Denise, can you see any sign of the creatures who are dining on your basil? Any residue or evidence of the insects themselves?

I would try spraying with Safers Insecticidal Soap if I thought it was insects (and not slugs for example). It's very safe for the environment (unless you are a bug) and you can still use the basil later. As far as I know it's okay on basil but you'd want to read the label carefully and maybe do a patch test before unloading a full sprayer bottle on your herbs.

I love Safers. We cut our own Christmas tree every year and it's always full of all kinds of insects. I spray it thoroughly with Safers and then rinse in the driveway before I bring it in. I used to be the laughingstock of the neighborhood but now people bring their trees by for a good sudsing. It makes a big difference. We have fewer uninvited guests and a clean tree is a pretty tree.