Those insects have most likely finished their job, so my opinion is, no chemicals are necessary. While the leaves don't look beautiful, the plant still needs those leaves. The new ones will be pretty again, and the holey ones won't be quite so obvious.
If a plant has diseased leaves, it's a different situation. Those, you pull off and discard and let the plant struggle with the deficit of leaf matter, which is the lesser of the two problems.
