Testing by seed analysts at the Minnesota Department of Agriculture concluded that Palmer amaranth found in the state last fall came from seed mixes sold by Green Valley Seed in Cottonwood.
Palmer amaranth was confirmed in September 2016 on 13 sites of first-year conservation plantings in Lyon and Yellow Medicine counties. The infestations were found on 30 Conservation Reserve Program plantings that total less than 200 acres.
“We think we’ve accounted for all the seed [sold by the company,]” says Cliff Watrin with MDA’s weed seed unit.
MDA did not have clear evidence that Green Valley Seed sold seed contaminated with Palmer amaranth, since it did not have a file of required seed samples available. MDA tested numerous samples of a seed mix component (black-eyed Susan) used on those sites, but none of the tests showed the presence of Palmer amaranth seed.
Even though no Palmer amaranth seed was initially found, the MDA’s investigation concluded that Green Valley Seed violated portions of Minnesota’s Seed Law:
• It mixed, labeled and sold a seed mix while not holding a current Minnesota Seed Permit. This permit is required to sell seed in the state.
• It sourced black-eyed Susan seed from Texas, but identified the seed as coming from Minnesota. This mislabeling of the seed origin is a violation of the Minnesota Seed Law.
• It incorrectly labeled the laboratory testing dates for components of the seed mix as well as the mix itself, which is also a mislabeling violation.
• It did not have complete records, including retaining a sample on file of each lot of seed sold in the state, as required by the Minnesota Seed Law.
Due to violations of the Minnesota Seed Law, Green Valley is being fined $4,000. It also must follow certain agreed-upon stipulations, such as properly reporting all seed sales, supplying seed samples to MDA and supplying seed source records to MDA. If Green Valley Seed follows the penalty conditions for three years, MDA will waive half of the levied fines.
MDA has taken several steps since the discovery of Palmer amaranth to ensure Minnesota’s seed industry remains free of the invasive weed. The stage agency is increasing seed monitoring and enforcement efforts in cooperation with the Board of Water and Soil Resources (BWSR), the Department of Transportation, the Department of Natural Resources and USDA. MDA also worked with the California Department of Agriculture and a private testing lab, Eurofins BioDiagnostics, to develop a molecular test that can identify Palmer amaranth seed.
“There are about 70 different species of amaranth, and you cannot tell them apart in the lab,” Watrin says. Having a molecular test available will help a lot in differentiating Palmer amaranth from other amaranth and weed species.
State partners to battle Palmer
Along with state agencies, additional conservation partners including conservation districts, nonprofit organizations and seed vendors are working to prevent the introduction of Palmer amaranth in conservation seed mixes, says Dan Shaw, a BWSR senior ecologist who works state-sponsored seed testing projects. BWSR recently finalized a seed testing policy that will apply to all of its projects that include plantings on conservation easements, Clean Water Fund projects and cost-share projects (see story section at bottom).
“If amaranth and/or pigweed seed is found in seed tests, vendors selling seed in Minnesota will need to have a molecular test done to verify that it is not Palmer amaranth,” Shaw says. A key part of the process is that seed vendors will need to send test information to local conservation staff before they can approve seed mixes for projects.
“Having MDA staff doing additional seed testing, and having site inspections conducted by conservation staff and other partners after planting, are also important parts of the process,” Shaw adds.
Palmer amaranth has quickly spread north from the Southwest U.S. via contaminated seed, hay, livestock feed and agricultural equipment, according to MDA. It has developed resistance to multiple classes of herbicides and their different modes of action, making it very difficult and expensive to control.
One Palmer amaranth plant can produce up to 250,000 seeds. It can grow 2 to 3 inches per day and commonly reaches heights of 6 to 8 feet. MDA said reported yield losses have been up to 91% in corn and 79% in soybean in some states.
Since 2014, Palmer amaranth has been listed on Minnesota’s Prohibited Noxious Weeds Eradicate List. All above- and belowground parts of the plant must be destroyed. Additionally, no transportation, propagation or sale of this plant is allowed. Failure to comply may result in enforcement action by the county or local municipality.
In November 2016, the MDA commissioner listed Palmer amaranth as a Prohibited Weed Seed. This means no Palmer amaranth seed is allowed in any seed offered for sale in the state. This includes agricultural, vegetable, flower, tree, shrub, and native grass and forb seeds sold in Minnesota.
If you suspect Palmer amaranth on your property, immediately call your local University of Minnesota Extension Educator or IPM specialist, crop consultant and/or the MDA’s Arrest the Pest line (888-545-6684) to report locations.
BWSR policy closes window on incoming Palmer, noxious weed seeds
The Minnesota Board of Water and Soil Resources incorporated new policy addressing the prevention of Palmer amaranth and other noxious weeds into its Native Vegetation Establishment and Enhancement Guidelines for projects.
The introduction of Palmer and other noxious weeds through seed mixes is a major concern in the state, BWSR notes, so it is important that Minnesota’s seed law is followed for all projects. Seed coming from counties within states where Palmer amaranth has become established is of particular concern.
The process for addressing Palmer amaranth concerns for any BWSR or Legislative-Citizen Commission on Minnesota Resources/Environment and Natural Resources Trust Fund-funded projects (and other agencies following this guidance) includes the following:
• Local seed sources must be the first priority for projects.
• To prevent Palmer amaranth in native and non-native seed mixes, as part of the bidding process, seed vendors must provide seed test results for any amaranth (pigweed) seed that was found in seed tests for the seed lots proposed to be used for the project.
• If amaranth species were found in the test results, the Minnesota Department of Agriculture requires that the vendor must also have a genetic test done to determine if the amaranth species are Palmer amaranth. These genetic test results must also be provided to project managers for the seed lots proposed to be used for the project.
• The test results must be provided to project managers. It is the project manager’s responsibility to ensure that vendors provide this information as part of the bidding process. Test results will also need to be available from vendors for random audits by MDA.
• After the acceptance of a seed bid, seed vendors must provide a preliminary seed label or tag for the proposed seed mix that lists any other weeds (restricted noxious and other weeds) that were identified in seed-lot tests for species in a seed mix. This step is intended to allow project managers to see any weeds in a mix that could cause problems for a particular project, and to seek final adjustments to a mix as needed. Official state seed labels or tags must be on or attached to seed bags, as required in state seed law. Seed labels and tags for seed mixes used for a project must be retained by project managers in the applicable project file.
• Project managers should work with the MDA if they have any concerns about seed mixes. MDA can assist with taking official seed samples in the field, as needed.
• Project inspections by local staff with plant identification expertise will play an important role as a final assurance that Palmer amaranth and other noxious weeds are not introduced into plantings.
BWSR says the new policy also is recommended for any planting to meet Minnesota’s Buffer Law.