Endophytic Entomopathogenic Fungi: Biology and Applications

Since the discovery of Beauveria bassiana 200 years ago, the use of fungi to combat insect pests has been deeply explored. A few years ago, the endophytic life of some entomopathogenic fungi has been revealed, and since then, extensive research was launched to unveil more species, understand their ecology, diversity, and mechanisms of action, in order to produce efficient biopesticides and develop better control practices. Besides their use as mycopesticides, scientists also explore potential secondary metabolites that could be used in medical treatments, industry, and environmental depollution. Endophytic insect-pathogenic fungi, commonly called EIPF, are fungi establishing a mutualistic relationship with their host plants, and at the same time are capable of infecting and killing insects by antibiosis or feeding dissuasion. The ability of EIPF to live in plant tissues and to parasitize insects suggests the involvement of complex and intimate interactions that are still not fully dissected. These multikingdom encounters have coevolved millions of years ago and enabled the development of both generalist and highly specialized EIPF species, as a key strategy to colonize and establish in a variety of different environments. This chapter presents the multifaceted mechanisms involved in these intimate interactions for a successful colonization and establishment of EIPF, their potential applications in agricultural biological pest management, pharmacology, medicine, and industry, as well as the possible limitations that might arise in their use.