Q: I noticed some worm-like protrusions on the trunks of one crape myrtle. It looks like sawdust so I assume it is some kind of borer. Can this be treated?
A: You have Asian ambrosia beetles boring into your crapemyrtle. The females began their excavation work in spring; now they are pushing the sawdust out of their holes. Part of their motivation was to lay eggs in the trunk and to introduce a fungus to feed their babies. Unfortunately, this maternal care could result in the death of your crapemyrtle. It all depends on how many eggs are in there and how much fungus is present. There’s nothing you can do right now except wait to see how badly the tree is damaged. Spray this plant and other susceptible trees in early spring when the beetles emerge. I have details plus how to make a monitoring trap at http://www.walterreeves.com/gardening-q-and-a/asian-ambrosia-beetle-on-crapemyrtle/.