that last paragraph had nothing to do with plants-- that was my recommendation on how to get rid of ants in your house, so I don't know why you're telling me that bleach and oil are more toxic than pyrethrins.
Pyrethrins are toxic to cats and dogs. Ironically, you find them in Hartz and several other brand's flea control products. Even though it's only .01% or whatever, if you go to hartzvictims.org or google "hartz killed my pet," you'll be surprised at how many complaints there are and after so many years of complaints the product is still on the shelf.
If the nearly 2000 complaints and painful stories about facial paralysis, itching, allergy, balding symptoms, etc. in pets, doesn't convince you, well that's too bad.
I'm not going to be smoking herb sprayed with the same poison that has killed hundreds of pets.
Nor do I want to be smoking stuff that can cause these symptoms: "Toxicity symptoms in humans include asthmatic breathing, sneezing, nasal stuffiness, headache, nausea, incoordination, tremors, convulsions, facial flushing and swelling, and burning and itching sensation."
Even if it's .01%, It might become concentrated after several applications or the plant absorbs it.
Also... I'm seeing less caterpillars now.. and finding more dead ones. Either the neem or BT is working so I'll just keep spraying like crazy and hand-picking.