|GBSA dG bind value of A23 with P. xylostella RyR was 117.611 kcal·mol-1. Monofluoroalkene was introduced into anthranilic diamide insecticides for the first time and brought a novel chemotype for insect RyR activators. The feasibility of fluoroalkenes as insecticide fragments was explored.

Mechanisms underlying the effects of low concentrations of chlorantraniliprole on development and reproduction of the fall armyworm, Spodoptera frugiperda

It is well known that sublethal dose of insecticides induces life history trait changes of both target and non-target insect species, however, the underlying mechanisms remain not well understood. In this study, the effects of low concentrations of the anthranilic diamide insecticide chlorantraniliprole on the development and reproduction of the fall armyworm (FAW), Spodoptera frugiperda, were evaluated, and the underlying mechanisms were explored. The results showed that exposure of FAW to LC10 and LC30 chlorantraniliprole prolonged the larvae duration, decreased the mean weight of the larvae and pupae, and lowered the pupation rate as well as emergence rate. The fecundity of female adults was also negatively affected by treatment with low concentrations of chlorantraniliprole. Consistently, we found that exposure of FAW to LC30 chlorantraniliprole downregulated the mRNA expression of juvenile hormone (JH) esterase (SfJHE), leading to the increase of JH titer in larvae. We also found that treatment with low concentrations of chlorantraniliprole suppressed the expression of ribosomal protein S6 kinase1 (SfS6K1) in female adults, resulting in the downregulation of the gene encoding vitellogenin (SfVg). These results provided insights into the mechanisms underlying the effects of low concentrations of insecticides on insect pests, and had applied implications for the control of FAW.

N-Cyano sulfilimine functional group as a nonclassical amide bond bioisostere in the design of a potent analogue to anthranilic diamide insecticide.

To explore the potential of the N-cyano sulfilimine group as an amide bond isostere, a derivative of the blockbuster anthranilic diamide, chlorantramiliprole, was synthesized and evaluated with regard to its physicochemical properties, permeability, and biological activity. Given the combination of N-cyano sulfilimine chlorantraniliprole 1 and its strong hydrogen bond acceptor character, high permeability, and excellent insecticidal activity, the N-cyano sulfilimine functional group could be considered as an amide bond isostere.

Design, synthesis, characterization and insecticidal screening of novel anthranilic diamides comprising acyl thiourea substructure.

Mosquito-borne pathogens constitute a major health problem worldwide. The extermination of the mosquito remains a significant issue in public health. Chemical insecticides have been used to control mosquitoes for decades. However, resistance has become a limiting factor for their control. The anthranilic diamide insecticides possess excellent insecticidal activities against Lepidoptera and its resistant strains by draining internal calcium stores on activating insect ryanodine receptors. However, the reports on the effect on mosquitoes are scarce and hence a series of novel anthranilic diamides comprising acyl thiourea substructure were synthesized and their insecticidal activities against three vector mosquito larvae namely, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi were evaluated as per WHO protocol. Also investigated the morphological observations of treated larvae. Novel anthranilic diamides containing an acyl thiourea substructure were synthesized and structures were established by 1 H nuclear magnetic resonance (NMR), 13 C NMR, Fourier transform infrared (FTIR) and high-resolution mass spectrometry (HR-MS). Mosquito larvicidal activity of the title compounds 6-a-s revealed that compound 6-l exhibited marked larvicidal activities against C.quinquefasciatus and A.aegypti 3rd instar larvae with median lethal concentrations (LC50 ) values of 0.0044 mm and 0.0070 mm, respectively, for 48 hours of treatment. Compound 6-g exhibited larvicidal activity against An.stephensi with LC50 value of 0.0085 mm. Peculiar morphological alterations in the body of the treated larvae leading to death were observed on microscopic examination. Novel anthranilic diamides containing an acyl thiourea substructure were designed, synthesized and characterized. Their bioassay results demonstrated significant mosquito larvicidal activity with striking morphological alterations in the body, which should ensure forthcoming designs of highly active diamide derivatives as mosquito larvicides. © 2022 Society of Chemical Industry.

Determination of Chlorantraniliprole Residue in Soil by Gas Chromatography-Mass Spectrometry

Gas chromatography-mass spectrometry method was developed and validated for the quantification of anthranilic diamide insecticide chlorantraniliprole residues in soil. The soil samples were extracted with acetonitrile and dispersive solid phase extraction clean up. The average recoveries of chlorantraniliprole were in the range of 94.10-96.82% with reproducibility and repeatability was ranged between 0.17 to 1.90 and 0.97 to 1.22%, respectively. The limit of quantification of the analytical method was 0.01 μg g-1 and the matrix effect was less than 1%.

Improving Insecticidal Activity of Chlorantraniliprole by Replacing the Chloropyridinyl Moiety with a Substituted Cyanophenyl Group.

Insect ryanodine receptors (RyRs) are molecular targets of the anthranilic diamide insecticides. In the present study, a new series of anthranilic diamides containing a cyanophenyl pyrazole moiety were rationally designed by active-fragment assembly and computer-aided design using the 3D structure of Plutella xylostella RyRs as a receptor and chlorantraniliprole as a ligand. Most of the titled compounds showed good toxicity against Mythimna separate, P. xylostella, and Spodoptera frugiperda. Compounds CN06, CN11, and CN16 with corresponding LC50 values of 0.15, 0.29, and 0.52 mg·L-1, respectively, against M. separate showed comparable activity to that of chlorantraniliprole (0.13 mg·L-1). Surprisingly, CN06, CN11, and CN16 with corresponding LC50 values of 1.6 × 10-5, 3.0 × 10-5, and 2.8 × 10-5 mg·L-1, respectively, against P. xylostella were at least 5-fold more active than chlorantraniliprole (1.5 × 10-4 mg·L-1). In the case of S. frugiperda, CN06, CN11, and CN16 had good potency but lower than chlorantraniliprole in terms of LC50 values (0.58, 0.54, and 0.56 mg·L-1 versus 0.31 mg·L-1). Molecular docking of CN06 and chlorantraniliprole to P. xylostella RyRs validated the molecular design, and the calcium imaging technique further proved the potential target of CN06 as RyRs. Compounds CN06, CN11, and CN16 could be more effective than chlorantraniliprole in targeting the resistant RyR mutants of S. frugiperda (G4891E, I4734M) through the binding mode and energy obtained by molecular docking. Density functional theory calculations (DFT) and electrostatic potential (ESP) studies gave the structure-activity relationship. Compounds CN06, CN11, and CN16 could be used as potent insecticide leads for further optimization.

Toxicological and transcriptomic effects in Mythimna separata (Lepidoptera: Noctuidae) exposed to chlorantraniliprole and functional characterization of glutathione S-transferases.

Chlorantraniliprole (CAP) is an efficient anthranilic diamide insecticide against economically important pests such as the oriental armyworm, Mythimna separata (Lepidoptera: Noctuidae). Resistance to CAP may develop due to enhanced enzymatic detoxification. The glutathione S-transferase (GST) superfamily in M. separata has not been systematically characterized. The aim of this study was therefore to explore the effects of lethal and sublethal doses of CAP on M. separata larvae, screen differentially expressed genes (DEGs) responding to CAP exposure, identify and characterize the GST superfamily, and analyze the metabolism of CAP by recombinant GSTs. The toxicity bioassay showed that CAP was active against M. separata third-instar larvae. LC50 was 17.615, 3.127, and 1.336 mg/L after 24, 48, and 72 h, respectively. Poisoned larvae showed contracted somites and disrupted midgut. Total GST activity in larvae was significantly elevated 24 h after CAP exposure. RNA-sequencing generated 43 055 unigenes with an average length of 1010 bp, and 567 up-regulated and 692 down-regulated DEGs responding to CAP treatment were screened. Thirty-five GST genes were identified from unigenes, including 31 cytosolic, three microsomal, and one unclassified. The expression profile of GST genes was analyzed using samples from different developmental stages, adult tissues, and CAP treatments. Metabolic assays indicated that CAP was depleted by recombinant MseGSTe2 and MseGSTs6. This study provides insight into the toxicological and transcriptomic effects in M. separata larvae exposed to CAP. The identification and functional characterization of the GST superfamily will improve our understanding of CAP detoxification by GSTs. © 2022 Society of Chemical Industry.

Degradation of anthranilic diamide insecticide tetrachlorantraniliprole in water: Kinetics, degradation pathways, product identification and toxicity assessment

In the present study, aqueous behavior and fate of diamide insecticide tetrachlorantraniliprole (TCTP) were investigated under laboratory-controlled conditions. Half-lives of TCTP photolysis in natural water and pH buffers were 1.4–2.8 h, comparing with those of 1.2–231 d for hydrolysis. Both processes were highly influenced by pH with respect to degradation kinetics and routes. The hydrolysis rate of TCTP was accelerated by elevated temperatures. The presence of nitrate enhanced TCTP photolysis while fulvic acid exhibited suppression, with the extent of both effects as a function of concentration. Four degradation products were identified using a variety of spectroscopic approaches. Key reactions involved in the degradation pathways include intramolecular substitution and cyclization. There was a reduction in the acute toxicity of all four products to Daphnia magna by comparison with TCTP, whereas they were still classified as category 1 or 2 hazardous substances to the aquatic environment according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) standards.