MICROLEPIDOPTERAN HAZELNUT PEST IN CENTRAL-EASTERN POLAND

The list of insects and mites associated with hazelnut shrubs is extremely long but only a few of them are harmful, the remaining ones being either beneficial or incidental. Pest incidence and importance has changed in time as well as the cultural practices used in the orchards. Some of the pest problems are primarily induced by the use of insecticides. In orchards where no chemical treatments and horticulture techniques are applied some pests like microlepidopteran species can have economic significance. The aim of this research was to establish the species composition of microlepidopteran occurring in two ecosystems formed by man to various degrees. Data were gathered at ten-day intervals during three growing seasons (1998-2000) in two ecosystems: a protected hazelnut orchard and an unprotected one. Six microlepidopteran species were found: Stigmella microtheriella and S. floslactella from the Nepticulidae family, Parornix avellanella, Phyllonorycter coryli and P. nicelli from the Gracillaridae family and Coleophora serratella from the Coleophoridae family. The main factor affecting the occurrence of microlepidopteran species feeding on the hazelnut, with regards only to quantitative composition, was the type of environment with different chemical treatments. Differences in microlepidopteran species composition between the two studied orchards were not confirmed. Species from the genus Phyllonorycter were dominant in both orchards, whereas S. floslactella and C. serratella occurred in the smallest number. Abandoning suitable chemical pest control and horticultural techniques resulted in an increase in the number of microlepidopteran species.