# Ethofumesate & tenacity mix rates for cool season lawn



## Jersey_diy (Sep 5, 2020)

I am wondering if anyone has experience tank mixing ethofumesate(poa constrictor) & tenacity. Are you guys using them at full label rates?

Full label rate for ethofumesate is 9/16 of an ounce(.56) per 1k and for tenacity is .5 tsp for 1k. Are you guys mixing with full rates or reducing for tenacity.

The goal is to reduce poa population in the lawn which has already germinated.


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## CarolinaCuttin (Sep 6, 2019)

You might make it mad but you won't get post-emergent control with those products in the spring. PoaConstrictor needs to be applied during the time of maximum germination in multiple apps for control. In NC this is mid October, probably a few weeks earlier for you in NJ.

Tenacity is not labeled for post-emergent control of Poa annua but I believe some on here have had marginal success on immature plants in fall. Not going to happen in the spring.

I would not make this application but if you are going to have any hope of killing some Poa it will need to be full strength. I would do a small test area before doing a blanket app. First to make sure it doesn't ding up your fescue too badly, and second to see what effects, if any, it has on the Poa.


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## corneliani (Apr 2, 2019)

I'll 2nd what carolinacuttin says. Just for kicks and curiosity I went with a concoction of Etho (1oz/1000) Tenacity (6oz/A) and Speedzone (for the slight carfentrazone kick), together with some NIS and low rate of Urea, and I haven't seen anything that would show its having any effect on the Poa, beside some whitening of the turf here & there. This is after having had applied 2 rounds of ethofumesate at overseeding time! I haven't had much luck with that product, at least not enough to justify the price.


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## Ballistic (Mar 19, 2018)

When i do this style application, and im trying to kill the POA. 
.50 oz per 1k of ethofumesate
1 oz MSO per Gallon of spray 
1/2 teaspoon of Tenacity per 1k


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## jha4aamu (Oct 16, 2017)

Jersey_diy said:


> I am wondering if anyone has experience tank mixing ethofumesate(poa constrictor) & tenacity. Are you guys using them at full label rates?
> 
> Full label rate for ethofumesate is 9/16 per 1k and for tenacity is .t tsp for 1k. Are you guys mixing with full rates or reducing for tenacity.
> 
> The goal is to reduce poa population in the lawn which has already germinated.


Theres an article of a university turf manager that outlined his spring Tenacity plan and how it controlled his poa A problem. I believe it was something like 4oz/A every 10 days for a total of 4 applications.

Edit: heres the link https://sportsfieldmanagementonline.com/2010/11/12/using-tenacity-for-poa-annua-control/4488/


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## Bigdrumnc (Mar 28, 2019)

I applied ethofusemate and mso a week ago , blanket spray on my whole back yard. I haven't seen anything noticeable yet. I am in eastern nc. I was curious to see just what it would do. So far nothing.


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## Greendoc (Mar 24, 2018)

Ethofumesate causes a slow decline in targeted weeds over a one month period. That is why it is applied at 30 day intervals.


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## Jersey_diy (Sep 5, 2020)

Well I didn't have a chance to read the input until now, I ended up putting down the ethofumesate and tenacity at the label rate. I will take some pictures in the morning and keep track of the progress.

If i can reduce the population that would be great.


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## Scagfreedom48z+ (Oct 6, 2018)

Jersey_diy said:


> Well I didn't have a chance to read the input until now, I ended up putting down the ethofumesate and tenacity at the label rate. I will take some pictures in the morning and keep track of the progress.
> 
> If i can reduce the population that would be great.


Following this for sure. Curious to see the outcome.


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## Greendoc (Mar 24, 2018)

Jersey_diy said:


> Well I didn't have a chance to read the input until now, I ended up putting down the ethofumesate and tenacity at the label rate. I will take some pictures in the morning and keep track of the progress.
> 
> If i can reduce the population that would be great.


That will help you. Ethofumesate is also a pre for crabgrass so it will be useful for more than Poa. Not usually used for that because it is shorter lived than Prodiamine.


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## Greendoc (Mar 24, 2018)

Jersey_diy said:


> Well I didn't have a chance to read the input until now, I ended up putting down the ethofumesate and tenacity at the label rate. I will take some pictures in the morning and keep track of the progress.
> 
> If i can reduce the population that would be great.


That will help you. Ethofumesate is also a pre for crabgrass so it will be useful for more than Poa. Not usually used for that because it is shorter lived than Prodiamine.


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## corneliani (Apr 2, 2019)

jha4aamu said:


> Jersey_diy said:
> 
> 
> > I am wondering if anyone has experience tank mixing ethofumesate(poa constrictor) & tenacity. Are you guys using them at full label rates?
> ...


Just got the chance to read the linked article and the concept is intriguing. I may just try this low-rate concept out this year. 
Thanks for sharing btw


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## ScottW (Sep 16, 2019)

Last spring I had a bunch of Poa a, hand pulled what I could, which was a lot. I forget how many buckets full (repressed memory).
In the fall I did one app of ethofumesate + tenacity at seed-down, then another ethofumesate app some weeks later. Did not make a second app of tenacity.

It's still a bit early to judge. The lawn is waking up slowly. I've noticed a couple poa plants, which I pulled. Not seeing an explosion of it, but it's still early.
The ethofumesate label only says to make fall apps on TTTF. Not sure if spring apps are bad for TTTF, or if there's anything to be gained from it. The label says post-emergence activity is limited to very early stages of poa. Plus my two apps last fall put me at the annual max rate.

Only issue with the strategy of 4 x 4oz/A of tenacity is that puts you at the annual max of 16 oz/A, which would then preclude its use at fall overseeding, which I do on a pretty regular basis with TTTF.


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## smsrmdlol (Nov 29, 2020)

ScottW said:


> Last spring I had a bunch of Poa a, hand pulled what I could, which was a lot. I forget how many buckets full (repressed memory).
> In the fall I did one app of ethofumesate + tenacity at seed-down, then another ethofumesate app some weeks later. Did not make a second app of tenacity.
> 
> It's still a bit early to judge. The lawn is waking up slowly. I've noticed a couple poa plants, which I pulled. Not seeing an explosion of it, but it's still early.
> ...


Any update?


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## Jersey_diy (Sep 5, 2020)

Sure, i would say the etho + tenacity was a great success. I don't have a full picture of the lawn, but i have a really good example of the level of control. I can see why the fall is recommended since the poa a is very immature, but even with more mature plants it really stunted it giving the good grass a chance to grow. It basically melted 70% of it away.



Today I did my final tenacity app of 2.0 oz per acre + Anuew .25 per 1k sq ft. Will be doing pgr for the rest of the growing season.


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## Scagfreedom48z+ (Oct 6, 2018)

Jersey_diy said:


> Well I didn't have a chance to read the input until now, I ended up putting down the ethofumesate and tenacity at the label rate. I will take some pictures in the morning and keep track of the progress.
> 
> If i can reduce the population that would be great.


Following this. I have tenacity and Poa constrictor that I'll be using this fall during my overseed. The Poa a this year is absolutely out of control in certain areas


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## ScottW (Sep 16, 2019)

smsrmdlol said:


> ScottW said:
> 
> 
> > Last spring I had a bunch of Poa a, hand pulled what I could, which was a lot. I forget how many buckets full (repressed memory).
> ...


Having gotten mostly through spring now I'd say the apps I did last fall drastically reduced the amount of Poa A that popped up this spring. The one area of my back yard that was pretty heavily infested in spring of 2020 barely had any pop up this year. Few enough to easily hand pull. Hard to really quantify it, but easily >90% and probably >95% eliminated. I'm calling it a success against Poa annua.

And for the record, because I know some are prone to wishful thinking or smoke blowing or are susceptible to unfounded claims of youtubers with no supporting data... none of this did jack squat against Poa triv as far as I can tell. That shit is as bad this year as any other year.


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## smsrmdlol (Nov 29, 2020)

Did you do any seeding with the ergo? What was the schedule like?


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## ScottW (Sep 16, 2019)

Last year I did a combined Etho + Tenacity app on the day I dropped seed, which was Sept 22. Much later seed drop than I wanted because we had a lot of rain in early Sept that posed a washout risk and otherwise made my back yard too muddy. I did observe the recommendation of timing the second/last app close to the first frost, so didn't make the second Etho app until Nov 14. That's a 7 week interval, quite a lot longer than what the label recommends. The second app was Etho only, not combined with Tenacity.

I did not apply Prodiamine last fall. I wanted to avoid the stress on the new grass, plus I figured I had the Tenacity & Etho giving pre-M suppression when weed germination would be highest. That seems to have worked, as winter weeds were also negligible this spring.


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## smsrmdlol (Nov 29, 2020)

ScottW said:


> Last year I did a combined Etho + Tenacity app on the day I dropped seed, which was Sept 22. Much later seed drop than I wanted because we had a lot of rain in early Sept that posed a washout risk and otherwise made my back yard too muddy. I did observe the recommendation of timing the second/last app close to the first frost, so didn't make the second Etho app until Nov 14. That's a 7 week interval, quite a lot longer than what the label recommends. The second app was Etho only, not combined with Tenacity.
> 
> I did not apply Prodiamine last fall. I wanted to avoid the stress on the new grass, plus I figured I had the Tenacity & Etho giving pre-M suppression when weed germination would be highest. That seems to have worked, as winter weeds were also negligible this spring.


Thank you!

I'll prolly type up a plan see if you agree with it


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## mowww (Jan 16, 2018)

@ScottW Thank you for the information!


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## Scagfreedom48z+ (Oct 6, 2018)

ScottW said:


> Last year I did a combined Etho + Tenacity app on the day I dropped seed, which was Sept 22. Much later seed drop than I wanted because we had a lot of rain in early Sept that posed a washout risk and otherwise made my back yard too muddy. I did observe the recommendation of timing the second/last app close to the first frost, so didn't make the second Etho app until Nov 14. That's a 7 week interval, quite a lot longer than what the label recommends. The second app was Etho only, not combined with Tenacity.
> 
> I did not apply Prodiamine last fall. I wanted to avoid the stress on the new grass, plus I figured I had the Tenacity & Etho giving pre-M suppression when weed germination would be highest. That seems to have worked, as winter weeds were also negligible this spring.


Great info! I'm going to follow this in the fall.
If you had been able to seed earlier, would you have applied a second app of tenacity/etho?

Also sorry if I missed this, did you do any spring follow ups this year with either herbicide?


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## ScottW (Sep 16, 2019)

Scagfreedom48z+ said:


> If you had been able to seed earlier, would you have applied a second app of tenacity/etho?


Getting into the realm of woulda coulda shoulda here. I believe my thought process was that with the grass really slowing down by the time I did the second app (couple days before a forecast frost), I didn't want Tenacity in there in case it would leave me with a prolonged whitening effect. I'm not sure if that's a legit concern or not. I've had Tenacity in the arsenal for probably 7-8 years but never applied it anywhere near that late in the year. If I had made the second app earlier when the grass was more actively growing, I suppose that would be less of a concern. But the Etho label says on TTTF to make 2 apps starting when weed germination is highest and ending as close to the first frost as possible. That's why the 7-week interval between the two apps.



> Also sorry if I missed this, did you do any spring follow ups this year with either herbicide?


No, haven't applied Tenacity or Etho this spring.
Reading the Etho label, I'd be dubious of it having much effect in spring. It says the post-M activity on Poa A is limited to the 2- or 4-leaf stage. I would think that any Poa A plants that managed to escape the fall herbicides and survive the winter and grow enough to be noticed in the spring will be well past that 2- or 4-leaf stage where they're susceptible.


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## Scagfreedom48z+ (Oct 6, 2018)

ScottW said:


> Scagfreedom48z+ said:
> 
> 
> > If you had been able to seed earlier, would you have applied a second app of tenacity/etho?
> ...


This is great, much appreciated. I'm definitely going to run my plan according to your experience.


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## smsrmdlol (Nov 29, 2020)

Jersey_diy said:


> I am wondering if anyone has experience tank mixing ethofumesate(poa constrictor) & tenacity. Are you guys using them at full label rates?
> 
> Full label rate for ethofumesate is 9/16 of an ounce(.56) per 1k and for tenacity is .5 tsp for 1k. Are you guys mixing with full rates or reducing for tenacity.
> 
> The goal is to reduce poa population in the lawn which has already germinated.


Is it safe to tank mix tenacity + etho?


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## Scagfreedom48z+ (Oct 6, 2018)

smsrmdlol said:


> Jersey_diy said:
> 
> 
> > I am wondering if anyone has experience tank mixing ethofumesate(poa constrictor) & tenacity. Are you guys using them at full label rates?
> ...


I did and didn't have any issues


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## Bigdrumnc (Mar 28, 2019)

I am looking to apply ethofusemate in eastern nc probably close to Halloween at the kbg rate. I didn't over seed until sept 20. My overseed consisted of a tttf kbg mix, so to be safe I am applying at the kbg rate. Lol I am neevous! I hope it doesn't wack the new grass!


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## Mardel74 (Aug 16, 2020)

Bigdrumnc said:


> I am looking to apply ethofusemate in eastern nc probably close to Halloween at the kbg rate. I didn't over seed until sept 20. My overseed consisted of a tttf kbg mix, so to be safe I am applying at the kbg rate. Lol I am neevous! I hope it doesn't wack the new grass!


What is the Kbg rate? I tough ethofumesate is not safe on kbg new grass


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## Bigdrumnc (Mar 28, 2019)

I am not near the label now but if I remember it s half the tttf rate.


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## Jersey_diy (Sep 5, 2020)

I am pretty sure that you're newly seeded lawn is not old enough...


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