Isn't that what burning sulfur does?
I hope that's not the case with Regalia, at least in my current situation. I got rid of everything associated with my old grow, cleaned like crazy, disinfected the entire area with ozone, and started from scratch with new seeds and new soil, as well as a small new aero set-up.
Like I said, this IPM is new to me, but from what I understand the Regalia (and Armor Si) is essentially making the plants immune system stronger so it can defend itself from powdery mildew, and so far, it's working...I'm in week 2 of flower with my new girls and no signs of any pm, and the Venerate is supposed to do the same with a variety of bugs.
Cost is low, plants are super healthy and huge. I really don't know how it works, only that it does work. The sulfur seems like more of another band aid, and from what I read, too many things can go wrong with it if you're not careful...Like death. I've breathed enough toxic shit for one lifetime.