Q.ponytail palm crack in bark and nothing but air below it
I’ve a ponytail palm that I’d saved from a car accident (it was run over) it is about 2′ tall, my problem is that it has a large crack in the bark by the base, up to 1′ up the tree forming a large void behind it. how can I save it before the pests finish it!
—Karl—

You can try splinting it with some wood dowels and tying them in place with some garden ties.
Spray the wound with Neem Oil it deter pests.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm