You have more than one problem with the pecans. The holes are most likely the pecan weevil. The black interiors can also be due to other insect and disease problems. Your County Extension Office has free copies of the "Homeowner's Guide to Pests of Peaches, Plums and Pecans" that will cover what needs to be done and when. You can also see a copy online at the following web site. When you get to the website click on "read publication".
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