The predatory soil mite Blattisocius mali (Oudemans) is highly efficient in controlling arthropod pests infesting stored flower bulbs and tubers. Still, its ability to control pests of crop plants has not been tested to date. This study aimed to assess whether B. mali could control Tyrophagus putrescentiae (Schrank) infesting young cucumber plants using two different methods of predator-prey release at two predator-prey ratios and varying observation frequencies. In one test, predators were released on plants on the same day as prey infestation at a 1:6.7 predator-prey ratio, while in the other test, predators were released after one day of prey infestation at a 1:33.3 ratio. The experiments were conducted under semi-natural conditions at 21-23 °C, 16L/8D photoperiod, and 80 ± 10% RH. Each treatment was replicated eight times. When predators were released simultaneously with prey infestation at a 1:6.7 ratio, a 95.50% efficiency was observed after just two days. Conversely, releasing predators one day after the initial infestation at a 1:33.3 ratio achieved 99.48% efficiency after five days. This study indicated that B. mali was highly effective at reducing T. putrescentiae populations on young cucumber plants in both tests and may be used as a practical alternative for managing acarid-mite pests infesting young cucumber plants. Further tests at a larger spatial scale under greenhouse and field conditions are necessary to confirm this.