In the air-polluted area of the eastern Kruąné hory Mts (Czech Republic), crown fauna of moth larvae was studied by the method of shaking down in the period 1986–2004. Of 145 species caught during our study the most important were Cabera pusaria (L.) (29.13%), Operophtera fagata (S c h a r f.) (15.21%), Cyclophora albipunctata (H u f n.) (7.02%), Coleophora serratella (L.) (4.29%), Teleiodes proximellus (H ü b n.) (3.23%), Orthotaenia undulana (D e n. and S c h i f f.) (3.07%), Agriopis aurantiaria (H ü b n.) (2.87%) and Ochropacha duplaris (L.) (2.60%). The seasonal and population dynamics of more numerous species was determined and the rate of threat to birch stands by these phytophages is discussed.