The cottonwood leaf beetle, Chrysomela scripta F., is a major defoliating pest of Populus in North America. As the use of Populus in short-rotation woody crop plantations continues to increase, there are increasing economic and environmental needs to develop rational pest management programs to reduce the impact of this insect. Our objective was to determine the economic injury levels for the second generation of the cottonwood leaf beetle during plantation establishment. Integrating the cost of the management, market value, insect injury, and host response to the injury, the economic injury levels for second generation cottonwood leaf beetle on 2-yr-old Populus were determined to be from 0.2 to 0.9 egg masses per actively growing terminal.