Chapter 19 Role of entomopathogenic fungi in biocontrol of insect pests

Chemical pesticides have an adverse impact on non-target organisms, and it leads to biodiversity loss, loss of food safety, development of insect resistance and resurgence in newer areas. All these have led scientists to create more ecofriendly alternatives, such as the use of entomopathogenic fungi against insect pests. Entomopathogenic fungus is a promising alternative to chemical insecticides that provides biological plant protection against insect pests in a sustainable pest control approach. Insect-infecting fungi are now classified into 90 genera and roughly 800 entomopathogenic fungal species have been documented. However, most commercial mycoinsecticides target just three genera: Beauveria bassiana, Metarhizium anisopliae, and Isaria fumosoroseus. They cause about 60 percent of insect diseases. These fungi are key contributors to soil insect population dynamics. Hence, entomopathogenic fungi are important biocontrol agents against insect populations. Insect-infecting fungi are found in several distinct groupings. Insect fungal pathogens include those from the phyla Chytridiomycota, Zygomycota, Oomycota, Ascomycota, and Deuteromycota, which are known to be the best entomopathogens against various insect pests. Entomopathogenic fungi kill or inactivate insects by attacking and infecting their insect hosts. Entomopathogenic fungi are soil-dwelling fungi that infect and kill insects by breaching their cuticle. Most insect-infecting fungi work through penetration. Entomopathogens produce these extracellular enzymes (protease and lipase) and toxins in their adaptive response. Together with a mechanical process via appressoria growth, these enzymes break the insect cuticle and enter the body of the insect to infect and kill it by getting their nourishment from the insect tissues. On the other hand, insects have developed many defense against these fungal pathogens. Insect pests are effectively killed by the soil fungus, Beauveria bassiana, and are easy to use in the field. Now mass manufacturing of new fungal formulations are possible. Further, modern genetic engineering and biotechnology approaches may assist in increasing the bioactivity of entomopathogenic fungi. This chapter discusses entomopathogenic fungi and their detailed usage description in the current scenario. It also explains the mode of infection, approaches, plans, and policies for entomopathogenic fungi.