Using insecticides on herbs

I'm growing herbs for the first time this year. Little flies/bugs are devouring the basil leaves. Is insecticidal soap the best thing to use?
Something is also going to town on the rhubarb leaves. Should I use the same thing, even though the leaves are toxic (at least, to humans - they don't seem to bother deer and the bugs)?
I would appreciate your expert input. Thanks.

limey at toad dot net
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