Lucky? is it luck? that you have daddy long legs spiders working for you.
I used diatomaceous earth the first sign of those beetles and reapplied it after rains. Three applications seems to have done it. I haven't seen anymore yet this year. This is the first year I have tried this solution, which I much prefer to squishing all those beetles and the larvae.
Does anyone know if this is efficacious in the long run?
The chicken did get into the garden and dug up two small potatoes which looked healthy and tasted very good for dinner that night. She did not give me her report on the number of beetles she found and ate because I picked her up and put her back into her run and she was so insulted she spurned me.
I haven't used diatomaceous earth in the garden so I don't know if it would work long term. I do think that if you can get rid of them before late summer, there won't be any that over-winter in your garden. That would help a lot because they would have to come from somewhere else then.