Help with Annual Bluegrass in Zoysia? (growing, back yard, seeds, ground)

[BC1960]

I live in NC and have zoysia in my back yard. I need to get rid of an infestation of annual bluegrass (poa annua), which has already started to produce seeds. I put out a pre-emergent herbicide a couple of weeks ago. Was i supposed to do that in the fall? Can I use atrizine to kill the currently growing bluegrass? When can I apply it? Thanks!

[Dirt Grinder]

I feel your pain. I'm constantly pulling those clumps from my bermuda. Unfortunately, when you pull the clumps, they spread seeds all over the ground. Pre-emergent has never worked for my lawn.