Aphids (Homoptera, Aphidodea) inhabiting the trees Crataegus x media Bechst. in the urban green area. Part II. Domination and frequency of aphids, their enemies and the damage caused by aphids

Abstract

The studies were conducted in Lublin in the years 1999-2001 in two sites (street and park ones) on the trees <i>Crataegus</i> x <i>inedia</i> Bechst. The purpose was to determine the domination and frequency of particular aphid species, their effect on the decorative character of plants as well as the occurrence of the aphidophagous in aphid colonies. It was found out that A. <i>pomi</i> was the dominating species in both sites. The decorative character of the studied trees was lowered by aphids A. <i>pomi</i> and aphids from the genus <i>Dysaphis</i>. Aphids from the genus <i>Dysaphis</i> also caused changes in the chemical composition of the injured plant parts. The presence of predatory arthropods was observed in aphid colonies occurring on hawthorn. The most numerous of these were the larvae of <i>Syrphidae</i> and <i>Coccinellidae</i>. The culture of parasitized aphids gave numerous flights of parasitoids and hyperparasitoids. Greater number of both predators and parasitoids of I and II grades were observed in the street site as compared to the park site.