Aphids (Homoptera, Aphidodea) inhabiting the trees Crataegus x media Bechst. in the urban green area. Part I. The population dynamics

Abstract

The studies were conducted in the years 1999-2001 in the green areas of Lublin, on the trees of Crataegus x media Bechst. The purpose of the studies was to establish the species composition and the population dynamics of aphids inhabiting hawthorn in the street and park sites. The studies found out the presence of four aphid species on the examined trees, namely Aphis pomi De Geer, aphids from the genus Dysaphis Börn., Ovatus crataegarius (Walk.) and Rhopalosiphum insertum (Walk.). More aphid species and bigger populations were found in the street site (A) as compa red with the park site (B).The weather conditions (air temperatures of over 30°C and stormy rainfalls) limited the population of all aphid species. On the other hand, a mild winter and a warm spring with the rainfalls within the norm caused that the number of aphids decreased considerably.