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Eco-Friendly Herbicide Awaits Approval

Modern, large-scale agriculture now depends heavily on synthetic crop protection products, such as glyphosate. So heavily, in fact, most current farming practices would not be possible without them At the same time there has been growing opposition to the increased used of chemicals in food production from environmentalists and consumers.

That environmental pressure was the initial impetus for creating a program to look at developing biological herbicides, says Russell Hynes, a research scientist at Agriculture and Agri-Food Canada’s Research Centre at Saskatoon. “It was primarily an environmental concern,” he says. “It was initially an academic interest in the 1990s, but it’s now moved into a full-fledged priority. The development of bio-pesticides is really growing globally.” And the Saskatoon Research Centre is home to Canadian research efforts.

But what exactly is a bioherbicide? “It’s a herbicide that, rather than using synthetic chemicals, uses natural products or living micro-organisms to manage weeds,” says Hynes. “bioherbicides could be derived from any natural living organism or plants themselves and applied in a very similar manner to conventional synthetic herbicides.”

Staff at the Saskatoon facility have focused on attempting to develop bioherbicides that mirror the effectiveness of synthetic products currently in use that control a certain group of weeds and don’t affect commercial crops. But allowing producers to apply them using existing equipment is also important. With the current variety of synthetic products and application methods, though, that gives researchers a lot of flexibility.

“Some of our bioherbicides can be applied to the soil where they will suppress germination of the (weed) seed,” explains Hynes. “Other bioherbicides can be applied to the foliar parts of the weed after it has germinated.”

COMMERCIAL APPROVAL IN THE PIPELINE

While research continues on a variety of different bioherbicides in Saskatoon, one is already undergoing regulatory approval. “We submitted the registration in the fall of 2009,” says Karen Bailey, the research scientist who developed the product. “We’re doing it under a joint review process of NAFTA; it’s being reviewed in Canada and the U. S. at the same time. We’re probably looking at 2012 before it comes out commercially.”

The bioherbicide, which uses the Phoma macrostoma fungus to control a variety of broadleaf weeds, including dandelions and Canada thistle in grass, will target the residential segment. The Scotts Company, a large lawn care product supplier has partnered with Agriculture and Agri-Food Canada to register, manufacture and commercially market the product.

But Bailey says further research is underway to expand the use of the same fungus to forestry and agricultural applications “We also see there is a lot of potential for other uses because it controls a large spectrum of weeds,” she says. “Agriculture is certainly a field I’d be interested in trying to see if we can make this work in. A lot of agricultural weeds are controlled by this particular organism.”

The testing in agricultural applications so far has involved looking at various application rates and the bioherbicide’s effectiveness in a crop environment, rather than in moist, well-manicured residential lawns.

The bioherbicide developed by Bailey is produced in granular form. “In turf grass we have two application methods. If we apply it as a pre-emergent, it doesn’t prevent germination, but it kills them as they emerge,” she says. For mature weeds, the bioherbicide requires two applications one month apart.

The product turns weeds white and prevents them from producing chlorophyll, so they are unable to feed themselves. As young weed plants emerge after germination, they are unable to produce any new energy. Once the reserves from the seed are used up, the seedlings die. But mature plants already have larger root systems and reserves. That, Bailey says, is why a second bioherbicide application is required to control them.

And although Bailey’s bioherbicide uses a naturally-occurring fungus, she says DNA tests of the soil in the year following application failed to show any traces of it, so it does not limit the range of crops that could follow in a rotation a year after application.

ORGANIC AND CONVENTIONAL APPLICATIONS

One of the most exciting benefits of bioherbicides may be their potential use in certified organic farming. Bailey says the processes used to develop and produce them involve only natural elements, so their eventual approval for use in organic systems is a strong probability. “There’s nothing in the processing that would make it non-organic,” says Bailey. “Organic farmers seem very interested. It gives them a whole new option for weed control, especially for things like Canada thistle which is very difficult to control in an organic system.”

While the organic industry stands to gain from the introduction of bioherbicides, Hynes says the primary focus of research at Saskatoon is aimed at the mainstream agricultural sector. “We are targeting a broad base of agricultural consumers for these products,” he says.

One of the aspects of bioherbicides, which would give them an enormous appeal in the broad commercial market, is they offer the potential to minimize herbicide resistance in weeds, which is a growing concern on the prairies. Rather than simply offering a new synthetic product that weeds will eventually develop resistance to, bioherbicides may overcome weeds prone to the problem.

“We don’t have a lot of evidence for this at the moment, but we’re seeing multiple modes of action by the plant pathogens on the weeds, which creates a great deal more difficulty for the weed to develop resistance,” says Hynes. “What’s also very good is that the living micro-organism (in the bioherbicide) is also changing. If the weed is attempting to get around the micro-organism, the microorganism is also attempting to get around the weed.” So bioherbicides may come with some built-in level of ability to combat resistance.

That is bound to attract a lot of attention from producers; but in the end, widespread adoption of bioherbicides may still come down to economics. One of the stumbling blocks limiting the use of many environmentally-friendly technologies in the past has been their high cost. But Hynes says researchers are mindful of the need to make any bioherbicide economically competitive. “Cost is foremost in our minds,” he adds.

In addition, bioherbicides aren’t the only products under development in Saskatoon. Researchers are also looking at biofungicides and bioinsecticides, which means producers could eventually have a full range of crop protection products developed entirely from biological organisms at their disposal.

And if all the Olympic gold medals won by Canadian athletes this winter weren’t enough to fill you with national pride, Hynes says the Saskatoon Research Centre may be home to the most advanced bioherbicide research on the planet. “We’re leading the world,” he says.

Scott Garvey is machinery editor for Grainews. He also runs a cow-calf operation at Moosomin, Sask. Email him at scott. [email protected]

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Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.

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