I had some problems with flea beetles last year chewing holes in the bok choy but this year the situation is worsen. There were several hot days and the flea beetle population exploded. They are particularly fond of cabbage family so my newly transplanted broccoli are almost gone. The big cabbage plants are OK because they are big enough to withstand the onslaught. I spread some diatomaceous earth on and around the plants but it is too late. So my worst enemies so far are slug and flea beetles. I read that I would need to cultivate the soil several time after the season is over to expose the beetle eggs. Gardening is never easy.