Farmers looking for the latest information on weed resistance and ways to ensure it doesn't materialize on their farm, now have two new information sources available to them.

The first is spearheaded by Dr. Hugh Beckie, Agriculture & Agri-Food Canada (AAFC), who chairs the Herbicide Resistant Plants Committee for the Weed Science Society of America, and Dr. Ian Heap, of Corvallis, Oregon who manages the International Survey of Herbicide Resistant Weeds. With the assistance of weed scientists in over 80 countries, Heap - whose PhD is in weed resistance - has established a one-stop source of all confirmed cases of existing resistant weeds worldwide. The site (located at www.weedscience.org) also outlines a process agreed to by the global academic community to document and confirm new herbicide-resistant weeds.

"The goal of the survey and web site is to maintain scientific accuracy in the reporting of herbicide resistant weeds globally, monitor the evolution of herbicide-resistant weeds, and assess their impact throughout the world," explains Heap. "We hope it provides accurate, useful and relevant information on confirmed cases of weed resistance for anyone interested in following this issue and looking for up to date information."

While the site tracks herbicide resistance throughout the world, of particular benefit for Canadian farmers is the research and weed species specific to Canada. Growers can look up resistant weeds by weed species or mode of action. When reviewing the information on glyphosate resistance, for example, the site shows growers that the use of glyphosate in North America has resulted in a low incidence of glyphosate resistant weeds and after more than 30 years of use, there are no confirmed cases of a glyphosate resistant weed species in Canada. In North America and globally, the incidence of weed resistance to glyphosate (Group 9 - glycines) is low when compared to the number of weeds resistant to herbicides in Group 1 - ACCase (Centurion(R), Select(R), Fusion, Assure(R) II, Poast, Horizon(R), Achieve(R), Puma(R), Venture(R)) and Group 2 - ALS (Refine(R), Express(R), Frontline(R), Muster(R), Odyssey and Pursuit) herbicides.

Although there have been some media stories suggesting a glyphosate resistant weed was found in Canada, www.weedscience.org confirms this is not the case. In fact, after finishing lab testing in Canada, Dr. Beckie has confirmed the one suspected case he was exploring for potential glyphosate resistance did not meet the criteria for classifying a resistant weed.

This leads to the second new information tool available to growers. Monsanto Canada has recently published a technical bulletin called, "Weed Resistance Management in Western Canada," that speaks specifically to the issue of glyphosate resistance.

With more glyphosate options available to growers and a number of herbicide tolerant cropping systems available in the marketplace, it is no surprise there has been an increased level of talk about glyphosate resistance in the past couple of years. As the manufacturer of Roundup(R) brand herbicides for over 30 years, Monsanto Canada's technology group felt it was important to take an active role in sharing both its technical knowledge and agronomic recommendations with growers.

"We want growers to fully understand that use of Roundup brand herbicides in Roundup Ready(R) canola, grown in crop rotation, does not significantly change the risk of glyphosate resistant weeds occurring in Western Canada," said Rob Neyedley, technology manager, Monsanto Canada. "Glyphosate is actually a low risk herbicide for developing weed resistance. Plus in Western Canada, Roundup brand herbicides used in Roundup Ready canola are rotated with other herbicide groups in other crops which could also lower the risk of weed resistance developing."

The new technical bulletin answers common questions or concerns growers might have about managing glyphosate resistance, as well as giving them agronomic recommendations to ensure they continue to have glyphosate available to them in the future.

Neyedley is the first to admit weed resistance to any herbicide should be taken seriously, but he doesn't want growers to over-react and make poor choices, suggesting growers shouldn't shy away from growing Roundup Ready crops or using Roundup brand herbicides for fear of developing glyphosate resistance. It is still best to get the facts before making final cropping and herbicide use decisions.

"Glyphosate may be applied at multiple times through the year in pre-seed, in crop and pre-harvest situations but it is usually applied in various fields," explains Neyedley. "These applications target different weed species and populations which minimizes overall selection pressure for glyphosate resistance. In fact, Roundup brand herbicides and Roundup Ready canola have actually helped manage weeds that are resistant to other herbicide groups for over 10 years now in Canada."

In keeping with its commitment to product stewardship, Monsanto Canada has also outlined a process for growers to report any and all suspected cases of resistance and it continues to recommend effective solutions to manage the issue of glyphosate resistance where it has occurred.

Chief among Monsanto's stewardship recommendations for managing weed resistance is to use the right herbicide product at the right rate at the right time in weed development. "This is by far the most critical action growers can take to minimize the risk of weed resistance," says Neyedley.

For other stewardship recommendations and more information on glyphosate weed resistance management growers can request a copy of "Weed Resistance Management in Western Canada" by calling Monsanto's CustomCare(R) line at 1-800-667-4944.

Roundup(R), Roundup Ready(R) and CustomCare(R) are registered trademarks of Monsanto Technology LLC, Monsanto Canada Inc. licensee. (C)2006 Monsanto Canada Inc. All other trademarks are the property of their respective owners.

Roundup Ready(R) crops contain genes that confer tolerance to glyphosate, the active ingredient in Roundup(R) agricultural herbicides. Roundup agricultural herbicides will kill crops that are not tolerant to glyphosate.