University of Missouri Extension’s weed science team is working on ways to understand and eradicate the millions of weed seed buried in every acre of U.S. cropland, especially seeds of highly invasive, herbicide-resistant weeds like waterhemp and Palmer amaranth. Only 5%-10% of these buried seeds germinate and emerge each year, but that small percentage can mean big yield losses, says Kevin Bradley, head of the Mizzou Weed Science team. Although most weed scientist talk about reducing the weed seed bank of croplands, very little information actually exists about the density and diversity of weed seeds in these areas, Bradley says. Waterhemp seed makes up for its tiny size with large numbers that are increasingly resistant to herbicides, dodging pre-emergence applications and still flourishing after post-emergence applications of non-residual herbicides such as glyphosate, glufosinate and 2,4-D. PHOTO: Mizzou Weed Science team is led by MU Extension weed scientist Kevin Bradley.