The weather has been pretty dry, so you might have some spider mites on the leaves. Check by running a leaf between your thumb and finger. If your fingers come away yellow or orange-y you have spider mites. Just spray the plants off thoroughly with the hose, being sure to get both tops and bottoms of the leaves. Do this every day for a few days, if it doesn't rain.
Spider mites do love hot, dry weather but are washed away if it rains or you spray your plants regularly. They make the leaves look hazy and light green by sucking out the plant juices from the leaf surface. Even if the damaged leaves die, the plants will recover, just like they do when the caterpillars eat them.
