C. caryae is vulnerable to attack by entomopathogens when entering the soil as a 4th stage larva and when the insect emerges from its cell as an adult (Lacey and Shapiro-Ilan, 2008). However, based on our research, once inside the pupal cell the insect’s vulnerability to infection by at least one common pathogen, B. bassiana, may be reduced due to antimicrobial properties. These findings expand our knowledge on host–pathogen relationships between insects and entomopathogens in the soil ecosystem; conceivably soil cells formed by other insects possess antimicrobial properties. In addition to B. bassiana, C. caryae can be infected by a number of other entomopathogens in the soil, e.g., entomopathogenic nematodes, Serratia marcescens, and other fungi such as Metarhizium species. Additional research is needed to determine the extent that these other pathogens are susceptible to antimicrobial properties of the pupal cell. Furthermore, research is required to determine the biological or chemical mechanisms that are the basis for antimicrobial activity in the pupal cell.