Glyphosate resistance scares the heck out of Jeremy Girillis of Double Diamond Farm Supply at Elgin, Man.
Girillis works closely with his clients to solve herbicide resistance problems and prevent new ones.
“So far, it’s only wild oat and millet resistance,” said Girillis. “It’s mostly the Group 1 resistance in this area, so producers can use Group 2 products like Everest and Edge where they fit. It’s only a small percentage of acres, but it’s definitely a big concern with the guys around here.”
The other concern is overuse of glyphosate. Girillis tells farmers that if they’re in zero tillage and using glyphosate two or three times a year already, he doesn’t think they should be use it in-crop on canola.
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“Lots of guys do a burnoff in the spring and then a preharvest in the fall. And, if they have Roundup Ready canola, they hit it once or twice with a lower rate application in-crop. I think that’s why more guys in our area are leaning toward the Liberty and Smart systems instead of the Roundup Ready systems.”
So far, his customers, like Daryl Perkin, have had “decent success” using 2,4-D to take out volunteer canola.
Perkin said there are a number of ways he tries to prevent herbicide resistance on his 4,500 acre farm.
“We don’t go chasing the markets with our crops.”
Perkin said a long rotation with nine crops is the basis of his crop protection plan.
“Changing acreage plans to follow the market isn’t for me. The rotation is more important. You can put in a bunch of acres of a certain crop trying to chase the market, and then the market goes soft and you’re stuck. It isn’t worth it.
“Over time, a good hedge on just those crops we want in the rotation probably does just as well financially as chasing markets. Sometimes I get a surprise high in the market or an unexpected low, but either way, it evens itself out in the long run. It lets me keep a nice even rotation that I like, right across the farm, and it helps us keep clean fields.”
In a typical year, Perkin grows spring wheat, barley, oats, canola, sunflowers, flax, fababeans, peas and winter wheat.
“I really like winter wheat in the rotation. It’s very competitive with wild oats and that helps me avoid using Group 1. I don’t just look at the crops in my rotation. I look at the chemical rotation, too. On any given field, I will only use a Group 1 once every four years.”
Perkin said his plan often puts a herbicide resistant canola on a field one year, followed the next year by wheat, which he can spray with a Group 1 herbicide.
“I look at the possibility of herbicide resistance in everything we do on this farm. They all say we’ll never see a glyphosate resistance problem, but I don’t know. I like to be on the safe side.”
With his farm in full zero till for the past six years, it’s hard for Perkin to turn his back on glyphosate.
“I burn off in the spring and most of the cereals get a preharvest shot, but I don’t like to use any more glyphosate than I have to.”
On new land or a weedy field, he uses Roundup Ready canola to clean it up. He has also had success with Clearfield and Liberty Link.
“The general rule is that if your herbicide program is working for you, then it’s time to change it,” said Bruce Murray, weed specialist with Manitoba Agriculture.
“If your chemical control program is working and you keep using it, then you are inviting herbicide resistance to your farm.”
Murray said farmers have a limited number of basic herbicide groups, and no prospects for another big bunch of products. In the past 15 years, the industry has registered only one new chemical group.
“That’s why rotations are so important,” said Murray. “You want to grow as many crops as possible to keep the weed population off balance. Producers who rely solely on herbicides for weed control are asking for trouble.
“If your area can grow eight or nine different crops, by all means you should consider doing that.
“In areas where that isn’t possible, try for a rotation with diversity of growth type.”
He said winter annuals like winter wheat and fall rye are always good for weed control. Cool season crops for early in the season and warm season crops for later in the season keep the weeds guessing about what’s coming next. It’s also helpful to put perennials in the mix if there’s a market.
The more cropping combinations a farmer throws at the weeds, the more he breaks up repetitions that lead to herbicide resistance.
Murray said not all herbicides are created equal. Some of the oldest products on the market today, 2,4-D, bromoxynil and MCPA, are the least likely to develop resistance problems.
“It tells us there is something about these chemicals which makes it difficult for the plants to develop a resistance. Some people might think these products are obsolete, but they definitely have a fit in fighting resistance. Who knows? Some of these older chemicals might be on the cutting edge in 20 years.”
The weed spectrum on the Prairies is changing as cropping patterns continue to change, said Myles Robinson, Manitoba sales manager for Nufarm.
“That means many of the older products that some people might want to call obsolete are actually new to the new weed spectrum,” he said.
“Dandelions are a good example. Just a few short years ago, dandelions were No. 30 on the weed list for Manitoba. But because of the increase in zero till acres, dandelions are now in the top 10 for problem weeds. Dandelions love zero till.
“One of the most effective controls for dandelions today is one of the oldest products on the market, Amitrol 240. As zero tillers try to limit their glyphosate use, they’re turning to Amitrol for dandelions.”
He said it’s ironic that Amitrol is not only an old product in a new niche, but the product sold today is actually a weaker solution than the traditional Amitrol product. Yet it’s deadly on dandelions.
“We’ve had Group 1 resistance in wild oats for about 14 years,” said Robinson.
“Trifluralin resistant millet in canola is another problem for us. These are all examples of nature at work, continuously adapting and changing.”
More recently, 90 percent of the kochia tested in Manitoba had Group 2 resistance, said Robinson.
“Producers are finding that a mature product like Estaprop has become quite valuable in combating kochia in wheat and barley. It’s economical and it still works on the kochia.”
Another mature product with a new use is Trophy, which is fluroxypyr with MCPA. It controls kochia and cleavers in wheat and barley.
Robinson agrees with weed specialist Murray in saying that farmers seeking a new batch of crop protection products may have a long wait.
He said that in the past decade, there have only been 15 new crop protection products developed globally. That includes five herbicides, four insecticides and six fungicides. With an average investment of $2 billion for research, development and registration for each new product, the industry does not expect to replace the present list of products soon.
“Many of the mature products we have now will be with us for a long time. Producers will have to rely more and more on crop rotations and chemical rotations to control weeds and, at the same time, combat herbicide resistance.”
