Guest blog: News You Can Use, WheatFoods.org (January, 2015)
A recent blog post making the rounds on the internet claims that domestically-grown wheat is commonly sprayed with an herbicide, RoundUp®, the primary ingredient of which is glyphosate, prior to harvest to facilitate the harvesting process. The blog alleges that such a practice causes domestic wheat to become toxic and is causing a long list of major health issues. The Wheat Foods Council compiled the following comments using information from bestfoodfacts.org, the Center for Food Integrity, and based on input from top agricultural scientists. ¹
- Only ten percent or less of the wheat crop is subject to this practice each year. This is not a common practice among wheat farmers nationwide. In the winter wheat areas of the Great Plains, the practice is extremely low.
- When herbicides are used at harvest, the amount used is extremely small. The common use rate for glyphosate is about one quart per acre. This is equivalent to evenly and accurately spreading one quart of liquid over a football field.
- Herbicides at harvest do not “kill” the wheat nor do they increase yield. Application of an herbicide at harvest is not used to “kill” the wheat since it is essentially non-living when applications are made. Nor is it used to increase harvest size since yield is already determined at this point.
- Wet field conditions and heavy weeds may force a farmer to use herbicides at harvest to avoid damage to the crop and equipment. Herbicides are used occasionally on mature plants (the grain is already “made”) such as when wet field conditions exist, because the herbicide assists in reducing weeds. An overabundance of weeds at harvest can cause damage to the part of the combine that cuts the crop, allow increased grain moisture that can cause storage problems, and increased foreign material or “trash” in the harvested grain. In some spring wheat (wheat planted in the spring instead of the fall) areas of the northern U.S., farmers sometimes use an herbicide to achieve more uniform drying of wheat plants across the field, while controlling weeds.
- Glyphosate residue is unlikely to be found on harvested grain. Individual grains are encased by mother plant tissue called the lemma and palea, which, in turn, are encased by the outer glume layer, similar to an envelope covering the seed, protecting it from the elements and holding it in place until harvest. The threshing process in the combine separates the grain from these maternal tissues, otherwise called chaff. Even with whole wheat the chaff is not consumed with the grain.
- Use of pesticides on crops is steadily decreasing in the US. According to USDA data, total pesticide use in the USA peaked in 1981 and has steadily decreased since. The U.S. wheat crop accounts for only 4.5 percent of the total amount of pesticides applied nationwide.
- Pesticides/ herbicides are expensive, and used only after careful consideration. Farmers use pesticides as sparingly as possible due to costs. Application of an herbicide like glyphosate could cost as much as $6.50/acre. For a typical wheat field in the southern Great Plains, that represents an additional $3,500 in costs that the farmer will likely choose not to incur.
¹ Angela Post, PhD, Weed Science Extension, Assistant Professor, Oklahoma State University; Jeff Edwards, PhD, Small Grains Extension, Warth Distinguished Professor of Agronomy, Oklahoma State University; and Brett Carver, PhD, Wheat Breeding & Genetics, Regents Professor and Wheat Genetics Chair in Agriculture, Oklahoma State U.