There may be a way for livestock farmers to spray weeds in a pasture and still have white clover and annual lespedeza survive.
University of Missouri Extension weed scientist Kevin Bradley had the opportunity to look at the herbicide ProClova from Corteva over the past two years.
“This will be first time that we have a herbicide that doesn’t kill white clover,” he said to a group gathered at the MU Crop Management Conference, “and it’s also safe on annual lespedeza.”
ProClova is a florpyrauxifen plus 2,4-D, currently in the EPA registration process. Corteva anticipates EPA registration during 2022. While florpyrauxifen is already labeled for pastures in the form of DuraCor, also by Corteva, this new formulation offers control not seen in the livestock industry by selectively killing broadleaf weeds.
ProClova provides broad-spectrum control of broadleaf species, including ironweed, cocklebur, wild carrot, buttercup, biennial thistles, ragweeds, plantain, wooly croton, poison hemlock and many others.
MU conducted trials looking at three products — DuraCor, ProClova and GrazonNext HL — evaluating injury to white clover along with weed suppression.
ProClova trial results
At six locations across the state during 2020-21, Bradley found that one week after a ProClova treatment, there was less than 20% injury to white clover, and that rate continued to fall — by 12 weeks after application, there was no injury.
He warned that farmers will see some initial response of yellow-up on the white clover, and it will likely droop over, but he adds it will survive over time.
On the flip side, the other products tested both showed the same white clover injury with about 30% affected after one week, and then almost 100% by 12 weeks.
While ProClova works for white clover, Bradley found it does not perform the same for red clover. “It is not labeled safe on red clover,” he said, “but as you might imagine, you can have some survival of red clover.”
MU trials found that eight weeks after treatment, there was 60% injury to red clover.
Weed control results
When it comes to weed control, ProClova performed similarly to DuraCor and GrazonNext HL, falling a little behind in musk thistle and common cocklebur, but outperforming the others for poison hemlock.
“So there is a trade-off here,” Bradley said. “Some of our common weeds that we might encounter, like the thistles, might have a little more survival than some of our standard treatments. But [ProClova] does work on certain species really well.”
He cautioned farmers about seeing the data and buying in to the new herbicide for its poison hemlock control. The weed was present at only one location in the trial. Still, he noted, for some reason ProClova did better than the other products.
Benefits for livestock producers
Many livestock producers rely on white clover and annual lespedeza in their pastures to improve forage quality for grazing and haying — and for what these legumes’ nitrogen-fixing properties bring to soil fertility and health, said Scott Flynn, Corteva Agriscience zonal biology leader.
“Without effective broadleaf weed control, the harm weeds cause to forage production and quality can outweigh the benefits these legumes provide,” he said. “That can be frustrating.”
ProClova, has no grazing or manure restriction, and only minimal haying restrictions after application.
Bradley added this new pasture weed control product is making livestock producers “pretty happy, pretty excited about the possibility of not killing clover. That’s always been something they’ve wanted.”