some pine trees only last so long....could be a bore bug or some other bugs having dinner...............so I would check on the label of Sevin and follow the instructions for your tree...............old long sleeved clothes, mask, goggles, gloves and a hat..........you are going to need a sprayer that will reach to the top. I bought one at the farm store.
Keep children & pets away from it until it is dry....
In the late fall, use dormant oil...check the label for strength mixed with water.........and you have to spray every part of that tree.....maybe someone can help you set up and spray. If some one had a lift or bucket you might be handy........just be careful you must wear protective gear as mentioned above.
If this tree lives you have to do this every year and when you see bores or bugs on it.
You also can call a forrester and he might tell you something better than I have said above.