Changes in arthropod population composition in IPM apple orchards under continental climatic conditions in Hungary

The effects of broad spectrum and selective insecticides on the structure o f phytophagous and zoophagous communities were investigated in a controlled experiment carried out in an apple orchard in Hungary. Following the cessa tion of intensive use of broad spectrum insecticides and the regular applic ation of selective insecticides (mainly insect growth regulator compounds) a characteristic succession commenced in the arthropod populations in apple orchards. The IPM strategy was developed against the arthropods occurring at a high population density in the apple orchards previously treated with broad-spectrum insecticides for many years (e.g Phyllonorycter blancardella , Leucoptera malifoliella, Panonychus ulmi). After the regular application of selective insecticides the population density of the pests Stephanitis p yri, Dyasphis devecta, Quadraspidiotus perniciosus increased, thus further improvement in the LPM program is still required. (C) 1999 Elsevier Science B.V. All rights reserved.