Yes, I found a couple of articles about some studies. [url=https://www.mastergardeners.org/publications/nematodes/beneficial_nematodes.html]Here's one[/url]. However, a simple solution of soap ... real soap, like Dr. Bronner's unscented liquid soap ... and water is very effective at controlling spider mites and would, I believe, be much less expensive. It's the cure I routinely use when I find spider mites on one of my plants, and it works every time.
Use 1 or 2 teaspoonfuls of soap in 1 quart of water. Spray the plant from all directions, until it's dripping. Retreat every 5 to 7 days, for a total of 5 treatments. Retreating is necessary to kill the juveniles as they hatch from any eggs that may be present on the plant.
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams