Spodoptera frugiperda is a serious invasive pest, which has attracted attention globally in recent years. Research on the sublethal effects of common insecticides on S. frugiperda is important for its comprehensive management in the field. In this paper, the sublethal effects have been studied for S. frugiperda exposed to the LC₃₀ concentration of three insecticides, chlorantraniliprole, dinotefuran, and beta-cypermethrin. The results showed that the pupation rates of the treatment groups were significantly lower than that of control group, but there were no significant differences in the eclosion rate. Chlorantraniliprole and beta-cypermethrin significantly inhibited fecundity of the F₀ and F₁ generations, and the number of eggs laid per female decreased by 67.4% and 43.1%, respectively, and that of the F₁ generation decreased by 28.0% and 21.7%, respectively. The intrinsic growth rate (r_m), net growth rate (R₀), and weekly growth rate (λ) of the F₀ generation in the chlorantraniliprole and beta-cypermethrin treatment groups were significantly lower than those in the control group. Additionally, dinotefuran had a certain role in promoting oviposition in the F₀ and F₁ generations, which may stimulate the growth of offspring population and cause the resurgence of pests. The results provide a reference for the effective implementation of the IPM plan in the field to control S. frugiperda.

In order to optimize crop production and mitigate the adverse impacts associated with the utilization of chemical agents, it is necessary to explore new biocontrol agents. Bacillus velezensis has been widely studied as a biocontrol agent because of its efficient and ecofriendly plant disease control mechanisms. This study shows that the strain ZN-S10 effectively reduces the area of leaf spots caused by the pathogen Colletotrichum changpingense ZAFU0163-1, which affects conidia production and germination, inhibits mycelium growth, and induces mycelium deformation. In antifungal experiments with crude extracts, we observed a delay in the cell cycle of conidia, which may be responsible for the inhibition of conidial germination. Among the bioactive metabolites detected through integrated LC-MS- and GC-MS-based untargeted metabolomics, 7-O-Succinyl macrolactin A, telocinobufagin, and surfactin A may be the main antifungal metabolites of strain ZN-S10. The presence of 7-O-Succinyl macrolactin A could explain the cell damage in germ tubes. This is the first report of telocinobufagin detected in B. velezensis. These results are significant for understanding the inhibitory mechanisms employed by B. velezensis and should serve as a reference in the production of biocontrol agents.

Associations between Sternorrhyncha insects and intracellular bacteria are common in nature. Mealybugs are destructive pests that seriously threaten the production of agriculture and forestry. Mealybugs have evolved intimate endosymbiotic relationships with bacteria, which provide them with essential amino acids, vitamins, and other nutrients. In this study, the divergence of five mealybugs was analyzed based up the sequences of the mitochondrial cytochrome oxidase I (mtCOI). Meanwhile, the distinct regions of the 16S rRNA gene of primary symbionts in the mealybugs were sequenced. Finally, high‐throughput sequencing (HTS) techniques were used to study the microbial abundance and diversity in mealybugs. Molecular phylogenetic analyses revealed that these five mealybugs were subdivided into two different clusters. One cluster of mealybugs (Dysmicoccus neobrevipes, Pseudococcus comstocki, and Planococcus minor) harbored the primary endosymbiont “Candidatus Tremblaya princeps,” and another cluster (Phenacoccus solenopsis and Phenacoccus solani) harbored “Ca. Tremblaya phenacola.” The mtCOI sequence divergence between the two clusters was similar to the 16S rRNA sequence divergence between T. princeps and T. phenacola. Thus, we concluded that the symbiont phylogeny was largely concordant with the host phylogeny. The HTS showed that the microbial abundance and diversity within P. solani and P. solenopsis were highly similar, and there was lower overall species richness compared to the other mealybugs. Among the five mealybugs, we also found significant differences in Shannon diversity and observed species. These results provide a theoretical basis for further research on the coevolution of mealybugs and their symbiotic microorganisms. These findings are also useful for research on the effect of symbiont diversity on the pest status of mealybugs in agricultural systems.

This study investigates the potential role of Acrocalymma dark septate endophytic (DSE) fungi in promoting the growth of Solanum lycopersicum (tomato). Recognized as important symbionts that enhance plant growth and resilience under stress, particularly Acrocalymma species, DSE fungi were the focus of this investigation. Specifically, four stains isolated from gramineous plant roots (Acrocalymma sp. E00677, Acrocalymma vagum E00690, Acrocalymma chuxiongense E01299A, and Acrocalymma chuxiongense E01299B) were examined. Morphological characteristics were observed using three different media, confirming typical DSE traits such as dark pigmentation and septate hyphae. Phylogenetic analysis using six genetic markers (ITS, LSU, SSU, tef1, rpb2, and tub2) placed the strains within the Acrocalymma genus. Co-culture test and physiological index measurements showed that all strains significantly enhanced root development, as evidenced by an increased root-to-shoot ratio and a higher number of lateral roots. Additionally, the Acrocalymma DSE strains elevated chlorophyll a, chlorophyll b, and total chlorophyll content, suggesting improved photosynthetic efficiency. Anthocyanin levels were also increased in the tomato leaves, indicating enhanced antioxidative defense mechanisms. Among these strains, Acrocalymma vagum E00690 exhibited the most substantial effect on root activity. The widespread presence of 325 Acrocalymma isolates from 25 countries underscores its broad ecological adaptability. These findings suggest that Acrocalymma DSE fungi positively influence tomato growth, with potential implications for improving plant resilience under environmental stress. This study highlights the importance of further exploring DSEs, particularly Acrocalymma fungi, to better understand their ecological roles in agricultural practices, particularly in tomato cultivation.