With climate change, introduction of new pests and changes in fruit production systems, the pest and beneficial arthropod assemblages of crops are also changing. Dr. Viktor Markó's current research on these processes focuses on three topics: Survey of green aphids (Aphis spiraecola and Aphis pomi) in European apple orchards under different climatic conditions and pesticide regimes and determine their pattern of distribution, abundance and fitness; Survey of the Dysaphis devecta species-complex with molecular methods in European apple orchards, and examination of the cuticular hydrocarbon composition of apple aphids and its role in the ant-aphid interactions. His recent interest has also turned to urban tree pests. In these studies, he examines how urbanisation affects urban tree pests, their natural enemies and generally the predator-prey relationships.