Iowa State Extension and Outreach is taking action to stop the spread of an aggressive, invasive weed that threatens croplands. Experts say "Palmer Amaranth" is native to the southwestern United States, but has made its way into Iowa over the years. It is confirmed in at least nine counties in the state. It's known to have high resistance to herbicides and has devastated the cotton industry in the south. The best way to manage the weed is to slow its spread into and within the state. ISU extension has a video available on its website as well as tips on identifying the weed and treating it.