So I have a Linden tree that's about 80 foot tall. The top 20 foot is dead. The bottom majority has lots of full, long branches covered in leaves that sweep down all the way to ground level. We love it.

This week branches started dropping from the top and I found borer exit holes. I am assuming Linden borer.

What is the mortality like with them? Do they just hit the top and move on or should I expect this thing to croak in the coming years?

I figured a picture was useless...but if you want one let me know.