Biocontrol toxicity of Trichoderma harzianum (Hypocreales: Hypocreaceae) derived chemical molecules against malarial mosquito Anopheles stephensi with molecular docking studies.

In this study, the crude chemical constituents extracted from Trichoderma harzianum and their toxicity were evaluated against the larvae, pupae, and adults of Anopheles stephensi at 24 and 48 h post-treatment. Additionally, the chemical constituents of the crude extracts were identified using gas chromatography-mass spectrometry (GC-MS) analysis, and their ability to bind with target proteins was confirmed through molecular docking studies. The results clearly demonstrated that the chemical compounds from T. harzianum exhibited promising mortality rates in larvae (98.66%), pupae (92%), and adult mosquitoes (81.33%) of A. stephensi 48 h after treatment. The study assessed the impact of crude extracts on insect enzymes 24 h post treatment, revealing significant alterations: a reduction in catalase activity and an increase in glutathione S-transferase levels compared to the control group. The treatment with crude chemical extracts resulted in mortality rates of 37.33% and 52% at 24 and 48 h, respectively, on Artemia salina , indicating minimal effects. After 48 h, the crude extract exhibited minimal toxicity on Eudrilus eugeniae, with a recorded mortality rate of 15% after 48 h. GC-MS analysis of T. harzianum-derived crude extracts identified ten major chemical constituents. Among these, chemicals, 2,4-bis(1,1-dimethylethyl) phenol (19.02%) was recognized as the predominant chemical component. This 2,4-bis(1,1-dimethylethyl) phenol molecule demonstrates a high binding affinity with target proteins, which is a key factor contributing to its insecticidal activity. This study concludes that the chemical constituents derived from T. harzianum are promising candidates for an eco-friendly, effective, and target-specific alternative control method for A. stephensi mosquitos.