PPDL Picture of the Week

October 21, 2019

Updates to Indiana's Noxious Weed List

Stephen Meyers, Assistant Professor of Weed Science, Department of Horticulture and Landscape Architecture, Purdue University

On September 18, 2019 the Office of the Indiana State Chemist received approval to add weedy amaranth species to its list of restricted noxious-weed seeds.  This means that weeds such as Palmer amaranth, waterhemp, and other weedy pigweeds will now be subject to restrictions under the state's seed law.  The restriction will not apply to Amaranthus species sold as vegetables, ornamentals, or edible grains for human consumption.  According to state seed law, "It is unlawful for any person to distribute agricultural seeds if the seed consists of or contains restricted noxious-weed seeds in excess of 0.25%, or if it contains more than 2.5% of all weed seeds. If less than 0.25% of such weed seeds by weight are present, the number per pound must be declared on the labeling."  Indiana joins Iowa, Minnesota, North Dakota, Tennessee, Washington, and Wisconsin in designating Palmer amaranth as a noxious-weed seed species.  Wisconsin also recognizes waterhemp as a noxious-weed seed species.  The official update to the Indiana noxious-weed seed list will be October 18, 2019 with enforcement starting January 1, 2020.

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Palmer amaranth (Photo by Bill Johnson)

Waterhemp (Photo by Bill Johnson)

Palmer amaranth, Waterhemp, and Redroot (Photo by Bill Johnson)