We have a large infestation of flea beetles, centralized in our garden. There are millions of the beetles. We put 1000 ladybugs out last night. The garden is approximately 60x100 ft. Do we need more lady bugs or is there another approach to kill these beetles?
I'm sorry to tell you this, but your application of lady beetles is not likely to help much since they are not active feeders on flea beetles. By looking at your photo, you might want to try a different approach since you have a large infestation. You might also want to start thinking about preventing such a severe infestation next year by cleaning up plant debris (the larval and overwintering stages are underground), rotating to a new bed and using row covers before the flea beetles show up.
This publication gives more information on biology and management of flea beetles.