Bionomy of spruce spider mite (SSM) (Oligonychus ununguis Jacobi) on five species/cultivars of spruce and two species of cypress was studied under laboratory conditions during rwo consecutive growing seasons. The study showed influence of host-plant food on development time, fecundity and longevity of SSM. The comparison of intrinsic rate of natural increase (r,J indicates the highest reproduction potential of SSM on Picea pungens (0.18), P. abies 'Nidiformis' (0.17), and P. glauca 'Conica' (0.14). SSM had much lowest rm on P. omorica (O.OS) and P abies 'Virgata' (O.Ol). The reproductive potential of SSM on rested species of cypresses was similar: 0.12 and 0.10 on Chamaecyparis lawsoniana 'Golden Wonder" and C. pisifera 'Nana Aureovariegata', respectively. The results obtained clearly indicate that the population parameters can be a proper indicator ofrelative susceptibility/resistance of commercially available species/cultivars of spruce and cypress plants to SSM.