Technical Abstract: The ambrosia beetle Xylosandrus germanus is an invasive pest with a wide host range and is a serious pest of orchards and nurseries in the eastern US. In this study we evaluated the potential of entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae as control agents against this beetle. Three commercially available strains of these fungi were assayed against adult females to determine their virulence and their impact on brood production. Among the three strains tested, B. bassiana Naturalis and M. anisopliae F52 were more virulent than B. bassiana GHA. Mortality observed 7 days post spray was 8.8 +/- 5.9%, 92.7 +/- 7.1% and 88.75 +/- 7.2% for GHA, Naturalis and F52, respectively, at a dose of approximately 600 conidia/mm2. Treatment of adult females did not affect their tunneling activity, but resulted in reduced gallery formation, brood production and brood numbers. Among the broods produced by treated females, 27 to 100% had fungal infection in some or all progeny. Infection was observed among larvae, pupae and adult progeny. These data suggest that the impact of fungal spray applications extends beyond the treated parent and that infection in the brood chamber could significantly affect beetle populations in the field.