Hmm, it is a bacterial culture so might be sensitive to salts (fert etc.) but should be ok along with fungicide.
I'm not big on combining things just because then you never know what caused what if there IS a problem. I try to apply single doses of stuff and wait a day or two to see the results especially if it's something new I'm using.
I haven't had to use Bt on my orchids for years, since they are mostly inside the cage, but I know people who use it on "jungle" orchids in their gardens all the time. I used to have more out on the trees but had problems with birds and squirrels, and even once a snake got entangled in one that was mounted with bird netting . . .
Ya just never know
