Soil-dwelling insects have developed various mechanisms to defend against pathogen infection. The
pecan weevil, Curculio caryae, spends two to three years in the soil inside an earthen cell. We hypothesized
that the cell may possess antimicrobial properties. In a laboratory study, we tested the hypothesis
using the fungus Beauveria bassiana as a model. B. bassiana is a common endemic pathogen of C. caryae.
We compared the number of colony-forming-units on selective media when B. bassiana was exposed to
autoclaved soil, non-autoclaved soil, or soil from a C. caryae pupal cell. Soil from C. caryae cells was suppressive
to B. bassiana. To our knowledge this is the first report of antimicrobial properties associated
with an insect soil cell. The findings expand our knowledge of host–pathogen relationships. Additional
research is needed to determine the basis for the suppressive effects observed.