# Has your pre emergent washed away?



## pennstater2005 (Jul 17, 2017)

An article I thought worth posting since pre emergents are going down and recent and ongoing heavy rainfalls/washouts have been occurring.

After the Flood - Weed Management Concerns for Nurseries and Landscapes (NCSU article)

Mine was delievered today but the rainfall looks heavy and so I think I'm going to wait. I'm probably late but late summer-early fall is the range so I'm not completely late


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## Powhatan (Dec 15, 2017)

From the article:

_*Should I Re-Apply Herbicide(s)?*

It is generally safe to assume that at least some of your residual herbicides have either moved off-target or degraded after an excessive rainfall event. So, it is generally a safe assumption that you will need to re-apply herbicides. Because some of the herbicide likely remains in the soil, we advise rotating to a different mode of action. For example; if your residual herbicide application was a combination of simazine and oryzalin, we would advise rotating to flumioxazin or indaziflam. Alternatively, if rotation to a different mode of action is not feasible (due to crop safety or other concerns), then apply the lowest labeled dose of the herbicide._


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## pennstater2005 (Jul 17, 2017)

Powhatan said:


> From the article:
> 
> _*Should I Re-Apply Herbicide(s)?*
> 
> It is generally safe to assume that at least some of your residual herbicides have either moved off-target or degraded after an excessive rainfall event. So, it is generally a safe assumption that you will need to re-apply herbicides. Because some of the herbicide likely remains in the soil, we advise rotating to a different mode of action. For example; if your residual herbicide application was a combination of simazine and oryzalin, we would advise rotating to flumioxazin or indaziflam. Alternatively, if rotation to a different mode of action is not feasible (due to crop safety or other concerns), then apply the lowest labeled dose of the herbicide._


Yeah, that is important. I would probably re apply same AI at lowest rate versus having to buy another product.


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## NewLawnJon (Aug 3, 2018)

That is part of the reason why I apply my pre-em at a lower rate more often. I also feel like applying at lower rates more often also can help with over/underapplying in any area as well. I prefer the 2-3 month rates compared to the 4-6 month rates.


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