The results you will get with Hypoaspis mites is variable and often is not successful. We did extensive studies with Hypoaspis mites in the mid 90's and found that although they will eat Ophionyssus natricis, they were most often not able to completely eradicate the problem. There were several reasons why. These mites are primarily used to control insects and arthropods on plants. They need a minimum amount of humidity to survive. We found that often, the humidity levels were not adequate in reptile cages which resulted in the Hypoaspis mites dying quickly. Type of substrate is another factor as some types helped maintain humidity better and provided better cover. The major problem we found is that Ophionyssus natricis will leave the cage to seek a proper location to molt/lay eggs (they can walk up to 11" per minute). The temperature at that location will determine how fast they will complete a life cycle/hatch before foraging for a host again. They can remain in such locations outside the cage for many months at cooler temperatures. The Hypoaspis mites will quickly die once they exhaust the food supply in the cage and even faster if their environment is not suitable, so will not be present when the snake mites return weeks to months later. They can't handle the dry conditions outside the cage or in many reptile cages as Ophionyssus natricis can. They will usually only survive for a couple of weeks. This is the primary reason why Ophionyssus natricis can spontaneously appear at a time after one thinks the problem is gone. There are other people who have found the same results and have posted them in the past. If one has a mild infestation, they might be able to eradicate the problem, but most often, they can't. One is also dealing with primary pest resurgence, which in the long run, will always favor Ophionyssus natricis over Hypoaspis mites.
More importantly, with the potential diseases and infections mites can carry, eradicating the problem after an infestation has occurred could be too late, possibly with devastating results. It is far better to create a program to prevent mites from becoming a problem in the first place. Proper quarantine procedures and products can avoid the problem altogether. In addition to getting mites from an infested reptile, they can also be transported by other means, including infested feeder rodents, infested dry goods purchased from a store that has a mite infestation (mites can infest everything around the cages holding the infested reptiles, especially bedding) and even on your own person if you came in contact with them at an infested location (trade shows can be good for this). Preventing the problem in the first place will insure the health of your animals and save you time and anguish in the long run.
Bob @ Pro Products
Pro Products