From 2013 2015, the release and establishment of predatory mites for the control of two-spotted spider mites, Tetranychus urticae, was conducted in five hop gardens of
The species compared were the autochthonous mites Typhlodromus pyri, Amblyseius andersoni and a mix of the two
allochthonous species Neoseiulus californicus and phytoseiulus persimilis. Main objective was the establishment of a permanent population of T. pyri in a hop garden by providing the predators with structures for their hibernation by undersown crops. We chose seeding of tall fescue Festuca arundinacea, a grassland seed mixture and
strawberries as an intercrop in the wheel lanes. During the three project years, 15 trials were conducted of which however only two yielded meaningful results. We found
that the cheapest and most effective way to release T. pyri in hops is the transfer of vine cuttings gathered during the pruning of vines in late winter. Besides, the mixture
of P. persimilis and N. californicus proved to be very effective. During samplings of the undersown crop of tall fescue in spring, predatory mites were recorded in low
numbers. This is evidence that tall fescue can serve as a hibernation quarter for predatory mites. More studies are however needed to give more detailed answers to
this thematic constellation
