Weed Control Roulette

November 17, 2010 07:00 AM

Greg Kerber is resisting. Glyphosate prices may have dropped nearly 50% over the past year, but he’s determined to continue rotating chemistries to avoid the longer-term cost of weed resistance.

“There’s nothing easier than the Roundup Ready system,” says Kerber, who farms near Gibson City, Ill. “I like to use glyphosate. That’s why it’s so important to protect it. If we are going to be good stewards of this technology, we have to look at other options.”

In 2010, the list of glyphosate-resistant weeds grew to 11. Common waterhemp is now resistant to five classes of chemistry in Illinois.

University of Illinois Extension weed specialist Aaron Hager says the new era of weed control is like the days before Roundup. “It means planning a management system rather than simply depending on one product,” he says.

Preliminary crop budgets from the University of Nebraska show the average price of herbicides climbing 3% in 2011. However, at the farmgate, the price of products isn’t as key as the number of products and application costs to get the job done.

Kerber used a burndown residual on every acre this year and plans to do the same for 2011. “It allows me to use a different mode of action and hold back water-hemp to give my post product a chance,” he says.

He admits it is difficult to pay the $8 to $12 per acre cost of a residual for soybeans versus corn.

Kerber started rotating to the LibertyLink platform for his soybean acres two years ago. It’s the only nonselective trait technology for soybeans currently without resistance. The cost of Ignite (glufosinate) herbicide is slightly more than glyphosate, but LibertyLink seed costs are slightly lower, he says.

“Weed control costs are more than just the cost of what’s in the jug,” Kerber says. “The seed tech fee and the cost of follow-up products must be considered.”

It’s not unusual for growers to follow up with several selective herbicides. “I can control [glyphosate-tolerant] volunteer corn with Ignite, which saves me $6 to $7 per acre for a selective herbicide,” he adds.

The Biggest Barrier. In March 2010, the latest USDA reporting period for chemical prices, glyphosate fell to $22.80 per gallon from $42.80 per gallon in 2009. For most farmers, that puts cost at $2.50 to $3.50 per acre per application.

Andy Hurst, Bayer CropScience product manager, says inexpensive glyphosate has been the biggest barrier to growers adopting the LibertyLink system. Prices for Ignite were lowered 20% in 2010, bringing product cost in the $8 to $9 per acre range. “We also recommend a residual be included—either as a burndown, at planting or in the first application of Ignite,” he adds.

For the first time in 2011, LibertyLink seed will be available across wide maturity ranges in corn, cotton, canola and soybean. “Farmers now have the ability to rotate herbicide mode of action on every crop,” Hurst says. “That’s particularly important in the South, where they are running out of options.”

Hager urges growers to try to keep revenue in mind when looking at the input cost side of the ledger. “In weed control, we don’t buy anything to increase crop yield. Everything we do is to preserve the yield potential of the crop,” he says.

Tips to resist resistant weeds

• Rotate crops: Crop rotation provides a good opportunity for herbicide diversity.

• Rotate herbicide-tolerant traits: Alternate herbicide-tolerant traits or use herbicide-tolerant stacks for more efficient rotation of both nonselective and selective herbicides.

• Rotate modes of action: Rotate your use of multiple modes of action to reduce selection pressure by overuse of a single mode of action.

Top Producer, Mid-November 2010

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