ABSTRACT
102 103Entomopathogenic fungi attacks on insect body, cause infection in series, and eventually kill them. These fungi are considered to play a vital role as biological control agent of insect populations and a large number of fungal species infect insects. These insect pathogenic species are found in a wide range of adaptations and infecting capacities including obligate and facultative pathogens. Entomopathogenic fungi are reported from the divisions of Deuteromycota, Ascomycota as well as Zygomycota, Oomycota, and Chytridiomycota. Entomopathogenic fungus varies in specificity widely within genera, between genera and among species. Entomopathogenic fungal infection cycle involves several steps: conidial attachment, germination, penetration through the insect cuticle, vegetative growth within the host, fungal protrusion outside the insect, and conidiogenesis. Mechanical force, some metabolic acids, and enzymatic processes are involved in initial interaction in pathogenesis and enzymes responsible for pathogenesis of insects can be grouped into lipases, chitinases, peptidases, and proteases. Different metabolites are produced by entomopathogenic fungi act as toxins and play a vital role in the infection development, and result in a number of symptoms in the insect. The characteristic of secondary metabolites to act toxin against the insect cellular lines can be the possibility in the development of new bio-insecticides. Many insect pathogenic fungus based bio-insecticides have been produced and commercially manufactured so far. The use of microbial insecticides should be a contribution toward all fields of agriculture, sustainable agriculture, forestry, and horticulture. Just like the genes of Bacillus thuringiensis, which are inserted in different crops through biotechnology to get resistance against different pathogens and insect pests, the genes (e.g., chitinases, proteases, etc.) of entomopathogenic fungus can be incorporated in different crops to get resistance against other pathogens and insect pests in future.
