# Pythium Blight?



## Amcnabb (Apr 4, 2020)

I'll try again with better pictures. Do we think this is Pythium Blight?

It's Ryegrass, and had been very humid, warm and wet in the Midwest last week or two.


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## nclawnguy (Jun 27, 2017)

Looks like it to me.


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## CarolinaCuttin (Sep 6, 2019)

Need to rule out dollar spot definitively but yes it appears to be pythium blight.


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## ScottW (Sep 16, 2019)

Been looking at fungus ID pics too this morning. Couple spots in my lawn after we received >1" of rain the past couple of days.

Both PB and DS have that powdery white filamentous looking fungi. DS leaves characteristic lesions on the leaf tissue that I'm not really seeing in yours, but the pics aren't super close-up either.


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## jha4aamu (Oct 16, 2017)

Typically in the areas ive had PB before, the blades of grass will look slimy and are matted down. Cant really tell if thats the case with those pics.


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## g-man (Jun 15, 2017)

@Amcnabb your profile says kbg, but are saying prg.

It looks more like PB to me. Get your hands in there and see if it is wet, sticky and slimy.


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## Amcnabb (Apr 4, 2020)

g-man said:


> @Amcnabb your profile says kbg, but are saying prg.
> 
> It looks more like PB to me. Get your hands in there and see if it is wet, sticky and slimy.


Sorry, I have KBG front yard, all Ryegrass I'm back yard. I'll prod around and see what it feels like. I did spray propiconizole the other night. That fungus was really looking healthy and thriving this morning.


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## g-man (Jun 15, 2017)

Propi won't help with PB. Check the fungicide guide for products. I will mess up and tell you one that is for homeowner use. I'm pretty sure azoxy covers PB.


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## Amcnabb (Apr 4, 2020)

g-man said:


> Propi won't help with PB. Check the fungicide guide for products. I will mess up and tell you one that is for homeowner use. I'm pretty sure azoxy covers PB.





g-man said:


> Propi won't help with PB. Check the fungicide guide for products. I will mess up and tell you one that is for homeowner use. I'm pretty sure azoxy covers PB.


Azoxysteobin appears to treat. Is liquid or granular better in this case? Thanks for the input BTW


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## g-man (Jun 15, 2017)

Use what you have at hand.


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## nclawnguy (Jun 27, 2017)

Azoxystrobin is good but more of a preventative, Mefenoxam is better curing PB from my experience. I keep some on hand for pithium blight, don't use it that often. My last house had more of an issue with it.

I agree if Azoxystrobin is what you have on hand, use it.


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## CarolinaCuttin (Sep 6, 2019)

nclawnguy said:


> Azoxystrobin is good but more of a preventative, Mefenoxam is better curing PB from my experience. I keep some on hand for pithium blight, don't use it that often. My last house had more of an issue with it.
> 
> I agree if Azoxystrobin is what you have on hand, use it.


+1

Mefenoxam (Subdue Maxx) and cyzamofid (Segway) are the industry leaders for pythium.


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## Scagfreedom48z+ (Oct 6, 2018)

CarolinaCuttin said:


> nclawnguy said:
> 
> 
> > Azoxystrobin is good but more of a preventative, Mefenoxam is better curing PB from my experience. I keep some on hand for pithium blight, don't use it that often. My last house had more of an issue with it.
> ...


Have you ever combined subdue maxx with Azoxy with any adverse reactions as a preventative?


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## CarolinaCuttin (Sep 6, 2019)

@Scagfreedom48z+ I have not personally mixed these two, but it's a good idea to either rotate fungicides or tank mix them to prevent resistance. As far I know there is no evidence that spraying fungicide A and then next time spraying fungicide B is a better or worse method than tank mixing A and B. As long as you aren't using mixing DMIs and you read the labels you should be fine tank mixing fungicides of different groups.


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## Amcnabb (Apr 4, 2020)

nclawnguy said:


> Azoxystrobin is good but more of a preventative, Mefenoxam is better curing PB from my experience. I keep some on hand for pithium blight, don't use it that often. My last house had more of an issue with it.
> 
> I agree if Azoxystrobin is what you have on hand, use it.


I had some disease ex on hand and put it down. Unfortunately only 10lbs over 4K sq ft. I bought some subdue max this AM and it's somewhat pricey; however after looking at mixing rates it seems you can use .5-1 oz per thousand in 2 gallons. So that's not terrible for a quart. Hope it gets here in time before it destroys the whole lawn.


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## g-man (Jun 15, 2017)

Water in the diseasex. I think you caught it on time.


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## Amcnabb (Apr 4, 2020)

g-man said:


> Water in the diseasex. I think you caught it on time.





g-man said:


> Water in the diseasex. I think you caught it on time.


Roger that


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## Scagfreedom48z+ (Oct 6, 2018)

CarolinaCuttin said:


> @Scagfreedom48z+ I have not personally mixed these two, but it's a good idea to either rotate fungicides or tank mix them to prevent resistance. As far I know there is no evidence that spraying fungicide A and then next time spraying fungicide B is a better or worse method than tank mixing A and B. As long as you aren't using mixing DMIs and you read the labels you should be fine tank mixing fungicides of different groups.


I just bought some from domyown. It's recommended to combine it with propriconozole for broader fungus coverage. I'm glad I read up on this thread. I didn't realize there was a better fungicide that can tackle PB. I currently have azoxy, prop, clearys in my arsenal.


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## SJ Lawn (May 7, 2018)

Consider a product called TKO Phosphite or a similar product for preventative use down the road. Not known to encounter resistance using it. Also "enhances" turf quality too.

Here's an article: https://turf.unl.edu/NebGuides/Pythium.pdf

Also: https://www.pitchcare.com/news-media/phosphite-whats-all-the-fuzz-about.html


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## CarolinaCuttin (Sep 6, 2019)

SJ Lawn said:


> Consider a product called TKO Phosphite or a similar product for preventative use down the road. Not known to encounter resistance using it. Also "enhances" turf quality too.
> 
> Here's an article: https://turf.unl.edu/NebGuides/Pythium.pdf
> 
> Also: https://www.pitchcare.com/news-media/phosphite-whats-all-the-fuzz-about.html


THIS. Great post. It won't work in this situation because it's only a preventative but for the average homeowner this is the type of product that should be used for preventing pythium.


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## troksd (Jul 27, 2018)

In a pinch use 1 cup of 3% peroxide to 1 gallon of water. I routinely use peroxide as part of my fungicide program.


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## Scagfreedom48z+ (Oct 6, 2018)

troksd said:


> In a pinch use 1 cup of 3% peroxide to 1 gallon of water. I routinely use peroxide as part of my fungicide program.


You've got me curious with this. I've been on top of my fungicide apps this year. Applied 2 rounds of prop/Azoxy at a preventative rate, prior to the 28 day deadline. We got nailed with a week of heavy humidity and wham, grass looks like complete crap. I've got brown patches and dead strands of grass showing up. Which makes me think it's PB. How quick does the peroxide and water app work? What's the duration?


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## troksd (Jul 27, 2018)

In my opinion, it works instantly. Think of this as a contact killer. For Pythium Blight, 2 to 3 times a week will stop the spread. It'll also aerate that slimy mess of grass.



Scagfreedom48z+ said:


> How quick does the peroxide and water app work? What's the duration?


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## Scagfreedom48z+ (Oct 6, 2018)

troksd said:


> In my opinion, it works instantly. Think of this as a contact killer. For Pythium Blight, 2 to 3 times a week will stop the spread. It'll also aerate that slimy mess of grass.
> 
> 
> 
> ...


How many side looks will I get walking out of the drug store with 15 bottles of hydrogen peroxide. So a cup per gallon? Can I apply it during the day at any time? :shock:


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## troksd (Jul 27, 2018)

So peroxide is used in gardening as a fungicide/soil aerator. Most gardeners use it during the evening. I have never exceeded 1 cup/gallon of water when spraying the lawn.



Scagfreedom48z+ said:


> Can I apply it during the day at any time? :shock:


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## Scagfreedom48z+ (Oct 6, 2018)

troksd said:


> So peroxide is used in gardening as a fungicide/soil aerator. Most gardeners use it during the evening. I have never exceeded 1 cup/gallon of water when spraying the lawn.
> 
> 
> 
> ...


I've got Mefenoxam coming from domyown, but for the cheap price of Hydrogen Peroxide, I'm going to give it a try. This is great to know for the future.

Do it work with any turf fungus?


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## troksd (Jul 27, 2018)

I use it as a supplement, not as a replacement.



Scagfreedom48z+ said:


> I've got Mefenoxam coming from domyown, but for the cheap price of Hydrogen Peroxide, I'm going to give it a try. This is great to know for the future.
> 
> Do it work with any turf fungus?


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## Scagfreedom48z+ (Oct 6, 2018)

CarolinaCuttin said:


> @Scagfreedom48z+ I have not personally mixed these two, but it's a good idea to either rotate fungicides or tank mix them to prevent resistance. As far I know there is no evidence that spraying fungicide A and then next time spraying fungicide B is a better or worse method than tank mixing A and B. As long as you aren't using mixing DMIs and you read the labels you should be fine tank mixing fungicides of different groups.


My qualipro mefenoxam arrived today. The directions for use is a little confusing.
I'm applying to established turf, not newly seeded lawn. Am I suppose to water this in after application or leave it on the foliage for a certain time?


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## ScottW (Sep 16, 2019)

The label says for established turf to use 0.2 to 1.0 oz in 1-5 gallons of water per 1000 sqft. 
They don't spell it out in the turf section of the label, but that much water suggests they are intending it to be mainly a soil application.

Elsewhere in the label it actually says this:


> APPLICATION INSTRUCTIONS (GENERAL)
> Apply Quali-Pro Mefenoxam 2 AQ by ground in sufficient water or liquid fertilizer to provide uniform coverage of the soil surface


and this:


> Do not make foliar applications unless specified since this practice may encourage
> more rapid development of insensitivity.


I would water it in after spraying.


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## Scagfreedom48z+ (Oct 6, 2018)

ScottW said:


> The label says for established turf to use 0.2 to 1.0 oz in 1-5 gallons of water per 1000 sqft.
> They don't spell it out in the turf section of the label, but that much water suggests they are intending it to be mainly a soil application.
> 
> Elsewhere in the label it actually says this:
> ...


That's exactly what I read myself. I read the vast amounts of water that can be used for the app but nothing that spelt anything out clearly. I can't apply anything over 2 gallon per 1M, for 30M that would be an all day affair.
I'll just apply gallon per 1M and water it in heavily with the irrigation.


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## CarolinaCuttin (Sep 6, 2019)

@Scagfreedom48z+ You can do whatever you want but you should absolutely apply this as a foliar spray and not water it in. You spray it on the leaf blade for pythium blight and water it in for pythium root rot.


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## Scagfreedom48z+ (Oct 6, 2018)

CarolinaCuttin said:


> @Scagfreedom48z+ You can do whatever you want but you should absolutely apply this as a foliar spray and not water it in. You spray it on the leaf blade for pythium blight and water it in for pythium root rot.


Interesting. How are you able to tell the difference between one and the other in terms of characteristics?


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## CarolinaCuttin (Sep 6, 2019)

@Scagfreedom48z+ Blight is on top, it's attacking the foliage and you can see the cottony growth in the morning dew. Both result in turf death. Pythium root rot is going to result in black roots of infected turf upon pulling a core.


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## NHlawn00 (7 mo ago)

Hello,

New to the forum and lawn care. Just purchased our first home and did a complete renovation and Swedes with Jonathan green ultra.. things were going well and I was filling in some patches but overwatered at night (I work until 2am) and I think I have Pythium. I sprayed prop/azoxy two days ago when I noticed it and ordered mefenoxam that should be here today. I emailed the extension office too. Can you guys look at these pics and let
Me know if I'm on the right track and if I should do anything else?

I have some seedlings in areas I'm not sure if this is too much for them.


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