# Dithiopyr winter preemergent?



## Oyster Shark (Aug 24, 2020)

Hey,

Looking for opinions on dithiopyr for winter preemergent? (Thanksgiving application, Southern NJ.)

Over seeded 9-13. Spot seeded 10-13. TTTF, PRG.

Local turf experts 3/3, opine that prodiamine is a no-go for young turf as it will trim the roots.

I guess I'm looking for that "winter barrier."

Thx


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## Delmarva Keith (May 12, 2018)

Dithiopyr inhibits root growth also. If the local experts recommend against prodiamine, the same logic would apply to dithiopyr. On the upside, most winter annuals are easy to kill in Spring, especially if you can catch them early.

Here's a short article: https://cropwatch.unl.edu/controlling-winter-annual-weeds


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## M32075 (May 9, 2019)

I wouldn't bother it's late in the season nothing should germinate by now if anything does it's a easy spring kill


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## Oyster Shark (Aug 24, 2020)

M32075 said:


> I wouldn't bother it's late in the season nothing should germinate by now if anything does it's a easy spring kill


Winter application is Thanksgiving in New Jersey..


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## Green (Dec 24, 2017)

Oyster Shark said:


> M32075 said:
> 
> 
> > I wouldn't bother it's late in the season nothing should germinate by now if anything does it's a easy spring kill
> ...


If you did an earlier app a few months ago and are doing a second one to keep it going, by all means put it down now, especially if you can water it in. If you have a history of Poa annua or even Triv, keeping a barrier up can prevent germination in late Fall and again in early Spring during freeze-thaw cycles. I generally like my pre-M to last at least through December. Poa annua can germinate during warm periods in early Winter, too.


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