18.5 Herbicide Resistance to PPO Inhibitors

At the time this chapter was published, four different weeds species in the US had been reported as being resistant to PPO Inhibitors.  These include: Palmer Amaranth (Amaranthus palmeri), Tall Waterhemp (Amaranthus tuberculatus (=A. rudis), Common Ragweed (Ambrosia artemisiifolia) and Goosegrass (Eleusine indica).  For the latest updated information on herbicide resistance, see The International Survey of Herbicide Resistant Weeds, a collaborative effort between weed scientists in over 80 countries, located at www.weedscience.org.