Előzetes adatok biológiai és hagyományos körteültetvények körtelevélbolháit (Cacopsylla spp.) predáló ízeltlábúak abundancia viszonyaihoz

Abstract

The samples were taken from two differently treated pear orchards, from the Georgikon Faculty’s pesticide treated orchard in Keszthely and from an old, abandoned non treated orchards in Alsópáhok. Beating method with collecting umbrella and knocking rod was used in this study. Sample collections of canopy-level arthropods in the two orchards were carried out twice a month, so altogether 12 collections per orchard were made between 9^th May 2016 and 30^th October 2016. There were a toal of 1490 predatory individuals, useful for plant protection, collected from the two sampling sites, 647 specimens from Alsópáhok and 843 from Keszthely. Predators represented seven insect orders (Coleoptera, Dermaptera, Diptera, Ensifera, Heteroptera, Neuroptera and Raphidioptera), and four Arachnida orders (Acari, Araneae, Opiliones and Pseudoscorpiones). The highest number of individuals were found in case of earwigs (Dermaptera) (723 individuals) and spiders (Araneae) (424 individuals) followed by ladybird beetles (Coccinellidae) (266 individuals). At the beginning of the growing season, the initial populations of the main predatory groups were significantly higher in Keszthely, which may have been linked to the population size of pear psyllids (Cacopsylla spp.), the main prey of these predators. Although their population sizes generally tripled in the coming months (June and July), the total predatory population fell sharply in the Keszthely plantation due to broadspectrum insecticide treatments and the lack of their main host (Cacopsylla spp.) populations. In contrast, in the plantations of Alsópáhok, it seemed to be stable and more colourful in September (late summer and early autumn).