Years ago when we were on 8 row 36" corn we planted 18" beans with a splitter bar behind the corn planter with 5 rows on it and 2 wheel tracks.

Cultivated with a 378 White that had 5 danish tines/corn row.     Took the middle danish tine off of each gang for cultivating beans.


For cultivating corn it had a 4" by each row followed by two 7" sweeps with a 10" sweep on the back, the 10" was the one that was removed for  beans.    So at most we were cultivating 11" in the 18" bean rows, in reality it was probably closer to 9".


Assuming these are RUP beans only (not enlist or xtend or Liberty), I would hit them with a high rate of RUP and the highest labeled rate of First Rate (I think that is .6 oz/acre but I'm not 100% sure of that), use atleast 15 gpa of water and possibly add a little crop oil.     It won't be a fast death and you probably won't get them all but you should get more of them than cultivating will.