I have used BT, Bacillus Thuringiensis, brand name Thuricide. Very effectively in my perpetual. I am pretty organic and examine my soil cultures under 100x oil microscrope. It hasn't had any detrimental effect on my micro's, bacteria or single cells, I and have been pest free for months now. Good Stuff.
Try ths link.
http://www.ext.colostate.edu/pubs/insect/05556.html
The BT isn't the problem, it's the agent they use to attach it to the digestive process of the insect. They don't know the effects of it if it were smoked. I was just saying watch out for it's systemic properties, I know it is known to make certain types of conifer's abort their cones prematurely.I understand how it works. I doubt it has any ill effect on the weed.
10-4 I'm gonna go do it now, and in a few days ill get back to ya! Thanks!
Spring tails won't harm your plants.