These nasty little bugs will strip an asparagus fern while you’re napping. My solution, which was popular once and still works, is to gather as many of those babies as you can, drop them in a blender with enough water (and a little dish soap), that you can churn them up and spray the resulting mix through a hand sprayer. Spray this on the ferns. Asparagus beetles, and other bugs, hate a dinner table covered with little bits and juices of their dead relatives.
One bit of advice: Do not use your wife’s blender. Pick one up at a yard sale. Otherwise, she will see what you’re doing, ask you how you made the mix, and then there’s no place to hide. Don’t be stupid, people. Trust me on this.