The National Farmers Union is again raising alarms about possible links between the use of the popular herbicide glyphosate and the devastating crop disease fusarium head blight.
The farm group has asked the Canadian Food Inspection Agency to halt approval of any new glyphosate-resistant cultivars and evaluate the varieties already on the market while more research is carried out.
“We have a solid indication that something is going on,” said union president Stewart Wells.
“That deserves to be looked at and understood before we plow ahead and double or triple the use of glyphosate.”
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The farmers union made its request in a Sept. 20 letter to CFIA president Francois Guimont. A CFIA spokesperson said the agency would reply directly to the NFU before responding publicly.
The NFU raised the issue in the wake of the publication in last month’s issue of the U.S. scientific journal Crop Science of a Canadian study identifying a statistical correlation between previous application of glyphosate and levels of fusarium head blight.
The study, the results of which were first made public two years ago, does not suggest the herbicide directly causes more fusarium.
However, it does say that previous application of glyphosate was the only crop production factor that was significantly associated with high fusarium levels in each year of the four year study.
The results are based on growing susceptible wheat varieties in a minimum tillage system in 659 crops in eastern Saskatchewan.
The study raises questions that merit further investigation, said lead researcher Myriam Fernandez, a plant pathologist at the Agriculture Canada research centre in Swift Current, Sask.
“Given the response that we have found … there is reason to continue this work and try to ascertain exactly what is happening,” she said, adding the study’s appearance in the prestigious peer-reviewed journal gives the findings greater credibility than may have been the case two years ago.
However a spokesperson for Monsanto, which manufactures the glyphosate product Roundup, said there is nothing new in the study, no need for CFIA to take any action and no need for further
research.
Trish Jordan said the issue has been studied extensively and no causal link has been found between the use of glyphosate and the incidence of fusarium.
“It appears the NFU needs to look at the entire body of research rather than using an isolated study to promote whatever their personal agenda is,” she said. “They can throw out this study and we can probably throw 50 others back.”
Phil Macdonald, national manager of plant biosafety for CFIA, said the publication of the study is unlikely to prompt the agency to agree to the NFU’s request for a moratorium on glyphosate-resistant cultivars.
“In and of itself, it would certainly be a leap for us to go there,'” he said.
The agency is aware of the potential links between glyphosate and fusarium, he said, and is “keeping a close eye” on research into the subject. But he added it may be more of a farm management than a regulatory issue.
“They have identified issues that need to be looked at,” said Macdonald. “Certainly from a grower perspective it indicates you may want to look at your own farm management and crop rotation practices, especially in years that may favour disease.”
Wells accused the CFIA of “going out of its way to ignore” the Fernandez study over the last two years, saying the agency should sponsor more research.
Fernandez said work is continuing. Leaves and roots collected during the fieldwork from 1999 to 2003 are being analyzed and the research group is trying to get access to land at research stations across Western Canada for more experimental work.
In July, Monsanto received regulatory approval from CFIA for environmental release of Roundup Ready alfalfa. It has not received varietal registration. Jordan said the company has no plans for commercial release of the product at this time.
