PGR via low rate glyphosate

Cool season grasses like Kentucky Bluegrass, Fescue & Rye
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kmw
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PGR via low rate glyphosate

Post by kmw »

Doing some nightly google scholar reading and came across the following article about using low rates of Glyphosate as a growth regulator: https://www.scielo.br/scielo.php?script ... 9000100158.

Anyone heard of this? I'd prefer safer, and/or more widely tested, PGRs, but the concept is interesting.

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Re: PGR via low rate glyphosate

Post by Green »

Legend has it, the goal was to make a PGR, but it worked great for killing stuff at high rate, so it was marketed that way. Something like that, or so the story goes. Not sure how true it is.

Lots of stuff acts as a PGR, but turf quality can really suffer. An example is Certainty Herbicide (no longer labeled for cool season turf due to undesirable injury being reported).
Front: Northern mix - mostly TTTF, KBG, TTPR. Back: Firecracker and Bullseye TTTF with America, Rugby 2, Bewitched KBG. Upper Side: Mostly TTPR, KBG. Lower Side: similar to front. Low-input: TF/FF, KBG, PR. Always seeding somewhere or fighting Triv.

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Re: PGR via low rate glyphosate

Post by kmw »

So it's the inverse of the sticky note origin story? Nice.

Anyway for KBG at least it's hard to ignore the positive studies about T-Nex, e.g., https://acsess.onlinelibrary.wiley.com/ ... NKm6tjyoJ8. Spoiler: not only does it slow growth...it actually improves the visual quality of the turf!

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Re: PGR via low rate glyphosate

Post by bernstem »

It will work, but the margin for error is probably pretty small and I expect you would see phytotoxicity at a dose that would regulate growth.

Trinexepac-ethyl works well with a good safety margin because it is targeted at the pathway in the plant that regulates growth. It doesn't affect other cellular processes to a great degree. Glyphosate stops DNA synthesis and has much broader effects on cellular metabolism.
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kmw
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Re: PGR via low rate glyphosate

Post by kmw »

bernstem wrote:
Wed Jul 01, 2020 6:37 am
It will work, but the margin for error is probably pretty small and I expect you would see phytotoxicity at a dose that would regulate growth.

Trinexepac-ethyl works well with a good safety margin because it is targeted at the pathway in the plant that regulates growth. It doesn't affect other cellular processes to a great degree. Glyphosate stops DNA synthesis and has much broader effects on cellular metabolism.
I was starting to wonder if high-rate applications of trinexepac would act like glyphostate, but your explanation helps me understand why that wouldn't be the case.

This still makes me wonder what other side effects may exist from common herbicide/fungicide sprays. 🤔

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Re: PGR via low rate glyphosate

Post by Green »

kmw wrote:
Wed Jul 01, 2020 9:52 am
This still makes me wonder what other side effects may exist from common herbicide/fungicide sprays. 🤔
A lot of the fungicides and some of the specialty herbicides act as PGRs. Also, at least one PGR has some selective herbicide properties from what I hear. The effects combine when used together.

I once made the mistake of combining Headway fungicide with T-pac on drought stressed/partly dormant grass. Needless to say, I didn't mow for about a month after.
Front: Northern mix - mostly TTTF, KBG, TTPR. Back: Firecracker and Bullseye TTTF with America, Rugby 2, Bewitched KBG. Upper Side: Mostly TTPR, KBG. Lower Side: similar to front. Low-input: TF/FF, KBG, PR. Always seeding somewhere or fighting Triv.

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Re: PGR via low rate glyphosate

Post by Kmartel »

kmw wrote:
Wed Jul 01, 2020 9:52 am
bernstem wrote:
Wed Jul 01, 2020 6:37 am
It will work, but the margin for error is probably pretty small and I expect you would see phytotoxicity at a dose that would regulate growth.

Trinexepac-ethyl works well with a good safety margin because it is targeted at the pathway in the plant that regulates growth. It doesn't affect other cellular processes to a great degree. Glyphosate stops DNA synthesis and has much broader effects on cellular metabolism.
I was starting to wonder if high-rate applications of trinexepac would act like glyphostate, but your explanation helps me understand why that wouldn't be the case.

This still makes me wonder what other side effects may exist from common herbicide/fungicide sprays. 🤔
Don’t be confused primo can kill your turf at a high enough rate!

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