I am using insecticidal soap to control aphids on a Mandevilla. Insecticidal soap is basically a potassium overdose in a fatty acid form with some emulsifier or surfactant added. It is safe for animals but coats the insects and delivers too much potassium and dehydrates them. It definitely works, but the vine is so extensive that I end up missing patches of aphids, and they quickly expand to new places. So I end up spraying the patches I find daily, and that is a hassle.
Does anyone make insecticidal soap in a larger bulk size, maybe as a concentrate I can mix? Does it make any sense to spray the entire plant? I get the sense that this damages the flowers on the vine, and dehydrates them, probably by a similar mechanism.