Neem oil and pyrethum and canola oil products are all acceptable sustainable pest management controls.

Those yellow and tan insects could be beneficials that are eating your pest problem or they could be the pest problem itself, the only way to know for sure is to properly identify what you have. If you are advertising your products as "pesticide free" and you spray them with anything, soaps or Neem included, you will need to take that sign down because your products will no longer be "pesticide free", because both are pesticides.

From what I can tell, I believe them to be Mexican Bean Beetles. Will the Neem be effective? I don't want to use it if not. Does anyone have experience with them?

I'm probably opening a real can of worms here by asking this, but here goes:

What is a "pesticide", organically speaking?

(kimmsr, thanks for being the sign police ;)

Mexican bean beetle look like ladybugs. Cucumber beetles are a bit more elongated, and may be stripey. I get those SOB's on my tomatillos.

A pesticide by definition is anything that kills, repels, mitigates, etc. pests. So neem is a pesticide, legally. But you could change your sign to read "No synthethic chemical pesticides used," (although technically, even most natural pesticides are prepared "chemically") or it could say "approved organic pesticides used only when necessary." Or you could cover your crops and keep the pests out altogether.
Good luck. I'm sure some of us struggle with these points occasionally.
Ann

Dan, to answer your question. Neem WILL work to protect your seedlings from further damage. I've used it successfully many times.

Bev

Floating row covers can provide good protection from both the Mexican Bean Beetle and the Cucumber Beetles, but Neem oil sprays will also kill the spined soldier bugs and parasitic wasps that are natural predators of both.
Neem Oil sprays are slightly less persistant in the environment than the pyrethrins that have been the staple for years and if something needs to be used that should be the first choice, but your products would not be "pesticide free" and your consumers should be told what you did use.

Dan, They do sound like the Mexican Bean Beetle. If so I have had success treating them with neem oil. Here's a homemade horseradish bug spray I found at a site:

Horseradish Pesticide
To make: Bring 3 quarts of water to a boil, add 2 cups of cayenne peppers, a 1 inch piece of chopped horseradish root, and 2 cups of packed scented geranium leaves, any kind. Let mixture steep for 1 hour, cool, strain and spray. Note: this can be made without the scented geranium leaves if you don't have them to spare.

I don't know whether your beans are enclosed in some sort of fence or not, but deer, when given the chance, will cleanly eat the tops off my bean plants. I didn't know if you had ruled this out or not. I, personally, have never had any sort of widespread damage caused by bugs on my beans, just the odd hole in the leaves, and have never had to resort to any sort of pesticides -- natural or otherwise.