From UVM Extension:

For conventional growers, pesticides containing pyrethroids or carbamates (Sevin) are generally effective. On organic farms, rotenone was often used in the past, but it is not ideal because it is has a relatively high mammalian toxicity and its availability has become limited. Other materials often recommended for organic farms include neem or insecticidal soap but recent research indicates that these are not very effective. Other insecticides containing pyrethrins (Pyganic) or kaolin clay (Surround) have worked well in some studies but not others. Good control has consistently been obtained with the organic pesticide containing spinosad (Entrust) but this product is not yet labeled for flea beetle control. Insect repellents containing hot pepper or garlic may also provide some control. If you are an organic grower check with your certifying agent to be sure any material you use is approved for your use.

I use Surround.

Dave

I had a bad case of flea beetle on my potato plants. I used neem oil. It worked. I also followed up with a dose of predatory nematodes Steinernema feltiae and Heterohabditis bacteriophora