The Facts About Glyphosate, Part 2: Growing a Quality Wheat Crop with Glyphosate

This blog is the second in a five part series, titled “The Facts About Glyphosate”, sharing the facts about glyphosate and it’s use in the wheat industry.

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The U.S. produces one of the best wheat crops in the world. It is the only country that can supply all six classes of wheat in large and reliable quantities at the highest quality, year in and year out. Each year, US wheat growers face different production challenges that may affect their financial stability. Because farming is their livelihood, growers are motivated to deliver a superior crop to market, which ultimately will become a wholesome product on the table of consumers.

Every year brings a new set of environmental conditions, and a new set of stresses to affect the wheat crop. Wheat growers rely upon tools and products designed to help the wheat plant alleviate these stresses. A grower will determine which tool is the most effective at reducing the stress to ensure a quality grain crop at harvest. For instance, in the southern Plains last fall, weather conditions were favorable to the growth of volunteer wheat prior to the new wheat crop planting. Volunteer wheat (a weed) can harbor a virus (wheat streak mosaic virus) and the curl mite that spreads it. Using glyphosate to prevent volunteer wheat from growing and infecting the new healthy crop is one management decision growers will make. If wheat streak mosaic virus is allowed to establish, unfortunately there is nothing that can be done to treat the infected plants and stop the spread of the disease. This virus causes yield loss and very small, light grain of poor quality. There are many management decisions a grower makes in a production year, and these decisions will direct which tools and resources a farmer will employ in his or her operation.

In our first “Truth about Glyphosate” blog, we explained that more than 65 percent of wheat acres do not receive any glyphosate application at all. Most of the remaining 33 percent of acres receive an application of glyphosate to help manage weeds. These applications occur before planting, at planting or after planting but before wheat emergence.

Another labeled, authorized use of glyphosate that growers have at their disposal, is to apply to the crop prior to harvest. The U.S. Environmental Protection Agency (EPA), which regulates all pesticides including herbicides like glyphosate, refers to this use as a “pre-harvest’ treatment.

Pre-harvest applications occur on 3 percent or less of wheat acres in the U.S. These applications are made after the wheat plant has shut down, when wheat kernel development is complete and the crop has matured, just a little more than 7 days prior to harvest. Therefore, the wheat plant is not absorbing the glyphosate, but the green weeds in the fields will be killed by the glyphosate. For farmers in the northern plains, this can be an important tool, helping complete a harvest that otherwise would not occur in some years of wet weather and increased weed competition. These conditions threaten harvest and can cause delays in the short growing season in the north.

The trace pesticides left in treated products or crops are called “residues”. A maximum residue level, or tolerance level determined by EPA, is the highest level of a pesticide residue legally tolerated in a food or feed when pesticides are applied under their label and considered by EPA to be safe. In the case of glyphosate, the label instructs farmers to apply a pre-harvest treatment when the wheat kernel is 30% moisture or less after grain development. The amount of glyphosate on the harvested wheat after a pre-harvest treatment has repeatedly tested well below the EPA approved maximum level.

If there was one part per billion of an herbicide residue in a l lb loaf of bread, a person weighing 150 pounds would have to eat 36,000 loaves in a day to reach the acceptable daily intake. Similarly, a person would need to drink over 50,000 bottles of beer or eat 450,000 standard 1.5 oz servings of oatmeal per day.

Regulatory bodies and scientific institutions have conducted science-based evaluations and concluded that typical glyphosate usage does not pose an unreasonable health risk to humans, when used according to label directions. For more than 40 years, the EPA has determined, through risk assessments and science-based evaluations, glyphosate is non-carcinogenic to humans. Glyphosate-based herbicides have had a long history of safe use in the U.S. and other countries.

Wheat growers rely on the federal government to make safety determinations and data, research and scientific evidence to make educated management decisions, and wheat growers also ensure they adhere to the regulations on use of pesticides set forth by the EPA. The decisions growers make day after day, year after year, on their farms are well-informed, carefully determined through adherence to US regulations and are ethically sound. The next time you consume bread, pasta, cereal or any other food made from wheat, think about the U.S. wheat farmer who proudly produces the safe, high-quality crop that found its way to your kitchen table.