Coal burning is a main concern for a range of atmospheric pollutants, including the environmentally sensitive element chromium (Cr). Cr migrates to the environment through stack emissions and can leach out from solid coal-burning byproducts, thereby causing adverse effects on the ecosystem. In this study, atmospheric emissions of Cr from six coal-fired power plants (CFPPs), as well as the distribution of Cr inside these CFPPs in Guizhou Province, Southwest China, were investigated. Among the six CFPPs, one was a circulating fluidized bed boiler and the others were pulverized coal boilers. The results showed that Cr in the feed fuel of these CFPPs ranged from 39.5 to 101.5 mg·kg⁻¹ (average: 68.0 ± 24.8 mg·kg⁻¹) and was approximately four times higher than the national and global average. Cr in the feed fuel correlated significantly with the ash yield, demonstrating that Cr in coal is closely associated with ash-forming minerals. After the coal combustion and the treatment by different air pollution control devices, most Cr (>92%) in the installation was retained in the captured fly ash and bottom ash, with less as gypsum (0.69–7.94%); eventually, only 0.01–0.03% of Cr was emitted into the atmosphere with a concentration of 1.4–2.2 μg·Nm⁻³. The atmospheric emission factors of Cr for these utility boilers were as low as 14.86 ± 3.62 mg Cr·t⁻¹ coal, 7.72 ± 2.53 μg Cr (kW·h)⁻¹, and 0.70 ± 0.19 g Cr·TJ⁻¹, respectively. About 981 kg·y⁻¹ of Cr was discharged into the atmosphere from Guizhuo’s CFPPs in 2017, much lower than previous reported values. Most of the Cr in the CFPPs ended up in solid combustion products, identifying the need for the careful disposal of high-Cr-containing ashes (up to 500 mg·kg⁻¹) to prevent possible mobilization into the environment.

Sclerodermus guani Xiao et Wu, Sclerodermus sichuanensis Xiao, Sclerodermus pupariae Yang et Yao, and Sclerodermus alternatusi Yang are four species of Sclerodermus that have been found in China on longhorn or buprestid beetle hosts. These parasitoids are of great importance to forest management because they control certain forest pests. Knowledge of their developmental differences is important for maximizing their use in bio-control programs, yet little about them is known. This study compared their number of offspring and developmental biology. There were significant differences in the four parasitoids’ egg, larval, pupal, and total developmental stages. The F₂ male offspring of each parasitoid emerged approximately one day ahead of the female. Additionally, there were differences in the number of F₂ male and female offspring, as well as in the sex percentage, among the four parasitoids. Compared to the other three wasps, S. alternatusi had a significantly lower F₂ female percentage of 67.07%, which was notably less than that of the other wasps (over 90%). The total F₂ offspring number and F₂ female offspring number of S. guani were the greatest. Sclerodermus alteratusi produced a larger percentage of winged females (5.66%) compared to S. pupariae (3.98%), and no winged females developed from S. guani or S. sichuanensis. Almost all individuals survived the 30-day experiment, the survival rate decreased to about half after 120 days at 12 °C, and there was no difference between the species. The biological differences between the four wasp species analyzed in this study will help improve the effectiveness of mass-rearing them for the biological control of forest pests.

Toxoptera aurantii is a globally distributed piercing-sucking pest that severely threatens tea production. While the direct damage caused by aphid feeding is well documented, the systemic effects of infestation on plant-associated and soil microbial communities remain poorly understood. Here, we employed full-length 16S rRNA gene sequencing and untargeted metabolomics to investigate the influence of T. aurantii infestation on the microbiota of tea plants (Camellia sinensis) and rhizosphere soil across four sample compartments: aphid bodies, healthy leaves, aphid-infested leaves, and root-zone soil. Our results revealed pronounced niche-specific microbial assembly patterns. The aphid microbiome exhibited the lowest diversity and was dominated by obligate endosymbionts, including Buchnera aphidicola and the secondary symbiont Serratia symbiotica. Soil harbored the highest microbial diversity with a balanced phylum-level structure. Aphid infestation significantly reduced phyllosphere microbial diversity (Shannon index) and shifted community composition, with a decline in a sequence putatively assigned to Methylobacterium brachiatum and a modest increase in a taxon assigned to the opportunistic plant pathogen OTU assigned to Dickeya chrysanthemi. This pattern suggests a hypothesis that aphid infestation may create conditions permissive for such opportunistic pathogens, although experimental validation is required. Concurrently, infestation was associated with profound metabolic reprograming in tea leaves, including upregulation of defense-related flavonoids and terpenoids and downregulation of several primary metabolites. Notably, the phyllosphere of infested leaves showed reduced microbial diversity and an increased relative abundance of a 16S rRNA sequence assigned to Dickeya chrysanthemi, while certain plant-derived antimicrobial metabolites were decreased. These patterns suggest a possible association between aphid infestation, altered antimicrobial metabolite profiles and increased relative abundance of Dickeya-assigned sequences. These findings demonstrate that T. aurantii infestation triggers a systemic response in the aboveground compartments (aphid and leaf), while the soil compartment maintains a distinct and highly diverse microbial community that serves as a potential reservoir. The study characterizes microbial communities across these three compartments without inferring infestation-driven soil remodeling. This study advances our understanding of tripartite interactions in tea ecosystems and provides a basis for developing microbiome-based strategies for sustainable pest management.

Spodoptera frugiperda is a highly destructive migratory pest that severely restricts global agricultural production. Chemical insecticides remain the primary means of field population control, yet the resistance evolution risk of S. frugiperda to two commonly applied insecticides, lufenuron and chlorfenapyr, remains poorly clarified in China. In this study, we found that the four field S. frugiperda populations collected from Jiangsu, Guangxi, Guizhou, and Yunnan Provinces exhibited susceptible or low-level resistance to chlorfenapyr, lufenuron, emamectin benzoate, and spinetoram. However, moderate resistance to chlorantraniliprole (resistance ratio > 5) was detected in the Guangxi and Guizhou populations, consistent with regional variation in diamide insecticide pressure. After 10 consecutive generations of indoor resistance screening, the selected resistant strains showed only 2.89-fold and 3.40-fold resistance increases to lufenuron and chlorfenapyr, respectively, indicating an extremely slow resistance development rate. Furthermore, the lufenuron-resistant and chlorfenapyr-resistant strains displayed negligible cross-resistance to emamectin benzoate, chlorantraniliprole, and spinetoram. Significant fitness costs were detected in both resistant strains, with marked declines in multiple growth, development and reproductive indicators. Collectively, these findings confirm that Chinese field S. frugiperda populations have a low evolutionary risk of resistance to lufenuron and chlorfenapyr, and resistance emergence is constrained by obvious fitness trade-offs. This study provides empirical evidence and theoretical guidance for the scientific formulation of S. frugiperda chemical control and resistance management strategies in China, while highlighting the need for region-specific monitoring of diamide resistance.