Drosophila suzukii (Matsumura) is an invasive insect pest native to Southeastern Asia that is now reported to have established populations in North America. We used traps baited with red wine vinegar to detect and monitor D. suzukii in four black cherry (Prunus serotina Ehrh.) and maple (Acer spp.) stands in the Allegheny National Forest in northwestern Pennsylvania. Stands ranged in age from 70 to 110 years old, with average basal area from 40 to 45 m²/ha. All stands are characterized as the intermediate Allegheny hardwood forest type with black cherry being the dominant species making up > 70% of the total stand basal area at each site (Eyre, 1980). Traps were placed in the crowns of mature black cherry from May to October 2012. In total, 11,000 D. suzukii were collected. The appearance of D. suzukii on the High Allegheny Plateau in northwestern Pennsylvania could have negative implications for fruit production, dispersal, and seed viability of black cherry and other forest species. With D. suzukii's predilection toward Prunus spp. and its unusual method of oviposition, this could be a contributing factor that impacts black cherry regeneration on the Plateau.