# Heat Stress or Fungus?



## NanserbE (Jun 29, 2018)

Hi everyone,

First post here, long time lurker.

A little about my problem:

Lawn planted last year in Aug. in Western WA where it rains 8 months out of the year.
PRG and Fine Fescue mix, mowed at 3", blades just sharpened by me.
This last few weeks have been in and out of the 80's and into the 70's with high humidity.
I currently water 0.5" at a time every 3-4 days as weather dictates.
Nutrients were nearly all on target as of April via a soil test sent to SoilSavvy. I need to find potassium somewhere.
I did not put down a prophylactic fungicide treatment, I now know better.

I've been having random blades of grass throughout the lawn turn brown from the root upwards, most of it seems to be seed stalks. I've spot treated for red thread here and there, and treated for rust disease last year as well.

I figure this is a fungus problem, but it's not patchy like most fungal problems, it's literally everywhere across my lawns mixed in. I went ahead and did a foliar application of Propiconazole at 2oz/1000sqft, letting it dry. I just ordered some azoxystrobin granules (Scotts) to put down and see if that helps too.

I just want to see if I'm on the right path or not.

The second picture is of from some rust disease, but it's not typical pattern like it was last year.


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## g-man (Jun 15, 2017)

PRG develops seed stalks around this time of the year. It gets mowed and then dies. It looks ugly until the stalk goes away and could lead to fungus (hot/humid/dead material). I dont see anything concerning in the images.

The blades do look torn. Since you sharpen the blade, I would check your engine rpm. Grassdaddy has a video here that shows one method to measure rpm.


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## NanserbE (Jun 29, 2018)

Thanks! I had noticed that the seed stalks were most of the dead stuff causing the browning, but wasn't sure why. I appreciate your help! I may put down a second dose of fungicide anyhow for preventative, a bag of Scotts DiseasEX just showed up in the mail today.


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## Green (Dec 24, 2017)

I have the same situation with brown stalks and some dormant blades, and a touch of disease. It's summer now and it's hard to avoid if you have ryegrass.


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## NanserbE (Jun 29, 2018)

Is there anything I can do in the future to keep the brown stalks from dying off?

Mow more often? Taller or shorter? Fertilize more or less?


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## Green (Dec 24, 2017)

NanserbE said:


> Is there anything I can do in the future to keep the brown stalks from dying off?
> 
> Mow more often? Taller or shorter? Fertilize more or less?


I don't think there's much you can do. My lawn still has new ones growing!


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## g-man (Jun 15, 2017)

@Green so there is something we could do for seedhead suppression. Previous years seedheads were a minor problem for me, but this year I had more than I wanted.

The product is called ethephon (Proxy) and it is another plant regulator. It gets mixed with primo (t-nex) and applied prior to seedhead development to suppress them.

I think @HoosierLawnGnome uses it. Im likely going to buy some for next year.


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## MarkAguglia (Jul 13, 2017)

I've had a similar issue the last couple weeks. I think I had dying Poa but I bet its PRG also. I can tell you that a light raking and double bag mowing will help eradicate a lot if it. I did like you and used fungicide as well. My lawn is looking quite a bit better since doing so.


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## NanserbE (Jun 29, 2018)

g-man said:


> @Green so there is something we could do for seedhead suppression. Previous years seedheads were a minor problem for me, but this year I had more than I wanted.
> 
> The product is called ethephon (Proxy) and it is another plant regulator. It gets mixed with primo (t-nex) and applied prior to seedhead development to suppress them.
> 
> I think @HoosierLawnGnome uses it. Im likely going to buy some for next year.


How does PGR (Tnex) do on lawns with Ryegrass & Fine Fescue?

I've been considering trying it since it seems to do really well at "thickening" KBG and giving the lawn more lateral growth than vertical.


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## g-man (Jun 15, 2017)

T-nex works great on all lawns. You just have to find the right rate for your lawn. Start small and go up.


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## Green (Dec 24, 2017)

g-man said:


> @Green so there is something we could do for seedhead suppression. Previous years seedheads were a minor problem for me, but this year I had more than I wanted.
> 
> The product is called ethephon (Proxy) and it is another plant regulator. It gets mixed with primo (t-nex) and applied prior to seedhead development to suppress them.
> 
> I think @HoosierLawnGnome uses it. Im likely going to buy some for next year.


Your're right! And he does use it. Not my thing, but go for it!


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## Green (Dec 24, 2017)

g-man said:


> T-nex works great on all lawns. You just have to find the right rate for your lawn. Start small and go up.


Yeah. The first year I used it, I used full rate and had bad spray technique, so over regulated. This year I'm using lower rates. Still have to mow about once a week at 3.75 inch HOC, but less fungal issues so far compared to in the past.


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## NanserbE (Jun 29, 2018)

Is there a positive health response overall? Thicker? Greener? Fuller?

Or is it just that you end up having to mow less often?


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## Green (Dec 24, 2017)

NanserbE said:


> Is there a positive health response overall? Thicker? Greener? Fuller?
> 
> Or is it just that you end up having to mow less often?


It does tend to thicken the lawn noticeably, as well as darken the color.


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## g-man (Jun 15, 2017)

T-nex regulates top growth. But the plant is still collecting energy from the sun. This means that the chlorophyll production continues but it is not used in new leaf (since there is reduced grow). This causes the lawn to go darker green from the higher concentration of chlorophyll. The extra energy is used in the only area it can grow, root density.

While it all sounds great (less mowing, less use of nitrogen/water, darker color, more roots), there are some risks. If you need to grow out of a fungus or some damage (flag football in the backyard), it will be slower. Also, if you cant apply for some time there is a rebound effect, it grows really fast. The applications are around every 2-3 weeks, depending on the weather. Plus the only way to apply it is in liquid.


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## shadowlawnjutsu (Jun 9, 2020)

I applied PGR like 10 days ago while I had fungus stress in my lawn. It's not patchy but yellow blades are visible. I already have some dead blades from fungus before I applied PGR. I was thinking that PGR will promote lateral growth and green up so I just went ahead.

Now it's been 10 days I can see that some of the blades are greener but I can still see some yellow blades and it doesn't look like it had some lateral growth because it looks thin.

I'm planning to just wait for the rebound and then dethatch to take advantage of the vertical growth rebound.

Is that a good idea or should I just reapply and wait for the lateral growth?


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## Babameca (Jul 29, 2019)

@shadowlawnjutsu It is not a magic wand. You won't have a noticeable by a naked eye lateral growth in 1 week. If your fungi issue starts clearing up, just drop to 1/2 rate for next time. Getting off regulation and then back to regulation is a stress for your lawn. All the above mentioned benefits except of the slow growth (which hits in about 4-6 days) are taking weeks...


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## shadowlawnjutsu (Jun 9, 2020)

Got it, thanks! I'll follow the 1/2 rate. Does that mean if I have a prg/kbg/fescue mix, instead of .75 ounce/1000, I'll put in .375/1000?

I'll wait for few more weeks.


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