Tenacity vs Poa Trivialis: Your Results

[andy10917]

While I positively adore the results that I have seen for "Tenacity vs Poa Annua", I personally have experienced that the "Tenacity vs Poa Trivialis" battle is not as successful. As a matter of fact, I resorted to the use of "Certainty" for Poa Trivialis control, with the expected harsh side effects and success against the PT.

I know that Certainty isn't an option for the TTTF crowd (and I feel for them), but I'd like to see whether others have had recurrence of Poa Trivialis after Tenacity treatments - maybe I'm doing something wrong.

If you used Tenacity for PT control and there has been a reasonable amount of time since completion of your regimen (maybe 90 days?), what were your results and regimen? I'd like to see if there were patterns in what worked and what didn't...

As a side note, please don't clog up this thread with "my success against Poa Annua" or other lawn weeds - let's try to stay focused on PT...

[MorpheusPA]

I had one fairly large patch (2 square feet) that went after two very light sprays ten days apart. It was about the same rate that True Green ghost-apps lawns with their sprayers.

That was in fairly full sun (shielded from early morning sun, but full sun from 10 AM to sunset), and that seems to help.

About a dozen (well, after yesterday more like 15) patches of P. triv have been sprayed. The one that was on its second spray is already ghost-white and dying visibly.

Considerations:

* I have very soft water. It might be worthwhile to use distilled water when mixing Tenacity as it does seem to accelerate the effects (not just on that, but on any herbicide).

* Ammonium sulfate calcium strips plants, and I use a great deal in my iron mixes. This may be accelerating or enhancing the effect. It has no effect on surrounding bluegrasses.

* I use 1% DMSO in my Tenacity solution. That definitely accelerates the effect and enhances it. Discoloration on surrounding bluegrasses is not increased.

* I try to spray in the early evening of a clear night with dew to keep the grass moist with the herbicide overnight for maximum absorption. That's true of any herbicide except Round Up, where it doesn't seem to matter.

[jglongisland]

Mine did seem to re-emerge after I thought it was taken out by my April/May Tenacity treatments. Its not nearly as dense and hard to spot as its interwoven as you indicated. This could be stuff that was dormant even in the spring and didn't wake up until we got 30 inches of rain in 4 weeks.

I used Certainty last week on it (and 7 days later it looks a tad lighter), today I used Tenacity as I was doing the last app of the season on my front hill and figured I would double down and zap it. Now if I could get a freeze in the next 2 weeks I think that would help, but that's not likely in Western LI. I also used Etho last Sunday.

Pure supposition; if you can weaken it with Tenacity and get an early hard freeze I think that might help.

[Hammbone]

I seem to be having success taking out the Poa Triv with Tenacity. My spots are about 12-18" in dia. I did 2 apps 7days apart. The last app was last Wednesday.

[CTShoreGuy]

I swear the patterns I had of white death, from the first salvo of Tenacity, have reappeared in a almost the exact same pattern. Total of 35%-40% white blades.

It came back after the OS was looking pretty good.

I just might be located on either an ancient PT burial ground, or I'm smack dab in the middle of PT's universe, it's epicenter.

I'm hopeful that JG is right and tenacity plus frost will help.

[jglongisland]

I swear the patterns I had of white death, from the first salvo of Tenacity, have reappeared in a almost the exact same pattern. Total of 35%-40% white blades.

It came back after the OS was looking pretty good.

I just might be located on either an ancient PT burial ground, or I'm smack dab in the middle of PT's universe, it's epicenter.

I'm hopeful that JG is right and tenacity plus frost will help.

I think its a multi-year process to kill this stuff and in the interim, when you beat it back you have to get other grass to grow in its place, or spread into it. As CT knows, this is really tough with TTTF as you can't use Certainty and there is no spreading. It seems to come back less dense each year, but always in the same spots. The stolons must be able to go dormant for a really long time, and even though we kill some of it there always seems to be more lying beneath the surface.

[CTShoreGuy]

I swear the patterns I had of white death, from the first salvo of Tenacity, have reappeared in a almost the exact same pattern. Total of 35%-40% white blades.

It came back after the OS was looking pretty good.

I just might be located on either an ancient PT burial ground, or I'm smack dab in the middle of PT's universe, it's epicenter.

I'm hopeful that JG is right and tenacity plus frost will help.

I think its a multi-year process to kill this stuff and in the interim, when you beat it back you have to get other grass to grow in its place, or spread into it. As CT knows, this is really tough with TTTF as you can't use Certainty and there is no spreading. It seems to come back less dense each year, but always in the same spots. The stolons must be able to go dormant for a really long time, and even though we kill some of it there always seems to be more lying beneath the surface.

My only option is to let it be, let MN take over, dormant seed in the winter. Then next spring start using Tenacity at 1/2 rate applications and spray & pray I don't have too much coming back. If I can knock down a considerable amount each year, that's progress.

Hey I think I just came up with a new Poa-ism -"To spray and pray"

I so I don't

[MorpheusPA]

As I noted here, anyway, the second year wasn't much better than the first...but it was a little better. Then the better-ness accelerated as the seed bank exhausted and the bluegrass spread and the existing stuff died out from creative chemistry.

This fall was not good for P. triv in the sense that a lot grew very easily. I'm up to about 30 patches of P. annua and P. triv in the lawn, most very minor, that have been Tenacity spot-sprayed. I'll be spraying again in spring, I'm sure.

[andy10917]

I just might be located on either an ancient PT burial ground, or I'm smack dab in the middle of PT's universe, it's epicenter.

You cannot be at the center of the PT Universe, because I am there. I just have the Certainty tool at my disposal, if I can drink enough to handle the ugliness. You don't have that, and therefore I bow to you as the PT Master of the Universe.

PS: I don't use exactly the same wording as you. My discussions of PT start with "You know how supposedly there is a place where the Elephants go when they are going to die?...".

[CTShoreGuy]

I just might be located on either an ancient PT burial ground, or I'm smack dab in the middle of PT's universe, it's epicenter.

You cannot be at the center of the PT Universe, because I am there. I just have the Certainty tool at my disposal, if I can drink enough to handle the ugliness. You don't have that, and therefore I bow to you as the PT Master of the Universe.

PS: I don't use exactly the same wording as you. My discussions of PT start with "You know how supposedly there is a place where the Elephants go when they are going to die?...".

Too funny Andy.. OK I have the POA T epicenter for TTTF, and you for KBG
Onwards my friend!

[Pirate Russ]

Okay - I hijacked this old thread as I was wondering if we have had any updates on Tenacity vs Poa Trivialis. Unfortunately, my renovation from last year has loads of Trivialis. It did not seem that bad last year and this spring I sprayed RU on a few spots. The trivialis is clearly intertwined with the TTTF. I guess that is why i did not see any dead spots in the summer. Anyway, it grows very fast and is lighter than the existing grass. At this point, RU is probably not an option as it would essentially end up being 2000 square foot reno. As a result, I was wondering if people had any updates to this older thread. I sprayed Tenacity on it 2 weeks ago and it did turn it white. Nonetheless, it did not kill it. Hopefully if someone has had success, they can post their successful approach (i.e. how much and how often, etc)....

[bergenite]

I applied Tenacity at 2 oz. / acre every 3 day for a total of 8 applications last fall. There was no triv at all in my yard when winter set in, however, even with a solid Guardrail barrier in place some returned in the spring. I estimate perhaps 80% control with this protocol.

[andy10917]

Bergenite's numbers are not bad for PT in a primarily sunny situation, but my experience is that Tenacity is far less effective in PT's favorite territory: shade. Since its action is light-related, no surprise there.

[Pirate Russ]

Guys - Thanks for the response. In regards to Guardrail barrier, I would not think a preemergent would work with PT since it can spread via stolons. Anyway, thanks for your help.

[sc4dr]

I can honestly say, that without tenacity, I would have a huge pt infestation. After 2 seasons of light continuos apps, I am left with only a couple small spots that pop up here and there...... Mostly on the other side of the property line.

So when used as a lawn regiment, I believe it to be quite effective.

[ Post made via iPhone ]

[MorpheusPA]

I've had great luck with 2 oz per K twice or three times, but I do some fiddling (DMSO, in other words). I have no shade except on the north face, and even that sees sunlight a bit for most of the year and is always in bright shade at worst.

[Pirate Russ]

Guys - Thanks. That is encouraging. In regards to the light applications, I have some questions. In my sprayer, I have the standard mix of 1tsp of Tenacity and 2 gallons of water. I use a fan tip sprayer. I really struggle with determining how much I am actually putting down using the fan tip sprayer. Do you guys typically go over the spot 1 or 2 times? I know I am overengineering this. Anyway, I will use Morph's advice and try distilled water. Thanks

[Billybob]

How long should you wait between applications? Is there an advantage doing them closer together? I applied at 2 oz. on Friday and I can see it turned a few patches white.

I think I read somewhere that 8 oz. was max per year. Is this a guideline or is it law?

[Drinyth]

1 tsp in 2 gallons is actually what I'd consider full rate (4 oz. / acre). Many folks (myself included) only use 1/2 tsp per 2 gallons.

As far as how much to actually put down, you really need to calibrate your sprayer and see how much liquid goes over a given area at your sprayers output and your own walking speed. That's really the only way to know as every sprayer is a little bit different and dependent on tank pressure and what not. Once you have your sprayer calibrated, you'll know how much product you're applying.

I typically don't go over a spot twice unless I'm mixing at half my intended rate. Otherwise, making two passes over the same area at my target strength is really putting down 2x as much product as desired.

Maximum for Tenacity, I believe, is 16 fl. oz. / acre annually. That's the manufacturer's recommendation and what they deem to be safe in accordance with their testing.

[mattya]

As far as how much to actually put down, you really need to calibrate your sprayer and see how much liquid goes over a given area at your sprayers output and your own walking speed. That's really the only way to know as every sprayer is a little bit different and dependent on tank pressure and what not. Once you have your sprayer calibrated, you'll know how much product you're applying.

I typically don't go over a spot twice unless I'm mixing at half my intended rate. Otherwise, making two passes over the same area at my target strength is really putting down 2x as much product as desired.

Maximum for Tenacity, I believe, is 16 fl. oz. / acre annually. That's the manufacturer's recommendation and what they deem to be safe in accordance with their testing.

+1.

I've seen people use all kinds of times in between sprays and be successful. Typically, the higher the rate, the longer you wait. I've been doing 7-10 days at the 4oz/acre rate. At just 2oz/acre, I've heard of as often as every 3 days.