Canadian pesticide use keeps increasing

Date:10-29-2012

Companies selling genetically modified (GM), herbicide tolerant (HT) crops claim their varieties are environmentally friendly since they require lower amounts of safer herbicides to control weeds than non-GM types. But in a recent column, I cited a study showing that U.S. farmers using HT varieties are actually applying more chemicals to control worsening weed problems.

American farmers growing HT crops are finding weeds harder to kill as they become herbicide resistant. They now apply more kinds of herbicides, and more of them, to get the same result. Fortunately, this hasn't become a big problem in Western Canada yet, but it is a cautionary tale for our farmers.

In a rebuttal of my column, published in this paper, U of S researcher Stuart Smyth chastised me for ignoring his research showing the use of HT canola varieties in Canada has resulted in reduced herbicide use and offers other positive environmental and economic benefits.

Smyth conducted a survey of 571 farmers and a majority told him HT crops work as promised. From the survey, he extrapolates a significant decrease in herbicide use in HT canola. Other research shows the glyphosate herbicide used with HT canola (marketed as Roundup and other brands) has lower environmental impacts than older herbicides.

Sounds good, but I thought I'd check his findings against data on Canadian pesticide usage. Given that almost all canola producers now use HT varieties, and canola is much more widely grown in Western Canada than in pre-HT times, I expected to find some decrease, or at least stabilization, in overall herbicide use.

Searching for statistics, I was surprised to find that Canada is the only OECD country that hasn't tracked pesticide use. The Auditor General's office began to decry this information gap in the 1990s but it was 2006 before rules passed requiring pesticide sales data to be released. The first Health Canada report on pesticide sales came out after 2008. Unfortunately, there is no equivalent benchmark from before the introduction of GE crops in the 1990s to facilitate the kind of detailed analysis of pesticide use employed in the U.S. study I cited.

In his rebuttal, Smyth scoffs at the U.S. study and its author and (wrongly) accuses him of ignoring key data. Yet the U.S. study used extensive USDA pesticide data obtained from a mandatory census of all American farmers, while Smyth builds his findings on a small sample. I am no expert, but it seems obvious which approach is more valid.

Though minimal, data from Agriculture Canada and the 2008 Health Canada inventory show that pesticide usage has increased dramatically in Canada since the introduction of GM crops. Back in 1995, at the dawn of the GM era, Ag Canada re-ported total pesticide use at 69.2 million kilograms, about 80 per cent herbicides. The 2008 report shows pesticide use has grown 26 per cent, to 87.5 million kilogram, including a 28 per cent increase in the use of herbicides.

This can't be attributed to higher acreage. For example, some 26.8 million Saskatchewan acres were sprayed with herbicides in 1995; that number had gone up just eight per cent by 2006. Instead, the increase is attributed to "pesticide use intensity." Alberta's agriculture department, which does track pesticide use, says pesticide application per hectare has increased 25 per cent compared to the pre-GE era, largely as a result of increased glyphosate usage.

I also checked with Crop Life Canada, the lobby group for agricultural chemical and GM seed companies. Their annual reports show that pesticide sales have gone up substantially in the years since HT crops have been introduced. Sales increased by close to 50 per cent over the period from 2001-2010, for example. They say higher sales are related to the increased amount of active ingredients, not just higher prices. They also say the percentage of all herbicides used in canola is rising in relation to other crops. Plus, seed treatments with fungicides and insecticides are up in canola.

Unfortunately, Canada hasn't collected sufficient data to verify the big conclusions drawn from Smyth's small survey. I hope he is right, but forgive me if I remain skeptical that GM crops are leading to an era of lower pesticide use.