Rob wrote:
Nicotine sulfate is (I believe) derived commercially from tobacco, not
synthesized. ..

Yep. And virtually all of it comes from India. You'd think the US
tobacco crop would be a source, but it isn't.

Nicotine will kill just about any bug on the planet, but it is readily
absorbed by human skin and can easily kill a careless user.

Anybody using Black Leaf 40, if they can find it, needs to wear long
sleeves, long pants, chemical goggles and long rubber gloves.

In use, the BL40 is mixed with an alkaline soap solution to produce the
alkaloid form of nicotine which is more potent than the sulfate form.

My grandfather used BL40 on his roses back in the 1950's-60's. It
worked..

J. Del Col