Cephalcia chuxiongica has caused significant damage to pine forests, becoming a major biological disaster that hinders the sustainable development of forestry in China. To investigate the efficacy of biological control measures, entomopathogenic fungi were isolated and purified from the larvae of Ce. chuxiongica that had succumbed to diseases. The pathogenic capacity of strains was assessed using bioassay methods, and their infection process was observed using scanning electron microscopy. ITS, LSU, and TEF analysis disclosed Clonostachys rogersoniana as the highly virulent strain responsible for the death of Ce. chuxiongica. The optimal medium for its mycelial growth and sporulation was found to be PPDA. In addition, the bioassay revealed that the median lethal time (LT₅₀) for Ce. chuxiongica was 24.34 h and median lethal concentration (LC₅₀) was 2.35 × 10⁵ conidia/mL, indicating that C. rogersoniana possesses potent virulence and demonstrates rapid pathogenicity. Furthermore, scanning electron microscopy demonstrated that C. rogersoniana initially entered the body of Ce. chuxiongica through the spiracle and progressively made its way into the body wall, resulting in the insect’s death. The mode of infection for C. rogersoniana is exceedingly rare. As a consequence, the results of this study can serve as a reference for the management of chewing insects, such as Ce. chuxiongica.

Rhododendron hybridum Ker Gawl, a widely cultivated horticultural species in China, is highly valued for its ornamental and medicinal properties. However, with the expansion of its cultivation, leaf spot disease has become more prevalent, significantly affecting the ornamental value of R. hybridum Ker Gawl. In this study, R. hybridum Ker Gawl from the Kunming area was selected as the experimental material. The tissue isolation method was employed in this study to isolate pathogenic strains. The biological characteristics of the pathogens were determined using the mycelial growth rate method. The pathogens’ influence on the host plant’s ultrastructure was investigated using transmission electron microscopy (TEM). Colletotrichum nymphaeae was identified as the pathogen implicated in the development of leaf spot disease in R. hybridum Ker Gawl across three regions in Kunming City through the integration of morphological traits and phylogenetic analyses of multiple genes (ITS, ACT, GAPDH, HIS3, CHS1, and TUB2). Its mycelial growth is most effective at a temperature of 25 °C. pH and light have relatively minor effects on the growth of mycelium. The preferred carbon and nitrogen sources were identified as mannitol and yeast extract, respectively. Additionally, TEM observations revealed significant damage to the cell structure of R. hybridum Ker Gawl leaves infected by the pathogen. The cell walls were dissolved, the number of chloroplasts decreased markedly, starch granules within chloroplasts were largely absent, and the number of osmiophilic granules increased. This is the first report of leaf spot disease in R. hybridum Ker Gawl caused by C. nymphaeae. The results of this study provide valuable insights for future research on the prevention and control of this disease.

To investigate the effects of the endophytic fungus Setophoma terrestris (isolated from Panax notoginseng roots) on the growth and rhizosphere microbiota of understory-cultivated P. notoginseng, we prepared liquid and solid fermentates of the fungus and applied them separately via irrigation. Rhizosphere soil of P. notoginseng was subjected to non-targeted metabolomics and microbiome sequencing for detection and analysis. Relative to the control, P. notoginseng treated with liquid and solid fermentates exhibited increases in plant height (3.5% and 0.7%), chlorophyll content (23.4% and 20.4%), and total saponin content (14.6% and 17.0%), respectively. Non-targeted metabolomics identified 3855 metabolites across 23 classes, with amino acids and their derivatives (21.54%) and benzene derivatives (14.21%) as the primary components. The significantly altered metabolic pathways shared by the two treatment groups included ABC transporters, purine metabolism, and the biosynthesis of various other secondary metabolites. Exogenous addition of S. terrestris significantly affected the composition of the rhizosphere soil microbial community of P. notoginseng and increased the relative abundance of genera such as Bradyrhizobium. In conclusion, the endophytic fungus S. terrestris enhances P. notoginseng growth and modulates both rhizosphere soil metabolites and microbial abundance. This study can provide certain data support for research on endophytic fungi of P. notoginseng.

The fungal pathogen Colletotrichum jiangxiense has a broad host range and high destructive potential. It is a major causal agent of brown spot disease in diverse plants. Antifungal mechanisms used by biocontrol fungi against plant pathogens include disruption of cellular structures and cell wall damage, which can lead to protoplast leakage and hyphal lysis. In this study, we investigated the antifungal mechanism of the endophytic fungus Diaporthe novem DJ13 against C. jiangxiense, the causal agent of rhododendron brown spot. DJ13 is an effective biocontrol strain previously isolated by our research group from healthy leaves of Rhododendron pulchrum. Physiological assays showed that treatment with DJ13 fermentation broth increased membrane permeability, elevated MDA content, reduced TCA cycle enzyme activities, and increased AKP activity. These findings suggest impaired membrane integrity, disrupted energy metabolism, and cell wall damage. Transcriptomic analysis of the treated pathogen identified 1680 significantly differentially expressed genes (DEGs), including 961 up-regulated and 719 down-regulated genes. Among these genes, ABC transporter genes were significantly up-regulated, whereas genes involved in membrane structure metabolism were significantly down-regulated. Chitinase genes were up-regulated, whereas α-glucanase genes were down-regulated. DASH family cryptochrome genes were significantly down-regulated, while genes related to reactive oxygen species (ROS) production, including xanthine dehydrogenase, were significantly up-regulated. In addition, FAD-dependent oxidoreductase genes were up-regulated, while respiratory-metabolism-related genes, including trimethyllysine dioxygenase, were down-regulated. Together, the physiological and transcriptomic data provide a correlative framework supporting the hypothesis that the antifungal mechanism of DJ13 fermentation broth may involve the coordinated action of four processes: cell membrane damage, cell wall disruption, oxidative stress, and inhibition of energy metabolism. These findings also identify candidate genes for future functional validation.

To explore efficient and sustainable biocontrol resources against anthracnose in Begonia benariensis, endophytic fungi were isolated from healthy host tissues and screened for antagonistic activity against Colletotrichum aotearoa SWBG5. Among 31 isolates, four showed strong inhibition, and the most potent strain, QYN6, exhibited an in vitro mycelial inhibition rate of 63.67%. Based on morphology and multi-gene phylogeny (ITS, TUB2, TEF-1α), QYN6 was identified as Nigrospora sphaerica. Mechanistic assays revealed that QYN6 secretes multiple cell wall-degrading enzymes (chitinase, β-1,3-glucanase, cellulase, protease) and displays hyperparasitism against the pathogen hyphae (entwining, deformation, swelling), acting synergistically to inhibit fungal growth. In greenhouse pot trials, QYN6 achieved a biocontrol efficacy of 48.91% against Begonia anthracnose. Additionally, QYN6 significantly activated host defense responses, increasing the activities of antioxidant enzymes (SOD, POD, PPO, CAT) and the contents of soluble protein and soluble sugar. Furthermore, QYN6 exhibited multiple plant growth-promoting traits, including IAA production, siderophore synthesis, and potassium solubilization. Inoculation with QYN6 markedly improved plant height, leaf number, root length, and biomass of B. benariensis. Overall, N. sphaerica QYN6 possesses dual biocontrol and growth-promoting potential, providing a promising microbial resource and theoretical basis for green management of Begonia anthracnose.

Impatiens hawkeri W. Bull (I. hawkeri) is popular among consumers due to its diverse flower colors and year-round blooming. However, changes in ecological conditions, cultivation methods, and planting scale have led to increased disease incidence and diversity, particularly the widespread and destructive leaf spot disease. Currently, studies addressing the pathogen species and its biological characteristics remain limited. In this study, a highly pathogenic strain (IH-4) was selected from previously isolated fungi associated with leaf spot in I. hawkeri. Its taxonomic status was confirmed using upright fluorescence microscope analysis, internal transcribed spacer (ITS)/large subunit (LSU)/RNA polymerase II second largest subunit (rpb2)/β-tubulin (tub2) rRNA gene sequencing, and phylogenetic tree construction. Additionally, the biological characteristics of the pathogen and its sensitivity to 8 chemical fungicides were assessed. Strain IH-4 was identified as Ectophoma multirostrata (E. multirostrata) through combined morphological and molecular approaches. Optimal growth conditions included a temperature of 25 °C, a pH of 7, Potato Dextrose Agar (PDA) medium, fructose as the optimal carbon source, and urea as the optimal nitrogen source, with the fastest growth observed under a semi-light photoperiod (12 h light/12 h dark). Fungicide sensitivity assays indicated that 25% azoxystrobin exhibited the lowest half-maximal effective concentration (EC₅₀, 0.0724 μg/mL) and the steepest virulence regression slope (1.7), demonstrating the strongest inhibitory activity and highest sensitivity. Microscopic observations revealed that IH-4 hyphae penetrate I. hawkeri leaf tissues via stomata, colonize internally, and consequently cause host damage. This study provides a theoretical foundation for the timely and effective management of leaf spot disease in I. hawkeri.