Yellowing in known problem area

Kentucky bluegrass, Fescue, Rye and Bent, etc
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Adam_M
Posts: 75
Joined: April 22nd, 2017, 12:29 pm
Location: Southwest PA
Grass Type: Midnight, Bewitched, Prosperity
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Yellowing in known problem area

Post by Adam_M » May 21st, 2020, 7:51 pm

Hi!

I'm not sure what's going on in this area. It's on top of a very small high spot, and is one of the areas the perpetually gets hit with what I think is summer patch in July/August, but declining this early is new. I didn't start the companion/serenade yet - although it was in the works for the weekend.

This doesn't look like summer patch, and it's not warm enough for it anyway, so any other ideas what could be happening and suggested course of action?

So far, this year:
10-20-20 Late April 1/2lb N/k (Grass was awake)
Milo 1 week later (followed by a cold spell, so I bet it just sat there)
Top dressed with 32 bags of peat moss. the next week. ugh.
19-19-19 last weekend (4 weeks from the 10-20-20) 1lb N/k

We've had plenty of water, but we haven't had rain for a couple days. Temperatures are in the 60's.

All mowing this year has been at 2.75", but as the grass has finally decided to start the spring flush, I'm taking it up to 3.25" this mowing and up to 3.75" before the heat really sets in.

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Adam_M
Posts: 75
Joined: April 22nd, 2017, 12:29 pm
Location: Southwest PA
Grass Type: Midnight, Bewitched, Prosperity
Lawn Size: 10000-20000
Level: Some Experience

Re: Yellowing in known problem area

Post by Adam_M » May 22nd, 2020, 3:29 pm

It got worse today, so I pulled a few leaves off and pulled one plant up to see the roots and did some reading.

It seems like it could be: Melting out (caused by Bipolaris sorokiniana) based on this paper from Purdue:
https://www.extension.purdue.edu/extmed ... -103-w.pdf
typically appears in April and May during cold,rainy weather. High nitrogen fertilization during the middle weeks of spring also favor the disease.

It's May, Cold, rainy, and I just put down some Nitrogen.

The linked paper recommends Heritage (among others) and I have a bag of disease Ex, which has the same AI, here.

Seem like a reasonable plan to drop Disease Ex at a curative rate?

I also had plans for a dose of Milo + boron this weekend - should I hold off on that?

Thanks!


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LeftField11
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Joined: July 25th, 2016, 10:30 am
Location: South Central PA - zone 6b
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Re: Yellowing in known problem area

Post by LeftField11 » May 22nd, 2020, 4:29 pm

I'm dealing with the same thing here in south central PA, and I've also come to the conclusion that it's leaf spot / melting out. I treated it a week ago with propiconazole based on a recommendation from this forum, but this source says azoxystrobin (Heritage, DiseaseEX) is more effective, http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf.

Since the application of propiconazole, my situation has not worsened. Yesterday I sprayed Serenade at 4 oz. / 1000 sf. I figured that for $100 I could buy enough Serenade to treat my lawn in a preventative measure all summer (2.5 gallons from Seven Springs Farms). One application of fungicide costs almost as much. And the Serenade isn't going to hurt anything.

My lawn also needs some fertilizer right now and I wasn't sure how to handle that. Yesterday I put down a Milo knock-off (ProActive) at a rate of about .8 lbs N / 1000 sf. My thought is that it's slow-release so hopefully it won't worsen the melting out. We'll see.

Temps go up next week and it looks dryer, I'm hoping that helps to clear up the melting out. Since my reno in 2016 I've never actively dealt with fungus, I always let it run it's course, and I always regretted that. So I'm very much experimenting my way through this, don't take anything I say as guidance, I'm generally just commiserating with you.

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bernstem
Posts: 4230
Joined: April 15th, 2011, 2:59 pm
Location: St. Louis, MO
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Re: Yellowing in known problem area

Post by bernstem » May 23rd, 2020, 10:07 am

Leaf spot seems to be very common this year and right now. Summer Patch would be early, but if it has been very dry you could be seeing some. Ideal treatment window for Summer Patch is early spring. The fungus does its damage to roots then, but you don't see it until it gets hot as the turf is able to compensate with lower temperatures and generally wetter conditions.

mvftw
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Re: Yellowing in known problem area

Post by mvftw » May 27th, 2020, 1:07 pm

Would Prophesy fungicide (0.72% propiconazole) be good for this...

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