Western flower thrips is the principal insect pest of spring flower crops in the northeastern United States. Neoseiulus cucumeris is a predacious mite reared commercially that is recommended for control of western flower thrips at a rate of ca 53 mites per sq m per week. We compared suppression of western flower thrips in spring bedding plants provided by this mite at the recommended rate versus the insecticide spinosad versus both combined. Our first trial was run in mixed bedding plants in commercial greenhouses and the second trial was in impatiens monocultures in University greenhouses. Conditions in commercial greenhouses made it difficult to detect any significant treatment effects. In the impatiens monoculture, we observed partial suppression of thrips larvae and adults by mites alone, but control from spinosad plus mites was not significantly different from that of spinosad alone. In a third trial (also in impatiens monocultures), we compared the commercially recommended rate of N. cucumeris to a rate 3-4-fold higher. We found that the higher release rate suppressed thrips larvae per stem by 50-75%. No reductions, however, were found in counts of adult thrips. We conclude that N. cucumeris at the higher rate, provides partial control of western flower thrips in impatiens bedding plants, but that biological control of western flower thrips with this predator is not a complete thrips IPM program.