Twitter chat tackles weed resistance issues

Colleen Scherer, 01/10/2013


Syngenta hosted an hour-long Twitter chat Thursday with Stephen Powles, Ph.D., on the multiple issues surrounding herbicide-resistant weeds in agricultural crops. Powles is a professor at the University of Western Australia and specializes in herbicide resistance and is directory of the Australian Herbicide Resistance Initiative.

Participants asked multiple questions regarding herbicide resistance and managing these hard to control weeds. Some of the questions included:

  • How does resistance management differ in Australia vs. the U.S.?
  • What can we in North America learn from Australia?
  • With the spread of resistant weeds in North America, what best practices do you recommend?
  • Could the Harrington Seed Destructor be effective in the U.S.?
  • Should ag industry pros look to increase their budget for dealing with herbicide-resistant weeds this year?
  • Where do you see glyphosate weed resistance in 10 years?
  • What weed(s) should U.S. farmers be most concerned about developing resistance in 2013?

Powles explained that herbicide resistance started earlier in Australia than it did in the United States, which forced Australia to adopt resistant management strategies earlier than the U.S. However, the U.S. can learn from Australia, he said.

“You can learn [that] the herbicides you have now are precious and yet we are wasting them, so [we] need to reduce sole reliance on herbicides,” Powles said.

He also offered his tips for best practices.

“Rotate every herbicide. Reduce glyphosate reliance. Introduce non herbicide tools that make economic sense for you. We rotate herbicides that still work and we use non herbicide tools, especially techniques to target killing weed seeds,” he said.

Several questions centered around the Harrington Seed Destructor (HSD), which is designed to capture and kill weed seed at harvest time.

“HSD is a new tool. Killing weed seed is crucial and needed in the U.S.,” he said. “[It is] still early days on HSD but late season weed seed kill techniques are a huge opportunity that is needed in the U.S. to counter resistance. Harvest weed seed control techniques (HWSC) include chaff carts, narrow [and] windrow burning. HSD is essential to reduce weeds and resistance management.”

Although the eradication of all weed seed is impossible, HWSC helps preserve herbicides, Powles stressed. He explained that the HSD is a tool to help reduce the weed seed. However, it is too early to know if the HSD is appropriate for use in the United States.

“This is a whole new paradigm for U.S. producers and I predict HWSC will become a part of future farming in [the] U.S.,” he said.

In looking to the future, Powles said North American ag professionals needed to plan for increasing their budgets for weed control. He explained that glyphosate resistant weeds will become a major Cotton and Corn Belt problem. In the next 10 years, he foresees glyphosate failing even worse. However, he remains optimistic that producers “will adapt and adopt alternatives to beome much more diverse in weed control tools.”

As for weeds to watch in 2013, he warned to watch for glyphosate resistant waterhemp and ragweed in addition to Palmer pig weed.

To view the entire chat on Twitter, follow the hashtag #RFC13.




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