Herbicide-resistant weeds are causing crop yield loss and reducing farm profitability in Minnesota. Confirming the presence of herbicide-resistant weed populations will help the farmers to plan for an effective weed management strategy. Currently, we are screening suspected herbicide-resistant waterhemp populations collected from corn, soybean, and sugar beet fields in Minnesota in 2020 and 2021.
Giant and common ragweeds are also troublesome weeds in row crop production fields in Minnesota (Photo 1). Previous research showed that giant and common ragweeds resistant to FirstRate (ALS inhibitor, Group 2) and glyphosate (EPSPS inhibitor, Group 9) are present in Minnesota. However, the distribution of herbicide-resistant ragweeds and the development of any new resistance cases are unknown.
Previous research showed that giant and common ragweeds resistant to FirstRate (ALS inhibitor, Group 2) and glyphosate (EPSPS inhibitor, Group 9) are present in Minnesota. However, the distribution of herbicide-resistant ragweeds and the development of any new resistance cases are unknown.
The ragweeds produce male and female flowers on the same plant; the male flowers are found at the top of the plant and the female flowers are in a group at the axils (the point of attachment of the leaf at the node). So, the ragweed seeds are also present at the axils and brown at maturity (Photo 2). The seeds have pointed tips and ridges on the top part.
Ragweeds seed samples requested
Please follow these steps while collecting the seed samples for herbicide resistance screening:
- Check whether matured ragweed seeds (Photo 2) are present on the plants.
- Ensure that the seeds are collected from the leaf axils (Photo 2) and not from the top.
- To make sure that there are enough seeds for resistance screening, please harvest seeds from 15 or more plants in the same field and place them in paper bags. DO NOT mix the seeds of two weed species – please bag them separately!
- The samples can be mailed directly to the UMN’s St. Paul campus:
- Attn: Debalin Sarangi
411 Borlaug Hall
1991 Upper Buford Circle
St. Paul, MN 55108
- Attn: Debalin Sarangi
- Samples can also be submitted to our local Extension Educators: here.
- Also, please provide your name, contact, county name, and GPS coordinate or Township of your farm (collection site) along with the samples.
Any questions should be directed to:
- Dr. Debalin Sarangi, Assistant Professor and Extension Weed Scientist
University of Minnesota
Phone no: 612-625-8130