# Pendimethalin & Prodiamine



## quattljl (Aug 8, 2018)

I have granular pendimethalin and WDG Prodiamine that I would like to put down for Poa Annua control this fall (i.e. this week). How should I go about putting these two chemicals out? Can I do both at the same time? Do I stagger the applications? If so, how much time in between applications? Does it matter which one I put down first? Sorry for what seems like a bunch of very basic questions. Poa is something I want to try to hit hard this fall as it has basically taken over my back yard and prevents me from getting a good start in the spring.


----------



## social port (Jun 19, 2017)

You may have trouble getting a lot of feedback on this question, because many of us use prodiamine and dithiopyr. I don't know much about Pendimethalin. It is a less frequently used alternative, and from what I understand, its effects are not as durable as the former two. But that is no reason why you shouldn't use it.
I don't have the expertise to definitively say that you should not use these pre-emergents at the same time. I am, however, willing to suggest that you not do so. At the least, I would be concerned about the unnecessary use of product. At the worst, I would be concerned about damage to roots. You should stagger.

I used a similar strategy in the spring of this year by using mesotrione as a preM and then following up the dithiopyr about 6 weeks after the mesotrione app.

The label should give guidance on how long each AI will be active, and I recommend that as your absolute reference for timing your apps.

Someone who has been in this position before may have firmer guidance on the matter (and that would be good), but I wanted to throw this response out there for the time being.


----------



## quattljl (Aug 8, 2018)

Thanks for the feedback. Pendimethalin is the AI in Scott's crabgrass preventer, which I picked up before I knew much of anything about herbicides or lawn care. I don't want it to go to waste now that I have prodiamine but I also don't want to misuse it.


----------

