Shane Blair – Minnesota Department of Agriculture
It’s weed season and with it comes the importance of being aware of invasive plants in the field. For example, Palmer’s pigweed is a fast-growing annual weed that harms row crops and can increase production costs for farmers already facing high input costs. Palmer’s pigweed has developed resistance to several classes of herbicides and their different modes of action, which makes it very difficult and expensive to control.
The Minnesota Department of Agriculture (MDA) considers Palmer’s pigweed a high priority noxious weed and is working closely with farmers, crop consultants and University of Minnesota extension educators to eradicate new infestations when discovered. Since 2016, the MDA has identified several pathways by which Palmer pigweed moves throughout Minnesota, including seed, feed, screenings, and manure.
During each growing season, the MDA Noxious Weed Program receives many inquiries about plants like Palmer’s Pigweed. Inquiries often include requests for identification, questions about how to manage weeds, and expected requirements of landowners and local governments under noxious weed law. To ensure MDA responds quickly to suspicious reports of species like Palmer pigweed, MDA rolled out a new pest case management system in 2021 to help identify suspicious plants more quickly.
If you were familiar with Arrest the Pest email and voicemail, they have now been renamed Report a Pest to work with the new pest case management system. Report a Pest allows the public and MDA responders to report suspected pest infestations online. It requires the user to submit information about the suspected species, location, and contact details so that MDA staff can request follow-up information if needed to confirm the report. If photos are provided, staff can quickly identify the species and determine if it is a species of special concern that would require further investigation. MDA staff can then create individual actions when species of concern are documented in these reports. All pest species can be reported, and MDA’s rapid response to Palmer infestations has been greatly enhanced by this new reporting system.
If you suspect Palmer’s pigweed on your property, immediately visit MDA’s Report a Pest page and enter the location of the suspect plants and your contact information into our online report form. If you have a phone or camera with you, take several photos of the plant (whole plant, leaves, flowers, etc.) and upload them with your report.
Once you have reported through Report a Pest, an MDA staff member will review you and contact you if more information is needed or to let you know what the next steps are. If a suspicious plant is found, mark it clearly so that it can be found quickly if the MDA decides to visit the site or remove it from the field and keep it until the species is confirmed. Living plant material should be placed in a plastic bag and refrigerated. Dead and dry plant material should be placed in a paper bag and stored at room temperature. If the MDA suspects the plant is Palmer’s amaranth, we may ask you to send plant tissue to a lab for genetic testing to confirm identification and send you a protocol for submitting a sample.
Visit the MDA’s Palmer Amaranth webpage in Minnesota where you can learn more about the plant and what characteristics to look for to identify it in the field.