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Agribusiness: No going back if Clearfield rice technology lost

The Clearfield Production System for rice is currently the only mechanism rice producers have for controlling red rice in commercial rice. Chemical and seed company representatives and university weed scientists are concerned the technology could be negated or made less effective if red rice or barnyardgrass develops resistance to the herbicides currently labeled for use on Clearfield rice. They have developed new Clearfield stewardship guidelines that include a wider application window for Beyond herbicide.

Rice farmers realize that if they lose the Clearfield technology; i.e., it won’t help them control red rice in commercial rice fields; there’s nothing else to fall back on.

The problem is that sometimes economic and time constraints and pressure from landlords can lead them to make decisions that may not be in the best interests of preserving critically important weed control tools.

“Everyone is passionate about protecting the Clearfield production system,” says Avi Deshmukh, Clearfield marketing manager with BASF, the company that developed the herbicide-resistant strain of rice that allows growers to control red rice in commercial fields of Clearfield rice.

Deshmukh was referring to what BASF learned during six teleconferences with more than 400 rice growers and retailers last October and November. The teleconferences, which were conducted by Beck Ag, were aimed at discussing the stewardship guidelines for the Clearfield rice production system.

“Our goal is to make the guidelines as effective as they can be,” said Deshmukh, interviewed at the USA Rice Outlook Conference in Biloxi, Miss., in December. “And it’s to help growers get the most out of their investment in the technology.”

Since the introduction of Clearfield rice several years ago, BASF, Horizon Ag and RiceTec Inc., the primary distributors of Clearfield rice seed, have promoted stewardship guidelines aimed at delaying the development of resistance in red rice.

This year, BASF hired the Beck Ag, Inc., consulting firm to conduct the series of teleconferences to get more farmer input on the Clearfield rice stewardship guidelines. They also talked to ag retailers and university weed scientists about those efforts.

“Most farmers know that if Clearfield rice becomes ineffective, there’s nothing else that’s known that would fill that gap,” says Alvin Rhodes, technical service representative with BASF. “So it’s very important that we follow the guidelines.”

Rhodes discussed one new feature– the approval of a wider application window for Beyond herbicide in Clearfield rice – during a presentation at the New Products from Industry Session at the Rice Outlook Conference.

“Previously, farmers could apply a single, ‘rescue’ application of Beyond herbicide to manage red rice breakthroughs late in the season,” said Rhodes. “With the Beyond label expansion, growers can now use Beyond within a wider application window, as a second treatment after one Newpath or Clearpath herbicide application, and as a late-season application to manage advanced, late-season weeds.”

Under the Residual Clearfield Rice Herbicide Program, growers should apply Clearpath herbicide along with the residual herbicides Prowl H2O or Command between emergence and second leaf. Newpath herbicide should be applied about two weeks later between the three- and five-leaf stages.

Beyond herbicide may be used as a single rescue treatment for weed breakthroughs any time following the Newpath application and prior to panicle initiation (or green ring). Facet herbicide may be applied as a soil treatment, after emergence, or between the two-leaf stage and permanent flood. No more than 0.67 ounces per acre of Facet should be applied per season.

Under BASF’s new Knockdown Herbicide Program, Clearpath should be applied to rice from emergence through five-leaf. Beyond herbicide should be applied about two weeks later, between the four- to five-leaf stages followed by the permanent flood.

Beyond can also be applied again as a rescue treatment prior to panicle initiation or green ring. (Beyond may also be applied up to 14 days following green ring or panicle initiation on Clearfield rice varieties.)

“We don’t care if they apply Prowl H2O or Command as long as they put a residual herbicide out there,” says Rhodes. “That’s as much for the barnyardgrass and other grasses which also have the potential for developing resistance.”

Rhodes said 2011 is shaping up to be a good year for another of the major tenets of the stewardship guidelines – rotating Clearfield rice with another crop.

“With these unusually high prices, it looks like a good year to go with soybeans,” he noted. “We’re not trying to turn people away from rice, but the current futures prices for soybeans are very attractive and a good reason for growers to follow Clearfield rice with soybeans.”

Other points for farmers to consider:

  • Growers should be cautious about moving equipment and transferring red rice seed to other fields.
  • They should make sure they spray all parts of the field and not allow red rice to gain a foothold along field edges, on levees or under power lines.
  • Practice good water management. “Some farmers seem to think that the new technology allows them to be less vigilant on water management,” said Rhodes. “Good water management is still critical for the efficacy of Newpath, Clearpath and Beyond.”


The 2011 Clearfield Rice Stewardship Guidelines:

  1. Start clean – utilize a burndown herbicide at planting.
  2. Plant Clearfield rice according to seed company recommendations for best cropping practices.
  3. Apply a residual herbicide, such as Prowl H2O herbicide, delayed pre-emergence, to increase grass control.
  4. Apply two applications of Newpath herbicide as labeled or one application of Newpath followed by one application of Clearpath herbicide or vice versa. Clearpath may be substituted for only one of the Newpath applications but not both. The second application provides residual for extended weed control. Beyond herbicide may be applied as the second application after the first application of Newpath or Clearpath.
  5. Water management:
  6. Flush within two days of first application.
  7. Initiate permanent flood within two days of second application or as soon as the growth stage of rice permits.
  8. Maintain good soil moisture until permanent flood.
  9. Maintain weed-free levees and red rice-free ditches and turnrows.
  10. Treat with Beyond to control escaped red rice at a proper growth stage according to Beyond label.
  11. Rogue for red rice escapes.
  12. Do not ratoon rice crop if red rice is present at harvest, regardless of plans to harvest or utilize as habitat.
  13. Roll and flush Clearfield rice fields after harvest to promote germination of weeds in the fall.
  14. After frost in the fall, destroy all remaining rice plants. 
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