The inconsistent performance of entomopathogenic fungi is often associated with an incomplete understanding of the ecological constraints of the biological system in which they are placed. Often, there is little or no knowledge of their biology outside of their insect host. However, these fungi are often inundatively introduced into the environment in the absence of their host in hopes that they will persist and infect their target once the host immigrates into the treated area. One system using this approach is the use of Metarhizium anisopliae to control the black vine weevil (BVW), Otiorhynchus sulcatus, a severe pest of nursery and small fruit crops worldwide. The ecology of M. anisopliae in the ornamental nursery industry for control of BVW was investigated. The population of M. anisopliae incorporated into soilless potting media (bark and peat-based) was relatively stable for up to 342 days in the screenhouse. In addition, the fungus colonized the rhizosphere and the fungal population was significantly greater in the rhizosphere than in the surrounding bulk soil. Rhizosphere colonized roots infected 76% of 2^nd and 3^rd instar BVW. Metarhizium anisopliae also persisted well when incorporated into the media at planting in the field at seven container nursery operations. The effect of individual potting media components (peat, fir bark, hemlock bark, coir, perlite) on fungal persistence was also studied and all were found to be compatible with M. anisopliae. Results of these studies have improved understanding the ecology of M. anisopliae for BVW control in container nursery production.