Currently, when protecting plants from insect feeding using entomopathogenic fungi, efforts are concentrated on applying large amounts of inoculum to increase the fungal population (i.e. a microbial insecticide). This technique presents numerous problems including: 1) necessity of large quantities of fungal inoculum, often making applications uneconomical, 2) difficulty with inoculum penetrating into the soil when applied to the surface or for fungal spores to persist on the foliage for an extended period of time and 3) A large amount of time, money and effort is spent protecting areas where the pest either does not occur or is not of concern. By developing techniques to use endophytic or rhizosphere competent isolates of entomopathogenic fungi, the costs and logistics of microbial control would be much more favorable. The entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae have been successfully used as endophytic and rhizosphere competent microbial control agents, respectively. Selecting fungal isolates for development as microbial control agents should focus on not only the virulence of the isolate towards the target insect but also on the biology of the isolate and its ability to persist and proliferate in the environment in which control needs to take place. It is clear that when selecting an entomopathogenic fungal isolate, understanding factors associated with entomopathogen biology outside their insect host is more important than its virulence in a laboratory bioassay when developing biologically-based pest management programs utilizing entomopathogenic fungi.