soo.. is that conventional beans? nothing will actually kill them now... you can try cobra.... but it will only hurt your beans yields....

uping the spray to 20 gal/ac + and making sure you get the proper coverage can help alot... however i still see those dang waterhemp poking up through in dads NGMO beans... they could be a fresh flush though...

try going to 20 or 22 gal/ac... using the same tip so you have a higher pressure and have to drive slower... that may help.