Share residual facts when selling hay

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A bundle of hay in a pasture

Supplemental labeling is required to sell grass hay treated with DuraCor® herbicide off the farm or ranch where it’s produced.

Weed-free grass hay — produced with a soil residual herbicide — comes with both a responsibility and an opportunity.

You’re reading the label for DuraCor® herbicide, and you notice this: “Hay from grass treated with DuraCor within the preceding 18 months can only be used on the farm or ranch where the product is applied unless allowed by supplemental labeling.”

Similar language appears on the labels for GrazonNext® HL and Chaparralherbicides. What does this mean? It means hay this weed-free comes with both an opportunity and a responsibility.

The opportunity is in documenting why the hay is so clean. The responsibility is telling buyers what the residual activity of the herbicide means in terms of how they use the hay, says Scott Flynn, Ph.D., a field scientist for Corteva Agriscience.


A supplemental label (find at allows you to sell treated grass hay in 23 states: Alabama, Arizona, Arkansas, Colorado, Florida, Georgia, Idaho, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, South Dakota, Tennessee, Texas, Utah and Wyoming.

The label spells out precautions for using hay that may still carry aminopyralid, one of the active ingredients in all three products. You have a responsibility to tell the hay buyer what he or she is getting.

“A word to the wise may be sufficient, but a copy of the supplemental label may be a better reminder,” Flynn says. “You may be able to use it to differentiate your hay from commodity hay.”


Aminopyralid provides soil residual activity to control weeds that germinate for weeks after spraying. Over the season, it breaks down in the soil and the residual activity dissipates.

While aminopyralid is still active in the soil, grasses absorb and store it in cell walls. In the live plant, it dissipates over 18 months as the grass is grazed or cut, regrows and dies in frost. But in grasses cut for hay, the aminopyralid remains stable until the hay is consumed or it decays into the soil. Hay stored in a barn will have as much aminopyralid in it as the day it was cut.

Never use treated-grass hay for mulch or compost. Enough aminopyralid may remain to damage broadleaf plants. Likewise, don’t feed treated hay on land to be planted to sensitive crops. The aminopyralid can pass through the animal in manure and urine.


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® ™
Trademarks of Corteva Agriscience and its affiliated companies. Under normal field conditions, DuraCor® is nonvolatile. Chaparral, DuraCor and GrazonNext® HL have no grazing or haying restrictions for any class of livestock, including lactating dairy cows, horses (including lactating mares) and meat animals prior to slaughter. Label precautions apply to forage treated with Chaparral, DuraCor or GrazonNext HL and to manure and urine from animals that have consumed treated forage. Chaparral, DuraCor and GrazonNext HL are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.

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