Minnesota Crop News

Sithin Mathew, Weed Science Graduate Student, Matt Pfarr, Former Crops Extension Educator, Debalin Sarangi, Extension Weed Scientist Figure 1. Asian copperleaf growing in a corn field in Rice County, MN (Picture by: Debalin Sarangi, UMN Extension) A New Report from Rice County In the fall of 2025, a new and concerning weed species has been identified in a corn field in Rice County, Minnesota: Asian copperleaf (Acalypha australis). Until now, this invasive species had only been reported in a handful of Iowa counties and in Illinois in the Midwest. Its presence in Minnesota is a significant development for farmers; it signals that the weed is spreading and could become a serious problem in corn and soybean systems if not managed early on. The USDA already recognizes Asian copperleaf as a “high-risk invasive weed”, and its arrival in Minnesota should serve as a wake-up call to scout fields carefully this harvest season. Where Did It Come From? Asian copperleaf is native to Eastern Asia, ...

Eric Yu, Extension Educator – IPM Crops, Dave Nicolai, Extension Educator – Crops As harvest approaches, now is a good time to scout fields and field edges for weeds that escaped earlier control. Mowing fence lines, field edges and other non-crop areas can help prevent weeds from producing seed and reduce the potential for weed seeds to move into fields during harvest. Despite the drier conditions across much of Minnesota this year, weeds continue to emerge and develop in fields and along field edges. Take time now to identify and manage these weeds before they produce additional seed and replenish the soil seedbank. Scout for escaped weeds Many weeds in corn and soybean fields are flowering or developing seed. Pay particular attention to waterhemp and other pigweed species, giant and common ragweed, kochia, common lambsquarters and annual grasses. Waterhemp is especially important to manage because it can produce viable seed within 10 days of pollination and is capable of producing hu...

By Liz Stahl, Extension Educator – Crops, Seth Naeve, Extension Soybean Agronomist, and Debalin Sarangi, Extension Weed Specialist

Sithin Mathew, Weed Science Graduate Student, Eric Yu, UMN Extension Crops Educator, and Debalin Sarangi, Extension Weed Scientist Herbicides often require the use of adjuvants to maximize weed control efficacy and minimize application-related risks. Although some herbicide formulations contain built-in adjuvant packages, few are designed to optimize performance across the wide range of environmental and application conditions. Therefore, the applicator often needs additional adjuvants to optimize the herbicide application for the specific conditions of the area being treated.  The most commonly used adjuvants can be grouped into four categories: 1) activator adjuvants [e.g., nonionic surfactant (NIS), crop oil concentrate (COC), and methylated seed oil (MSO), etc.], 2) water conditioners [e.g., ammonium sulfate (AMS), and volatility reduction agent (VRA), etc.], 3) spray solution modifiers [e.g., antifoam agents, and drift reduction agents (DRA)], and 4) adjuvant mixtures. Adjuvan...