giving up the fight

The lily beetles have won.
This spring, I had a brain wave. Why not try sprinkling spent coffee grounds on my emerging lilies to kep the beetles at bay? And it worked. Numbers went down about 90 percent.
But then I went away on vacation, and when I got back, this is what I found. The plants were totally devastated. Every green leaf was grey and dry, and the flower buds obviously were never going to open.
So - I give up. Even though I hate punishing the victim, I pulled out all the lilies, and I won't be growing any more in the future. I've been told that everything is cyclical, and that any population will swell and then crash. Let's hope that happens with this red menace.