If only a few, squish them. If lots, and on a large plant, power hose them into oblivion.

soap, neem oil or orange oil all work well if the hosing spray doesn't slow it down enough.
Happy Planting David

If they are large as mine are, you can use the new systemic insecticide for Beyer for shrubs. It works thru the tissue and does a great job for at least three months. I cut mine back every Fall so I can drag them thru the doorway. They are part of the family now, and last year I tried this new product and it worked great.