Your farmer customers could be unknowingly planting Palmer amaranth anywhere Conservation Reserve Program (CRP) mixes are grown or pollinator mixes are established. To date, Palmer amaranth seed in CRP planting mixes has been identified in Illinois, Indiana, Iowa, Minnesota and Ohio.
“We have no idea how many individual fields are infested, but we started with five counties in 2013 and now we’re at 49,” says Bob Hartzler, Iowa State University (ISU) Extension weed scientist. An estimated 23 counties have fields infested due to CRP mixes. “When you look specifically at fields with infested CRP plantings it’s about 50 to 100 plants per acre.”
This past year marked Minnesota’s first Palmer amaranth discovery, and it was in CRP native seed mixes. Palmer amaranth is considered a noxious weed in Minnesota, as well as Ohio and Delaware, which gives the state more authority to track and eradicate the weed.
“There are 13 farm sites and 30 plantings within the two infected counties,” says Jeff Gunsolus, University of Minnesota Extension weed scientist. “Known infestation is less than 200 acres, all associated with conservation planting.”
Weed Look-Alike. CRP mixes infested with Palmer amaranth is a tough issue to tackle. Palmer amaranth seeds can easily mimic other native seeds and growing CRP demand leads to outsourcing beyond company-only production.
In south-central Iowa, owner and operator of Prairie Seed Farms John Osenbaugh is tracking the Palmer issue closely. His 36-year-old company does 90% of its business providing CRP mixes. The company produces about 50% of its seed and buys the balance from other growers.
Federal labels don’t require native seed providers to list what weed seeds are present, so Osenbaugh performs additional testing. “If we find pigweed seed we just have to assume it is Palmer amaranth even if we don’t know. If a grower sends us something with pigweed, we reject it,” he says.
The same way the Federal Seed Act requires corn and soybean seed companies to label each seed bag, CRP seed providers are required to list the same information. But just because a bag says 0.0% weed seed doesn’t mean it’s true. If in doubt, consider doing your own seed testing. Buying locally from professional seedsmen can also help.
By being more aware of the CRP seed-mixes issue, retailers can help farmers keep Palmer amaranth from taking root in their fields.