PGR to Suppress Annua?

Kentucky bluegrass, Fescue, Rye and Bent, etc
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oze
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PGR to Suppress Annua?

Post by oze » April 26th, 2016, 8:34 am

This, I'm sure, falls squarely in the middle of the "too good go be true" category, but I want to see what y'all think or have heard of this. I was looking into PGRs, and came across this generic brand of Sygenta's Trimmit 2SC: http://utaarmortech.com/products/growth-regulators (22% Paclobutrazol). According to the Sell Sheet, the product will, among other things, "Suppress Poa annua in bentgrass and perennial ryegrass greens, fairways and tees". Now, my lawn is far from any of those, but that sure sounds promising in my mostly rye lawn. I'll continue to look, but if any of you experts around here have any input, I sure would appreciate it. Tanks!

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Re: PGR to Suppress Annua?

Post by probasesteal » April 26th, 2016, 10:38 am

I asked this question about PGR and seedhead prevention, here was OSUTurfman's response:
T-Pac alone will not suppress seedheads. You would need to add another PGR known as Proxy to your mix and make two apps, two weeks apart. See my post to HLG from last year regarding Primo/Proxy

http://aroundtheyard.com/northern/kbg-s ... xy#p217720

Embark would TOAST your TTTF with one app. There are not many tolerant grasses out there, with creeping bentgrass and Poa annua being the two predominant grasses that are.

If you are trying to get rid of Poa annua I would recommend not trying to suppress seedheads. While this may sound counter-intuitive the idea behind it is simple. Seedhead production in any plant takes a significant amount of energy to complete and when we suppress seedheads (and top growth as a result) all that energy that was going to be used for seedhead production suddenly helps grow roots. Those roots can then help some of those Poa annua plants survive the summer (less likely in NC but more likely further north) and on into fall.

By not supressing seedheads, you now have a plant that is in a energy-stressed state heading into a time where the weather should be heating up nicely for you. Whether or not you spray Tenacity, shut the water off the first one or two dry stretches where temps are consistently in the 80's. Poa annua will begin to die out under those types of conditions.

For all the talk about Poa annua control on here and at the professional level, the best control out there is hand removal. Using Tenacity to highlight plants is a great way to mark your target. If you stay on top of it maybe once every month or two you should be able to get the Poa annua out with a pocket knife pretty easily. Plugging it out and transplanting with plugs from out-of-the-way areas of your lawn or pots are several great ways to stay ahead of it.
Here was the thread where the question was asked http://aroundtheyard.com/post260556.html#p260556 and he provided a link above.

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Re: PGR to Suppress Annua?

Post by osuturfman » April 26th, 2016, 11:46 am

Paclobutrazol will absolutely suppress Poa annua and reduce populations significantly over the course of several years, if used properly and aggressively. However, there are a couple things working against you on using this product:

- It is not labeled for residential lawns and states that very clearly on the label.

- Some cultivars of Kentucky Bluegrass and Perennial Ryegrass are very tolerant while others are not at all tolerant to paclobutrazol. You could very well injure or kill desirable grasses and not know until it's too late.

It's a damn good product that is used widely on golf turf for the exact reason you specified. That said, it might not be the best product on a home lawn for reasons listed above.

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Re: PGR to Suppress Annua?

Post by ligrass » April 26th, 2016, 12:06 pm

What's the difference between Proxy and Primo/Tpac ?

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Re: PGR to Suppress Annua?

Post by oze » April 26th, 2016, 12:16 pm

osuturfman wrote:Paclobutrazol will absolutely suppress Poa annua and reduce populations significantly over the course of several years, if used properly and aggressively. However, there are a couple things working against you on using this product:

- It is not labeled for residential lawns and states that very clearly on the label.

- Some cultivars of Kentucky Bluegrass and Perennial Ryegrass are very tolerant while others are not at all tolerant to paclobutrazol. You could very well injure or kill desirable grasses and not know until it's too late.

It's a damn good product that is used widely on golf turf for the exact reason you specified. That said, it might not be the best product on a home lawn for reasons listed above.
...and it's not cheap, either!!!!
Damn, I knew it was too good to be true!
Thanks for the informative (as usual) reply, OSU! :hello:


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Re: PGR to Suppress Annua?

Post by osuturfman » April 26th, 2016, 2:20 pm

ligrass wrote:What's the difference between Proxy and Primo/Tpac ?
Great question!

The most simple answer is they each target different parts of the plant's natural growth cycle. I'll break it down below.

Proxy (ethephon) works by accelerating the release of ethylene in the plant. Why is this important? Ethylene is nature's ripening agent. When those green bananas are sitting in a giant warehouse somewhere they don't look very appealing. So right before they go to the supermarket, they pump the room full of ethylene to get the bananas to the perfect color of yellow, which is a byproduct of ripeness.

What does this mean for turf? Proxy is typically used in combination with Primo/T-Pac to suppress seedhead production in Poa annua or Kentucky Bluegrass. The way this works is by accelerating ethylene with the Proxy to rapidly increase how quickly the inflorescence, or seedheads, develop. Couple that effect with a reduction of the main plant hormone for tissue growth, gibberillic acid, with Primo and you have some very tiny, perhaps unnoticeable seedheads.

Using Proxy by itself is not something that is typically done due to the medium to long term changes in the physiology of the plant. Namely, the stimulation of ethylene makes for shorter leaf blades that are closer to the crown of the plant. Even at mowing heights of 2"-2.5" this can lead to a scalped look over portions of the turf. This is not to say that it could not be done but, one must use caution and be observant if they choose to go this route.

Primo/T-Pac works in a much different way. As I alluded to above, Primo/T-Pac works to inhibit the production of gibberillic acid in the plant. Again, gibberillic acid is a plant hormone that the plant produces on it's own to grow green tissue. By inhibiting the plant's synthesis of gibberillic acid, the energy the plant has must be used or stored. If the plant is under heat stress that energy may go to respiration and transpiration, which are normal physiological processes. If the plant is not under stress that energy can be stored in roots as carbohydrate reserves.

The big part of the reason the "rebound effect" exists with Primo/T-Pac exists is because the energy of the plant does not diminish while under regulation. It's the reduction in gibberillic acid that ultimately regulates turf growth after an application. Once the chemical is no longer present in the plant, that energy shifts from other uses/carbohydrate storage right into gibberillic acid production. Hence the growth surge typically seen coming out of regulation.

Hopefully that helps differentiate between the two you mentioned. If you have questions, let me know.
Last edited by osuturfman on April 26th, 2016, 2:35 pm, edited 1 time in total.

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Re: PGR to Suppress Annua?

Post by osuturfman » April 26th, 2016, 2:23 pm

oze wrote:
osuturfman wrote:Paclobutrazol will absolutely suppress Poa annua and reduce populations significantly over the course of several years, if used properly and aggressively. However, there are a couple things working against you on using this product:

- It is not labeled for residential lawns and states that very clearly on the label.

- Some cultivars of Kentucky Bluegrass and Perennial Ryegrass are very tolerant while others are not at all tolerant to paclobutrazol. You could very well injure or kill desirable grasses and not know until it's too late.

It's a damn good product that is used widely on golf turf for the exact reason you specified. That said, it might not be the best product on a home lawn for reasons listed above.
...and it's not cheap, either!!!!
Damn, I knew it was too good to be true!
Thanks for the informative (as usual) reply, OSU! :hello:
It is expensive but it goes down at rates significantly lower than even Primo. A high rate of paclobutrazol would be 16-24 fl oz per ACRE. That gallon goes a long, long way.

Now if you can just get your lawn re-zoned to commercial you'll be all set. Who says you can't fight City Hall?

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Re: PGR to Suppress Annua?

Post by oze » April 26th, 2016, 3:55 pm

osuturfman wrote:
It is expensive but it goes down at rates significantly lower than even Primo. A high rate of paclobutrazol would be 16-24 fl oz per ACRE. That gallon goes a long, long way.

Now if you can just get your lawn re-zoned to commercial you'll be all set. Who says you can't fight City Hall?
So sad, OSU. I did get the impression that the person at the store which shall remain nameless would have sold me the product if I hadn't balked at the price. I'm glad that I did hesitate, and that you have set me straight on not being allowed to use it on my lawn. I shudder to think of the black helicopters hovering over my yard.

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Re: PGR to Suppress Annua?

Post by osuturfman » April 26th, 2016, 4:25 pm

oze wrote:
osuturfman wrote:
It is expensive but it goes down at rates significantly lower than even Primo. A high rate of paclobutrazol would be 16-24 fl oz per ACRE. That gallon goes a long, long way.

Now if you can just get your lawn re-zoned to commercial you'll be all set. Who says you can't fight City Hall?
So sad, OSU. I did get the impression that the person at the store which shall remain nameless would have sold me the product if I hadn't balked at the price. I'm glad that I did hesitate, and that you have set me straight on not being allowed to use it on my lawn. I shudder to think of the black helicopters hovering over my yard.
Yep, they can sell anything that's not restricted use to anyone in most states. It's up to the end-user to read, follow, and obey the label.

Glad I could be of assistance.

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Re: PGR to Suppress Annua?

Post by probasesteal » April 26th, 2016, 5:48 pm

Thanks for the post OSU.

[ Post made via Android ] Image

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Re: PGR to Suppress Annua?

Post by ligrass » April 26th, 2016, 9:07 pm

osuturfman wrote:
ligrass wrote:What's the difference between Proxy and Primo/Tpac ?
Great question!

The most simple answer is they each target different parts of the plant's natural growth cycle. I'll break it down below.

Proxy (ethephon) works by accelerating the release of ethylene in the plant. Why is this important? Ethylene is nature's ripening agent. When those green bananas are sitting in a giant warehouse somewhere they don't look very appealing. So right before they go to the supermarket, they pump the room full of ethylene to get the bananas to the perfect color of yellow, which is a byproduct of ripeness.

What does this mean for turf? Proxy is typically used in combination with Primo/T-Pac to suppress seedhead production in Poa annua or Kentucky Bluegrass. The way this works is by accelerating ethylene with the Proxy to rapidly increase how quickly the inflorescence, or seedheads, develop. Couple that effect with a reduction of the main plant hormone for tissue growth, gibberillic acid, with Primo and you have some very tiny, perhaps unnoticeable seedheads.

Using Proxy by itself is not something that is typically done due to the medium to long term changes in the physiology of the plant. Namely, the stimulation of ethylene makes for shorter leaf blades that are closer to the crown of the plant. Even at mowing heights of 2"-2.5" this can lead to a scalped look over portions of the turf. This is not to say that it could not be done but, one must use caution and be observant if they choose to go this route.

Primo/T-Pac works in a much different way. As I alluded to above, Primo/T-Pac works to inhibit the production of gibberillic acid in the plant. Again, gibberillic acid is a plant hormone that the plant produces on it's own to grow green tissue. By inhibiting the plant's synthesis of gibberillic acid, the energy the plant has must be used or stored. If the plant is under heat stress that energy may go to respiration and transpiration, which are normal physiological processes. If the plant is not under stress that energy can be stored in roots as carbohydrate reserves.

The big part of the reason the "rebound effect" exists with Primo/T-Pac exists is because the energy of the plant does not diminish while under regulation. It's the reduction in gibberillic acid that ultimately regulates turf growth after an application. Once the chemical is no longer present in the plant, that energy shifts from other uses/carbohydrate storage right into gibberillic acid production. Hence the growth surge typically seen coming out of regulation.

Hopefully that helps differentiate between the two you mentioned. If you have questions, let me know.
Excellent explanation that Mr. Google couldn't come close to matching. Thank you!

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Re: PGR to Suppress Annua?

Post by LoneRanger » April 27th, 2016, 1:26 am

Yep. Always "layn sum noledg on yo azz".

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Re: PGR to Suppress Annua?

Post by oze » April 27th, 2016, 8:42 am

ligrass wrote:
Excellent explanation that Mr. Google couldn't come close to matching. Thank you!
Well put, LI! Although I do make use of the site donations bucket http://aroundtheyard.com/site-questions ... t2197.html, I think that there should be a separate, additional bucket for many of the really expert members here who offer such outstanding advice. You know who you are! THANKS AGAIN to you all! :clapping:

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Re: PGR to Suppress Annua?

Post by oze » May 3rd, 2016, 5:49 pm

I chickened out and bought a gallon of the generic Primo Maxx, and am sticking with the slow transition rates of Velocity. Baby.

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Re: PGR to Suppress Annua?

Post by probasesteal » May 6th, 2016, 12:33 pm

I'm happy to report that after spraying T-pac on my front yard I have seen about an 75% reduction in seed heads on the Poa annua. The seedheads typically drive me to mow every 2-4 days, but at 5 days after mowing very few are now visible. I realize this may slow down the eventual death of Poa, but I'm all about spring gratification...
It was unseasonably hot the last week, I suppose that could have something to do with it also.

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