Flea Beetle

We've got a bit of a flea beetle infestation.  It's enough that my arugula & kale seedlings arent even making it past their first leaves. Beet greens are covered in holes, as are sunflowers, rhubarb & horseradish ( they can have those leaves). Lettuce seedlings I just planted are already hopping. Next year I'll be sure to do crop rotation, & I'll likely use row covers next year too. Is there anything I can do this year? I've heard a few mentions of ditamaceous earth, but I'd like to get some thoughts here first. Thank-you.

Consider an "organic" labeled pesticide, and apply it with consideration for any pollinators that may be visiting your garden. An infestation that serious calls for a serious response, then you can transition over to the physical barriers for pest control.

I've found I get really bad pest problems when the soil is poor or I am not watering enough or maybe it is raining too much and the soil is saturated, or even that I am trying to grow plants out of season, for instance, trying to keep cool season plants alive through the warm season.  Some of these pests, in my experience, help indicate when conditions are not quite right for the plant, and I'm not actually helping the plant if I try to kill the pest, who is just telling me the plants aren't happy.

Pfaf.org mentions Catnip as a Flea beetle deterrent. I guess that means you have to brew it into a strong tea and strain it and have enough on hand to retreat the area after it rains.