Originally from Asia, Cydalima perspectalis Walker, the boxwood moth, has spread throughout the world in a short time due to its good adaptability. In Europe, it was first detected in 2007 in Germany and the Netherlands, where it was introduced on infected boxwood seedlings (Buxus sp.). In Croatia, it was found for the first time in 2012 in Istria. Damage to boxwood plants is caused by caterpillars of all developmental stages. They feed intensively by biting and chewing all parts of the plant, which leads to defoliation and, in case of heavy infestation, to the death of the plants. The boxwood moth is easily recognized by the characteristic appearance of its wings and the coccon and silk threads that it attaches to the branches and leaves of the box tree. The aim of the study was to determine the length of a particular developmental stage, i.e. the biology of this pest under the conditions of continental Croatia, and to determine the optimal control conditions based on the obtained data. A total of 292 caterpillars were collected from the locality of Garešnica after overwintering on boxwood plants (April). The collected caterpillars were placed in entomological cages and observed. The length of development of all developmental stages of the moth was observed for six months. The results showed that C. perspectalis emerges from hibernation in early April and begins to cause damage. At the end of August, the diapause begins and thus the activity ends. It has been noted that the caterpillars do not have to go through all stages of development before they pupate. They may reach the pupal stage at stages L4 and L5. The biology of Cydalima C. perspectalis is most affected by temperature and the ratio of light to darkness. In this study, under the conditions of continental Croatia, the occurrence of two generations of the boxwood moth per year was detected. Based on established biology, the recommended period for boxwood borer control is when the caterpillars hatch from hibernation in April to May and again in the last decade of June to the first decade of July, when the second generation of caterpillars appears. Suppression of caterpillars hatching from hibernation reduces the number of second generation caterpillars. Suppression of the second generation of caterpillars reduces the number of second generation butterflies and thus the number of overwintering generation that causes damage in the spring of the next year.