- Reject unlabeled seed
- Check labels—and keep all labels used in a specific planting
- If restricted noxious weeds are present make sure they’re present at a rate of less than 25 seed per pound
- Don’t use seed with any prohibited noxious weed seeds
- Ask seeding contractor for planting records including: seed lots planted in specific locations, planting procedures, site preparation and equipment used with equipment cleanout records
- Keep invoices and paperwork
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 and he knows one slip up could be destructive—not only to his business, but the farmers and landowners he works with, too.
“We raise some of our own seed and buy some from other growers, about 50/50,” Osenbaugh says. Each seed bag is required to have certain information on the tag, and when they get seed from an outside grower they perform additional purity tests.
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. Look for information including what species are in the bag, percent of pure seed, percent of weed seed present, percent inert matter and germination rate.
Federal labels don’t require native seed providers to list what weed seeds are present, and that’s one of the reasons Osenbaugh performs additional testing. “If we find pigweed seed we just have to assume it is Palmer amaranth even if we don’t know,” he says. “If a grower sends us something with pigweed, we reject it.”
Right now it’s hard to differentiate seeds from the 197 different pigweed species because there is no definitive DNA test, although researchers in Illinois have made progress. Seed companies and growers who provide native seed mixes have to rely on physical identification when checking seed lots for contamination.
This leaves room for error and can cause some native seed companies to spread Palmer with their seed mixes. “We haven’t had any issues with Palmer amaranth in our seed mixes yet, and I would be cautious of companies that have,” Osenbaugh says.