Prarie Bowyer,
that suspicious worm hole, is a beetle hole, much like the pine borer, and it will flat out ruin your bamboo!
Spray, it or heat it really well, and kill the little S.O.B.!!!
Have them here, and they have ruined a few of my better arrow supply! It seems great, and just as you are starting to bend with heat, it suddenly folds in!! Then, you see all this dust fall out! And then you see the little S.O.B., that caused it! So mash the snot out of him! And all the others that are in there also! Or put them in the fire place, and get rid of the eggs also!
Wayne