Just because you see a caterpillar on your beloved plant, it may not necessarily be bad. Lots of caterpillars become butterflies. We all need butterflies in our lives.
As butterflies, whatever they eat up as caterpillars from our gardens - They repay with compound interest, now as pollinators. But this, unfortunately, hardly anyone realizes... Of course, I don't appreciate it when I see caterpillars on my limes. So for this, I have an ungrafted lime bush also, that I grew from seed. It doesn't produce any fruit, but has lots of leaves. So I pull off the caterpillars from my other limes - And put them on this undrafted one. End result is that no caterpillars are harmed, and so they always emerge out of their cocoons as beautiful butterflies. And since that ungrafted lime never produces any fruit, means that it spends all it's energy in sprouting extra leaves. So the plant too isn't harmed - As there is no shortage of leaves.