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Monday, November 24, 2014

Overuse of herbicides erodes their effectiveness; companies seek to add new patents to old formulas

Farmers use chemical weed killers to save time and labor. They must keep using more when a chemical begins to lose its effectiveness. "Now there's a move afoot to add new patents to some of the old chemicals," Richard Oswald writes for the Daily Yonder.

Oswald writes that his father used the herbicide Roundup, Monsanto's brand name for glyphosate, to kill weeds and grasses and learned to be careful not to spray it too close to the crops. His father died just before Roundup Ready soybeans—genetically engineered to be resistant to Roundup—were released in 1994. He ran a farm-supply business and sold feed, fertilizer and farm chemicals. "It wasn't unusual for me to have a stiff neck by the end of the day, something Dad said was the result of being so close to so many pesticides," or herbicides, Oswald writes. His father wasn't concerned about it.
Roundup Ready wheat is not yet available, but farmers are still using the herbicide on it. "With few reservations, glyphosate can be applied to wheat and small grains as a desiccant, which removes moisture by causing the plant to die," Oswald reports. In the '60s and '70s, farmers used atrazine, but over time it became completely ineffective for weed control.

Dow Chemical Co. plans to patent a gene that makes crops resistant to 2,4-D, a herbicide linked to health effects many Vietnam veterans experienced. "But scientists say it wasn't 2,4-D in the mix that sickened people, but the dioxin that was part of the mixture," Oswald writes. The herbicide is still effective on most broadleaf weeds. Some are concerned about planting 2,4-D-resistant crops because "the chemical might be applied throughout the growing season with many adverse effects on less tolerant crops and ornamental vegetation when vapors or spray drifts well beyond the edges of treated fields," Oswald writes. Planting crops genetically resistant to 2,4-D could lead to the the herbicide's loss of effectiveness.

"Development of crops that resist 2,4-D is kind of a freebie for seed and chemical companies," Oswald writes. "They could develop a profitable, new patented gene based on an old chemical, in lieu of doing expensive research on new, better, safer herbicides." (Read more)

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