Growth in herbicide-resistant weed populations is accelerating. University and ag industry speakers hammered home this message at Bayer CropScience's Pan American Weed Resistance Conference Tuesday in Miami.
Over extensive areas in North and South America, they stressed, Group 1 and 2 herbicides have already lost much of all of their value. Products in other herbicide groups are also coming under resistance pressure. And the fears are that glyphosate could be next.
Herman Steubler, director of herbicide research at Bayer headquarters in Germany, explained that glyphosate's dominant role in weed control was not due solely to its performance in the field.
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| Bayer's Herman Steubler suggests glyphosate-tolerant crops may be at risk of being victimized by their own agronomic and commercial success. |
The herbicide landscape, he said, had changed dramatically within the past five to 10 years. In addition to the commercial success of glyphosate-resistant crops, the ag chemical industry has consolidated, regulatory hurdles have increased, production of generic herbicides has expanded, and crop rotations have tightened.
As a result, in some regions and crops, glyphosate has pushed other weed-control technology, both chemical and mechanical, to the sidelines or right out of the ballpark.
Steubler and other speakers at the conference displayed table after table, and graph after graph, showing sales of other herbicides shrinking sharply, in lockstep with acreage increases for glyphosate-tolerant crops. But these speakers went on to suggest that glyphosate's success carries the seeds of future disaster.
"Nature has fought back," Steubler said, in a reference to the ability of living organisms to overcome attempts to kill or control them. By 2018, he projected, glyphosate-resistant weeds in North American corn and soybeans will jump.
The good news for Canadian farmers who depend on glyphosate is that no resistant weeds have been found north of the border. That's probably due to the use of rotations with small grains and other crops in which glyphosate is not used. But given the rapid expansion of resistant weeds in the U.S., Canada's farmers should probably not count on this situation lasting into the long term.
Conference speakers could offer little in the way of a fast fix. Many weed control alternatives exist, they pointed out, but they're generally more costly, less effective, or otherwise inferior to glyphosate resistance technology. Not, they hastened to add, that growers shouldn't use alternative strategies such as crop and herbicide rotations, or even tillage where appropriate.
Longer-term, Steubler saw ground for optimism. The crop protection industry, he said, knows what's needed in terms of new modes of action, environmental safety, resistance-breaking capacity, and so on.
Bayer, for example, has established a herbicide discovery system using new and more effective research techniques that will eventually, and possibly quite soon for some products, bring results.