Aim of study: The box tree moth, Cydalima perspectalis (Lepidoptera: Crambidae), is an important alien invasive species on box, Buxus sempervirens, in Turkey. It was first detected in 2011 in Istanbul. It is a native pest of box plants in Asia. Its first discovery in Europe has been made in 2007 in Germany. Since then it has been successfully established in various ecosystems in Europe. Caterpillars feed on box leaves and cause severe defoliation and tree deaths. In this study, damage level and defoliation percentage were investigated on ornamental and naturally growing box plants.