"I've never seen anything that had this major an impact on our agriculture in a short period of time," said Ken Smith, a weed scientist at the University of Arkansas.
This past summer, Pace Hindsely of Coffee Creek Farms and other farmers started noticing the chemicals they routinely used were no longer working.
"The last three years it's really just exploded. There is no rhyme or reason as to how we can control it," Hindsely said. "I am worried about the future or what these fields will look like next year and the year after if we don't control this weed."
The weeds have adapted, and this year they're choking more than a million acres of cotton and soybeans.
In the last three months, Jim Hubbard of Double H Farms has spent more than $500,000 fighting the pig weeds, and they still won't die.
"Technology is great, but it can only go so far," said Hubbard. "As technology goes forward, so does mother-nature. As far as the weeds and everything, they adapt and overcome."
"Some of the causes related to the issue are the use of a single crop year after year. There are issues around using the herbicide without any other herbicides, and quite frankly, trying to control weeds that were too big," said Rick Cole, technology development manager at chemical maker Monsanto.
Pig weed is one formidable weed. It grows up to three inches a day, and at its base it's as thick as a baseball bat. It kills crops and destroys heavy machinery, keeping farmers from bringing their combines and cotton pickers into the fields.
"They get so big that sometimes you can't pull them up, so it's getting to be an extremely, extremely bad problem," Hubbard said.