Answer: Without seeing the problem I can't really diagnose it and provide treatment suggestions. Since you know exactly what the problem looks like, you might want to visit the Texas A&M website (http://pecankernel.tamu.edu/diseases/index.html) that discusses insect and disease problems of pecan trees and has lots of photos.
Hope this helps you determine just what the problem might be. Good luck with your tree!
Q&A Library Searching Tips