i have an infestation of fungus gnats and I want to make sure mosquito dunks are safe for my phalaenopsis orchids. i plan on using it on my phals that are planted in moss.
Yes, they're totally safe. I've been using them for a couple of years on all my orchids during the winter months. They really work too, if you remember to use them regularly.
They work great as aachenelf said. Go for it, it's only BT, safe as safe can be!