Occurrence and transport of aerially applied herbicides to control invasive buffelgrass in Rincon Mountain District, Saguaro National Park, Arizona

First posted July 21, 2022 For additional information, contact: Director,Arizona Water Science CenterU.S. Geological Survey520 N. Park AvenueTucson, AZ 85719 Resource managers of the Saguaro National Park are concerned about the spread of the invasive species Cenchrus ciliaris L. (buffelgrass) and the threat it poses to desert ecosystems. Glyphosate-based herbicide treatments seem to be one of a few viable options to control the spread of buffelgrass in the mountainous terrain of the National Park. The U.S. Geological Survey completed a 4-year study with the National Park Service that investigated the potential for glyphosate and associated byproducts to remain in soil and transport with stormwater runoff to ecologically important surface waters after aerial application of glyphosate-based herbicides. The results of this study are helping managers and park administrators better understand the long-term effects of treating buffelgrass with glyphosate-based herbicides.