I have used cypress for a good many of my animals for years now, including boas and ball pythons (with proper ventilation it can be kept at a multitude of humidity levels as well as being great for holding high humidity). It also depends on where you are getting your cypress mulch. The double milled stuff you are getting specifically for animals I have never had any bugs or mites of any sort come in. If you are getting it at your local hardware store this is frequently another story. I havent had any harmful buggers come in with it but if you are concerned you can put it on a tray and bake it for a while. That will kill off the majority of whatever might be hanging out in it. I hope this is helpful.
THanks,
Mike
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