EXCERPTS: The weed's evolution is rooted in genetically engineered cotton - called Roundup-Ready cotton...

"For moderate growers or those that have too much on their plate, it's going to be a major devastating impact" - Stanley Culpepper, a weed expert at the University of Georgia
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Georgia cotton growers fight pigweed
Associated Press, July 8 2006
http://www.macon.com/mld/macon/news/politics/14995325.htm

A variety of pigweed resistant to the herbicide Roundup is spreading in Georgia cotton crops, already identified in nearly 50 fields.

The plant - known as Palmer amaranth - is the first resistant weed identified in Georgia, said Stanley Culpepper, a weed expert at the University of Georgia. So far, the weed has popped up in Macon, Dooly and Taylor counties.

The cost of treating weeds increases "drastically" without the luxury of using Roundup, Culpepper said.

"For moderate growers or those that have too much on their plate, it's going to be a major devastating impact," Culpepper said.

UGA agriculture researchers are working on ways to control the weed. So far, the most successful strategy is using a combination of residual herbicides and tilling, Culpepper said.

But residual herbicides are expensive compared to Roundup, which costs about $4.50 per acre to apply compared to the $10-$12 an acre. Farmers also have increased fuel and irrigation costs from the distribution of the herbicides, which require multiple applications.

Pigweed grows 1 to 2 inches per day, flourishes even in a drought and produces an average of half a million seeds. It tolerates many herbicides and easily grows 6 to 8 feet tall.

The weed can't be killed once it reaches a certain height and clogs cotton harvesters.

The weed's evolution is rooted in genetically engineered cotton - called Roundup-Ready cotton - developed a decade ago. The cotton, used by the majority of farmers, allows weeds to be controlled by Roundup without harm to the crop.