We have a beautiful old tree in our front yard and it is dying and what do we do to prevent it from deteriorating further?

Carol, I would really need more information before I could address your tree's problem. Since you are here in Champaign, I would suggest bringing in a sample of the stems, ones in different stages of decline to our office at 801 North Country fair Drive in Champaign. Also how old is the tree. If you could bring in or email me pictures of the whole tree that would also help.