Two strains of the entomopathogenic fungus Metarhizium anisopliae and a strain of Nomuraea rileyi failed to initiate spherical growth or germ-tube production in distilled water. However, a prolonged period of soaking (up to 20 h) in distilled water accelerated spherical growth and germ-tube formation once a nutrient was provided.

The increased rate of germination of soaked M. anisopliae conidia was matched by an enhanced rate of uptake of a nutrient (N-acetyl-D[1-14C]glucosamine). Soaked conidia possessed substantially higher levels of protein and RNA synthesis than controls and showed ultrastructural changes similar to those of conidia in the early stages of germination.

It is concluded that water activates an initial pre-swelling phase of germination in M. anisopliae conidia, spherical growth and germ-tube formation being dependent on an exogenous carbon source.