Purdue: Atrazine provide efficient, cost-effective weed control

American agricultures oldest and most well established herbicide, atrazine, is a component of an inexpensive and effective way to protect corn against many types of weeds, said Purdue University weed scientist Bill Johnson.

In Indiana, millions of pounds of atrazine are applied annually to corn and sorghum to control broadleaf and grassy weeds and it is the main ingredient in about 40 name-brand herbicides.

Currently, the Environmental Protection Agency is reviewing the safety of atrazine for the third time since the early 1990s. In each of the two previous reviews the EPA ruled in atrazines favor, most recently in 2006 after considering 6,000 studies and 80,000 public comments.

Some ways farmers can ensure atrazine is applied as safely and effectively as possible are to follow all label instructions and know when and where to apply the herbicide.

"Farmers need to understand both the rate restrictions of atrazine for different soil types and the setbacks from water sources," Johnson said. "Like any chemical, they shouldnt apply atrazine right before a big rain in order to prevent runoff."

Other safe-handling techniques include establishing 66-foot grass buffer strips along bodies of water and ditches to help filter out atrazine from water flowing across fields, switching to herbicides that are tank-mixed with atrazine to reduce the amount used, turn off sprayers when crossing grass waterways and choosing crops that dont require the use of atrazine when planting near water sources.

Not only is atrazine inexpensive and easily obtainable because it is off patent, but corn farmers can apply the chemical as early as 30 days before planting to the time corn reaches 12 inches tall. Because it also can be used as a foundation herbicide, additional herbicides can be applied to control weeds atrazine does not.

Annually in the United States, atrazine saves farmers an estimated $2 billion by increasing crop yields and helping producers avoid other, more costly herbicides.

"There are a lot of herbicides labeled for corn, but only a select few control as many weeds at as low a cost as atrazine," Johnson said. "Herbicides with more narrow spectrums drive up costs and eliminate the simplicity atrazine offers."

Source: Ohio State/Purdue University Ag Answers