Question
Do this trees attract carpenter ants and various types of wasps? If so, how can this be controlled?

Answer
Tom,

I'm not aware of anything about crepe myrtle that would make it attractive to either wasps or carpenter ants. Carpenter ants seek cavities to start their nests so if the tree is starting to hollow out a carpenter ant nest could get started. Likewise some wasps use cavities in which to build their colonies. In both cases the cavities can be anywhere (trees, stumps, the wall voids in your house).

Hope this helps. If you have specific questions about carpenter ants or wasps post a follow up.

Jack DeAngelis