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Trichogramma dendrolimi, a key egg parasitoid for lepidopteran pest control, faces potential risks from neonicotinoid insecticides like acetamiprid used in integrated pest management (IPM). This study evaluated acetamiprid’s acute and sublethal toxicity to T. dendrolimi and assessed population-level risks via species sensitivity distribution (SSD). Acute toxicity assays using glass-vial residues revealed a 24 h LC50 of 0.12 mg a.i. L−1 for adults, three orders of magnitude below the maximum field rate (100 mg a.i. L−1). Sublethal exposure (1/2–1/100 LC50) significantly reduced parasitism and emergence rates (NOEC = 2.3 μg a.i. L−1) but did not affect offspring survival. Acetamiprid also shortened offspring development at 11.5–57.5 μg a.i. L−1. SSD analysis identified T. dendrolimi as the most sensitive parasitoid to acetamiprid (HC5/HC50) = 0.11/5.88 mg a.i. L−1), with field rates (30–100 mg a.i. L−1) indicating a potentially affected fraction (PAF) of 76.8–97.9%. These findings underscore the need to integrate sublethal effects into pesticide regulations to conserve parasitoid-mediated ecosystem services.

A novel glucose biosensor is developed based on a tilted fiber Bragg grating (TFBG) functionalized with a pH-responsive polyelectrolyte multilayer membrane, onto which glucose oxidase (GOD) is immobilized. The sensing film is constructed via layer-by-layer self-assembly of poly(ethylenimine) (PEI) and poly(acrylic acid) (PAA), which undergoes reversible swelling and refractive index (RI) changes in response to local pH variations. These changes are transduced into measurable shifts in the resonance wavelengths of TFBG cladding modes. The catalytic action of GOD oxidizes glucose to gluconic acid, thereby modulating the interfacial pH and actuating the polyelectrolyte membrane. With an optimized (PEI/PAA)4(PEI/GOD)1 structure, the biosensor achieves highly sensitive glucose detection, featuring a wide measurement range (10−8 to 10−2 M), a low detection limit of 27.7 nM, and a fast response time of ~60 s. It also demonstrates excellent specificity and robust performance in complex biological matrices such as rabbit serum and artificial urine, with recovery rates of 93–102%, highlighting its strong potential for point-of-care testing applications. This platform offers significant advantages in stability, temperature insensitivity, and miniaturization, making it well-suited for clinical glucose monitoring and disease management.

Background Neonicotinoid insecticides are applied worldwide for the control of agricultural insect pests. The evolution of neonicotinoid resistance has led to the failure of pest control in the field. The enhanced detoxifying enzyme activity and target mutations play important roles in the resistance of insects to neonicotinoid resistance. Emerging evidence indicates a central role of the gut symbiont in insect pest resistance to pesticides. Existing reports suggest that symbiotic microorganisms could mediate pesticide resistance by degrading pesticides in insect pests. Results The 16S rDNA sequencing results showed that the richness and diversity of the gut community between the imidacloprid-resistant (IMI-R) and imidacloprid-susceptible (IMI-S) strains of the cotton aphid Aphis gossypii showed no significant difference, while the abundance of the gut symbiont Sphingomonas was significantly higher in the IMI-R strain. Antibiotic treatment deprived Sphingomonas of the gut, followed by an increase in susceptibility to imidacloprid in the IMI-R strain. The susceptibility of the IMI-S strain to imidacloprid was significantly decreased as expected after supplementation with Sphingomonas . In addition, the imidacloprid susceptibility in nine field populations, which were all infected with Sphingomonas , increased to different degrees after treatment with antibiotics. Then, we demonstrated that Sphingomonas isolated from the gut of the IMI-R strain could subsist only with imidacloprid as a carbon source. The metabolic efficiency of imidacloprid by Sphingomonas reached 56% by HPLC detection. This further proved that Sphingomonas could mediate A. gossypii resistance to imidacloprid by hydroxylation and nitroreduction. Conclusions Our findings suggest that the gut symbiont Sphingomonas , with detoxification properties, could offer an opportunity for insect pests to metabolize imidacloprid. These findings enriched our knowledge of mechanisms of insecticide resistance and provided new symbiont-based strategies for control of insecticide-resistant insect pests with high Sphingomonas abundance.

Background/Objectives: The bird cherry-oat aphid, Rhopalosiphum padi, is a major global pest of cereal crops and exhibits wing polyphenism, producing both winged (dispersive) and wingless (reproductive) morphs. Methods: To identify potential RNAi targets that could specifically disrupt the migratory winged morph, we conducted a comparative transcriptomic analysis of adult aphids. Differentially expressed genes (DEGs) were identified, annotated for their functions, and analyzed for their involvement in metabolic pathways. Results: Significant differences were observed in 121 genes between morphs: 13 were upregulated in the winged morph, while 108 were downregulated. Most DEGs were enriched in lipid metabolism and circadian rhythm pathways, suggesting that wing polymorphism may be adaptively linked to energy resource allocation strategies. Conclusions: This study firstly reveals the adult-stage-specific regulatory roles of lipid metabolism and circadian rhythm pathways in wing polyphenism, identifying six candidate genes (BCORL1, AMP-L, Pfl, Lip3L, HLFL(X7), and HLFL(X4)) for RNAi-based biocontrol strategies targeting migratory morphs.

The resistance of cotton aphids to various forms of commonly used pesticides has seriously threatened the safety of the cotton production. Afidopyropen is a derivative of microbial metabolites with pyropene insecticide, which has been shown to be effective in the management of Aphis gossypii. Several field populations of Aphis gossypii were collected from the major cotton-producing regions of China from 2019 to 2021. The resistance of these populations to afidopyropen was estimated using the leaf-dipping method. The LC50 values of these field populations ranged from 0.005 to 0.591 mg a.i. L−1 in 2019, from 0.174 to 4.963 mg a.i. L−1 in 2020 and from 0.517 to 14.16 mg a.i. L−1 in 2021. The resistance ratios for all A. gossypii populations ranged from 0.03 to 3.97 in 2019, from 1.17 to 33.3 in 2020 and from 3.47 to 95.06 in 2021. The afidopyropen resistance exhibited an increasing trend in the field populations of Cangzhou, Binzhou, Yuncheng, Kuerle, Kuitun, Changji and Shawan from 2019 to 2021. This suggests that the resistance development of the cotton aphid to afidopyropen is inevitable. Therefore, it is necessary to rotate or mix afidopyropen with other insecticides in order to inhibit the development of afidopyropen resistance in field populations.

The Aphis gossypii is an important pest that can damage cotton plants and can cause a huge economic loss worldwide. Chemical control is a main method to manage this pest, but the cotton aphid resistance to insecticides has become a severe problem in the management of the cotton aphid. It is important to introduce a novel insecticide for rotational application with other insecticides. Broflanilide, as a meta-diamide insecticide with a special mode of action, showed high efficiency against lepidopterous larvae. However, we found that broflanilide possessed high insecticidal activity against the sap-sucking pest A. gossypii. The susceptibility of A. gossypii to broflanilide from 20 field populations in main cotton planting areas of China in 2021 was determined by the leaf-dipping method. LC50 values of broflanilide to A. gossypii ranged from 0.20 μg mL−1 to 1.48 μg mL−1. The susceptible baseline of A. gossypii to broflanilide was established with the LC50 value of 0.41 μg mL−1 and might be used to calculate the resistance ratio (RR) of cotton aphid population in broflanilide resistance monitoring. The RR value of field populations in China was from 0.49 to 3.61 in 2021. It suggested that the broflanilide may be a potential agent in the resistance management of A. gossypii to insecticides. These results are significantly useful for the rational chemical control of cotton aphids.

The resistance of cotton aphids to various forms of commonly used pesticides has seriously threatened the safety of the cotton production. Afidopyropen is a derivative of microbial metabolites with pyropene insecticide, which has been shown to be effective in the management of Aphis gossypii. Several field populations of Aphis gossypii were collected from the major cotton-producing regions of China from 2019 to 2021. The resistance of these populations to afidopyropen was estimated using the leaf-dipping method. The LC[sub.50] values of these field populations ranged from 0.005 to 0.591 mg a.i. L[sup.−1] in 2019, from 0.174 to 4.963 mg a.i. L[sup.−1] in 2020 and from 0.517 to 14.16 mg a.i. L[sup.−1] in 2021. The resistance ratios for all A. gossypii populations ranged from 0.03 to 3.97 in 2019, from 1.17 to 33.3 in 2020 and from 3.47 to 95.06 in 2021. The afidopyropen resistance exhibited an increasing trend in the field populations of Cangzhou, Binzhou, Yuncheng, Kuerle, Kuitun, Changji and Shawan from 2019 to 2021. This suggests that the resistance development of the cotton aphid to afidopyropen is inevitable. Therefore, it is necessary to rotate or mix afidopyropen with other insecticides in order to inhibit the development of afidopyropen resistance in field populations.

The control of Aphis. gossypii has relied on the application of insecticides, but the resistance to insecticides has become a key factor in the successful management of A. gossypii. It is a critical measure to introduce a novel insecticide with a different action mode in the resistance management. We found that broflanilide has high insecticidal activity against A. gossypii. Broflanilide susceptibility was determined in field populations of A. gossypii from main cotton planting areas of China. Meanwhile, the susceptible baseline of the cotton aphid to broflanilide was established. These results suggested that the cotton aphid possessed high susceptibility to broflanilide. The susceptible baseline provides a comparative basis for the future resistance monitoring in the management of cotton aphids. The Aphis gossypii is an important pest that can damage cotton plants and can cause a huge economic loss worldwide. Chemical control is a main method to manage this pest, but the cotton aphid resistance to insecticides has become a severe problem in the management of the cotton aphid. It is important to introduce a novel insecticide for rotational application with other insecticides. Broflanilide, as a meta-diamide insecticide with a special mode of action, showed high efficiency against lepidopterous larvae. However, we found that broflanilide possessed high insecticidal activity against the sap-sucking pest A. gossypii. The susceptibility of A. gossypii to broflanilide from 20 field populations in main cotton planting areas of China in 2021 was determined by the leaf-dipping method. LC[sub.50] values of broflanilide to A. gossypii ranged from 0.20 μg mL[sup.−1] to 1.48 μg mL[sup.−1] . The susceptible baseline of A. gossypii to broflanilide was established with the LC[sub.50] value of 0.41 μg mL[sup.−1] and might be used to calculate the resistance ratio (RR) of cotton aphid population in broflanilide resistance monitoring. The RR value of field populations in China was from 0.49 to 3.61 in 2021. It suggested that the broflanilide may be a potential agent in the resistance management of A. gossypii to insecticides. These results are significantly useful for the rational chemical control of cotton aphids.

Trehalase is an indispensable component of insect hemolymph that plays important role in energy metabolism and stress resistance. In this study, we cloned and expressed the gene encoding soluble trehalase (HaTreh-1) of Helicoverpa armigera (cotton bollworm) and characterized the enzyme. HaTreh-1 had a full-length open reading frame encoding a protein of 571 amino acids. Sequence comparison indicated that HaTreh-1 was similar to some known insect trehalases. Two essential active sites (D321 and E519) and three essential residues (R168, R221, and R286) were conserved in HaTreh-1. The recombinant trehalase was expressed in Escherichia coli and purified by nickel exchange chromatography. Molecular weight of the recombinant protein was about 71 kDa, and the optimum HaTreh-1 enzyme activity is at 55°C with pH 6.0. Enzymatic assays showed a Km value of 72.8 mmol/liter and a Vmax value of 0.608 mmol/(liter·min). Inhibition assays in vitro indicated that castanospermine, a polyhydroxylated alkaloid, was an effective competitive inhibitor of trehalase with a Ki value of 6.7 μmol/liter. The inhibitor action of castanospermine was linked to its modification effect on trehalase structure. The circular dichroism spectrum showed that the percentage of α-helix increased under the presence of castanospermine. Results of our study will aid in developing effective trehalase inhibitors for controlling H. armigera in the future.