Answer: Once the kernals are filled, you can harvest your popcorn and allow it to dry. It is best to leave it on the stalk for it to fully fill and dry, but it sounds like your ears are mature enough now.
In the future you might consider making applications of B.t. (available in a number of product names) to combat the caterpillars and prevent them from entering and feeding on the ears. I have also had decent success at controlling the earworms by putting 2-4 drops of mineral oil in the tip of the ears when silks are about 4" long. This can be tedious but works quite well.
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