Whatever you chose to fight them with, be sure to do regular applications (unless recommended not to on the instructions) to make sure to upset the life cycles.
Just one example: with neem, you need to spray every 3 days and for at least three applications. (Other chemicals/soaps may have different methods similar to this, but be sure to do research on whatever you use. Utilize the search feature within the forum - type the spray name that people recommend and see what other people have to say)