Hmm that looks like swamp smartweed to me. http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=240

While I don't have any in the fields, I do have some along roadsides which I have been trying to eliminate over the years. I use crossbow so I don't kill the grass. Scroll down this link to swamp smartweed for control options: https://www.btny.purdue.edu/WeedScience/NoTillID/CT-2.html

Your pics threw me off for awhile. My swamp smartweed has fuzzy leaves. You pics showed smooth leaves, so I was thinking it was honeyvine milkweed: http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=600 but that is a while different animal. I have some of that too.

No easy answers for either, other that a concerted multi-year effort.