So as I was walking around with a spray bottle looking for little bits of poa annua that I could zap I thought about how remarkable Tenacity is. In year's past we would be playing around with all these other chemicals and/or techniques that worked on the margin against poa annua.

There were some relatively big patches by my front door in October; I don't see any evidence of them after two hits with the spray bottle and KBG filling into the void.

Over the past few weeks I've noticed that if you hit annua 3-4 days before a mid-20 degree night, you'll have dead annua about 10 days later. In the past we had to stare at brown spots or use the paint brush technique. I'm down to about 5-6 areas that I can see right now in my backyard. Knowing that I can hit do a blanket spray in April and spot spray whatever turns is such a relief.

On my front lawn I truly can't find anymore, and I've been trying. I credit a strong pre-M barrier plus full sun and the ability to water much less now that I have some OM in the soil for part of the success. There were a couple of small patches near my neighbor, but I've been hitting them. The KBG isn't even blinking.

As an aside, I've found that if you hit the triv with Certainty and then Tenacity a week later, I get a better kill (or Tenacity first then Certainty). Tenacity by itself can take some of it out, but the one-two punch is pretty potent.

I will second that!

andy10917 wrote:Fourthed. I just wish I could find the secret to other's success with Tenacity on Triv. I still keep the Certainty around, just for the Triv.

Are you doing the Anti-Poa dance while applying?

andy10917 wrote:

Are you doing the Anti-Poa dance while applying?

Of course!!! Forward, backward and also on my head.

Notice that I've offered an opinion many times that it doesn't seem to work as well in the shadier areas. Please notice the following (which I just found on Wiki) that may indicate that I'm on to something (text bolded by me):

Mesotrione is an herbicide sold under the brand names Callisto and Tenacity. It is a synthetic analog of leptospermone developed to mimic the effects of this natural herbicide.[1] Mesotrione works by inhibiting the plant enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) which is necessary for carotenoid biosynthesis.[2] Without the protection from carotenoids, the chlorophyll necessary for plant growth is degraded by sunlight.

Hmmmmmmmmmmmmmmm.....

Definitely makes sense. Much, much harder to kill poa in my part-sun backyard than my front which is full sun.

gotcrabgrass wrote:I have a question regarding Tenacity:

For a 10K sqft lawn, the only application option seems to be to get an Earthway Spray Pro Push Sprayer . Am I wrong? I can only find sprayers for $250, which is a bit much on top of the $70 Tenacity bottle. Are there any other good options for a full pre-emergent application?

I have a 1 gallon Round-up carry sprayer, but I am not looking for ward to refilling it n times. If nothing else, having to stop so many times will really interrupt the Poa dance...

Couple of comments:

1) A 4 gallon backpack sprayer is definitely good enough for $10,000 sq. ft. Probably 2.5 tankfuls, give or take depending on how you calibrate.

2) Tenacity is not a great pre-M, you are much better off with Prodiamine to prevent Poa. The combination of a Prodiamine/Barricade application in mid-late March (just guessing since you are farther south) with an initial blanket spray of Tenacity at a low rate and then spot spray whatever turns around April is a decent plan, then use the rest of your capacity in the fall.

+1 to JG a backpack sprayer would work just fine.

+1 again on not using tenacity as a pre M. It helps out at seeding time but for the price I would not use it all year long as a pre M.

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If you are going to overseed than Tenacity is a great tool.

gave20 wrote:Man I don't know what I did wrong but I hit some poa in mid to late sept. 3 different times about a week apart each time but now the damn stuff is coming right back.

Once it was killed did you apply a pre M? This winter has been perfect for poa. It has not been cold and we have had some good rain. It might not have been you applied it wrong but what you did not do to prevent it from coming back.

[ Post made via Android ]

simpson wrote:

gave20 wrote:Man I don't know what I did wrong but I hit some poa in mid to late sept. 3 different times about a week apart each time but now the damn stuff is coming right back.

Once it was killed did you apply a pre M? This winter has been perfect for poa. It has not been cold and we have had some good rain. It might not have been you applied it wrong but what you did not do to prevent it from coming back.

[ Post made via Android ]

+1 - you might have had new poa germinate in the spot. Each of those f___ing plants can create hundreds of seeds that are just waiting for the right time to germinate (which would be now in the Northeast with this jetstream throwing 50 degree temps on us on New Year's Eve).