Metarhizium anisopliae is a fungal insecticide, and conidia is the effective component of its insecticidal activity.
When conidia contacting and attaching to cockroach, it germinates and penetrates the cockroach body walls; then invades into the body, grows and reproduces rapidly in the blood of the cockroach, and compete for the nutrients with the tissues of cockroach, making them weak and stop feeding.
At later stage, the fungi secretes toxins, which affects the central nervous system of cockroach, destroys its various organs, and dehydrates its tissues, then causes death of cockroach.
The hyphae of Metarhizium anisopliae in the dead cockroach extend through the internode membrane and produce conidia.
The conidia continue to infect other pest individuals through contact infestation or air-borne and wind diffusion, and form repeated infestation in the roach population.