What is Roundup Weed Killer? Who Makes It?

By - November 5, 2018
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Ever since agriculture was began thousands of years ago, farmers have had to do battle with weeds. For farmers, weeds are much worse than an eye sore. In addition to plant disease and bugs, weeds can damage crops and destroy harvests. Weeds cause problems in the fields because they rob water, sun and nutrients from the crops that farmers want to grow.

To help farmers protect their crops from many weeds, Monsanto offers a variety of weed killing solutions. Roundup Weed Killer by Monsanto is the most popular herbicide sold in the United States. All Roundup Weed & Grass Killer products have the same active ingredient – glyphosate. This ingredient targets an enzyme that is found in plants but is not in pets or people, according to company claims.

Farmers and homeowners have been using Roundup and other products that contain glyphosate for more than four decades to protect their crops.

Monsanto Claims About Glyphosate

Monsanto states on its corporate website that glyphosate has been a major breakthrough for farming. It says that not only do glyphosate products work well on weeds; they also assist farmers to grow crops in a more sustainable way.

For instance, Monsanto states that glyphosate has assisted farmers to adopt what is known as ‘conservation tillage.’ This is where farmers can till less soil and drive tractors less. That is why farmers can reduce the erosion of soil and carbon emissions, which helps the environment. It is estimated that conservation tillage can actually reduce the erosion of soil by as much as 90%. In 2014, this resulted in reduced carbon emissions by an amount equal to taking nearly two million cars off our roads.

Monsanto states that glyphosate is just one tool in the toolbox of farmers to tamp down and kill weeds. Most farmers will let you know there is no one magic bullet to stop weeds. In fact, if a farmer begins to relay too much on a single tool, no matter how well it works, the weeds can even become resistant to the tool over time. To avoid and manage weeds that are resistant to chemicals, farmers use many tools and practices in a concerted effort. Monsanto reports that it works with industry stakeholders, university researchers and others to offer farmers with advice on how to combine different practices and tools.

Monsanto adds on its site that like all pesticides, glyphosate is regularly reviewed by various regulatory authorities to ensure that it is safe. In the US that is the EPA. Monsanto claims that EPA’s process is comprehensive and is based upon modern science.

How Roundup Works

According to the company website, after you apply Roundup to weeds, glyphosate works through the plant down to the root and eventually kills it. The company warns that glyphosate is unable to discriminate between unwanted weeds and wanted plants, so you should use care that the Roundup does not touch any plants that you want to keep.

The company website states that after Roundup is applied, people and pets can go back to the area where it was applied. For most Roundup products, this will take anywhere from 10 to 30 minutes. But it depends upon the climate, product and weather. For the gel version of the product, it can take approximately two hours. Once the plant has been dried, rain will not wash off the Roundup.

Monsanto states that most Roundup products deliver results in a few hours. But some can take a bit longer than that. For Max Control 365, it can take 12 hours to actually see the results.

What Monsanto Says About Negative Glyphosate Reports

According to a Monsanto report, there is abundant data that demonstrates the low human health risk associated with glyphosate. So, it is important to consider the adverse health effects reported that are associated with the chemical. Allegations about harms that glyphosate cause often get more attention than the reports that indicate a low overall risk to human health.

Monsanto claims that reports that the chemical disrupts the endocrine system, accumulates in milk, leads to kidney disease and disrupts gut bacteria have been circulating through the media for years.

Monsanto also says there are claims that surfactants used in herbicides with glyphosate is more harmful than initially thought. But by looking at each claim, the company says it is possible to understand that none of the reports are based upon reliable science (this statement is strongly contested by many experts).

The company says one of the most concerning allegations about glyphosate is the one by the International Agency for Research on Cancer that classified the chemical as a probable carcinogen in 2015. This conclusion, the company claims, stands in contrast to every other regulatory agency or authoritative body that has reviewed the chemical.

In 2015, the IARC brought together a panel to review the active ingredient glyphosate. Based upon the partial review it did of published literature, IARC classified glyphosate as most likely a human carcinogen class 2A. The finding was in contrast to regular reviews of the chemical and concerns were raised that the reviews had actually overstated the chemical’s hazard. Monsanto claims that IARC’s monograph does not show any new research or data and it is not really a study in the traditional sense. The body did not assemble a report or consider new data on the hazard of exposure or risk of the chemical.

All key studies that were considered by IARC have been reviewed in the past by other regulatory agencies. After IARC’s announcement, regulators in the EU, Canada and Japan stated that glyphosate is actually not a carcinogen. Monsanto claims that IARC failed to consider the total weight of the scientific evidence that is available for this chemical. Monsanto argues that complete consideration of the entire dataset as done by regulators around the world, supports overwhelmingly conclusions of safety and lack of the carcinogenic potential of glyphosate.


  • How Do Roundup Weed Grass Killer Products Work? (n.d.). Retrieved from https://www.roundup.com/en-us/library/learning-basics/how-do-roundup-weed-grass-killer-products-work
  • Glyphosate Herbicide. (n.d.). Retrieved from https://monsanto.com/company/media/statements/glyphosate-herbicide/
  • Glyphosate Benefits and Safety. (n.d.). Retrieved from https://monsanto.com/app/uploads/2017/07/Glyphosate-benefits-and-safety_public-FINAL.pdf

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