Resistant marestail just showed up in this area last year. I used firstrate (I don't recall rate) in my RR beans with lots of water and a spreader to get as good of coverage on the leaves as I could. I had very few escapes...(and those got hand pulled).

In my Liberty Link beans I did not need to add anything. At this time, Liberty is still effective on larger marestail. So, you may want to look into LL beans for next year. I've been growing them since they came out with great luck.