Answer: Based on your description, I am not certain what would be eating the barberry foliage. Deer generally leave barberry alone, and slugs would leave behind their tell tale silvery trail. There are very few insect pests of barberry, however there is a weevil that can damage the leaves. I would strongly suggest you consult with your local Penn State county extension for a more specific identification of the pest and based on knowing that, how to control it. If a chemical control is needed they will have the most up to date information on what to use and how/when to apply it for maximum results. It is always better to identify the pest before trying to treat for it.
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