Q.White Flies
my 20+ year old areca palm has whiteflies! how do I get rid of them before they kill the whole tree? (about 8 ft tall) also my Hawaiian tea plant has them also! I have sprayed them down with soapy water, physically washed each leaf with soap and water, rinsed them outside, and literally doused them both with insecticidal soap spray! what else can I do to save them and how to prevent this again? thanks!

Certified GKH Gardening Expert
This article will help you deal with white flies:
https://www.gardeningknowhow.com/plant-problems/pests/insects/whitefly-control.htm