The Results are in: WSSA Survey Ranks Most Common and Most Troublesome Weeds in Grass Crops, Pasture, and Turf Share Article The latest survey conducted by the Weed Science Society of America (WSSA) shows that Palmer amaranth is the hardest to control weed in grass crops, while foxtail species are the most prevalent. Stanley Culpepper, professor and extension weed scientist at the University of Georgia, says “Palmer amaranth grows rapidly, has an extensive root structure and produces massive amounts of seeds that are easily transported and spread.” WESTMINSTER, Colo. (PRWEB) May 11, 2021 The latest survey conducted by the Weed Science Society of America (WSSA) shows that Palmer amaranth is the hardest to control weed in grass crops, while foxtail species are the most prevalent.