Poa Triv Invasion Counter-offensive

Kentucky bluegrass, Fescue, Rye and Bent, etc
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oze
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Poa Triv Invasion Counter-offensive

Post by oze » April 30th, 2022, 11:35 am

Hey Folks,

As you can see below, I have a major Poa trivialis problem in an area of my back yard that i am finally going to address this year. The lawn is mostly PRG and I have a supply of Velocity, so I plan to use it to try to save the few islands of resistance rather than go full tactical nuke with glyphosate. I'll use the rapid conversion technique per the Velocity label, which should have the area ready for repair by late August.

Image

Obviously, reseeding in the Fall is out, as a second application of pre-emerge then is clearly required. I'm thinking of growing seed pots, using PRG mixes that include Sideways and Barenbrug RPR cultivars, both of which are stoloniferous and do spread, albeit not as quickly as KBG. But this it going to take *a lot* of plugs! Also, that area stays wet for days after any moderate rain, and is shady from mid-afternoon on, once the bald cyprus leafs out.

I am open to suggestions, including non-PRG mixes that could survive there, even if they only moderately blend in with the rest of the back yard. Except, that is, for the #1 recommendation that I found for growing under those conditions: Poa trivialis :banghead: Or are more drastic (non-turfgrass) measures the only hope? 5 years or so ago, Mrs. oze would have welcomed the invitation to extend her garden of hostas and native plants, but as she grows older, her gardening energy is waning. We are thinking about a rain garden in *another* problem area, but not here.

Anyway, as always, tanks for your help!

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Re: Poa Triv Invasion Counter-offensive

Post by edslawn » April 30th, 2022, 10:59 pm

This should be interesting! Good luck and thanks for sharing your experience.

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Re: Poa Triv Invasion Counter-offensive

Post by Green » May 1st, 2022, 12:12 am

Oze,

I agree with the rapid conversion. I killed a lot of lawn a few years ago trying frequent low dose apps. Eventually, they caught up to the desirable grass.

Also, I would use distilled water with it, and somewhere there is legit info about using a surfactant and Ammonium Sulfate with it, even though the label expressly says not to add anything. Apparently, when the same AI is used on rice fields, adjuvants are always prescribed. Actually, I experimented last year or the year before with additives. I'll have to dig up my notes for specifics.

Yiu should start seeing results a couple of weeks after the first app. If it fails, you can still do glyphosate on one or more of these islands in June if the weather cooperates.

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Re: Poa Triv Invasion Counter-offensive

Post by Masbustelo » May 1st, 2022, 9:49 am

I would suggest using tenacity. It is much less complicated, and in my experience highly effective. I had so much last year, I used 22 gallons to spray it all. Yesterday I hit what is left with two gallons.

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Re: Poa Triv Invasion Counter-offensive

Post by Green » May 1st, 2022, 3:34 pm

Masbustelo,

You and Morph both. Please consider detailing your timings, rates, and experience at some point. It could be useful! I've never had luck with Tenacity on Triv.


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Re: Poa Triv Invasion Counter-offensive

Post by moejoe » May 1st, 2022, 7:25 pm

Oze,

I too have been fighting triv for years!! Blanket sprayed velocity at 3/4 tsp/gallon per 1000sq ft monthly in May thru Sept.

This has been the worst year I have had it. A couple of questions/observations:

1. I used fungicides heavily last summer with bad brown patch etc - do you think this promoted the persistence of the triv for this year?
2. I have been religious about pre-emergents bi annually - it really has no effect on the triv. This late summer and fall I am going to skip it and do an overseed.
3. No winterizer nitrogen and only a light fall feeding - maybe less nitrogen in the fall may help prevent it.

It is insanity doing the same thing over and over again and expecting different results as they say.

I am going with velocity treatments each month, no fungicides, little water and not fall pre emergents with a heavy overseed - will see if this changes anything next year.

JM

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Re: Poa Triv Invasion Counter-offensive

Post by oze » May 1st, 2022, 8:31 pm

Thanks for all of the replies, guys. That area in the picture in the OP started out with a few spots 2 years ago. I ignored them, and overseeded the entire yard in the fall, so no 2nd pre-emerge. Last spring, the spots grew into islands. Same response from me, except for an experiment:
Image
This picture was taken 2 days ago. Last summer, I used the rapid conversion on an island of triv/prg mix. 3 apps later, it was an island of brown triv with scattered outposts of green. A couple of lessons: 1)Velocity does work on rye infested with triv.
2)Make sure to spray Velocity past where you think the boundaries are
3) Barenbrug RPR does indeed spread to fill in bare spots

I'm going to start the Velocity applications as soon as things dry up. The weather's not looking good, but hopefully before June. I still don't know what's going to replace the triv in that large wet area.

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Re: Poa Triv Invasion Counter-offensive

Post by oze » May 1st, 2022, 8:43 pm

moejoe wrote:
May 1st, 2022, 7:25 pm
Oze,

I too have been fighting triv for years!! Blanket sprayed velocity at 3/4 tsp/gallon per 1000sq ft monthly in May thru Sept.

This has been the worst year I have had it. A couple of questions/observations:

1. I used fungicides heavily last summer with bad brown patch etc - do you think this promoted the persistence of the triv for this year?
2. I have been religious about pre-emergents bi annually - it really has no effect on the triv. This late summer and fall I am going to skip it and do an overseed.
3. No winterizer nitrogen and only a light fall feeding - maybe less nitrogen in the fall may help prevent it.

It is insanity doing the same thing over and over again and expecting different results as they say.

I am going with velocity treatments each month, no fungicides, little water and not fall pre emergents with a heavy overseed - will see if this changes anything next year.

JM
It would be an understatement to say that I feel your pain! I look forward to hearing about your results.

Since I haven't tried fall pre-em apps yet , I'm going to try that and Velocity. I also know that this will be an ongoing battle.

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Re: Poa Triv Invasion Counter-offensive

Post by moejoe » May 1st, 2022, 11:30 pm

oze wrote:
May 1st, 2022, 8:43 pm
moejoe wrote:
May 1st, 2022, 7:25 pm
Oze,

I too have been fighting triv for years!! Blanket sprayed velocity at 3/4 tsp/gallon per 1000sq ft monthly in May thru Sept.

This has been the worst year I have had it. A couple of questions/observations:

1. I used fungicides heavily last summer with bad brown patch etc - do you think this promoted the persistence of the triv for this year?
2. I have been religious about pre-emergents bi annually - it really has no effect on the triv. This late summer and fall I am going to skip it and do an overseed.
3. No winterizer nitrogen and only a light fall feeding - maybe less nitrogen in the fall may help prevent it.

It is insanity doing the same thing over and over again and expecting different results as they say.

I am going with velocity treatments each month, no fungicides, little water and not fall pre emergents with a heavy overseed - will see if this changes anything next year.

JM
It would be an understatement to say that I feel your pain! I look forward to hearing about your results.

Since I haven't tried fall pre-em apps yet , I'm going to try that and Velocity. I also know that this will be an ongoing battle.
You can try the pre emergent in the fall for other winter weeds but believe me, it will do nothing to prevent triv. I have experimented with prodiamine and dithipyr at different doses over the years and actually did a split fall application (august and Nov) -still comes back with a vengeance.

The only thing I haven't tried is no fungicides and no late nitrogen - this is my 10th year and 2 renos later. I pray that someone comes up with something to kill and prevent this crap before I die!!!!

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Re: Poa Triv Invasion Counter-offensive

Post by oze » May 3rd, 2022, 6:34 pm

moejoe wrote:
May 1st, 2022, 11:30 pm
oze wrote:
May 1st, 2022, 8:43 pm
moejoe wrote:
May 1st, 2022, 7:25 pm
Oze,

I too have been fighting triv for years!! Blanket sprayed velocity at 3/4 tsp/gallon per 1000sq ft monthly in May thru Sept.

This has been the worst year I have had it. A couple of questions/observations:

1. I used fungicides heavily last summer with bad brown patch etc - do you think this promoted the persistence of the triv for this year?
2. I have been religious about pre-emergents bi annually - it really has no effect on the triv. This late summer and fall I am going to skip it and do an overseed.
3. No winterizer nitrogen and only a light fall feeding - maybe less nitrogen in the fall may help prevent it.

It is insanity doing the same thing over and over again and expecting different results as they say.

I am going with velocity treatments each month, no fungicides, little water and not fall pre emergents with a heavy overseed - will see if this changes anything next year.

JM
It would be an understatement to say that I feel your pain! I look forward to hearing about your results.

Since I haven't tried fall pre-em apps yet , I'm going to try that and Velocity. I also know that this will be an ongoing battle.
You can try the pre emergent in the fall for other winter weeds but believe me, it will do nothing to prevent triv. I have experimented with prodiamine and dithipyr at different doses over the years and actually did a split fall application (august and Nov) -still comes back with a vengeance.

The only thing I haven't tried is no fungicides and no late nitrogen - this is my 10th year and 2 renos later. I pray that someone comes up with something to kill and prevent this crap before I die!!!!
This is an interesting thought; any comments from other experts with respect to how to treat the areas with 67%P.trivialis33%PRG? Should I avoid watering and fertilizing this entire area as I slowly kill the triv with Velocity, or should I treat it as normal, hoping to encourage the PRG to thrive as its limey neighbors die? Tanks again!

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Re: Poa Triv Invasion Counter-offensive

Post by Wally » May 4th, 2022, 7:34 am

Interesting article on the subject. Spring battle seems to work best overall. They had no success with Tenacity.

https://www.golfdom.com/an-integrated-s ... trivialis/

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Re: Poa Triv Invasion Counter-offensive

Post by Wally » May 4th, 2022, 7:40 am

For large infestations, consider beginning a renovation with Velocity applications in midsummer, followed by multiple glyphosate applications in late summer before seeding. Then apply Velocity as soon as one week following seeding — at least with creeping bentgrass — to limit rough bluegrass reestablishment.

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Re: Poa Triv Invasion Counter-offensive

Post by edslawn » May 5th, 2022, 12:45 pm

Wally wrote:
May 4th, 2022, 7:34 am
Interesting article on the subject. Spring battle seems to work best overall. They had no success with Tenacity.

https://www.golfdom.com/an-integrated-s ... trivialis/
Interesting... and depressing :(

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Re: Poa Triv Invasion Counter-offensive

Post by Masbustelo » May 6th, 2022, 9:10 pm

My Tenacity regimen is Distilled water, Tenacity 1/4 Teaspoon per gallon, 2 Tablespoons DMSO per gallon, 1 tablespoon Ammonium Sulfate per gallon, and any Non Ionic Surfactant. Apply this every ten days. Be relentless, keep it on the ropes. Morpheus recommends eye protection, and rubber gloves and rubber boots. Showering upon completion of spraying.

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Re: Poa Triv Invasion Counter-offensive

Post by Green » May 7th, 2022, 3:09 am

Masbustelo,

Interesting. I think I remember using DMSO a couple of times in organic chemistry labs. Having read all the info on it here, using it mixed with an herbicide in spray equipment is not a risk I want to take on. Existing herbicides like regular Tenacity, Glyphosate, Ester of Triclopyr, Certainty, and Velocity are unquestionably safer to use.

I would consider spot spraying DMSO separately soon after a standard herbicide app, and letting it mix on the plant, but the weird physical properties of the chemical (becoming solid at 66F even though we want it in the liquid phase), and its strange cult following among certain groups, also put me off, so I'm unlikely to do even that.

That said, it would be my guess that the DMSO could be largely responsible for your success of Mesotrione on Triv.

I did find a study showing a tank mix of Tenacity, Xonerate, and a certain surfactant that I I can't recall, applied several times, could kill Triv. So, maybe if the price of Xonerate comes down, that would be a mix I might try someday.

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Re: Poa Triv Invasion Counter-offensive

Post by oze » May 8th, 2022, 7:05 pm

I'm going with the slow Velocity conversion campaign (2oz/acre/month through September). The invasion is so widespread that it would look horrible if I killed the triv invaders too quickly. Might get ugly anyway.

I should have an idea by July how Year 1 of the counter offensive is going. As of now, I'm thinking about doing some RPR plugs, and a Fall pre emerge, but not ruling out stopping the first year of chemical warfare a month early and overseeding. I'll try to remember update this "before" picture each month.

Image

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Re: Poa Triv Invasion Counter-offensive

Post by MorpheusPA » May 9th, 2022, 8:48 pm

I'm going to admit to using DMSO in my Tenacity here. This is one reason why it works so well, along with doggedly being...tenacious...with its use, and timing it well in April and May. I also avoid irrigation in areas that have any observed problems with invading P. annua or P. trivialis for that summer. If it fries, it fries--and so much the better if it does.

You do have to understand the risk--I strongly suggest gloves, long pants and sleeves, and doing this on a relatively windstill day. I wear Neoprene.

I only add about 1 Tbsp per gallon, however.

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Re: Poa Triv Invasion Counter-offensive

Post by Green » May 9th, 2022, 11:48 pm

Tenacious...lol.

Morph,

I am seriously going to try Methylated Seed Oil with my Tenacity on Triv, instead of nonionic surfactant. This is after reading a study showing it actually increased penetration through leaf tissue (not specifically in Poa species, just generally). Now, it may not be as effective as dimethyl sulfoxide, but it's something to try...and a lot safer for me.

Velocity is hit or miss (this is accepted by the experts). That's just how it goes. Some years it works well, other years not so much. I don't think that's why it was discontinued; it was one of the most effective herbicides against Triv when it worked, according to studies.

Certainty is pretty effective. Unfortunately, I have found what appear to be resistant strains of Poa Triv, for which it does not do much (even after 4 applications).

All this together is my reason for wanting to experiment more with Tenacity. Just not using DMSO. that's my hard limit. So, Methylated seed oil is going to be the next experiment. After that, probably Tenacity plus Triclopyr ester and no surfactant. Maybe some Topramezone will be in my future, too. Xonerate plus Tenacity plus a certain surfactant showed excellent control with several apps (as good as Certainty or Velocity when it works), but that is still on patent and way too expensive.

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Re: Poa Triv Invasion Counter-offensive

Post by Wally » May 10th, 2022, 7:25 am

edslawn wrote:
May 5th, 2022, 12:45 pm
Wally wrote:
May 4th, 2022, 7:34 am
Interesting article on the subject. Spring battle seems to work best overall. They had no success with Tenacity.

https://www.golfdom.com/an-integrated-s ... trivialis/
Interesting... and depressing :(
Smaller areas could be patched but larger areas? The lawn might have to take one for the team one season.

On the bright side, less mowing!

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Re: Poa Triv Invasion Counter-offensive

Post by oze » June 9th, 2022, 6:18 pm

Update:

Here's an updated picture, 30 days after the first application of Velocity. So far, the Velocity is starting to put a hurt on the Triv, with the Rye looking unaffected. Not part of my trial, but I have also added mechanical stress to an area that I also sprayed; I stood in a 10 x 5 foot area working on my chipping in the backyard. Triv *really hates* mechanical stress!

Image

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