This study identified five native fungal strains (Metarhizium anisopliae) from Taiwanese soils that can kill the tobacco caterpillar pest (Spodoptera litura). The most effective strain, PT-01, showed strong ability to infect and kill caterpillar larvae, particularly at early life stages. The research demonstrates that these fungi could be developed into environmentally-friendly pest control alternatives to chemical pesticides, protecting crops while maintaining ecosystem health.