Abstract
With the purpose to study the structure, ecology of spider mite spec1es iп Latvia grass land and woodlaпd vegetatioп was investigated iп 11 administrative districts. Оп 52 species of plaпts be!ongiпg to 21 families 12 spccies of spider rnites were revealed, pertaiпiпg to 4 genera: Scliizotetranychus, Tetranychus, Panonychus, Olygonychus. 5 of theese species (Schizotetranychus pruni Oud., S . populi Koch, S. uncatns Garm., S. carpini Oud ., S. textor Waiпst.) were iпvestigated for the first time iп Latvia. Two taЫes are given, showiпg the distributioп of spider mites оп various species of plaпts, the density of their populatioп and locatioп in Latvia. Most harrnful 1п Latvia are the folloiпg species: Tetranychus urticae Koch, T. cinnabarinus Boisduval, Panonychus ulmi Koch. Besides spider mites 3 species of predaceous mites of the Phytoseiidae family were also fouпd: Typholodromus fiпlaпdicus Oudemans . Paraseiulus incognitus Wainsteiп, Phytooseius salicis Waistein.
