Abstract: A simple shake-and wash technique for monitoring mites was developed. A faunal survey documented twenty-five species of phytoseiids. Typhlodromus pyri was abundant only in some of commercial sprayed orchards and vineyards, or was absent. The residual leaf-dip tests indicated considerable differences in susceptibility of T. pyri strains to azinphos-ethyl (Gusathion A). Local resistant populations of T. pyri were revealed. The seasonal history of T. pyri was described and data on population dynamics, number of generations, feeding, mating and reproductive habits as well as seasonal distribution within the apple tree canopy were collected. It was documented that communities of predatory phytoseiid mites and spider and eriophyid mites were influenced by specific type of chemical treatment. The long-term residual efficacy of 16 pesticides to the predatory phytoseiid mite T. pyri was evaluated in laboratory bioassays. Consequently specific spraying program against noxious tortricid moths and fungi in orchards and vineyards was set up to be compatible with T. pyri. A residual leaf-dip test proved a different innate susceptibility of susceptible and resistant strains of T. pyri, Euseius finlandicus, and Phytoseius echinus to azinphos-ethyl. E. finlandicus was the most susceptible whereas a susceptible strain of T. pyri the most tolerant. Esterase and glutathione S-transferase activities gave a good correlation between susceptibilities of these strains to azinphos-ethyl and activities of glutathione S-transferases. In summer, resistant populations of T. pyri were transfered to the predatory mite-free vineyards and orchards on one-yr shoots of apple or vine whereas in winter textile carrier strips with hibernating females were used. Life tables of overwintered females and their progeny of T. pyri fed on Tetranychus urticae and Cecidophyopsis ribis were constructed. Also powdery mildew affected parameters of development and proved to be important alternative food for T. pyri.