Pr1A a subtilisin-like protease was generated by Metarhizium is known to involved in the early stages of fungal invasion of arthropod hosts. Current intended to establish a link between cotton bollworm mortality H. armigera expression on levels of the conidial pr1A gene in Metarhizium. Intriguingly, subtilisin-like proteases were emitted by defensive metabolism on volatile organic compounds in H. armigera products. Fifth day after treatment, conidial of M. anisopliae, M. robertsii, M. majus (6.59, 4.65, and 4.65 × 10⁵ conidia/ml) respectively, resulted in greater than 95% mortality rates. We used particular primers were existence of pr1A genes in M. anisopliae, M. robertsii, M. majus through the pr1A expression was confirmed. Subsequently, investigated Pr1A expression using RT-qPCR and discovered that the Pr1A gene was strongly expressed for conidiogenesis or pathogenesis at 72 h, showing that gene expression is time-dependent. The time pr1A gene expression is critical to understanding its role in disease or fungal development. Finally, secondary metabolic were playing a significant role in VOCs compounds by beta-caryophyllene, octanonene, 1-octadecene, benzene, 1,2-dimethoxy, methylheptenone, benzaldehyde, 9-octadecenoic acid (E), and methyl salicylate though the microbe defence signals by H. armigera interactions Therefore, our research haven been showed, it can be helpful to examine the expression of genes related to conidiogenesis or pathogenesis in M. anisopliae, M. robertsii, M. majus their pathogenic with saprophytic life phases. In the creation techniques to detecting and deploying pathogenic biological control agents.