Answer: I would cut away the bad leaves and see if you can find evidence of caterpillars as you are removing the affected leaves. Caterpillars munch holes out of leaves and as they do, they leave little black pellets called frass (bug poop). If you find frass on the ground beneath your collards, or between the leaves, caterpillars are the culprits. You can use Dipel or Thuricide to control them.
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