Question
Bradford Pear approx 9 years old. leaves are dying and falling off. Sawdust build-up around bases of tree and tracks of sawdust from base to approx 3' high.
Treated with Neem oil, 98 degrees may be some of dying leaf problem. Any suggestions?

Answer
Does sounds like borers. spray the trunk with an insecticide called Merit. This insecticide will penetrate the bark and wood and kill the borer. Check with your local nursery from Merit. Neem oil will not kill borer insects in the trunk.
Borers attack trees under stress. I would water the tree with 1 inch of water per week-place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. If you have not done so mulch around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk. This will help hold moisture.