Rain water mistake

My green thumb came only as a result of the mistakes I made while learning to see things from the plant's point of view.  ~H. Fred Dale (Thanks, Anne)

I have to confess...........................Made a Big, Big.................Mistake

We have two rain barrels that catch overflow from rain totes.  Being open, they will draw mosquitoes. Thus, I plunked the MosquitoDunk  disk in each barrel.

I DID NOT READ THE INGREDIENTS AND WARNINGS.

Sad to say, I have killed some of my cone flowers and 2 allysum plants.  KILLED THEM.

The label clearly states that the ingredient is Bacillus thuringiensis and some other baaad sounding stuff.
 The dunk also stays active for 30 days.

I am not even going to spend time researching. If it is not the bacillus thing, something in that water killed my precious cone flowers.  The only good thing?  I ONLY WATERED 4 PLANTS!!!