# Question About Pre-Em Combos



## JayGo (Jun 13, 2019)

When using multiple herbicides for a Fall/Spring pre-emergent program, do you use full application rates of EACH herbicide?
For example, if using dithiopyr and simazine (or some other herbicide from a different group) as a Fall pre-em, do you use a full app rate of dithiopyr as well as a full app of simazine for your Fall application?


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## Green (Dec 24, 2017)

Just to clarify...

By stacking, do you mean applying two different pre-Ms simultaneously?

Because applying one when the other is about to wear off would be considered a split app, but that doesnt seem to be what you're asking about here.


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## JayGo (Jun 13, 2019)

@Green, I'll admit I don't recall why I chose to use the word stacking. Combinations of pre-em herbicides is what I was essentially getting at.


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## Green (Dec 24, 2017)

JayGo said:


> @Green, I'll admit I don't recall why I chose to use the word stacking. Combinations of pre-em herbicides is what I was essentially getting at.


Ok, but do you mean applying them at the same time to get multiple modes of action? Because I'm not familiar with that.

What I am familiar with is, applying, say, Pendimethalin in March, and then Dimension in May...a split app. That works fine, even with different modes of action. I believe the grassfactor covered it a while back. Someone did.


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