I never had a problem with flea beetles in all the years I had gardened... And then out of no where-This little army of devastation attacked and I had them for years after.
Apparently they like shade, love mulch and boc choy . Be sure to treat the mulch around the base of the plants as well. grow your calciferous plants is the sunniest part of your garden for a few years.
I ended up moving plots, but I know you have raised beds so that is not an option.
I think we brought ours in. We would drive around and pick up bags of leaves waiting for the refuse trucks on trash day, and use them for mulch. We should have composted them first.
The older I get the worse my eyesight gets, but my hind sight is getting sharper.
They started on my joi choy... Everything is mulched, I'm thinking they came with the new soil... Where I mulched with grass over the wood chips though, no sign of them. Thank you for the advice, most of my beds aren't raised so I can shift things around next year... I think I'll get some hay today, toss it on top...