Do you know which weeds are affecting soybean production in your county?

Use this tool to find out... and to discover any chemical resistance that is occurring.

Simply choose a county from the Counties dropdown menu at the left or "hover" your cursor over the place on the map you want to check. A pop-up window detailing the occurrence of Common Waterhemp, Horseweed (Mare's Tail) and Palmer Amaranth in that county will appear for your review. 

In addition, we have provided photo galleries to help you identify the weeds at various growth stages. For additional weed management guidance, see our Helpful Links page. For a chronology of herbicide resistances in Illinois, click here.

Note:  SOA = site of action. SOA is similar to herbicide mode of action (HMOA) but is more precise because it differentiates not only mode but site as well. For example, glyphosate and ALS inhibitors have the same mode of action, but different sites of action.

Only single herbicide resistance traits are listed. Please be aware, however, that two or more resistance traits (i.e., multiple resistance) may exist within a single population, and such cases of multiple resistance are not listed in this database.

Click here for the mobile-friendly version of the map.