While the Brugmansias are indoors they are extremely susceptible to bugs, so get one of the yellow sticky traps to catch any adults before they lay eggs again. I put one at soil level in each large Brugmansia or group of small ones, and hang another in any other area with plants.
I get my traps at Hanzeleys.
I have also heard of homemade sticky traps but can't remember how it was done, other than it needs to be done on yellow paper.