We found that, in B. bassiana, Fkh2 was required not only for cell cycle progression, hyphal septation, and cell size and density but for many more biological processes of the fungal entomopathogen than of the model yeasts, including carbon/nitrogen utilization, asexual development, host infection, and cellular responses to fungicides, osmotic agents, high temperature and UV-B irradiation. The gene discussed is FOXG1; the disease is infection.