Life Cycle, Virulence, and Mechanism of Action of Entomopathogenic Fungi

Crop production is significantly influenced by various environmental factors, with insect pests being a primary concern, leading to substantial yield losses ranging from 18 to 26%. The excessive application of pesticides has caused pest resistance, environmental contamination, soil health degradation, and disruption of natural predator–prey relationships. As a sustainable alternative, using insecticidal fungi as biocontrol agents has gained prominence due to their eco-friendly and safer nature. Entomopathogenic fungi employ a sophisticated array of adhesins, secondary metabolites, low-molecular-weight proteins, and lytic enzymes in their infection process, targeting specific insect hosts. These fungi respond dynamically to the internal environment of insects by releasing secondary metabolites tailored to enhance virulence and infection efficiency. Extensively studied and utilized as biocontrol agents against various insect pests are Beauvaria bassiana and Metarhizium anisopliae. Endophytes also help plants grow, reduce stress, and make them more resistant to biotic stresses by competing for nutrients, activating plant defenses, releasing bioactive chemicals, and encouraging growth. Combining parasitoids with entomopathogenic fungi can improve biological control by working together to eliminate pests more effectively. This chapter goes into detail about the life cycle, virulence mechanisms, and interactions of entomopathogenic fungi and other organisms that are related to them. It provides information about long-term ways to control pests and the complex dynamics of ecological interactions in agricultural ecosystems.