Minnesota keeps Palmer amaranth at bay by pulling by hand, blow torching
COTTONWOOD, Minn. — Propane blow torches, herbicide, the sharp blades of mowers, hand pulling, and most important of all, the vigilant eyes of landowners.
These are among the weapons the Minnesota Department of Agriculture has employed to eradicate Palmer amaranth from 30 conservation plantings in Yellow Medicine and Lyon counties.
And so far, it's been working.
"I think everything we have been doing has been successful, but there is just a series of things we need to keep doing to keep sure we're not getting any mature plants out there,'' said Anthony Cortilet, noxious weed program coordinator with the Department of Agriculture.
He said the department is in the process of employing someone to work full time on the eradication effort this year.
The state launched its eradication effort after it was discovered that 13 landowners had unknowingly spread seed mixes containing Palmer amaranth on the 30 conservation sites last year. The contaminated seed was tracked to a family-owned company in Cottonwood, Minn.
News that Palmer amaranth had been found in Minnesota raised alarm bells in the agricultural community.
Cortilet said the Department of Agriculture has been receiving a number of calls from farmers and crop consultants about suspect plants they have found this year, and some have sent in samples.
"So far so good,'' said Cortilet during a phone interview Friday. None of the samples have proven to be Palmer amaranth.
Sometimes termed a super weed, Palmer amaranth is an annual broadleaf native to the southwestern U.S. It is difficult to control, can significantly reduce corn and soybean yields if not managed, and has a hard, woody stem that disrupts harvesting, according to published reports.
The contaminated seed mixes were spread on only about 175 acres total in Minnesota. Still, it is like looking for a needle in a haystack to find the weed amidst the conservation plantings, according to Cortilet. On a 40-acre site, maybe 40 to 80 Palmer amaranth plants could be found, he explained.
The Minnesota Conservation Corps sent workers with propane blowtorches to the fields last fall to eradicate any plants that were found before they could produce seed. A single plant can produce up to 500,000 seeds, so all of the effort has been focused on not letting one female plant mature to that point.
Cortilet said they have also applied herbicide on many of the acres, and landowners have also done their own mowing and hand pulling.
If needed, more flame weeding, mowing and hand pulling will occur this season.
Flowering could start in early August if there any plants that escape detection. The flowered plants must be pollinated before they produce seeds. The flowered plants are easy to spot, so Cortilet remains optimistic that they could be eradicated before producing seeds.
Cortilet said the affected landowners have been very cooperative, and vigilant.
"We're really lucky to have some very knowledgeable people that are familiar with their lands, know what they are doing and what they are looking for now. They've been the biggest help we could ask for,'' he said.
The eradication effort on the 30 sites will be ongoing, and Cortilet is optimistic about its outlook. But he cautions that vigilance is still needed.
The plant has been found in conservation and crop fields in many Iowa counties, he said.
"The potential for it to keep spreading into the state is there, unfortunately,'' Cortilet said. "We can't prevent that from happening, but we can do our best by letting these growers know the issue in cleaning equipment and being vigilant about what they buy and where they buy it from and all that kind of stuff.''
No state has been able to stop Palmer amaranth as it continues to spread beyond the Southwest. The last stand is here.
As Cortilet likes to point out: "How many states north of Minnesota are there?"