Tests identify weed seeds in pollinator mixes

Palmer amaranth with seed head, growing in a Colorado crop field.

The seed industry has access to rapid DNA tests to avert Palmer amaranth contamination in pollinator seed mixes, a company executive says.

Palmer amaranth is considered the most troublesome weed in the nation, according to the Weed Science Society of America

The California Department of Food and Agriculture and Eurofins BioDiagnostics have an independently validated a DNA sequencing test, and weed scientists at the University of Illinois developed a more sensitive DNA test that can detect a single Palmer amaranth seed in a 100-seed sample, according to the society.

Awareness of the tests’ availability is a “huge step forward,” said Lee Van Wychen, director of science policy for the organization. Results are back in days instead of the months it would take to grow out an entire sample of seed mix, he said.

Van Wychen believes the problem arose as a result of a big push for pollinator seed mixes at the federal level and a shortage of seed.

The problem first surfaced in Iowa and Minnesota in August 2016, said Norm Poppe, general manager of Applewood Seed Co. in Arvada, Colo. He is a former chairman of the environmental and conservation seed committee of the American Seed Trade Association.

The tests were in place by early 2017, Poppe said. He recommends pollinator seed mix buyers ask sellers if the seed has been properly tested and determined to be negative for Palmer amaranth.

Poppe said his company sends seed to the University of Illinois whenever it finds any amaranth seed through routine tests. It holds onto that particular lot until it’s confirmed to be weed-free and offers test results if customers have questions.

“We’ve made the choice that for the $50 it costs us to send every sample to get a definitive yes or no, that’s a small price to pay compared to our reputation of over 50 years in the seed business,” Poppe said.

In the meantime, farmers should be aware of what’s in their seed mixes and take the time to monitor their fields, Van Wychen said.

“Don’t assume you have absolutely 100 percent weed-free seed,” he said. “If you go and plant 100 acres of (Conservation Reserve Program land), you should go back, scout and look at what’s coming up and what’s planted.”

Poppe believes scientists, seed control officials and companies need to collaborate on potential risks. Seed companies have to follow state seed laws, he said. Some states didn’t have palmer amaranth listed as a noxious weed until the problem arose, he said.

Recommended for you