Laboratory infection trials with Beauveria bassiana, a fungal entomopathogen, demonstrated that healthy eggs, larvae, pupae, and adults of Enaphalodes rufulus collected in northwest Arkansas forests were susceptible to infection. Field trials were conducted during peak adult emergence, in July 2003. The bark of 10 northern red oaks, Quercus rubra, were sprayed with diluted B. bassiana suspension on the bole of each tree. Survival in treated and untreated portions of the trees was statistically different with means of 2.4 (SE ± 1.1) and 8.2 (SE ± 0.9) live larvae/sample, respectively. This research demonstrates susceptibility of E. rufulus eggs and/or 1st instar larvae to infection.