It is in very thick in some of our hay fields but it makes good hay so it has never been a problem. My problem is I didn't kill of the vegetation before putting in 3 small plot this year....and that stuff is extremely thick in one of my plots, existent in another, and third and largest appears be free of it.
The one where it has taken over, I have killed of the grass and kept it cut short. There is a decent amount of clover in places, other spots just sericia. Tomorrow I will spot treat with gly and try to spare as much clover as possible, then reseed in a month.
We'll see how it turns out in a few months.