Preparation and Application of Volatilized Wormwood Essence Derived Naturally into Green Insecticide.

Naturally occurring substances and their derivatives function as vital resources for pesticides that can be used in fields, such as insecticide production and fungicide development. As a botanical entity displaying multifaceted biological functions, wormwood has received thorough scrutiny across multiple sectors. The insect repellency potency combined with antibacterial and antifungal activities of wormwood position it as a potential candidate for prospective development into eco-friendly chemical pesticides. In this research, Wormwood essential oil was procured via ethanol water under ultrasonic scenarios and subsequently diluted with PEG 400 to formulate green chemical pesticides. The defensive efficacy of this green pesticide on plants was validated through 2 weeks of clustered plant growth experiments. Active constituents that exerted their effects were scrutinized by GC-MS. Furthermore, this green pesticide also displays efficacious effects on the prevention and management of aphids, exhibiting a dose-dependent relationship. 4-terpenol, eucalyptol, carvacrol, and L-borneol were identified by GC-MS as the predominant active constituents in this green chemical pesticide. Wormwood can be leveraged to develop green chemical pesticides, which can protect plants without contaminating the environment.

microRNA-3037 targeting CYP6CY2 confers imidacloprid resistance to Sitobion miscanthi (Takahashi).

The wheat aphid Sitobion miscanthi is a dominant and destructive pest in agricultural production. Insecticides are the main substances used for effective control of wheat aphids. However, their extensive application has caused severe resistance of wheat aphids to some insecticides; therefore, exploring resistance mechanisms is essential for wheat aphid management. In the present study, CYP6CY2, a new P450 gene, was isolated and overexpressed in the imidacloprid-resistant strain (SM-R) compared to the imidacloprid-susceptible strain (SM-S). The increased sensitivity of S. miscanthi to imidacloprid after knockdown of CYP6CY2 indicates that it could be associated with imidacloprid resistance. Subsequently, the posttranscriptional regulation of CYP6CY2 in the 3' UTR by miR-3037 was confirmed, and CYP6CY2 participated in imidacloprid resistance. This finding is critical for determining the role of P450 in relation to the resistance of S. miscanthi to imidacloprid. It is of great significance to understand this regulatory mechanism of P450 expression in the resistance of S. miscanthi to neonicotinoids.

UDP-Glycosyltransferases UGT350C3 and UGT344L7 Confer Tolerance to Neonicotinoids in Field Populations of Aphis gossypii.

The cotton aphid, Aphis gossypii, is a polyphagous pest that stunts host plant growth via direct feeding or transmitting plant virus. Due to the long-term application of insecticides, A. gossypii has developed different levels of resistance to numerous insecticides. We found that five field populations had evolved multiple resistances to neonicotinoids. To explore the resistance mechanism mediated by uridine diphosphate glycosyltransferases (UGTs), two upregulated UGT genes in these five strains, UGT350C3 and UGT344L7, were selected for functional analysis of their roles in neonicotinoid detoxification. Transgenic Drosophila bioassay results indicated that compared with the control lines, the UGT350C3 and UGT344L7 overexpression lines were more tolerant to thiamethoxam, imidacloprid, and dinotefuran. Knockdown of UGT350C3 and UGT344L7 significantly increased A. gossypii sensitivity to thiamethoxam, imidacloprid, and dinotefuran. Molecular docking analysis demonstrated that these neonicotinoids could bind to the active pockets of UGT350C3 and UGT344L7. This study provides functional evidence of neonicotinoid detoxification mediated by UGTs and will facilitate further work to identify strategies for preventing the development of neonicotinoid resistance in insects.

S431F mutation on AChE1 and overexpression of P450 genes confer high pirimicarb resistance in Sitobion miscanthi.

Sitobion miscanthi is a destructive wheat pest responsible for significant wheat yield losses. Pirimicarb, one of the most important representatives of N, N-dimethylcarbamate insecticides, is widely used to control wheat aphids. In present work, heterozygous S431F mutation of acetylcholinesterase 1 (AChE1) was identified and verified in three pirimicarb-resistant S. miscanthi populations (two field populations (HA and HS, >955.8-fold) and one lab-selected population (PirR, 486.1-fold)), which has not been reported in S. miscanthi yet. The molecular docking results revealed that AChE1 containing the S431F mutation of S. miscanthi (SmAChE1S431F) showed higher free binding energy to three insecticides (pirimicarb, omethoate, and methomyl) than wild-type AChE1 of S. miscanthi (SmAChE1). Enzyme kinetic and inhibition experiments showed that the recombinant SmAChE1S431F was more insensitive to pirimicarb and omethoate than the recombinant SmAChE1. Furthermore, two overexpression P450 genes (CYP6K1 and CYP6A14) associated with pirimicarb resistance of S. miscanthi were verified by RNAi. These results suggested both target alteration and enhanced metabolism contributed to high pirimicarb resistance of S. miscanthi in the field and laboratory. These findings lay a foundation for further elucidating the mechanism of pirimicarb resistance in S. miscanthi, and have important implications for the resistance management of S. miscanthi control.

Discovery of Pyrido[1,2-α] Pyrimidinone Mesoionic Compounds as Potential Control Agents Against Potato Virus Y.

Potato virus Y (PVY) relies on aphids and tubers to spread in the field and causes serious economic losses in the potato industry. Here, we found that pyrido[1,2-α] pyrimidinone mesoionic compounds with insecticidal activity against aphids possessed a good inhibitory effect on PVY. Among them, compound 35 had the best inhibitory activity against PVY (EC50 = 104 µg/mL), even superior to that of ningnanmycin (125 µg/mL). The fluorescence and qPCR results confirmed that compound 35 could inhibit the proliferation of PVY in Nicotiana benthamiana. Preliminary experiments on the mechanism of action indicated that compound 35 had good binding affinity with the coat protein (CP), which plays an essential role in aphid-PVY interactions. Molecular docking revealed that compound 35 could bind to the pocket of CP formed by Ser52, Glu204, and Arg208. Compound 35 had substantially lower binding affinity (Kd) values with CPS52A (219 µM), CPE204A (231 µM), and CPR208A (189 µM) than those with CPWT (5.80 µM). A luciferase assay confirmed that mutating Ser52, Glu204, and Arg208 significantly affected the expression level of CP and further reduced virus proliferation. Therefore, the broad-spectrum activity of compound 35 provides a unique strategy for the prevention and treatment of PVY.

Rational Design of Triazinone Derivatives with Low Bee Toxicity Based on the Binding Mechanism of Neonicotinoids to Apis mellifera.

Bees, one of the most vital pollinators in the ecosystem and agriculture, are currently threatened by neonicotinoids. To explore the molecular mechanisms of neonicotinoid toxicity to bees, the different binding modes of imidacloprid, thiacloprid, and flupyradifurone with nicotinic acetylcholine receptor (nAChR) α1ß1 and cytochrome P450 9Q3 (CYP9Q3) were studied using homology modeling and molecular dynamics simulations. These mechanisms provided a basis for the design of compounds with a potential low bee toxicity. Consequently, we designed and synthesized a series of triazinone derivatives and assessed their bioassays. Among them, compound 5a not only displayed substantially insecticidal activities against Aphis glycines (LC50 = 4.40 mg/L) and Myzus persicae (LC50 = 6.44 mg/L) but also had low toxicity to Apis mellifera. Two-electrode voltage clamp recordings further confirmed that compound 5a interacted with the M. persicae nAChR α1 subunit but not with the A. mellifera nAChR α1 subunit. This work provides a paradigm for applying molecular toxic mechanisms to the design of compounds with low bee toxicity, thereby aiding the future rational design of eco-friendly nicotinic insecticides.

Hesperidin as a Species-Specific Modifier of Aphid Behavior.

Hesperidin is a highly bioactive natural flavonoid whose role in ecological interactions is poorly known. In particular, the effects of hesperidin on herbivores are rarely reported. Flavonoids have been considered as prospective biopesticides; therefore, the aim of the present study was to examine the influence of hesperidin on the host plant selection behavior of three aphid (Hemiptera: Aphididae) species: Acyrthosiphon pisum Harrris, Rhopalosiphum padi (L.), and Myzus persicae (Sulz.). The aphid host plants were treated with 0.1% and 0.5% ethanolic solutions of hesperidin. Aphid probing behavior in the no-choice experiment was monitored using electropenetrography and aphid settling on plants in the choice experiment was recorded. The results demonstrated that hesperidin can be applied as a pre-ingestive, ingestive, and post-ingestive deterrent against A. pisum, as an ingestive deterrent against R. padi, and as a post-ingestive deterrent against M. persicae using the relatively low 0.1% concentration. While in A. pisum the deterrent effects of hesperidin were manifested as early as during aphid probing in peripheral plant tissues, in M. persicae, the avoidance of plants was probably the consequence of consuming the hesperidin-containing phloem sap.

Design, Synthesis, and Bioactivity of Trifluoroethylthio-Substituted Phenylpyrazole Derivatives.

As the first marketed phenylpyrazole insecticide, fipronil exhibited remarkable broad-spectrum insecticidal activity. However, it poses a significant threat to aquatic organisms and bees due to its high toxicity. Herein, 35 phenylpyrazole derivatives containing a trifluoroethylthio group on the 4 position of the pyrazole ring were designed and synthesized. The predicted physicochemical properties of all of the compounds were within a reasonable range. The biological assay results revealed that compound 7 showed 69.7% lethality against Aedes albopictus (A. albopictus) at the concentration of 0.125 mg/L. Compounds 7, 7g, 8d, and 10j showed superior insecticidal activity for the control of Plutella xylostella (P. xylostella). Notably, compound 7 showed similar insecticidal activity against Aphis craccivora (A. craccivora) compared with fipronil. Potential surface calculation and molecular docking suggested that different lipophilicity and binding models to the Musca domestica (M. domestica) gamma-aminobutyric acid receptors may be responsible for the decreased activity of the tested derivatives. Toxicity tests indicated that compound 8d (LC50 = 14.28 mg/L) induced obviously 14-fold lower toxicity than fipronil (LC50 = 1.05 mg/L) on embryonic-juvenile zebrafish development.

Computational Modeling Oriented Substructure Splicing Application in the Identification of Thiazolidine Derivatives as Potential Low Honeybee Toxic Neonicotinoids.

With the aim of identifying novel neonicotinoid insecticides with low bee toxicity, a series of compounds bearing thiazolidine moiety, which has been shown to be low bee toxic, were rationally designed through substructure splicing strategy and evaluated insecticidal activities. The optimal compounds A24 and A29 exhibited LC50 values of 30.01 and 17.08 mg/L against Aphis craccivora, respectively. Electrophysiological studies performed on Xenopus oocytes indicated that compound A29 acted on insect nAChR, with EC50 value of 50.11 µM. Docking binding mode analysis demonstrated that A29 bound to Lymnaea stagnalis acetylcholine binding protein through H-bonds with the residues of D_Arg55, D_Leu102, and D_Val114. Quantum mechanics calculation showed that A29 had a higher highest occupied molecular orbit (HOMO) energy and lower vertical ionization potential (IP) value compared to the high bee toxic imidacloprid, showing potentially low bee toxicity. Bee toxicity predictive model also indicated that A29 was nontoxic to honeybees. Our present work identified an innovative insecticidal scaffold and might facilitate the further exploration of low bee toxic neonicotinoid insecticides.

Design, Synthesis, and Insecticidal Activity of Pyridino[1,2-a]pyrimidines Containing Indole Moeites at the 1-Position.

Research on mesoionic structures in pesticide design has gained significant attention in recent years. However, the 1-position of pyridino[1,2-a]pyrimidine is usually designed with 2-chlorothiazole, 2-chloropyridine, or cyano moieties commonly found in neonicotinoid insecticides. In order to enrich the available pharmacophore library, here, we disclose a series of new pyridino[1,2-a]pyrimidine mesoionics bearing indole-containing substituents at the 1-position. Most of these target compounds are confirmed to have good insecticidal activity against aphids through bioevaluation. In addition, a three-dimensional structure-activity relationship model is established to allow access to optimal compound F45 with an LC50 value of 2.97 mg/L. This value is comparable to the property achieved by the positive control triflumezopyrim (LC50 = 2.94 mg/L). Proteomics and molecular docking analysis suggest that compound F45 has the potential to modulate the functioning of the aphid nervous system through its interaction with neuronal nicotinic acetylcholine receptors. This study expands the existing pharmacophore library for the future development of new mesoionic insecticides based on 1-position modifications of the pyridino[1,2-a]pyrimidine scaffold.

Rifampicin synergizes the toxicity of insecticides against the green peach aphid, Myzus persicae.

Myzus persicae is an important pest that has developed resistance to nearly all currently used insecticidal products. The employment of insecticide synergists is one of the effective strategies that need to be developed for the management of this resistance. Our study showed that treatment with a combination of the antibiotic, rifampicin, with imidacloprid, cyantraniliprole, or clothianidin significantly increased their toxicities against M. persicae, by 2.72, 3.59, and 2.41 folds, respectively. Rifampicin treatment led to a noteworthy reduction in the activities of multifunctional oxidases (by 32.64%) and esterases (by 23.80%), along with a decrease in the expression of the CYP6CY3 gene (by 58.57%) in M. persicae. It also negatively impacted the fitness of the aphids, including weight, life span, number of offspring, and elongation of developmental duration. In addition, bioassays showed that the combination of rifampicin and a detoxification enzyme inhibitor, piperonyl butoxide, or dsRNA of CYP6CY3 further significantly improved the toxicity of imidacloprid against M. persicae, by 6.19- and 7.55-fold, respectively. The present study suggests that development of active ingredients such as rifampicin as candidate synergists, show promise to overcome metabolic resistance to insecticides in aphids.

Toxicological, biochemical, and in silico investigations of three trehalase inhibitors for new ways to control aphids.

Insect trehalases have been identified as promising new targets for pest control. These key enzymes are involved in trehalose hydrolysis and plays an important role in insect growth and development. In this contribution, plant and microbial compounds, namely validamycin A, amygdalin, and phloridzin, were evaluated for their effect, through trehalase inhibition, on Acyrthosiphon pisum aphid. The latter is part of the Aphididae family, main pests as phytovirus vectors and being very harmful for crops. Validamycin A was confirmed as an excellent trehalase inhibitor with an half maximal inhibitory concentration and inhibitor constant of 2.2 × 10-7 and 5 × 10-8 M, respectively, with a mortality rate of ~80% on a A. pisum population. Unlike validamycin A, the insect lethal efficacy of amygdalin and phloridzin did not correspond to their trehalase inhibition, probably due to their hydrolysis by insect ß-glucosidases. Our docking studies showed that none of the three compounds can bind to the trehalase active site, unlike their hydrolyzed counterparts, that is, validoxylamine A, phloretin, and prunasin. Validoxylamine A would be by far the best trehalase binder, followed by phloretin and prunasin.

Design, synthesis, and evaluation of novel arecoline-linked amino acid derivatives for insecticidal and antifungal activities.

A series of arecoline derivatives with amino acid moieties were designed and synthesised using an acylamide condensation strategy, taking arecoline as the foundational structure. The insecticidal efficacy of these compounds against Aphis craccivora and Tetranychus cinnabarinus was evaluated. Notably, derivatives 3h and 3i demonstrated superior insecticidal activity compared with arecoline. Additionally, 3h and 3i showed good fungicidal effectiveness against two types of plant fungi. Moreover, molecular docking analyses suggested that 3h and 3i could affect the nervous systems of A. craccivora and T. cinnabarinus by binding to neuronal nicotinic acetylcholine receptors. These findings suggest that compounds 3h and 3i represent promising leads for further development in insecticide and fungicide research.

A relaxin receptor gene RpGPCR41 is involved in the resistance of Rhopalosiphum padi to pyrethroids.

Rhopalosiphum padi is a global pest that poses a significant threat to wheat crops and has developed resistance to various insecticides. G protein-coupled receptors (GPCRs), known for their crucial role in signaling and biological processes across insect species, have recently gained attention as a potential target for insecticides. GPCR has the potential to contribute to insect resistance through the regulation of P450 gene expression. However, GPCRs in R. padi remained unexplored until this study. We identified a total of 102 GPCRs in R. padi, including 81 receptors from family A, 10 receptors from family B, 8 receptors from family C, and 3 receptors from family D. Among these GPCR genes, 16 were up-regulated in both lambda-cyhalothrin and bifenthrin-resistant strains of R. padi (LC-R and BIF-R). A relaxin receptor gene, RpGPCR41, showed the highest up-regulated expression in both the resistant strains, with a significant increase of 14.3-fold and 22.7-fold compared to the susceptible strain (SS). RNA interference (RNAi) experiments targeting the relaxin receptor significantly increase the mortality of R. padi when exposed to the LC50 concentration of lambda-cyhalothrin and bifenthrin. The expression levels of five P450 genes (RpCYP6CY8, RpCYP6DC1, RpCYP380B1, RpCYP4CH2, and RpCYP4C1) were significantly down-regulated following knockdown of RpGPCR41 in LC-R and BIF-R strains. Our results highlight the involvement of GPCR gene overexpression in the resistance of R. padi to pyrethroids, providing valuable insights into the mechanisms underlying aphid resistance and a potential target for aphid control.

Exploration of Some Heterocyclic Compounds Containing Trifluoromethylpyridine Scaffold as Insecticides Toward Aphis gossypii Insects.

Five types of heterocyclic compounds containing trifloromethylpyridine scaffold namely; 3-cyano-2-(N-phenyl)carbamoylmethylthio-6-(thiophen-2-yl)-4-trifluoromethyl-pyridine (6a), thieno[2,3-b]pyridines 3-5 and 7a-c, pyrido[3',2':4,5]thieno[3,2-d] pyrimidines 8-13 and 15a-c, pyrido[3',2':4,5]thieno[3,2-d][1,2,3]triazines 16a,b, and 9-(thiophen-2-yl)-7-(trifluoromethyl) pyrido [3',2':4,5]thieno[2,3-e][1,2,4]triazolo[1,5-c]pyrimidine (14) were synthesized in excellent yields and very pure state. The structures of these compounds were confirmed by elemental and spectral analyses. Most of the synthesized compounds were evaluated as insecticidal agents toward Aphis gossypii insects and promising results obtained. Among all tested compounds, only 6, 7a, 7c and 15c being the most potent compounds against nymphs and adults of Aphis gossypii and their activities are nearly to that of acetamiprid as a reference. The effect of 6a compounds 7a, 7c and 15c on the Aphis digestive system from histological point of view was also included.

Layer-by-layer assembled decomposable nanocapsules for light-responsive release of pesticide imidacloprid on Aphis craccivora Koch.

BACKGROUND: Conventional pesticide formulations are often inefficient because of low biological uptake after spraying. Controlled release nanopesticides can release pesticides precisely in response to specific stimuli, thereby killing pests and pathogens using the least effective concentration. This study aims to develop nanocapsule-based photo-decomposable nanopesticides for efficient pesticide control. RESULTS: The target nanopesticides were successfully fabricated using layer-by-layer assembly of the negative azobenzene-grafted hyaluronic acid (azo-HA) and positive polydimethyldiallylammonium chloride (polyDADMAC), confirmed by UV-visible, dynamic light scattering, Zeta potential and transmission electron microscopy measurements. The particle size and Zeta potential of the fabricated nanocapsules were 220 nm and +46.1 mV, respectively, and the nanocapsules were found to remain stable for up to 30 days. The optimized drug loading and encapsulation ratio of imidacloprid (IMI) in IMI/azo-HA@polyDADMAC were 21.5% and 91.3%, respectively. Cumulative release of IMI from the nanopesticides increased from ~50% to ~95% upon UV light irradiation (365 nm). The half lethal concentration (LC50) value of the nanopesticides toward Aphis craccivora Koch decreased from 2.22 to 0.55 mg L-1 upon UV light irradiation. CONCLUSION: The trans to cis transformation of the azo group in HA decomposed IMI/azo-HA@polyDADMAC nanopesticides upon UV irradiation, thus facilitating the release of IMI, resulting in a decrease in the concentration of pesticides required for efficient pesticide control. Our work demonstrated the great potential of light-responsive nanocapsules as a controlled release nanocarrier for efficient and eco-friendly pesticide control in sustainable agriculture. © 2024 Society of Chemical Industry.

Exogenous ABA promotes resistance to Sitobion avenae (Fabricius) in rice seedlings.

BACKGROUND: Over the course of evolution, plants have developed various sophisticated defense mechanisms to resist pests and diseases. The phytohormone abscisic acid (ABA) has an important role in the growth and development of plants and confers tolerance to selected abiotic stressors, such as drought. Previous studies have shown that ABA promotes the deposit of callose in response to piercing/sucking insect pests. The English grain aphid, Sitobion avenae Fabricius, causes huge losses in rice and is especially harmful to rice seedlings. RESULTS: Exogenous ABA promoted growth and reduced the feeding behavior of S. avenae nymphs in rice. Our results suggested that enhanced trichome density and increased expression of related genes may be associated with rice resistance to aphids. An analysis of volatiles revealed the production of seven compounds associated with pest resistance. CONCLUSION: These results indicate that ABA reduces aphid feeding in rice. Our findings provide a basis for understanding ABA-mediated defense responses in rice and provide insights on more environmentally-friendly approaches to control. © 2024 Society of Chemical Industry.

Discovery and properties of novel analogues of the aphid pheromones nepetalactone and nepetalactol.

BACKGROUND: Pheromones have unique advantages for pest control. Current aphid pheromone research focuses on alarm and sex pheromones. However, practical applications are limited so far, as (E)-ß-farnesene has only been investigated to a small extent as an alarm pheromone and only male aphids are targeted by sex pheromones. Previous literature reports electrophysiological responses and repellent behavior of asexual aphids to nepetalactone (1B), therefore our objective was to modify nepetalactone's structure to identify key fragments responsible for repellent effects, as guidance for subsequent modifications and further investigation. RESULTS: In this study, seven derivatives were designed and synthesized based on nepetalactol (1A) and nepetalactone (1B) as lead compounds. Free-choice tests, conducted using cowpea aphids (Aphis craccivora), revealed that the lactone moiety was crucial for the repellent activity, and the removal of the carbonyl group eliminated the repelling effect. Compound (±)1I, an analogue of nepetalactone (1B), demonstrated a significantly higher repellent value than nepetalactone (1B) at three different concentrations, and even at 0.1 mg/mL it maintained a considerable repellent effect (26.5%). Electrostatic potential and density functional theory calculations supported the importance of the carbonyl group for the repellent effects. CONCLUSION: The newly discovered para-pheromone (±)1I shows improved repellent effects and potential for development as a novel biological control agent. Based on our innovative findings, analogues with improved efficacy and properties can be designed and prepared. Our research contributes to understanding the effects of structural modifications on pheromone activity and properties, which is crucial for exploring novel pheromone-based products for crop protection. © 2024 Society of Chemical Industry.

Effect of the mycotoxins enniatin B and deoxynivalenol on the wheat aphid Sitobion avenae and on the predatory lacewing Chrysoperla carnea.

BACKGROUND: Fusarium species are responsible for Fusarium head blight (FHB) in wheat, resulting in yield losses and mycotoxin contamination. Deoxynivalenol (DON) and enniatins (ENNs) are common mycotoxins produced by Fusarium, affecting plant, animal and human health. Although DON's effects have been widely studied, limited research has explored the impact of ENNs on insects. This study examines the influence of DON and enniatin B (ENB), both singularly and in combination, on the wheat aphid Sitobion avenae and one of its predators, the lacewing Chrysoperla carnea. RESULTS: When exposed to DON (100 mg L-1) or DON + ENB (100 mg L-1), S. avenae exhibited significantly increased mortality compared to the negative control. ENB (100 mg L-1) had no significant effect on aphid mortality. DON-treated aphids showed increasing mortality from 48 to 96 h. A dose-response relationship with DON revealed significant cumulative mortality starting at 25 mg L-1. By contrast, C. carnea larvae exposed to mycotoxins via cuticular application did not show significant differences in mortality when mycotoxins were dissolved in water but exhibited increased mortality with acetone-solubilized DON + ENB (100 mg L-1). Feeding C. carnea with aphids exposed to mycotoxins (indirect exposure) did not impact their survival or predatory activity. Additionally, the impact of mycotoxins on C. carnea was observed only with acetone-solubilized DON + ENB. CONCLUSIONS: These findings shed light on the complex interactions involving mycotoxins, aphids and their predators, offering valuable insights for integrated pest management strategies. Further research should explore broader ecological consequences of mycotoxin contamination in agroecosystems. © 2024 Society of Chemical Industry.

Effects of thiamethoxam on physiological and molecular responses to potato plant (Solanum tuberosum), green peach aphid (Myzus persicae), and parasitoid (Aphidius gifuensis).

BACKGROUND: To improve integrated pest management (IPM) performance it is essential to assess pesticide side effects on host plants, insect pests, and natural enemies. The green peach aphid (Myzus persicae Sulzer) is a major insect pest that attacks various crops. Aphidius gifuensis is an essential natural enemy of M. persicae that has been applied effectively in controlling M. persicae. Thiamethoxam is a neonicotinoid pesticide widely used against insect pests. RESULTS: The current study showed the effect of thiamethoxam against Solanum tuberosum, M. persicae, and A. gefiuensis and the physiological and molecular response of the plants, aphids, and parasitoids after thiamethoxam application. Thiamethoxam affected the physical parameters of S. tuberosum and generated a variety of sublethal effects on M. persicae and A. gefiuensis, including nymph development time, adult longevity, and fertility. Our results showed that different thiamethoxam concentrations [0.1, 0.5, and 0.9 µm active ingredient (a.i.)/L] on different time durations (2, 6, and 10 days) increased the antioxidant enzyme activities SOD, POD, and CAT of S. tuberosum, M. persicae, and A. gefiuensis significantly compared with the control. Our results also showed that different thiamethoxam concentrations (0.1, 0.5, and 0.9 µm a.i./L) on different time durations (2, 6, and 10 days) increased the expression of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione-S-transferase (GST) genes of S. tuberosum, M. persicae, and A. gefiuensis compared with the control. CONCLUSION: Our findings reveal that using thiamethoxam at suitable concentrations and time durations for host plants and natural enemies may enhance natural control through the conservation of natural enemies by overcoming any fitness disadvantages. © 2024 Society of Chemical Industry.