I have a fruit salvia that look perky and happy except every couple of days, a few leaves yellow and fall off. First problem.

Second problem, some kind of insect is eating the healthy

leaves but I can't find the culprit. No traces except leaves with holes in them. Second problem.

What do I do about the first problem and what is safe to use for the second problem? I would like to use some leaves in tea, etc. so I'd really like to use a safe alternative to insecticides. But if I can't oh well, I guess.