I brought this up some time ago, but have never followed it up. I originally found an article from the USDA about it. No idea where it was? But the article also mentioned grapefruit leaves as having the best potential for knock down.
I don't use it myself and I agree with what you have to say about it Joe. But there are and probably always will be those that can't help themselves wanting to be the bees hero and kill the evil boogeyman.
"Other uses of smoke are also possible in a bee colony. Most recently, that from tobacco has been reported to reduce Varroa populations. Unfortunately, this natural material is difficult to control, and the exact dosage that kills mites but doesn't harm bees is unknown. "Smoking" Dr. Frank Eischen, working at the Weslaco Bee Laboratory, has taken this idea to another level (USDA ARS Agricultural Research, August 1997). So far, he has treated bees with the smoke of over 40 plants. The technique is to take cages with 300 to 400 mite-infested bees, expose them to smoke for 60 seconds while covered in plastic, and then count the number of mites that fall off. Most smokes don't kill the mites, it seems, they are simply knocked off the bees. If not caught by a sticky board, the mites, like the bees, "pick themselves up, dust themselves off and do it all over again." It is not clear, Dr. Eischen says, whether the mites are confused or just irritated. Two materials that show the most promise are smoke from creosote bush and dried grapefruit leaves."
"Success is not final, failure is not fatal: it is the courage to continue that counts." Winston Churchill