# Fungicides - Have we had it all wrong?



## GrassDaddy (Mar 21, 2017)

Hey Guys

So I've been going on the advice of someone that said fungicides kill the good bacteria in a lawn. I may have even repeated that. Well, I was reading on Iowa State University, and they stated:



> Fungicides are pesticides that can kill or inhibit growth of fungi on plants, but *they are not effective against bacteria*, nematodes, or viral diseases.


https://hortnews.extension.iastate.edu/2011/6-1/fungicides.html

What is also interesting is talking to local lawn supply shop about fungicides, he said that applying with biofungicides is a great idea. And then there is this quote:



Lawndad said:


> When I spoke with the Companion rep. he of course said that his was much better and* that it should be used with a synthetic fungicide*


Anyways, I'm all for learning and coming to conclusions yourself.. Anyone have any other actual documentation either way?

Tim


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## j4c11 (Apr 30, 2017)

Probably meant they kill the good fungi in a lawn. Mycorrhizae and such.

Doesn't surprise me the local shop thinks it's a great idea to sell you two products instead of one.


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## GrassDaddy (Mar 21, 2017)

Nah they don't sell the biofungicides there. But I've been told if you use Serenade to prevent lawn disease, you shouldn't apply fungicides because it will kill the serenade bacteria. This indicates that isn't true.


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## j4c11 (Apr 30, 2017)

It's possible that fungicides affect other soil life, including bacteria. Here's a study on that issue:

https://www.hindawi.com/journals/isrn/2011/130289/


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## LIgrass (May 26, 2017)

> Fungicides are pesticides that can kill or inhibit growth of fungi on plants, but they are not effective against bacteria, nematodes, or viral diseases.


That is correct. I remember having a PM discussion with jglongisland about this. Wish I could copy and paste it here but we know what happened with the PMs. You can use the two together though, no problem.


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## GrassDaddy (Mar 21, 2017)

So the bacteria will actually fight the fungus on top of the chemical fighting it systemically.. sounds like a win win


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## LIgrass (May 26, 2017)

GrassDaddy said:


> So the bacteria will actually fight the fungus on top of the chemical fighting it systemically.. sounds like a win win


I'm far from an expert on this but chemicals should only be used as a last resort. Besides resistance issues, I believe they kill other beneficial organisms in your soil.


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## GrassDaddy (Mar 21, 2017)

LIgrass said:


> GrassDaddy said:
> 
> 
> > So the bacteria will actually fight the fungus on top of the chemical fighting it systemically.. sounds like a win win
> ...


Well thats what Im getting at.. at least one university says it doesn't so where is the info coming that it does?


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## kolbasz (Jun 7, 2017)

Should we discuss the how when why.

With or without Surfactant
With or without watering in
When do you want it or the ground vs the foliage 
Temps when not to etc


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## Virginiagal (Apr 24, 2017)

GrassDaddy said:


> LIgrass said:
> 
> 
> > GrassDaddy said:
> ...


The problem is that fungicide kills the good fungi too.


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## j4c11 (Apr 30, 2017)

Bottom line - fungicides do not target bacteria, but may affect/inhibit bacteria depending on concentration. Here is a very recent study on the compatibility on Bacillus Subtilis with chemical fungicides:

https://www.ijcmas.com/6-3-2017/H.%20Basamma%20and%20Shripad%20Kulkarni.pdf

It is compatible with some fungicides, not so much with others. The strain found in Serenade is probably one of those compatible with typical lawn fungicides at typical lawn application rates.

I would think that with foliar applications, the net effect of fungicides on soil bacteria would be negligible.

Fungicides definitely kill some of the "good" fungi too. No fungicides will kill the entire fungi population. If you can get away with not using fungicides, that's ideal. If you do get fungal disease, my personal approach is to attack it swiftly - I feel like when you have blood poisoning you take the antibiotic and worry about the bacteria in your gut later. If the potential for loss of turf and/or turf quality is acceptable, then one can try and manage fungal disease through cultural practices without fungicides.


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## Virginiagal (Apr 24, 2017)

I would be interested in reading that article but Safari puts up a warning sign about the site's certificate. Can you summarize it?


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## j4c11 (Apr 30, 2017)

Here's an alternate download link:

https://NoFile.io/f/rKQKlOkmD7x/H.+Basamma+and+Shripad+Kulkarni.pdf


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## Virginiagal (Apr 24, 2017)

Thanks for the links.


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