Watching Out For Weed Resistance
March 1, 2010 In January, more than 300 weed scientists from North and South America gathered in Miami Beach to share knowledge on the growing problem of weed resistance. The Pan-American Weed Resistance Conference, which was sponsored by Bayer CropScience, paid particular attention to glyphosate resistance.
Bill Buckner, president and CEO of Bayer CropScience, welcomed the group. “We are pleased to host this type of forum for these industry experts in the U.S., building upon the success of similar forums held in Europe.”
What Would Darwin Say?
While Florida has been spared so far of resistance problems to glyphosate, other parts of the U.S. and globe have not been so lucky. Stephen Powles, a weed scientist with the University of Western Australia, said his country’s experience and what is happening in parts of the U.S. should serve as a cautionary tale to Florida agriculture. Currently, Australia holds the title of being the worst country in the world for weed resistance, but Powles said the U.S. will likely take that spot soon. This is because of reliance on glyphosate in Roundup Ready row crops.
Powles posed the question during his presentation at the conference: “What would Charles Darwin say about today’s weed resistance problems?” he asked. “He would say ‘nature would win.'”
“In large parts of North and South America, glyphosate is being driven to redundancy because it will not work on the major weeds,” he said. “That is lamentable because glyphosate is simply the best herbicide in the word. It is one of those once in 100 years discoveries. We must do everything we can to preserve it as long as possible.”
Unfortunately, there are three biological mechanisms for resistance to glyphosate — two are target-site mechanisms and one non-target. The more mechanisms there are to achieve resistance, the greater the opportunity for the problem to spread quickly.
“Just a few years ago, there were a lot of scientists who said there was no way we’d see resistance to glyphosate,” he says. “Today, we have three different ways to develop resistance.”
Diversity Is Key
“My advice to a Florida grower is if you have glyphosate working, you do all you can to keep it working,” said Powles. “And, you do that by not relying on it so much. It is a precious chemical, and you want it to work for future crops and future generations. If you overuse it, resistance will develop.