# Fungus or Heat Stress



## KM1 (May 23, 2019)

Had a pretty high heat wave in the Chicago Area, I live in the suburbs. It got up to the mi to upper 90's, like 98, for the last several days, with heat indexes well into the 100's due to high humidity. During that time I had some brown spots develop in my lawn in a couple areas. The pictures below show what I am describing.

Now I have used Scotts DiseaseEX twice already this summer...once earlier in June, and most recently in early July. Not sure if this is just burnt grass from high heat or fungus.

Should I leave it alone and see what happens....or do I need to do something about this. The grass does not just pull out....but the entire blade is brown as shown.


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## keatingseeds (Jul 22, 2019)

Disease is a strong possibility with the temps and humidity levels in recent weeks. It looks like you Tall Fescue is doing very well through this summer stress period and you PRG and KBG are getting hit. Wide spread spot & patch diseases could be a sign of excess thatch layers, drought stress or improper Nitrogen fertilization. If the fungus is still active you be able to see the mycelium in the early mornings when there is dew. If not active it's no longer spreading and would not worry about it.

My philosophy on my lawn is that the strongest survive. When overseeding, new seed varieties should matter and be considered. New types and varieties are being introduced to the market with better disease packages, more drought tolerant, and take less inputs. Varieties of turf type tall fescues I've overseeded with in the past are Raindance, 4th Millennium, Rebounder, Rhambler II, and Saltillo. I usually try and blend at least 4 of those varieties with 10% of a Kentucky Bluegrass called Tirem.


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## corneliani (Apr 2, 2019)

Any lesions on the nearby blades? The ring shape says fungus, not as much heat stress. See if you can find any green blades that are beginning to show discoloration and post a pic.


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## KM1 (May 23, 2019)

corneliani said:


> Any lesions on the nearby blades? The ring shape says fungus, not as much heat stress. See if you can find any green blades that are beginning to show discoloration and post a pic.


Ok...below are 3 close ups of 3 different brown spots. Just used Disease Ex 2 weeks or so ago...maybe 3. These just showed up after the BIG heat wave. It is now cooled down to the low 80's high 70's.


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## tgreen (Oct 20, 2018)

The frogeye on the second pic bottom right could be summer patch on KBG which is a root disease. Really, impossible to diagnose based on pics. Could also be dollar spot. If it's summer patch root disease then not much you can do now. Does this pattern occur every year? If it were me, I'd probably just let it go and not treat it. Start running nitrogen hard in about 30 to 45 days and maybe throw out some seed to repair damage.


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## KM1 (May 23, 2019)

Ok....here are some early morning pics of my lawn as a whole....and closer ups of the damaged area. Not seeing any mycelium....but maybe I don't know what it looks like.

As far as a pattern every year.....depends. Really hot summers I've gotten brown like this, only A LOT more of it spread over more areas...only that was before I was personally taking better care of my lawn.

Will probably let it go and simply continue my program until fall (maybe up the Nitrogen when it cools down late summer, early fall). Then Aerate and over seed heavily, especially in damaged areas, with Johnathan Green's Black Beauty Fall Mix and starter fertilizer. Winterize fertilizer late October and see what happens.


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## rockinmylawn (Mar 25, 2018)

tgreen said:


> The frogeye on the second pic bottom right could be summer patch on KBG which is a root disease. Really, impossible to diagnose based on pics. Could also be dollar spot. If it's summer patch root disease then not much you can do now. Does this pattern occur every year? If it were me, I'd probably just let it go and not treat it. Start running nitrogen hard in about 30 to 45 days and maybe throw out some seed to repair damage.


Same as the OP.
Thought I had it covered since mid May using cycle of Azoxy/Cleary's/Eagle fungicide but same type of yellowing occurred where there is no lesions or spots to speak of.
Mine's though is in the same spot every year. 
I can maybe think it's heat stress by the sidewalk - though I irrigate very thoroughly & regularly.
But the other spots by the side edges of my yard, seems to get yellow every year & that gets irrigated completely also.

Might have to look into this summer patch root disease you speak of.


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## keatingseeds (Jul 22, 2019)

rockinmylawn said:


> tgreen said:
> 
> 
> > The frogeye on the second pic bottom right could be summer patch on KBG which is a root disease. Really, impossible to diagnose based on pics. Could also be dollar spot. If it's summer patch root disease then not much you can do now. Does this pattern occur every year? If it were me, I'd probably just let it go and not treat it. Start running nitrogen hard in about 30 to 45 days and maybe throw out some seed to repair damage.
> ...


If you have this problem year after year in the same area then it's more of a soil problem that is affecting the plant vs. the plant getting a disease. It could be as simple as compaction or thatch layer is too thick, then over time you could develop anaerobic conditions. Aerate and topdress could be a solution. Also, there is a new product on the market called C20 that will eat up you thatch layer naturally and make your soil more porous.


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## tgreen (Oct 20, 2018)

keatingseeds said:


> rockinmylawn said:
> 
> 
> > tgreen said:
> ...


"In turf stands where the disease has been established for several years, the infected areas have field patterns that resemble frogeye patches or arcs and rings of damaged turf." I'm not saying it is definitely summer patch but the frog eye could indicate disease. I would dig it up and send to a turf pathology lab for confirmation.

Also, isn't C20 basically ground up corn cobs, etc? I used it last year. Didn't notice any difference. Have you used it?

https://www.extension.purdue.edu/extmedia/BP/BP-115-W.pdf


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## KM1 (May 23, 2019)

Actually.....this is the first time I've seen that brown show up where it showed up...at least that I can remember. And if you look at the rest of my lawn....seems to be pretty good especially after that BAD heat spell we had, over the last several days, in the Chicago area.


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## keatingseeds (Jul 22, 2019)

tgreen said:


> keatingseeds said:
> 
> 
> > rockinmylawn said:
> ...


C20 is supposed to reduce soil bulk density, loosen soil for root penetration, reduce thatch, and enhance microbial activity in the soil. You might not see the benefits in the plant's leaf tissues, but you will see an improvement in you soil structure and you plants root development. In effect, this will help with drought tolerance, disease susceptibility, and other stress related issues. And it is 100% Organic.

I did see benefits with C20 on compacted soils that could not grow anything before adding C20 as a soil amendment.


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## g-man (Jun 15, 2017)

@keatingseeds do you have a study or images that show the improvement with C20?


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## rockinmylawn (Mar 25, 2018)

keatingseeds said:


> rockinmylawn said:
> 
> 
> > Same as the OP.
> ...


Yes - that is another thought I have had but my soil test didn't show anything odd in these spots & I made sure to test there.
That said, will soil tests address any of the mechanical issues - aeration/top dressing - that you mentioned?


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