A lot of consumers have concerns about Roundup (aka glyphosate). Yesterday we once again were bombarded with attacks on the much-maligned herbicide in the yearly “March Against Monsanto”. Many will also remember the World Health Organization’s classification of glyphosate as a “probable carcinogen”. When faced with such a maelstrom of public disapproval (even if it is a vocal minority) it’s very difficult to separate fact from fiction. What is right and what is wrong? Is glyphosate dangerous? If so, should farmers be allowed to use it at all?
I think the best way to cut through such a deluge of hostile press is to delve into the facts about this much-maligned chemical. I keep hearing how we farmers “douse” our crops with glyphosate; that we apply massive quantities with no concept of safety, ignoring label rates, and simply apply it as many times as we want to whatever crop we want.
This couldn’t be further from the truth. Here’s the reality.
Is Glyphosate Toxic?
Glyphosate is one of the safest herbicides ever developed for mass use. It is a non-selective (meaning it kills most plants) chemical that targets and blocks the so-called shikimic acid pathway. This is required for amino acid synthesis in plants. Without amino acids, plants wilt and die from starvation. Since the shikimite pathway is not found in humans, glyphosate is of very low toxicity (read more here).
Now, science jargon aside, if you consume enough glyphosate, yes, it will be poisonous. Of course, it would take quite a lot; the LD50 (lethal dose for 50% of test animals) of glyphosate is 5,600 mg/kg. That’s over 5.6 grams of glyphosate for every kilogram you weigh. You weigh 80 kg? You would need to consume 450 grams (that’s half a kilogram, or close to a pound) of glyphosate in one sitting for a potentially lethal dose. If you’re consuming that much of anything I’d say you should be concerned (read more here).
How Much Do We Use?
Below is a picture I took of a typical rate of glyphosate. In that Gatorade bottle there is 600 mL of Roundup. That little bottle will treat one acre of land. Now, I understand that an acre is a little hard to visualize. One acre is 43,560 square feet, or about three quarters of an American football field. That 600 mL spread over one acre amounts to .014 mL per square foot. That doesn’t sound like much, does it?
Here’s the other thing; most of the Roundup we spray in a year doesn’t get sprayed on crops at all. We use it to clean fields up before seeding and after harvest. Yes, some Roundup Ready crops get glyphosate throughout the season (e.g. canola, soybeans), but that really only amounts to about 20% of our acres. And even then, we are only talking about one or two applications per year to growing crops.
The reality is we simply don’t use that much glyphosate on a per-acre basis. Is glyphosate the only herbicide we use? Of course not! We use a variety of pesticides on our farm to control a variety of pests. Do we still need glyphosate? Unquestionably yes. Without it, no-till would be next to impossible. We would be forced to go back to tillage to clean our fields before seeding. That would be an environmental tragedy.
All of these products are used to control weeds, diseases, insects and so on. We need them all to keep each of our many different crops clean; but glyphosate is still the base we build our entire year upon. It is the one herbicide that controls them all. That is why careful management of it, and creative tank mixes with products like tribenuron, sulfentrazone, carfentrazone and so on is so important to ensure its long-term survival. Tank mixing other chemistries makes it much more difficult for weeds to become resistant – the infamous “superweed”.
The concerns about so-called superweeds are real, to a degree. Yes, too much glyphosate spraying on the same land over too many years can cause weed resistance. However, too much tillage on the same land year over year can actually cause the same problem; it is far from unique to glyphosate and GMOs (read more here). Any pest can and will become resistant to a control measure over time; it’s natural selection at work.
Separating Fact From Fear
I realize how difficult it is to separate facts from fear. There is a lot of data, a lot of studies, and a lot of people with an agenda pushing you to believe one thing or another.
If you don’t trust anyone else, trust farmers. We use this stuff, and have for decades. We wouldn’t put ourselves, our families, and our customers at risk if we believed glyphosate and other pesticides were truly dangerous. I use glyphosate and other pesticides because I believe the benefits outweigh the risks. I believe they are the best tool we have to look after our land in a sustainable fashion.
The reality is you are the one buying what we’re growing. It is your choice. Just know that glyphosate, despite all the hostile attacks on its safety, is one of humankind’s greatest achievements. This venerable herbicide, with nearly 40 years of use behind it, is still one of the most important tools we farmers possess. It allows us to control weeds without threatening the future of our soils. The dose makes the poison, and at the rates we apply this incredibly low-toxicity herbicide, you have nothing to fear.