Borers can be found in all trees but are only harmful to trees that are not healthy or trees that are under stress.  Trees can be under stress for the following reasons:-

1. Soil deficiency
2. Age
3. Moisture (either too much or too little water)
4. Air and water supply being cut off from the roots by plastic, concrete, soil compaction either from vehicles or human and animal foot traffic.

Once the tree is under attack of borers they have a natural defence mechanism to fight off the borers.   In gum trees they produce a red substance called kino, in wattles they produce gum, figs produce a white milky substance called latex and pines produce resin.

Resin, gum, latex and kino are the 4 most common natural defence mechanisms in trees.

The female adult borer, whether she be a moth, weevil or a beetle, lays her eggs in every tree she can. The eggs hatch into young larvae and start eating the tree, usually in or under the bark. If it is a healthy tree then the tree drowns the insects with kino, gum, latex or resin and that gets rid of the problem.

If the tree is not healthy or under stress and cannot produce enough kino, resin, latex or gum the borers will attack the tree and eventually the tree will die.

There is no treatment for borers.   You can try to improve the health of the tree.