# Fungicide in Fall or Spring



## Getoffmylawn (Sep 6, 2018)

My nomix lawn has several soccer ball sized brown patches. I aerated/overseeded in late August and have been watering frequently to germinate the new seed. I suspect the brown patches are fungus. Temps just dropped from mid 80's to the 50's this week (Indianapolis)and the extended shows 30's at night. Will the temps alone stop any fungus progressions? I am debating whether to treat with propiconazole now or wait until next spring.





Third pic shows neighbors yard, brown spot has been there since mid summer and is creeping my direction.


----------



## g-man (Jun 15, 2017)

Welcome to TLF

I will suspect you actually had dollar spot. We got hit hard with it a week or so ago (the hot. and foggy am we had). Post an image to confirm.

Mine has a ton of it and most of the neighbors too. The cure now is to push new grow with nitrogen, but our cold cloudy days are not helping. Drop some nitrogen and let hope things warm up again. Our lawns typically still grow until the first week of December.


----------



## Avalawn T (Sep 11, 2018)

I would still like to know about the temperature and fungus question too please. I have new seedlings coming in and the weather has finally cooled off. Should I still be worried or are the temps in my favor? Thanks


----------



## g-man (Jun 15, 2017)

@Avalawn T I don't recall seeing a chart/table that shows the fungus as a function of temperature. Now that temps have dropped, I worry about rust in a new grass.


----------



## Green (Dec 24, 2017)

g-man said:


> Our lawns typically still grow until the first week of December.


@g-man, I've been posting the same a lot lately as I answer questions. So we are the same...I typically have growth until early Dec. as well. I always thought our climates were similar (similar lattitude), and this is more evidence.


----------



## g-man (Jun 15, 2017)

I was wrong. That's not dollar spot. I can't zoom in enough. It looks like Pythium blight

Read more at: https://www.turffiles.ncsu.edu/diseases-in-turf/pythium-blight-in-turf/

I would treat it.


----------



## Deere Jr (Dec 7, 2017)

I would use propiconazole. That fungicide is also good at preventing snow mold.


----------



## MarkAguglia (Jul 13, 2017)

Deere Jr said:


> I would use propiconazole. That fungicide is also good at preventing snow mold.


So a fall app would help prevent snow mold in Spring? If so i'd like to try it, I got snow mold so bad last year..


----------



## craigdt (Apr 21, 2018)

MarkAguglia said:


> Deere Jr said:
> 
> 
> > I would use propiconazole. That fungicide is also good at preventing snow mold.
> ...


I dont think it lasts quite that long... We'll wait for the experts, but I think you'd want to apply it several times for winter-long protection.

But, of course, you generally want to rotate fungicides to avoid resistance.

A very nice fellow, *ahem*, is selling small bottles of popiconazole at prices that are very good value in the marketplace, if you are interested. Its dropped to the second page now.


----------



## Deere Jr (Dec 7, 2017)

If you wait as long as possible to spray it down, but before the snow comes, it will still be effective. Here in central MN, I watch the forecast in mid November for a snow and apply it the day before. Ideally, it won't leech into the soil much as the ground is starting the freeze.


----------



## MarkAguglia (Jul 13, 2017)

craigdt said:


> MarkAguglia said:
> 
> 
> > Deere Jr said:
> ...


Thanks! I'd love to hear someone chime in on this. I have some propiconazole already but thanks for the heads up on that too!


----------



## Getoffmylawn (Sep 6, 2018)

I chose to hit it with propiconazole at label rate for dollar spot/brown patch as an experiment. I have not found sufficient evidence to support treating this fall vs. waiting until next year. I suppose worst case it will do little except provide limited protection from rust and snow mold. Propiconazole is not labeled to treat pythium blight as earlier suggested so I may need to add a different treatment next season.


----------



## g-man (Jun 15, 2017)

Read the fungicide guide in my signature. SJL posted some rotations.


----------



## Getoffmylawn (Sep 6, 2018)

g-man said:


> Read the fungicide guide in my signature. SJL posted some rotations.


Excellent, just saw that after posting! I am really enjoying the collective knowledge here as a newb.


----------



## jbny914 (Oct 12, 2018)

Getoffmylawn said:


> Propiconazole is not labeled to treat pythium blight


Mefenoxam appears to be the least expensive of the most effective fungicides for Pythium.

I found this guide useful for comparing the fungicides listed for Pythium Blight: https://www.turffiles.ncsu.edu/diseases-in-turf/pythium-blight-in-turf/

I used first Azoxystrobin (Scotts Disease EX) granules because they were inexpensive and available locally, but they don't appear to have done much as a curative.

So I ordered liquid generic Subdue- Mefenoxam 2AQ, which is rated as most effective for active PB. Even this late in the season I wanted to get it down because it was all over the property, and I realized I'd seen it last year too in a patch I tried to seed.

Will rotate it with fungicides from the other groups next year, to prevent resistance.


----------



## Getoffmylawn (Sep 6, 2018)

jbny914 said:


> Getoffmylawn said:
> 
> 
> > Propiconazole is not labeled to treat pythium blight
> ...


Wow, fungicide prices are not for the faint of heart. Thanks for the info on Mefenoxam, I will plan on adding it to my rotation.


----------



## jbny914 (Oct 12, 2018)

Getoffmylawn said:


> Wow, fungicide prices are not for the faint of heart. Thanks for the info on Mefenoxam, I will plan on adding it to my rotation.


Yeah they must figure exactly what the golf courses and high end landscapers and/or agribusiness are willing to pay and charge accordingly.

I found the generic mefenoxam for $134 shipped on Amazon, for 32 oz, and 0.5-1 oz covers 1000sf, so even if I do 4 applications per year it would theoretically last me 8-16 years.

With larger lawns it could add up. But yes the other top rated fungicides for Pythium were $400 minimum (Stellar, Segway).

Stellar has Medium disease resistance tendency for PB as opposed to High for Subdue and Segway. The Stellar is $500 but that is for 104 ounces and has the same application rate as the Mefenoxam/subdue, so maybe Stellar makes sense for large lawns with bad pythium problems. Makes no sense for a 1000SF lawn though, as it would be enough for 50 years.


----------

