BT is bacillus thuringiensis. Milky spore is (or used to be) bacillus popilliae. Different bacteria. BT just kills caterpillars. Doesn't do anything to "future generations" because the caterpillars that eat the BT don't live long enough to produce any.

Yeah there are at least 5 different bacillus forms that I know of. And B.p (Milky Spore) doesn't do anything to the current generation of beetles. It only affects the grubs in the soil once they move up to the top couple of inches of soil near the end of their 3 year cycle.

Haven't looked at it in long time but it used to come with instructions for very specific application methods and times of the year to apply (like March and then Sept.). Grubs have already pupated and emerged for this year and egg laying hasn't begun yet.

Dave