Q.Avocado low yield
Plant has pale to yellow leaves, alligator bark, whole in trunk with fine dirt like debris. Tried to fertilize but not very successful. What can be done to correct problem or help to revive to better yield in fruit? This is a private resident and tree is old (35 yr.).

With visible signs of Borer damage that you mention I would suggest you have a professional Arborist examine the tree.
Here is a few articles for you with more information.
http://www.ipm.ucdavis.edu/PMG/r8300411.html
https://www.gardeningknowhow.com/edible/fruits/avocado/avocado-pests-and-diseases.htm