Phytonemus pallidus fragariae Zimmermann (Trombidiformes: Tarsonemidae), is one of the most destructive pests in strawberry production, causing significant yield and quality losses, particularly under greenhouse conditions. Biological control using predatory mites has become an important alternative to chemical pesticides due to resistance, residue, and environmental concerns. Neoseiulus californicus (McGregor) sensu Athias-Henriot (Mesostigmata: Phytoseiidae) is an effective predator mite species that plays a crucial role in the biological control of mites. The present study aimed to evaluate the effectiveness of different release ratios of both commercial and native populations of N. californicus against P. p. fragariae on greenhouse-grown strawberries in Ordu (Türkiye). The experiment was conducted under greenhouse conditions from April to November in both 2023 and 2024. The study focused on Albion, Monterey, and San Andreas strawberry cultivars. For each cultivar, eight treatments were established: a chemical control (Abamectin 18 g L-1), an untreated control, and six biological control treatments. The biological treatments consisted of three predator-prey release ratios (1:10, 1:20, and 1:30) involving both commercial and native populations of N. californicus. A randomized block design was used for the experiment. Twenty plants were used per treatment, resulting in 160 plants per cultivar and 480 plants in the entire experiment. The results demonstrated that both commercial and native populations of N. californicus provided effective control of P. p. fragariae under greenhouse conditions in Ordu (Türkiye). The biological control treatments were as effective as the chemical control treatment with abamectin. No significant differences were observed between the three predator release ratios in controlling the pest. Overall, the results highlight the potential of both commercial and native populations of N. californicusas an effective biological control agent against P. p. fragariae in strawberry cultivation. This study provides valuable insights that may contribute to the development of effective biological control strategies for P. p. fragariae in strawberry cultivation Acknowledgment: This study was supported by Scientific and Technological Research Council of Türkiye (TUBITAK) under the Grant Number 222O041. The authors thank TUBITAK for their support. This study partly draws on the first author’s doctoral thesis and also includes additional data. The authors are also grateful to Prof. Dr. Edward A. UECKERMANN (North-West University, South Africa) and Dr. Farid FARAJI (Institute for Biodiversity and Ecosystem Dynamics (IBED), Faculty of Science, University of Amsterdam) for confirmation of species identification.