Walt Corcoran calls it the “nightmare from Georgia” — a monster-sized weed that tears up equipment, gobbles up profits and spreads even after being socked with the farmer’s most trusted herbicide.It’s called Palmer amaranth, or more commonly, Palmer pigweed. And Corcoran’s Barbour County farm north of Eufaula has it — lots of it.At last estimate, he figured the weed had infested about half of the 5,000 acres he farms with his brother Tom and nephew Liston Clark in Barbour, Russell and Henry County, Alabama and Quitman County, Georgia.Of course, Palmer pigweed can grow two to four inches a day and each plant can produce as much as a half million seeds. So there’s no telling exactly how much land it now covers. All he knows is that it’s in his cotton, his soybeans, his peanuts and, to a lesser extent, his corn. And it’s not going away on its own.He first noticed the stubborn weed about three years ago, about the same time Dr. Stanley Culpepper of the University of Georgia Extension System discovered that Palmer pigweed had developed a resistance to glyphosate, and was spreading across central Georgia farmland like the ocean’s tide.Almost 1 million acres are now believed to infest Georgia as farmers work to find a suitable alternative to glyphosate, the active ingredient in the popular Roundup brand from Monsanto.Glyphosate-resistant Palmer pigweed has also been found in North Carolina, South Carolina, Arkansas, Virginia and Tennessee.”I’m not sure these are exactly Palmer amaranth, but they’re a close cousin or a hybrid of them,” said Corcoran. “There are several kinds of pigweed and all are hard to kill with what was once possible with herbicides like Roundup or Staple.”Dr. Michael Patterson, an Extension weed scientist from Auburn University, says the Corcoran farm may actually have both Palmer pigweed and another species of glyphosate-resistant pigweed. “These things hybridize fairly easily,” said Patterson, who says Extension is currently studying pigweed from Corcoran’s Barbour County farm as well as other sites in Houston and Baldwin counties.”The Georgia Extension people have found that resistance can be transmitted from the pollen of a resistant plant to a non-resistant plant, and then the seed will have some resistance due to that resistant pollen,” said Patterson. “The gist of that is we’re not going to be able to stop the spread of the resistance through the state. It was inevitable that this would happen, and it’s happening pretty much all across the Southeast.”Corcoran said he first noticed the glyphosate-resistant pigweed in his cotton fields in 2005. Last year, it had spread to his peanuts — not surprising since both crops use the same type of herbicide chemistry. The corn, however, utilizes an older herbicide known as Atrazine, and hasn’t been plagued as much by the pigweed.”We’ve upped the rates of what we were using and tried a different chemical but it was in the same family, and it didn’t work,” Corcoran said. “After a little while, you realize you can’t keep spending money on it, and you just give up. Or you drop back and punt — plan better for the next year.”Patterson, who believes heavy reliance on glyphosate has contributed to the development of resistant weeds, says any battle plan should include crop and herbicide rotation strategies and a return of older, pre-Roundup herbicides to the farmers’ arsenal.”These good commodity prices we’re seeing for corn and soybeans are encouraging rotation which is good,” Patterson said. “When we rotate into those crops, we also rotate in the herbicides that are different from the cotton herbicides. We’re going to have to start using some of these older products — we’ll still use Roundup Ready because it still kills a bunch of weeds.”Patterson has established plots on the Corcoran farm, testing various herbicide applications in corn, cotton, peanuts and soybeans. “Maybe we can see how to best control them in each crop,” said Corcoran, adding that the plots will be part of a field day event sponsored by Extension at the farm on Sept. 5.Even so, the cost of fighting the pigweed is high. Corcoran says farmers who’ve been using Roundup alone will likely see their herbicide costs triple. Other studies indicate that glyphosate-resistant pigweed will add as much as $45 per acre to their herbicide costs.Yet, another solution, says Patterson, may ultimately be one that no-till farmers fear most — plowing the pigweed under and burying the seed deep. A study to explore that approach is now in its third year at the E.V. Smith Research Center in Tallassee, and Patterson says “we’ve had a little success with that.”Corcoran, however, says that’s not something he’s willing to try — at least not yet. “The benefits of strip till are probably just too great to do that,” he said. “Once you flipped it (deep-tilled the soil), you destroy everything you’ve been doing.”No matter what the farmers try, however, Patterson says it will be an uphill battle.”My colleagues in Georgia will tell you that this weed is so aggressive and so large — you’re talking about a weed that grows eight-feet tall and can have a stem on it as big as your arm — if you don’t control that one weed in a row crop, you don’t make anything. You won’t harvest any crop,” Patterson said.”Ninety-nine percent control is not good enough,” he added. “If you pick up a shovel full of soil, you may have a million seeds in that shovel full of soil. It sounds unbelievable but it’s true. So, if you’ve got a million plants on an acre of ground and you control 99 percent of them, you’ve still got 10,000 plants left per acre. So you’ve got to maintain complete control because this weed is so competitive and produces so much seed. And with our current technology, we’ll never exhaust the seed supply in the soil in these fields. This is going to be a long-term problem.”One reason for that, Patterson says, is because it would take as much as 10 years for chemical companies to bring any new “miracle” product to market.”They may slow it down, but I don’t think farmers can save their farms waiting for that to happen,” he said. “Too bad we can’t find a use for it, maybe grow it for biomass and make fuel out of it. That thing gets so big…maybe we should be looking at that. You know, if you can’t beat ’em join ’em. It’s a bad boy.”