# Tenacity's "yearly maximum"... why?



## sheepfescue (Jul 29, 2019)

Does anyone know, specifically, why Tenacity has a yearly maximum use level? Do you think there is some sinister effect of the material on the environment, animals, and/or people?

My question of course assumes that there is a specific and important rationale for having the yearly-maximum, and that it was/is not just a "checked-box" for when the manufacturer in recent years sought approval for residential lawn use?

Was there a "yearly maximum" for corn fields?

Was Tenacity repurposed for residential lawn use because it stopped being profitable for agriculatural operations... or it stopped being effective... or its use was discouraged in agriculture for some reason?


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## g-man (Jun 15, 2017)

I think you should call syngenta and ask them. Their customer support is really good. I know it is still sold for AG under a different name.


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## always_creative (Aug 28, 2020)

New York's herbicide registration letters are easy to find. Mesotrione's original approval is here:
http://pmep.cce.cornell.edu/profiles/herb-growthreg/fatty-alcohol-monuron/mesotrione/callisto_reg_0602.html

Based on the letter, it seems to me that the limit is to ensure that all tenacity has broken down and left the environment before further herbicide is applied in the following year. This isn't explicit, but it seems logical IMO based on their data.


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## isuhunter (Sep 23, 2020)

g-man said:


> I think you should call syngenta and ask them. Their customer support is really good. I know it is still sold for AG under a different name.


Correct its Callisto used in corn production


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