The Facts About Glyphosate, Part 3: How does USDA collect farm data?

This blog is the third in a five-part series, titled “The Truth About Glyphosate,” sharing the facts about glyphosate and its use in wheat production.

The US has the safest, most abundant food supply in the world. Other countries rely on the U.S. to set safety standards that impact people globally. Wheat growers raise all of their crops with care to ensure they are as safe for families everywhere as they are for their own.

As discussed in a previous blog, herbicides are one tool for any grower to manage weeds in any crop and produce the best quality product possible in any given year. U.S. wheat growers are no exception. After mandatory pesticide training to obtain an applicator’s license, wheat growers follow EPA approved label directions when applying any type of crop protection material. Labels are developed to insure the products are used correctly, to provide effective performance, are safe to the people handling them, for consumers and the environment.

The U.S. Department of Agriculture (USDA) surveys farmers about many of their agronomic practices, which include the use of herbicides such as glyphosate. The NASS Agricultural Chemical Use Program is USDA’s official source of statistics about on-farm chemical use and pest management practices. The examination of pesticide use trends is their objective and is critical to make informed, science-based decisions. These NASS surveys are not done annually for every pesticide, but are on a rotating schedule.

As mentioned, the USDA survey focuses on pesticide use trends. Their surveys are designed to understand which pesticides are used to produce a given crop and how much pesticide is applied. They are not designed to understand how or when the pesticide is applied. The main difference between USDA’s National Ag Statistical Service (NASS) collected data for wheat and other sources of pesticide use survey data is the inclusion of application timing. For instance, GfK, an independent consumer research firm, collects data annually which includes when the application was made. This information is used to distinguish applications “to” a crop from applications made “before” a crop is planted or even “after” the crop is harvested. Applications made when the wheat crop is not present are meant to control weeds during fallow periods to prevent weeds from using valuable moisture in semi-arid regions of wheat production, and prevent weeds from spreading disease to the next planted crop.

When used “in” wheat, glyphosate use is limited to a pre-harvest application. The use of pre-harvest applications has been consistent over time, staying between 1-3 percent of total acres for 17 years of approved, safe, legal use. Cessna et al. (1994) examined residue levels of glyphosate in harvested wheat grain that had been treated with glyphosate at different rates and at different times of pre-harvest applications. This study showed no indication that any of the application rates or timings would result in glyphosate residue levels greater than the EPA approved tolerance. These results are supported by data on glyphosate residues in cereal crops collected in the EU where pre-harvest uses of glyphosate are also legally allowed.

Taken together, the available data and information demonstrate that pre-harvest applications of glyphosate are not a common occurrence in U.S. wheat crops, and current application timings have little potential to result in glyphosate being present on harvested grain.

The bottom line: The U.S. food supply is safe. Using available technology to improve pest management and provide an abundant, safe, high-quality food supply is essential to meeting the demands of a growing world population. Remember, if you have questions about how your food is raised, ask the expert; ask a farmer.