Chemical insecticides are among the most important tools for pest control. However, the unscientific application of chemical insecticides in agricultural production has led to the development of pest resistance to various classes of insecticides, severely restricting the green development of agriculture in China. Elucidating the toxicology of insecticides and the mechanisms underlying insecticide resistance in pests can facilitate rational insecticide use and resistance management, as well as support the development of novel pesticides. Insecticide resistance refers to the phenomenon that, under long-term selection pressure from insecticides, pest populations undergo genetic variation. Susceptible individuals are eliminated while resistant individuals survive and reproduce, gradually leading to a heritable decrease in susceptibility to the insecticide, ultimately resulting in reduced efficacy or even complete failure of pest control. Common mechanisms of insecticide resistance include metabolic resistance, target-site resistance, behavioral resistance, penetration resistance, sequestration resistance and symbiont-mediated resistance. In recent years, Chinese researchers have made remarkable progress in the field of insecticide toxicology and resistance mechanisms in pests, achieving key outcomes across multiple research directions. In this review, we summarized the latest advances in insecticide toxicology and resistance mechanisms in pests worldwide, introduced the main contents of papers in this special issue, and proposed three noteworthy research directions: (1) Construction of advanced prediction and dynamic evolutionary models for insecticide resistance based on artificial intelligence and multi-omics; (2) Dissection of multi-mechanism synergistic resistance networks and discovery of novel intervention targets; and (3) Sustainable resistance intervention strategies based on gene drive and ecological adaptation.

【Aim】 This study aims to assess the risk of Spodoptera frugiperda developing resistance to tetraniliprole and to elucidate the impacts of sublethal concentrations of tetraniliprole on the development, reproduction and detoxification enzyme activities of S. frugiperda, so as to lay a theoretical foundation for the rational application of tetraniliprole in pest management strategies.【Methods】 The resistance selection of S. frugiperda to tetraniliprole was carried out using the diet incorporation method. The realized heritability (h²) of resistance was calculated via the threshold trait analysis method, and the numbers of generations required for S. frugiperda to develop 10-fold resistance to tetraniliprole under different selection pressures were predicted based on h². The age-stage, two-sex life table was employed to analyze the effects of sublethal concentrations (LC₁₀ and LC₃₀) of tetraniliprole on the developmental and reproductive parameters of S. frugiperda, including larval duration, prepupal duration, pupal duration, female and male adult longevity, and number of eggs laid per female. Moreover, the synergistic effects of three synergists including triphenyl phosphate (TPP), diethyl maleate (DEM) and piperonyl butoxide (PBO) on tetraniliprole were determined, and the changes in the activities of mixed-functional oxidase (MFO), glutathione S-transferase (GST) and carboxylesterase (CarE) in the 3rd instar larvae of S. frugiperda after treatment with sublethal concentration (LC₃₀) of tetraniliprole were measured. 【Results】 After 14 generations of laboratory resistance selection with tetraniliprole, the resistance ratio of S. frugiperda was 2.4, with the h² of 0.077. The highest resistance (5.3-fold) during the entire screening process was observed in the 11th generation, with the h2 of 0.206. Based on this h², it was predicted that under the pesticide selection pressure at 50% mortality, it only took 15.9 generations for S. frugiperda to develop 10-fold resistance to tetraniliprole. After treatment with sublethal concentrations (LC₁₀ and LC₃₀) of tetraniliprole, the larval duration, prepupal duration, pupal duration, female adult longevity, male adult longevity, and total pre-oviposition period of S. frugiperda were all significantly prolonged, as compared with those in the untreated control. The number of eggs laid per female was significantly reduced, the intrinsic rate of increase (r_m), net reproductive rate (R₀) and finite rate of increase (λ) in the treatments with LC₁₀ and LC₃₀ of tetraniliprole were all significantly decreased, as compared with those in the untreated control. The gross reproductive rate (GRR) of S. frugiperda showed a trend of decreasing after treatment with low sublethal concentration (LC₁₀) of tetraniliprole and increasing after treatment with high sublethal concentration (LC₃₀) of tetraniliprole. The synergistic ratios of the synergists TPP, DEM and PBO on the toxicity of tetraniliprole to the 3rd instar larvae of S. frugiperda were 1.3, 1.0 and 1.6, respectively. At 72 h after treatment with LC₃₀ of tetraniliprole, the MFO activity in the 3rd instar larvae of S. frugiperda was significantly higher than that of the control. 【Conclusion】 There is a certain resistance risk of S. frugiperda to tetraniliprole. Treatment with sublethal concentrations of tetraniliprole can prolong the developmental duration of S. frugiperda and reduce its population fecundity. However, there is a phenomenon that the number of eggs laid by some individuals may increase due to the stimulation of the pesticide, resulting in an increase in GRR. S. frugiperda mainly metabolizes and detoxifies tetraniliprole by enhancing the MFO activity.

The South American tomato leafminer, Tuta absoluta is a globally significant invasive pest that poses severe threats to tomato production in China due to its cross-border spread and rapid evolution of insecticide resistance. In this article, we systematically reviewed the chemical control strategies of T. absoluta, starting from the types of insecticides and their field efficacy, analyzed its molecular mechanisms of insecticide resistance including metabolic detoxification, target-site mutations and gene dispersal patterns, and further summarized the progress in integrated control measures, covering agroecological regulation, natural enemy-microbe collaboration, precision pesticide application, and genetic improvement in host resistance, while proposing directions for future optimization of control strategies. Key findings revealed that T. absoluta develops resistance through multiple mechanisms, including enhanced metabolic detoxification pathways and target-site mutations. For example, transgenerational expression activation of cytochrome P450 monooxygenases (P450s) significantly amplifies metabolic resistance. Mutations at the key target sites such as sodium channel and nicotinic acetylcholine receptor genes markedly reduce the susceptibility of T. absolute to neurotoxic insecticides. Furthermore, new mutations in ryanodine receptor genes exacerbate resistance of T. absolute to diamide insecticides. Currently, integrated pest management strategies strive to balance effective chemical control with ecological safety by integrating agroecological regulation, natural enemy-microbe collaboration, and precision pesticide application. However, challenges persist, including single target site of insecticides, transgenerational transmission of resistance genes, and insufficient field-level integration of advanced technologies. Future research should prioritize deciphering epigenetic regulatory networks of insecticide resistance, developing multi-target “smart” insecticides, and establishing resistance-natural enemy interaction models. The convergence of molecular biology, chemical ecology and smart agricultural technology will drive a transformation from chemically intensive to ecologically oriented control strategies. This integration will provide a solid theoretical basis and technical framework to ensure the green and sustainable development of China’s tomato industry.