despite intensive chemical plant protection conducted in ornamental nurseries in Poland, spider mites are still one of problematic pests. In view of increasing resistance of spider mites on acaricides, searching for alternative methods of nursery plants protection against those pests, seems to be reasonable. In this work it was important to find out which cultivars of Norway spruce grown in nurseries are threaten by infestation by large amounts of spider mites and to verified if and which species of phytoseiid mites occur on spruces grown in chemical protected nurseries. Density and species composition of tetranychid and phytoseiid mites were also investigated on Norway spruces growing in forests. Our investigations showed that, almost all cultivars of Norway spruce that are offered for sale in nurseries are inhabited by spider mites. Cultivars ‘Inversa’, ‘Remontii’, ‘Waldbrund’, ‘Nidiformis’ or ‘Pumila Glauca’ were identified as especially threatened with massive infestation by those pests. Also some predatory mites, such as Typhlodromus tiliae Oudemans, were observed in nurseries, but their density was several times lower than on spruces growing in natural conditions. Additionally in forests we observed also Anthoseius bakeri (Garman) and Amblyseius andersoni (Chant).

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