Sergio Villegas, aphids are present still; on the youngest, most tender parts of the tree. Try a strong stream of water, pruning to reduce - not eradicate! - the population. Leave some to attract predators.

The older leaves in the second image, show another problem - probably a rust.

Or just old leaves?

Bauhinia is a semi-deciduous tree.

How did you plant it. And how have you watered it since then?

Let's see the entire tree, please.