I use garlic-pepper spray on my garden plants. (I use a pre-mix which doesn't contain citrus and I usually spot treat with a citrus spray when I can see the pests and spray it directly on them.) It seems to work well to repel leaf-eating insects long after it's dried since the residue clings to the leaf surface. I usually re-apply it after it rains.
As for ants, have you tried a barrier of diatomaceous earth (DE) in addition to the spray?
I have put out some DE but it is sort of hard to throw it all around the porch where you are always walking. Thus, I thought the spray might work