Weeds
Learn more about problem weeds in Iowa, utilizing different management tactics to help control problem weeds, and more about how to minimize the spread of herbicide resistance.
Tools and Resources
- All Weeds and Weed Control Publications
- Herbicide Options for Palmer Amaranth in CRP
- Iowa's Noxious Weed Law: Chapter 317
- Palmer Amaranth Identification
- Weed Identification Fact Sheets
- Weed Identification Field Guide 2nd Edition
- 2025 Herbicide Guide: Iowa Corn and Soybean Production
- Weed Content Index
Timely Insights on Weeds
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December 9, 2024Content Author
Key Points
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September 11, 2024Authors
As corn and soybean are taken out of fields, some fields may reveal an unexpected mat of Asian copperleaf lurking below the canopy. As of this summer, we’ve identified Asian copperleaf (Acalypha australis) in crop fields in eight counties: Calhoun, Humboldt, Boone, Wright, Franklin, Hardin, Grundy, and Black Hawk. Early identification of this species is key to adopting effective management tactics to reduce its spread to other fields.
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August 22, 2024Authors
Key Points:
Precision spray technology is available in the ag marketplace to provide selective post-emergence herbicide applications. Iowa State University conducted a field scale demonstration of a commercial precision spray system on five conventionally managed soybean fields totaling 415 acres. Herbicide savings per field was 90.6%, 87.6%, 87.2%, 71.2%, and 43.9% respectively. Herbicide savings were directly influenced by the initial weed pressure in the field. Average product savings across all fields was 76% and had an economic savings of nearly $6,500 ($15.7/ac) from reduced herbicide use. -
July 29, 2024Content Author
The benefits of intercropping in agricultural systems include the potential for better management of pests, pathogens, and weeds. Relay cropping (RC) consists of two or more crops grown in sequence with some overlap in the growth cycle, leading to sustainable intensification of the existing cropland. We hypothesized that the intercropping system affects crop productivity and the growth of weeds.
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July 3, 2024Content Author
I’ve received several phone calls in the last couple weeks regarding waterhemp or other species that survived postemergence herbicide applications (in some cases, more than one!). While most herbicide applications have finished, it isn’t too late to evaluate how well your program worked, whether fields would benefit from a “last ditch effort” to reduce weed seed production, and what changes might be necessary for next year.
