It was once thought that weeds would not become resistant to herbicides.  However, in 1968, the first case of evolved resistance was reported.  Since then, over 180 species have developed resistance to one or more of 19 herbicide families.  Horseweed (Conyza canadensis) was the first weed to demonstrate glyphosate resistance in the mid south.  Extensive research has developed recommendations for good control of this altered biotype.  Amaranthus palmeri (also referred to as Palmer amaranth and Palmer pigweed) is considered the most troublesome weed in mid-south cotton production. The rapid growth, aggressive competition, extremely prolific seed production and germination throughout the season make pigweed a multimillion dollar pest each year in our area. Glyphosate tolerant crops, especially cotton has been readily adopted by farmers and greater than 98% of all cotton planted in the mid-South contains the glycol gene and is considered glyphosate tolerant. Adoption of glyphosate tolerant crops has allowed farmers to increase conservation tillage programs and farm larger number of acres with less equipment and labor.  In Arkansas, the number of farms with greater than 2000 acres has increased by 30% since the adoption of glyphosate tolerant crops.  Most of the commonly used agricultural practices in use today are built around the use of this technology