# Fungicide: Preventative vs. Currative



## Ohio Lawn (Mar 20, 2019)

Should I apply a preventative fungicide, or hold off and see how it my TTTF does without it? I have a new lawn that I planted last year using a quality mix of TTTF that did well in the NTEP brown patch trials. 
Thanks.


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## bernstem (Jan 16, 2018)

If you don't have a fungus or known recurrent fungal issues, you don't need preventive fungicides. With a new lawn and new cultivars, I would hold off and see what happens even if you have had brown patch in the past, though I would probably keep something on hand just in case, but any hint of off color drives me crazy. Your tolerance for a less than perfect lawn might be higher.

Checked your journal thread and soil test. Are you really planning to run 2 lbs/M of Nitrogen this spring? That might be a bit high and can lead to diseases like Brown Patch, though I'm not sure much of the early 15-15-15 application Nitrogen got to your grass as it may have been asleep, so that is likely only a partial N application and was really early. Carbon-X is a good choice for your second fert of the season. It has a lot of slow release properties and will carry you for almost three months through the summer for a single application. It will also avoid a big N spike going into summer like a balanced 15-15-15 would (unless you found a rare one with slow resease N). If you feel like the lawn is still lagging after the Carbon-X, I would consider spoon feeling low rates of Nitrogen (0.1-0.2 lbs/k) using a fast release source every 2 weeks rather than more Carbon-X. That will give a bit more control over how much Nitrogen is goign to the grass at any time. Stacking a lot of slow release fertilizer can be hard to predict 4, 6, or 8 weeks into the future.

Sorry, this got to be a bit long for your initial question, but Nitrogen mismangement is often the cause of disease problems. The take home should be that you try to match the Nitrogen given to the grass to what it needs. Too much Nitrogen leads to overgrowth and diseases. Too little leads to malnourished grass and different diseases. Nitrogen should be Goldilocks. Not too much. Not too little.


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## Ohio Lawn (Mar 20, 2019)

bernstem said:


> If you don't have a fungus or known recurrent fungal issues, you don't need preventive fungicides. With a new lawn and new cultivars, I would hold off and see what happens even if you have had brown patch in the past, though I would probably keep something on hand just in case, but any hint of off color drives me crazy. Your tolerance for a less than perfect lawn might be higher.
> 
> Checked your journal thread and soil test. Are you really planning to run 2 lbs/M of Nitrogen this spring? That might be a bit high and can lead to diseases like Brown Patch, though I'm not sure much of the early 15-15-15 application Nitrogen got to your grass as it may have been asleep, so that is likely only a partial N application and was really early. Carbon-X is a good choice for your second fert of the season. It has a lot of slow release properties and will carry you for almost three months through the summer for a single application. It will also avoid a big N spike going into summer like a balanced 15-15-15 would (unless you found a rare one with slow resease N). If you feel like the lawn is still lagging after the Carbon-X, I would consider spoon feeling low rates of Nitrogen (0.1-0.2 lbs/k) using a fast release source every 2 weeks rather than more Carbon-X. That will give a bit more control over how much Nitrogen is goign to the grass at any time. Stacking a lot of slow release fertilizer can be hard to predict 4, 6, or 8 weeks into the future.
> 
> Sorry, this got to be a bit long for your initial question, but Nitrogen mismangement is often the cause of disease problems. The take home should be that you try to match the Nitrogen given to the grass to what it needs. Too much Nitrogen leads to overgrowth and diseases. Too little leads to malnourished grass and different diseases. Nitrogen should be Goldilocks. Not too much. Not too little.


Wow thank you so much for the great information! I really appreciate it. I did apply the 19-19-19 a little early. I was planning on doing Milorganite 4 weeks after my most recent Carbon-X app, but maybe I will hold off. I like the idea of seeing how the lawn does this year with fungus. But just in case, I definitely want a fungicide on hand. Should I get Propiconazole, Azoxy, or both?


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## bernstem (Jan 16, 2018)

What do you expect to treat? I don't have TTTF, so don't know exactly what is common. One of the TTTF member might have more insight. but it looks like Azoxystrobin is a better choice than Propiconazole for Brown Patch.

https://content.ces.ncsu.edu/brown-patch-in-turf


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## Grass Clippins (Apr 30, 2018)

Here's a good video on it. It's not 100% relevant because you're not in the transition zone but I would take @bernstem advise have it on hand for when it's needed. This would include reading the label ahead of time and knowing exactly what the plan will be. I have fescue in GA did my last N application 4/7, that's it until the fall. I'm trying to slow the growth going into the heat so I don't stress it out and make things worse with fungus.

He tells you in the video what to get. Propiconazole and Axozy.


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## badtlc (Aug 22, 2019)

You might go read the suggestions by your local ag school where you live and see what they say about your nitrogen application patterns.

I'm in Kansas city and both large ag schools in the area (Missouri and Kansas State) are consistent in recommending 3lb of N per year for TTTF and KBG but only in the fall. They specifically recommend not using nitrogen in spring and summer as it feeds fungus as well as the grass. I also ready that (i think it was the Missouri information) the spring nitrogen can cause the foliage and roots to be out of balance creating the need for more watering to keep the plant healthy and also the increase growth rate from the nitrogen causes the grass to burn through its carb storage that it built up to help get through the hot summers.

Ohio is obviously a different climate than where I am but you will be surprised how much detailed data your local university will have for you.


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## corneliani (Apr 2, 2019)

If you get past the initial sticker shock of the cost of fungicides, coupled with your lawn size.. I don't see the downside to applying it preventively, especially on new turf. First year turf is most susceptible to stress & (subsequently) disease, mostly due to still-shallow roots. So if the $25-30/application (4-5x/season) is too much to justify then just sit back and see what happens. Just know that curative applications require a higher amount of fungicide to address which may negate any savings from not doing the preventative. I've been humbled by BP before so I take the preventative route, but it's not a clear-cut choice. Use my feedback as a 'flip side of the coin' argument when you weigh your options.


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## Ohio Lawn (Mar 20, 2019)

I appreciate everyone who weighed in. I see both sides. I think I will monitor it closely and see how it does. I will buy some Prop & Azoxy and hit it at the first sign of fungus. Maybe it will do ok, maybe not.


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## double_e5 (May 3, 2020)

I'm with @bernstem on this one. I'd shy away from preventative fungicide applications unless you've had previous issues with your current cultivars. I don't want to harm the beneficial organisms in my soil unless I have to. Good cultural practices are the best way to prevent problems with disease/fungus. Like already discussed, nitrogen management being a big one.


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## j4c11 (Apr 30, 2017)

It's easier to stay out of trouble than to get out of trouble. Preventive fungicide applied as a foliar spray should have minimal impact on soil life. And truth be told, even granular fungicide. If fungicide was so destructive, we wouldn't have all these recurring fungus issues, would we. Nor would it re-manifest as soon as we stop spraying, or even just spray late.

On a first year fescue lawn, it's a no brainer imo. Azoxystrobin and propiconazole through mid September.


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## Ohio Lawn (Mar 20, 2019)

j4c11 said:


> It's easier to stay out of trouble than to get out of trouble. Preventive fungicide applied as a foliar spray should have minimal impact on soil life. And truth be told, even granular fungicide. If fungicide was so destructive, we wouldn't have all these recurring fungus issues, would we. Nor would it re-manifest as soon as we stop spraying, or even just spray late.
> 
> On a first year fescue lawn, it's a no brainer imo. Azoxystrobin and propiconazole through mid September.


Just when I think I made up my mind... lol. With this advice, would you start applying when might time temps stay above 65?


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## tgreen (Oct 20, 2018)

Yes, I would definitely look to run fungicide when night temps are consistently above 65. The main concern is brown patch on tall fescue at this time of year. You can run azoxystrobin (scotts disease-ex or similar) on a 28 day interval. You need to rotate after 3 apps. Unfortunately, there are no other effective classes to rotate unless you want to spray and go off label. So....wait as long as you can to start the first app but yeah, I'd go now if night temps are above 65.


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## Ohio Lawn (Mar 20, 2019)

tgreen said:


> Yes, I would definitely look to run fungicide when night temps are consistently above 65. The main concern is brown patch on tall fescue at this time of year. You can run azoxystrobin (scotts disease-ex or similar) on a 28 day interval. You need to rotate after 3 apps. Unfortunately, there are no other effective classes to rotate unless you want to spray and go off label. So....wait as long as you can to start the first app but yeah, I'd go now if night temps are above 65.


I just bought Azoxy and Prop today. I should have it in a couple days. I was planning on mixing the two. What third fungicide would you rotate?


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## gasdoc (Jul 24, 2019)

I'm in the same situation with a first year TTTF Reno.

It's interesting watching the lawn the last week and observing it's micro-climates. I have some areas that are needling and clearly drought stressed ( full sun, near mature trees, crappy soil) and others that have obvious fungus/mycelium (north facing, shady, moist). I think that illustrates that the every lawn is different mantra rings true.

I have azoxy and propiconazole as well. Watching @grassfactor and reading threads around here it seems like the most up to date recommendation is to run them both in combination. The idea is this will lead to less resistance as the fungus needs to have two mutations to have resistance to two mechanisms of action. And the treatment is probably more effective but I'm not deep enough into this to know if this has been proven academically.

I was back and forth but after finding the fungus patch yesterday I'm just going to put down the preventative on the whole lawn. Wouldn't want to see the wife's face if I got ravaged by brown patch over night after all the time and money I've spent lol. That being said, it wouldn't be the the of the world. You're clearly talented at this so even in worst case with watch and wait you would be able to fix it.


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## bernstem (Jan 16, 2018)

@gasdoc You are correct. Be aware that Azoxystrobin use increases the future risk of Dollar Spot on Bluegrass so treating with Fungicides may mean a full season of treatment. Propiconazole is a good treatment for Dollar Spot.


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## tgreen (Oct 20, 2018)

Ohio Lawn said:


> tgreen said:
> 
> 
> > Yes, I would definitely look to run fungicide when night temps are consistently above 65. The main concern is brown patch on tall fescue at this time of year. You can run azoxystrobin (scotts disease-ex or similar) on a 28 day interval. You need to rotate after 3 apps. Unfortunately, there are no other effective classes to rotate unless you want to spray and go off label. So....wait as long as you can to start the first app but yeah, I'd go now if night temps are above 65.
> ...


Unfortunately, there are no other good ones labeled for home lawns after azoxystrobin. That's why it's good to not go out too early with it. Wait as long as you can.

Enclave is incredibly effective but not labeled for home lawns. I was mixing Velista last year with success but the literature is questionable on its effectiveness on BP. I may have just been lucky.


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## mowww (Jan 16, 2018)

@tgreen I respectfully disagree. I worked in the chem industry for 6 years and there are plenty of good options outside of azoxy and propiconazole- those two are over relied on in the residential market. Here's a chart I made combining a few university studies for fungicides labeled for home lawns:



@Ohio Lawn preventative is always more effective than curative but timing is important- timing when the pressure is about to build or when the pathogen is susceptible in root borne diseases. Remember, the goal of fungicides is population control. You spray and kill say 99% of a pathogen for example- 99% of a million killed will take longer to rebound than if you spray and kill 99% of a billion of the pathogenic fungi. On the same note 50% control of a million rebounds quickly too. Choosing the right product, timing, rotation- all important.

Most of these products do not hang around terribly long, especially above the thatch layer, the length of control you're getting is based off of the length of time it takes for a population to rebound after you knock it down to a particular level.

Source: Dr. Rick Latin (retired, Purdue)


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## g-man (Jun 15, 2017)

This is a great article.

http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.pdf


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## tgreen (Oct 20, 2018)

Thanks for the chart. I try to keep it simple though. The OP has a tall fescue lawn. The disease I'd be most concerned with here is brown patch. It's very common and can cause moderate damage. The only other devastating disease on TF is gray leaf spot and that is less common and a topic for a different discussion. Everything else is basically an annoyance. For example, I would not be worried about root diseases since tall fescue is hardly susceptible.

The only good homeowner-available fungicide that is proven on brown patch is azoxystrobin. Propiconazole is proven ineffective on BP and at least one study suggests propy makes BP worse. Insignia is a strobilurin so would not be a good rotation with azoxy. I don't have first hand experience with Prostar but know others on the forum have used it so this could be a good alternative for the OP, assuming he wants to spend the $ and spray.

Not looking to start an argument here. Understanding turf disease can be overwhelming and throw in all the fungicide classes (some of which are labeled for certain disease yet are proven ineffective) and you need a PHD. Also, in my experience turf disease doesn't always present like the textbooks show. I think it helps to keep it simple with most people. If you have TF then I'd worry about brown patch and I'd use azoxystrobin.

Good luck everyone!


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## Grass Clippins (Apr 30, 2018)

@tgreen You are correct about turf disease being overwhelming. I think the only way to figure it out is to keep and open mind and try different things until you find what's right for your climate and turf type. I read about the importance of rotation in different groups to avoid building a tolerance but then I see someone like Pete @ GCI running the Headway Mix (Prop & Azoxy) on TTTF all season with great result. I never understood how he was able to pull that off until a few days ago @kb02gt shared a link to a Clemson study that, at the very bottom, states:
_
"Resistance to the fungicide by the brown and large patch fungi will develop from continued exclusive use of products containing only azoxystrobin or fluoxastrobin. Always alternate these fungicides with one of the others. Alternatively, choose a product, such as Headway G or Pillar G, each of which contain 2 active ingredients. These can be used in repeated applications against brown or large patch without an increase in resistance to the fungicide treatment. Follow directions on product label for use. In general, azoxystrobin or pyraclostrobin will control brown and large patch for 28 days. The other three fungicides will control the diseases for 14 days. Irrigate according to label directions after application of granular products."
_Like you, I like to keep it simple so this was good news to hear. I personally like to go out early on disease and throw the first punch in the transition zone. Regardless of location the first sentence of the application instructions on the Axozy 2SC label say that it should be applied prior to disease development.


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## kb02gt (Aug 23, 2019)

mowww said:


> @tgreen I respectfully disagree. I worked in the chem industry for 6 years and there are plenty of good options outside of azoxy and propiconazole- those two are over relied on in the residential market. Here's a chart I made combining a few university studies for fungicides labeled for home lawns:
> 
> 
> 
> ...


Nice chart. Just saved it to my "Evernote". However do want to point out that the Frac code for Headway is 3, 11 instead of 7, 11.


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## mowww (Jan 16, 2018)

@kb02gt thanks, good catch.


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## gregdg (Jun 26, 2021)

How long do I have to wait to mow after applying a liquid fungicide ?


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