FLORAL AND FAUNAL SPECIES-DIVERSITY AND ABUNDANCE OF APHID PREDATORS IN ECOLOGICAL APPLE ORCHARDS

Faunistic and floristic characters of organic orchards with extensive and intensive vegetation management (mulching) were investigated. In t he extensively mulched orchard more floral species were observed. Gene rally, in summer, flowering nectar-providing plants occurred only occa sionally. Effects on species diversity and composition of the arthropo d fauna on the trees was shown. In spring, diversity was higher in the extensive orchards, but this switched in July, when, in the intensive orchards, arthropods migrated on the trees. Aphid predators followed aphid population density. This may be due to the late occurrence of pr edators after a period of low temperatures in spring. Extensive mulchi ng seems also to increase the abundance of Typhlocyba frogatti Baker ( Cicadellidae).