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A Brief Shock, Then White Clover Recovers With New Herbicide
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New NovaGraz™ herbicide is the first product to offer broad-spectrum weed control in pastures while preserving white clover and annual lespedeza. But, after application, white clover will yellow slightly and lodge for a short period.
“The effect is short-lived, and white clover recovers, but we don’t want people to be surprised. You should expect to see that,” says Jodie Crose, field scientist, Corteva Agriscience.
By spraying with NovaGraz, producers can control weeds, profit from clean pastures and still keep all the benefits of white clover and annual lespedeza growing with grasses.
The benefits of white clover and annual lespedeza include both improved forage quality for better animal performance and improved soil fertility due to legumes’ nitrogen-fixation and nitrogen-cycling processes.
Before NovaGraz, pasture herbicides couldn’t take out broadleaf weeds without also removing white clover.
Application Recommendation
Crose recommends spraying NovaGraz when at least 90% of target weeds have emerged and are growing well. For biennials such as musk thistle, that’s usually early to midspring or late in the fall. For species such as spiny pigweed, ironweed and cocklebur, it may be late spring to early summer.
Use NovaGraz at the labeled rate of 24 fluid ounces per acre in at least 15 gallons of water per acre. Include 1% methylated seed oil (MSO) by volume.
“MSO is the only adjuvant that should be used,” Crose says. “Don’t substitute with organosilicones, nonionic surfactants (NIS) or blends. Straight MSOs are required.”
White Clover Response
After application, expect white clover to turn slightly yellow and lodge within one to two days. When lodging occurs, plants appear to lay over and lack vertical growth. Plants usually will remain lodged and yellow for two to three weeks. Annual lespedeza, on the other hand, shows very little effect with a slight yellowing of leaves and no lodging. About three weeks after application, white clover will begin to regain vigor and grow out of the lodging phase.
“At four to six weeks, white clover will fully regain its vigor and possibly bloom,” Crose says.
Several things can affect recovery of white clover, Crose says. Any weather that slows growth of normal plants will likely slow recovery of white clover and lespedeza. Farmers and ranchers know about too hot, too cold, too wet and too dry, but grazing management also affects recovery.
Graze Before and After Spraying
“NovaGraz is not residually active in the soil. It relies on leaf contact to control susceptible weeds,” Crose says. Grazing before application reduces leaf cover of white clover and annual lespedeza, effectively reducing those plants’ contact with the herbicide and uptake.
“And we highly recommend grazing within two to four weeks after application with NovaGraz,” Crose says. “However, where toxic plants, such as poison hemlock or larkspur, are present, it is best to remove livestock because these plants often become more palatable after being sprayed.” Livestock can return to treated pastures after the poisonous plants are dry and no longer palatable.
After application, grasses will have a competitive advantage. Aggressive growth of grasses can prolong the recovery period or crowd out the stressed white clover and annual lespedeza. Crose advises producers to delay a hay cutting until at least two weeks after an application of NovaGraz™ herbicide. That allows enough time for weed uptake of the herbicide to achieve control. Harvesting at two weeks removes competitive grasses just as white clover and annual lespedeza are beginning to regain vigor.
Omit Nitrogen in Fertilizer
“If you plan to fertilize a pasture treated with NovaGraz, don’t include nitrogen,” Crose says. Nitrogen gives grasses a boost in growth and allows them to crowd white clover and annual lespedeza. It also inhibits nitrogen fixation by the legumes.
Crose notes white clover varieties that are bred for yield and vigor are generally more tolerant to applications of NovaGraz than common, low-growing, white clovers that have become naturalized in pastures.
For more information about maintaining desirable forages while controlling broadleaf weeds, visit Corteva.us/ByTheNumbers/Steward.
NovaGraz™ is 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 area. Always read and follow label directions.