Q.Can You Help Me? See Below Please.
My bonsai ficus has above ground roots that are eroding and the tree trunk has a hole that I can put my finger in. The tree is still green and is making new leaves but something is terribly wrong. This has been going on for several years. Bonsai grown by myself from seed and is 21 years old.

Certified GKH Gardening Expert
Unfortunately, your photos did not come through. It could be that the tree has an infection, but there could be other issues, as well, depending on how often you feed or repot.
In the meantime, these articles that can with the care of the tree:
https://www.gardeningknowhow.com/houseplants/ficus/ficus-losing-leaves.htm
https://www.gardeningknowhow.com/houseplants/ficus/ficus-tree-care.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm