entomopathogene

An entomopathogen is a pathogen that infects and often kills insects. The term covers a variety of organisms, including bacteria, fungi, viruses, microsporidia, and nematodes, many of which occur naturally in soils, on plant surfaces, or within insects. Entomopathogens contribute to the natural regulation of insect populations and are widely utilized as biological control agents in agriculture and forestry.

Key groups include: entomopathogenic fungi such as Beauveria bassiana and Metarhizium anisopliae, which infect by producing spores that penetrate the insect cuticle and proliferate inside the body; entomopathogenic bacteria like Bacillus thuringiensis, which produce insecticidal toxins (Cry proteins) and are used as microbial insecticides and in some transgenic crops; entomopathogenic nematodes of the genera Steinernema and Heterorhabditis, which carry symbiotic bacteria (Xenorhabdus or Photorhabdus) that kill the host from within; and entomopathogenic viruses, notably baculoviruses (nucleopolyhedroviruses and granuloviruses) that infect via ingestion and cause death of susceptible larvae. Microsporidia such as Nosema locustae also infect insects and are used in specific pest management programs.

Host range varies: some entomopathogens are highly host-specific, targeting a narrow range of species, while others have broader host spectra. They often act through infection, toxin production, or septicemia, and may persist in the environment as spores or dauer-like stages, enabling repeated encounters with hosts. Safety and regulatory considerations emphasize high specificity and minimal non-target effects, making entomopathogens valuable components of integrated pest management strategies. Resistance management and product formulation remain active areas of research to optimize field performance.