Wei Lu

Systematic field data on adjuvant-amended microbial-derived pesticides against L. pratensis in arid, high-ultraviolet cotton regions remain scarce. This study systematically evaluated the laboratory toxicity and field efficacy of four kinds of microbial-derived pesticides (abamectin, emamectin benzoate, B. bassiana, and M. anisopliae) and their combinations with adjuvants against L. pratensis in Xinjiang cotton fields. As a comprehensive regional study, this work elucidates the differential enhancement patterns of d-limonene and mineral oil on antibiotic insecticides and entomopathogenic fungi, providing targeted field data for pesticide reduction strategies. The laboratory toxicity of seven microbial-derived pesticides was determined using the leaf-tube residual film method. Four effective agents were selected and combined with d-limonene or mineral oil for field efficacy trials. Abamectin and emamectin benzoate exhibited rapid and high insecticidal activity, with 48 h LC₅₀ values of 1.198 mg/L and 3.424 mg/L, respectively. The two entomopathogenic fungi exhibited slower insecticidal activity than the chemical insecticides but maintained relatively stable control effects throughout the observation period. In field trials, when abamectin or emamectin benzoate was applied at a 30% reduced rate in combination with mineral oil or d-limonene, the control efficacy was equivalent to or higher than that of the full-rate application of the pesticide alone. The treatment of abamectin (4.20 g a.i./hm²) plus mineral oil achieved the highest control efficacy (89.24%) at 3 days post-treatment. For B. bassiana and M. anisopliae, reduced-rate adjuvant-amended treatments showed numerically higher initial and residual efficacy than the full-rate single-agent fungal treatments. The treatment of M. anisopliae (7.35 × 10¹² spores/hm²) plus d-limonene reached 70.50% efficacy at 7 days post-treatment, which was significantly higher than that of the full-rate fungal treatment alone. No phytotoxicity symptoms were observed on cotton plants. Under the tested conditions, the rational combination of microbial-derived pesticides with appropriate adjuvants demonstrates the potential for a 30% reduction in pesticide dosage while maintaining or improving field efficacy, providing region-specific reference for the sustainable management of L. pratensis in Xinjiang cotton fields.

This study aimed to investigate the inhibitory effect of toosendanin (TSN) on the growth and development of Spodoptera litura (Fabricius, 1775), especially in terms of feeding preference, larval growth and development, nutritional indices, and enzyme activities. The feeding preference of S. litura, larval growth and development, and nutritional indices were evaluated using the diet incorporation method. The activities of three detoxification, three digestive, and three antioxidant enzymes were determined using spectrophotometric, micro-assay, and microplate methods. The feeding preference of S. litura exposed to TSN indicated that the larvae had a significant preference for the untreated (control) feed compared with the TSN-supplemented feed. The growth and development results showed a prolongation of the larval developmental period by approximately one instar in S. litura larvae fed TSN-supplemented feed. At the highest concentration (100 μg/g), larval weight was 0.76 times that of the control group, with a 27.34% reduction in the pupation rate and a 23.58% reduction in the emergence rate. All differences were statistically significant compared with the control group. In addition, the pupal and adult deformity rates were significantly higher than those in the control group, being 14.68 and 5.67 times higher, respectively, at this concentration. Growth inhibition increased with increasing TSN concentration. In terms of nutritional efficiency, TSN treatment reduced food intake and decreased food conversion rate, thereby inhibiting the relative growth rate of the 4th instar larvae. Further, TSN treatment significantly increased the activities of trypsin, α-amylase, glutathione S-transferase, carboxylesterase, superoxide dismutase, peroxidase, and catalase, and had no significant effect on lipase activity, and significantly reduced cytochrome P450 enzyme activity. TSN can significantly inhibit the digestion and absorption of nutrients in S. litura larvae, slow down their growth and development, and increase the pupal and adult deformity rates, thereby protecting plants against infestation by S. litura.

The practical efficacy of Azadirachtin (AZA)—a botanical insecticide valued for its strong antifeedant activity—is often undermined by its poor environmental stability, arising from rapid photolysis and thermal decomposition. Herein, amino-modified mesoporous silica nanoparticles (MSNs) were employed as nanocarriers to encapsulate AZA, yielding the AZA@MSNs−NH₂ nanoinsecticide. Under UV irradiation (254 nm), the degradation rate of AZA@MSNs−NH₂ was more than 35% lower than that of commercial AZA after 24 h of exposure. In biosafety tests, MSNs at 50–800 mg/L enhanced cotton seed germination and seedling growth, whereas MSNs below 200 mg/L caused no observable harm to zebrafish survival. Free AZA (0.5–10 mg/L) showed limited efficacy in bioassays against Helicoverpa armigera and Apolygus lucorum, reducing larval weight gain only marginally in the former (mortality < 5%) and performing poorly against the latter. In contrast, AZA@MSNs−NH₂ significantly boosted both growth inhibition and lethal effects against both pests, yielding > 80% growth inhibition and 62.65% corrected mortality for H. armigera, as well as strong lethality toward A. lucorum. Overall, this work confirms that nanoformulation of AZA not only circumvents its physicochemical drawbacks but also boosts its insecticidal performance against cotton pests, supporting the advancement of sustainable cotton pest control.

Cotton Verticillium wilt, caused by Verticillium dahliae, is a devastating soil-borne disease that severely limits global cotton production. While Myxococcus fulvus KS01 has demonstrated potent antagonistic activity and multi-functional biocontrol effects against V. dahliae, its practical application has been hindered by low myxospore yields and inconsistent efficacy in initial solid-state fermentation (SSF). This study aimed to optimize the SSF process for strain KS01 to maximize myxospore production and systematically evaluate its biocontrol efficacy against Verticillium wilt. Using a mixture of wheat straw and Protaetia brevitarsis frass (an agricultural byproduct) as the base substrate, we utilized single factor experiments and Response Surface Methodology (RSM) to optimize nutritional supplements and fermentation parameters. The optimized SSF process was determined as follows: a 3:1 (w/w) frass-to-straw ratio, supplemented with 3.08% potato starch and 1.05% yeast powder, with a 15.03% inoculum size, 65.05% moisture content, and an initial pH of 7.0, fermented at 30 °C for 6 days. Under these conditions, the myxospore concentration reached 6.61 × 10⁷ CFU/g, representing a 131.2-fold increase compared to unoptimized conditions (5.0 × 10⁵ CFU/g). Greenhouse pot trials showed that the optimized KS01 solid agent achieved a control efficacy of 71.9%. In field trials conducted in heavily infested soil, the agent maintained control efficacies of 71.2% at the budding stage and 54.5% at the bolling stage, significantly outperforming the commercial fungicide Benziothiazolinone (51.4% and 41.4%, respectively) and the sterile substrate control. Furthermore, application of the KS01 agent significantly promoted cotton growth, with seed cotton yield reaching 5380.0 kg/ha, equating to a 50.4% reduction in yield loss compared to the untreated control. Our results demonstrate that the valorization of P. brevitarsis frass through optimized SSF significantly enhances the production and field performance of M. fulvus KS01. This study provides a novel technical framework and a robust microbial resource for the sustainable management of Verticillium wilt in saline alkali cotton production systems.

Nanopesticides are pesticide formulations in which intentionally designed nanoscale carriers shape how an active ingredient (AIng) is deposited, transformed, and released. These systems can improve retention and efficacy, but carrier complexity introduces challenges: nanomaterials can transform in real soil–water matrices, reshaping exposure and risk. These processes are hard to quantify because test protocols and risk assessment frameworks for nanopesticides remain underdeveloped. In this review, we relate design choices across major carrier families—including polymer and lipid particles, nanoemulsions, porous inorganic carriers, and bio-based nanomaterials—to transformations in soil–water systems. We then connect these transformations to ecotoxicological evidence across key non-target taxa. We also address a central “measurement gap” in current risk assessment. Many standard tests were developed for dissolved chemicals. As a result, they do not capture (i) particle stability in realistic matrices, (ii) particle-bound versus dissolved (and ion-released) forms, or (iii) time-resolved exposure. Finally, we propose a Safe-and-Sustainable-by-Design roadmap that prioritizes low-hazard materials, predictable degradation, life-cycle thinking, and staged data generation to enable scalable, field-relevant adoption.

Xinjiang is an autonomous province in northwest China