"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.
Farmers are on the attack, hiring laborers to walk through their crops and chop the plants down before they spread. The scientists who created the herbicide blame their customers -- the farmers -- for over-use. They say it was only a matter of time before Mother Nature came up with a way to work around the chemicals.
Scientists are engineering a solution, but it won't be ready for another seven years.
"Herbicide resistance is not a new issue to us," Smith said. "We've always known we'd have herbicide resistance. But we always had new technology coming into the marketplace. We have no new technology coming in now."
In the meantime, farmers will continue to lose their fields to the enemy, and in the coming weeks some of them may be forced to harvest their crops -- by hand.