56 / SEEDWORLD.COM SEPTEMBER 2017 GROWING 2 TO 3 inches per day, Palmer amaranth, also known as Palmer pigweed, can have a devastat- ing impact on crop yields. Its stems are tough enough to damage rugged farm equipment, and it’s extremely prolific — a single plant can produce as many as a million seeds during the growing season. According to the U.S. Department of Agriculture, yield losses up to 91 percent in corn and 79 percent in soybeans in the Midwest have been found. The weed isn’t just a problem for farmers; it’s also proved to be a challenge for seed companies, as some states have proposed the addi- tion of Palmer amaranth to their noxious weeds list. This proposed change has been approved in Delaware, Minnesota and Ohio. Minnesota has a zero-tolerance policy, meaning that if any Palmer ama- ranth is found in a seed lot, it cannot be sold in the state. Both the American Seed Trade Association (ASTA) and seed testing com- panies have ramped up efforts to help industry cope with the destructive weed. “Weeds like Palmer amaranth move through many different routes, so con- trolling them requires an active, unified strategy, including growers, industry and government,” says ASTA President and CEO Andy LaVigne, who hosted a meet- ing to discuss a collaborative approach to addressing Palmer amaranth and other weed seed issues. Grower groups, seed companies and state government officials all participated in the meeting, which served as a produc- tive information exchange and strategic dialogue about potential short- and long- term solutions. When it comes to purchasing seed, meeting participants underscored the need to communicate with growers the importance of buying professionally produced seed from a company licensed to do business in the state, and specifi- cally checking if seed was tested both for performance and for presence of Palmer amaranth and other weeds. The Challenge However, Toni Bartling, a research scientist with Eurofins BioDiagnostics, says until recently, no seed test existed that could identify Palmer amaranth from other ama- ranth species in a seed lot. Bartling and her team had a keen eye for what was coming down the pipeline As farmers struggle to keep fields free of weeds, the seed industry looks for solutions to help address the challenges caused by the very prolific Palmer amaranth. Julie Deering Strategies to Cope with Palmer Amaranth and began working on solutions. In 2016, the Eurofins BioDiagnostics seed testing team began working with the Minnesota Department of Agriculture to develop a genetic test. “This proved no easy task,” Bartling says. “We had to be able to extract enough DNA to test, and Palmer amaranth seed is very small.” With the help of Robert Price, senior seed botanist with the California Department of Food and Agriculture Plant Pest Diagnostics Branch, the team devel- oped a test that uses DNA sequencing and analysis of internal transcribed spacer (ITS) region that allows for the identification of individual Palmer amaranth seeds in a seed lot. Price had been using ITS sequencing in his laboratory to identify fungal diseases. Bartling first recommends growers use a purity noxious test to sort out any noxious weed seeds that might be Palmer amaranth. Then ITS sequencing can be used to test if the seed is Palmer amaranth. “If Palmer amaranth is confirmed, then it must be marked on the report, and that seed cannot be sold in the state,” she says. “However, if no Palmer amaranth is found, we can amend the report and the cus- tomer can sell their seed.”