INTRODUCTION: Smooth Pigweed (Amaranthus hybridus (syn: quitensis)) is a dicot weed in the Amaranthaceae family. In Uruguay this weed first evolved resistance to Group 9 (Legacy G) herbicides in 2022 and infests Corn (maize), and Soybean. Group 9 (Legacy G) herbicides are known as Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (Inhibition of EPSP synthase). Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other Group 9 (Legacy G) herbicides. Copyright © 1993- 2023 WeedScience.org All rights reserved. Fair use of this material is encouraged. Proper citation is requested.