Weed resistance is becoming more of an issue for farmers, retailers, advisors and the chemical industry. In the past two years, there have been seminars and large-scale plot tours to highlight and focus attention on the issue.
By Ralph Pearce
Weed resistance is becoming more of an issue for farmers, retailers, advisors and the chemical industry. In the past two years, there have been seminars and large-scale plot tours to highlight and focus attention on the issue. Now, in the past year, there has been a bevy of news articles detailing researchers’ confirmations of a growing number of cases of weed resistance. All of this is pointing to a future that, in spite of higher commodity prices (at least for the time being), will be defined more for its challenges to growers in the field of weed management.
US sources cite an increasing frequency of herbicide resistance in weeds, and although glyphosate is most commonly identified, the list of herbicide groups continues to grow. Most recently, University of Nebraska researchers confirmed resistance to 2,4-D in waterhemp plants in a field of grasses in that state. Seeds from the weeds found in a few fields of warm-season grasses were gathered in 2009 and 2010, and tested extensively, finally yielding the positive result in October 2011. Still, that means there are now six different herbicide groups to which waterhemp has developed some level of resistance in the US Midwest. The same is true for Palmer pigweed, an Amaranth species that has crippled growers in much of the Midsouth region, including Arkansas and Tennessee. Here at home, the problem can be seen in giant ragweed plants, which are also showing resistance to glyphosate.
One step forward. . .
In spite of the efforts of the universities, the ministries and the chemical and traits companies, this problem is only going to worsen before it ever gets better. In fact, from a perspective that is purely based in agribusiness, the focus now seems to be on traits and stewardship, as well as seed treatments and inoculants. Although all of those platforms are worthy and much needed, there may be a more pressing sense of urgency to help growers with management strategies to handle weed resistance. And it is not a matter of the chemical companies coming up with “another glyphosate.” That strategy was dismissed in summer 2010, during a field day in Arkansas. Researchers and retailers alike called glyphosate a “once in a lifetime discovery,” noting they wanted it available for many years to come. Switching to some other so-called silver bullet solution, such as glufosinate, would only land farmers in trouble in another five years, when they would face similar resistance issues with that new active ingredient.
The key, said the researchers and retailers, is similar to profitability: people do more to manage their money than hope for the lottery to smile on them. And weed resistance has a similar outlook.The only good news in this case is that US examples are our “canary in the coal mine” here in Ontario. It is not a matter of “if” but “when.”
Good luck, Heather
One last note here: Page 6 contains the swan song of Dr. Heather Hager, our field editor here in Eastern Canada. For the past three years, Heather has provided crystal-clear writing, an uncanny ability to simplify even the toughest subjects, and a value to this magazine that is just too hard to measure. She is moving on to the University of Guelph, where I am certain she will become as treasured and valued as she has been at Top Crop.
You will be missed, Heather.