I think these are actually Stink Bugs.

You might speak to the ag extension service in your area. Also, the link below might be helpful. They talk about growing different vegetables that stink bugs don't like, when insecticides are helpful, and the use of row covers - which would allow you to remain organic :-).

Do a search on "stink bugs" and see what else you come up with that might be possible for you to implement.

Here is a link that might be useful: Stink Bugs

I LOATHE these things. I've never been a big pesticide user, however, with these things, you must be aggressive. This is the first year I DON'T have them. What works on them is carbaryl...found in Sevin. I've sprayed them regularly (I actually alternate between Seven, Malathion and one other which escapes me right now - using one every 7 - 10 days,and rotating them). The key is, as I understanding it, spraying when your plants are first in the ground, because you must get these things in the young stage. Otherwise, the pesticide is ineffective on them as adult insects. For years, I tried very hard to garden organically, but these critters were killer! Hope this is helpful.