# Prodiamine and Dithiopyr? Use together? Or several months apart?



## bassadict69 (Apr 2, 2018)

Does anyone apply both prodiamine and dithiopyr together? Or is it always a one or the other type thing?


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## Ware (Jan 28, 2017)

They have similar modes of action. I would not apply them together.


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## bassadict69 (Apr 2, 2018)

OK, thanks! I'm just trying to get all my spring time ducks in a row...


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## CenlaLowell (Apr 21, 2017)

I definitely do not apply them together for the reason @Ware mentioned. I usually apply one month apart. The only pre emergent I'm going to try to apply together this season is simizine and pennant Magnum.


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## thesouthernreelmower (Aug 28, 2018)

We do prodiamine in January and dithiopyr in feb/march. Dithiopyr does have some post emergent control of crabgrass, hence why it's applied in last spring


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## Movingshrub (Jun 12, 2017)

Pick one or the others.
Prodiamine is generally cheaper and last longer per app. 
Dithiopyr has some very early post em effects.

I use prodiamine.


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## SCGrassMan (Dec 17, 2017)

Here's my lawn after using Diopthyr in the spring. This year I'm doing Prodiamine to see how it works out. I definitely have less weeds than my neighbors, but that's a low bar.


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## Oceanus (Sep 17, 2018)

[contrarian]I don't think waiting a month or two matters that much[/contrarian] :shock:

Yes, these prevent emergence in similar ways (they are both 'root pruners'). 
Prodiamine being more of a root pruner than dithiopyr. Bermuda has a strong root system so it can tolerate these at labelled rates.

_However_, I don't think waiting a month or two matters that much because...
Prodiamine can last up to 9 months (it's either pruning roots or it's not). So what's the difference between immediately adding dithiopyr or waiting 2 months? The prodiamine effect hasn't changed, so the impact will be similar until the prodiamine is gone.

I think the primary consideration is financial. Prodiamine is less expensive. If it works, then your done. Why waste money on dithiopyr? It seems dithiopyr is (only) used when you prefer to focus more on broad-leaf weeds or for the slight post emergent control of early crabgrass.


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## Ware (Jan 28, 2017)

Same - everyone's situation is a little different, but I haven't ever had the need to double down on my pre-e apps.


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## rhanna (Jun 7, 2017)

Oceanus said:


> The prodiamine effect hasn't changed, so the impact will be similar until the prodiamine is gone.


I think this is the question. I would think both would be highly effective at the beginning and then less control as it wears off


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## Ecks from Tex (Apr 26, 2018)

SCGrassMan said:


> Here's my lawn after using Diopthyr in the spring. This year I'm doing Prodiamine to see how it works out. I definitely have less weeds than my neighbors, but that's a low bar.


Neither will stop the bluegrass/sedge looking weed.

An application of pre-em in the spring may or may not last long enough to stop the winter broadleaf I see in your pic.

I would expect both of those based on the facts in your post, no matter the pre-em.


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## Art_Vandelay (Nov 20, 2018)

SCGrassMan said:


> Here's my lawn after using Diopthyr in the spring. This year I'm doing Prodiamine to see how it works out. I definitely have less weeds than my neighbors, but that's a low bar.


When was this picture taken?


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## Green (Dec 24, 2017)

For seeded grass types, conventional wisdom is that root pruning is definitely something you want to avoid shortly after esranlishing.


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## rhanna (Jun 7, 2017)

Looks like Matt has a good video on preemergents that I'll have to watch later.


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## SCGrassMan (Dec 17, 2017)

Ecks from Tex said:


> SCGrassMan said:
> 
> 
> > Here's my lawn after using Diopthyr in the spring. This year I'm doing Prodiamine to see how it works out. I definitely have less weeds than my neighbors, but that's a low bar.
> ...


It's Poa, and I put out pre em in the fall.


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## SCGrassMan (Dec 17, 2017)

Art_Vandelay said:


> SCGrassMan said:
> 
> 
> > Here's my lawn after using Diopthyr in the spring. This year I'm doing Prodiamine to see how it works out. I definitely have less weeds than my neighbors, but that's a low bar.
> ...


I realize it was worded poorly. Diopthyr was put down in the fall, and this pic was taken in late January.


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## g-man (Jun 15, 2017)

What rate you use in the fall? When in the fall (Oct or Dec 20)? Prem are effective if you apply them before the weeds establish.


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