Entomopathogenic fungi are both a feasible system for the control of insect pests in
agriculture with a growing market and an important model for studies of host-pathogen
interaction. In the last ten years the actual use of fungi, mainly Metarhizium anisopliae
and Beauveria bassiana, is increasing reaching commercial scale in Countries like Brazil,
China and Mexico among others. At the same time important progress has occurred in the
understanding of the molecular aspects of the pathogenesis and in the development of
tools to validate putative virulence factors by the construction of over-expressing and
knock-out strains. This wealth of knowledge is helping to access more efficient strains from
the biodiversity and to optimize formulation for large scale use of this efficient, economic
and environmental safer form of insect plague control. Here we focus some of the progress
accumulated specially in M. anisopliae and give an overview of the host infection process.