EN
Leaf miner moths on common hazel in urban habitats and in the forest and on cultivated hazel on productive plantation without chemical treatments were studied regarding the composition of their species and structure of their abundance in 2000–2002. The presence of six microlepidopteran species belonging to 3 families was shown: Nepticulidae (2 species), Gracillariidae (3) and Coleophoridae (1). The main factor affecting the occurrence of microlepidopteran species feeding on hazelnut with respect only to quantitative composition, was the type of environment with variable degree of anthropogenic. Species from Phyllonorycter genus were dominant on cultivated hazel and on common hazel growing in urban habitats, while on hazel growing in the forest Phyllonorycter nicellii and Stigmella microtheriella species were dominant. The best conditions for development of mining Lepidoptera were on cultivated hazelnut plantation, where their abundance was significantly higher compared with common hazelnut.