Yeah looks like Triv, which is tougher to remove. Where did you get your seed? Was it a sun shade mix? I read on another forum that Poa Triv is added for shade tolerance in some big box store brands. Tenacity will whiten Poa Triv but not kill easily, I don't think. Is that all you have? If yes dig it up with weed removal tool and get every last bit of root. if you have turf type tall fescue do not use Certainty , you may need Velocity which recently became available for residential use.

This is just me, but I blanket spray to get offenders to start bleaching. Then I will spot spray for as long as it takes. I do not pay attention to max application rate because I spot spray. Am I wrong here? According to my notes you are doing the recommended for spot spraying so 3.7oz/A rate. You can do 4 applications yearly before you hit the max yearly. Lastly, I should reiterate, white does not mean dead. It has to shrivel up with hues of brown.

:/ I've had pretty limited success with Tenacity and Poa Triv. I have an app down right now and the triv likes it the least, but it always bounces back. Basically, I'm using the tenacity to bleach/ locate it so I can take the super targeted approach of the tiny paintbrush and 40% Gly on some of the of the leaves. I look at it more that I'm delaying the inevitable...a Poa Triv lawn. I think it is evident I have improved varieties probably hydroseeded in.

okay resurrecting this one. I posted the original here and just following up. So since July, we've had pretty extended drought and heat (well it's been cooler the past few weeks now with autumn sun angle...). My poa triv is STILL dormant ( know better than to say dead). I was waiting to hit with Tenacity as Morpheus suggested above, but haven't because presuming it's so dormant in ain't growing thus the effect of Tenacity is a waste. Any suggestions on what to do now? Also - have some prodiamine granular form and will apply this weekend (for some poa annua in same areas for the most part as the Triv). I have and will reread the directions for how much to use for pre-em time - thinking from now thru the early spring months as well so a few months, minus the winter temps. Is there any trick to calculating? Seems like all based on acreage and I'm talking just a few 100 square feet I'd like to treat with probably 1 tank sprayer. I understand it's not the amount of water that's used but the amount of prodiamine applied within that tank sprayer. I'm sure I can literally calculate it out with square footage vs an acre but seems like I'm splitting hairs at that point. Any advice appreciated! Thanks!