Posts Tagged ‘Roundup’

Glyphosate and Prop 65

The latest story in the glyphosate saga is that it will now be put on California’s “Prop 65 List”. What is this Prop 65 list? It is a list of all chemicals the public may be exposed to in California that may cause cancer or birth defects. This list was born from the ballot initiative passed in 1986 called “The Safe Drinking Water and Toxic Substances Act”. The section of the act that cause the list to be made was the part that prohibited business from knowingly exposing the public to toxic substances without giving clear and reasonable warning. Products are required to carry a warning and business are required to post signs clearly stating the warning that substances known to cause cancer or birth defects are present. Any chemical that has a 1 in 100,000 chance of causing cancer over a 70-year period or birth defects or other reproductive harm in two ways are required to be listed. Signs are everywhere in California and most people don’t even notice them. Any place that sells coffee has a sign as there are chemicals in coffee that are listed. One of my favorite signs is this one below. Clearly they are not much of a concern to most people.


California does not do any of its own research to determine if chemicals meet this criteria so they have a system of reviewing research done by other organizations to figure out what chemicals should be listed. There are four ways a chemical can be listed and those can be found at California’s OEHHA site. The criteria that put glyphosate on the list is the first one, “At a minimum, the list must contain chemicals identified by reference in Labor Code section 6382(b)(1) or (d).  Labor Code section 6382(b)(1) incorporates chemicals identified by the World Health Organization’s International Agency for Research on Cancer (IARC) as causing cancer in humans or laboratory animals.” Because the IARC listed glyphosate as a “class 2A carcinogen” California was compelled by regulation to put glyphosate on the Prop 65 list. Monsanto sued the State of California mainly on the merits of the scientific evidence, or lack thereof, that glyphosate was a carcinogen, but since the Prop 65 regulation doesn’t address the merits of the research, just that it is on a qualified list, Monsanto lost that battle. If it is on the IARC list, it is on the Prop 65 list.

But did Monsanto have cause to doubt the IARC listing? There is certainly plenty of suspicion on the process the IARC went through on making their determination. Faulty science reviews and cherry picking which data to include along with facts about members on the review team being tied to anti-GMO activist groups.  David Zaruk, an EU science communication specialist has written extensively on this subject and even was a victim of censorship from some EU outlets because of what he uncovered about what the IARC was doing. You can find a full review of his writings on this issue on his site the Risk Monger. I’ll give a summary below.

There are many more scientific bodies that do not agree with the IARC findings of glyphosate being carcinogenic. Three other WHO agencies, The International Programme on Chemical Safety, The WHO Core Assessment Group and WHO Guidelines for Drinking Water Safety all disagree with the IARC on this issue (there was also the mysteriously disappearing EPA review that was posted and then pulled that also disagreed with the IARC findings. No one seem to know what happened to that report). Two other EU agencies that European Food Safety Authority (EFSA) and the German Institute for Risk Assessment (the BfR – responsible for managing the EU’s glyphosate risk assessment) have also come to the opposite view on glyphosate from the IARC. These two agencies do risk assessments. They looked at all the data available, asked for more data to fill data gaps, and then concluded that the herbicide could be safely managed and did not pose a risk to human health.

On the other side, IARC doesn’t do risk management but merely decides whether a substance can be considered as a carcinogen. But in their process on reviewing glyphosate they already had the conclusion they wanted decided upon before they started the review process. Thus they only used data and studies that fit the narrative they wanted to produce. Some of the studies they used were even discredited by scientific peer review as being flawed and providing very poor conclusions. Thus they came to the conclusion that glyphosate was a hazard and needed to be banned. “Risk management is the reduction of exposures to known hazards. The scientific community (including EFSA and the BfR) has largely determined that glyphosate is a minimal hazard (low toxicity) whose exposure can be easily managed so that we (farmers and consumers) can enjoy the benefits of better agricultural yields. IARC feels there is a hazard and it needs to be restricted”, concludes David Zaruk in his summary of the situation.

So where does this leave glyphosate and California’s Prop 65 list? Well, for now it stays on the list. If the pressure on the IARC to remove glyphosate from their list prevails and they pull it from their list California can decide to take it off the Prop 65 list. How will being on the Prop 65 list affect the products that contain glyphosate? Well if the traffic at Disneyland and Starbucks is any indication of the effects of something being on the Prop 65 list, I’d say sales of Roundup won’t be affected too much. But having it on the list could be a focus point for activist group looking for reasons to ban its use. California seems to be on a track for limiting pesticide use based on hazard alone. Managing risk seems to have gone out the window as more regulation is based on fear instead of a reasoned, scientific based foundation. When the country as a whole wants to get back to relying on science to make policy and regulation maybe the tides will turn.

The Evils of Roundup?

The last couple of months have been pretty busy for this Plant Doctor. As I begin to get the almonds ready for harvest by cleaning up the weeds on the orchard floors, I look back at all the herbicide recommendations I’ve made over the years and wonder about all the questions that come up about “the evil Roundup”. Yes, I recommend a lot of it. Out of the 8000 acres I take care of probably over half get at least one application, and only 140 of those acres is GMO Roundup Ready. What is it that everyone is so up in arms about?


Roundup (glyphosate) is “toxic” and causes cancer: I have read many studies and many discussions about studies that claim to show that glyphosate causes cancer. I have yet to find a study that hasn’t been disproved by a number of researchers and scientists. The one study many people seem to point to regarding Roundup and cancer is the one done on rats by Seralini. You can find plenty of information on how bad that study was. None of that information can be taken seriously. A long discussion on the topic of Roundup and cancer can be viewed on Reddit as well. There are plenty of other “studies” that people seem to find but I’ve yet to see one that hasn’t been picked apart through scientific reviews. Studies showing links to glyphosate causing autism and being found in breast milk have also been busted. Following the science is a bit tedious and time consuming and I can’t say I’ve looking into everything but the studies I have looked at touting adverse health effects of glyphosate don’t seem to lead to anything credible.

Now it is true that the International Agency for Research on Cancer, an arm of the World Health Organization, issued a report that classified glyphosate as a “probable” cause of cancer. Micheal Specter’s article on Roundup and Risk Assessment in the New York Times points out that “ ‘Probable’ means that there was enough evidence to say it is more than possible, but not enough evidence to say it is a carcinogen..” The dictionary definition of probable is “supported by evidence strong enough to establish presumption but not proof”. Proof is something that is lacking in the link between glyphosate and cancer. Many studies have been done and no connection has been found. There are many things on the IRAC list of probable carcinogens. Glyphosate has many benefits and without any real proof of harm there is no credible reason not to use it.


Roundup is overused in GMO crops and is producing “super weeds”: Weeds that are resistant to herbicide are not unique to glyphosate. Resistance management drives many decisions on pesticide use. I advise the farmers I work with to only have one herbicide resistant crop and do not plant that back to back in the same field. Roundup is not the only herbicide I use and most of the time when I use it, it is in combination with another product since combinations slow down the development of herbicide resistance. I certainly won’t refute that there are weeds resistant to glyphosate. But there are weeds resistant to other herbicides as well so it isn’t “Roundup” but it is the way people use it that causes the problems.

Roundup is killing the soil: There was an article in the NY Times about soil degradation and glyphosate use. Looking at the article and the actual study (if you can call it that) there are so many variables that were not taken into account that you can hardly attribute the effects just to the glyphosate use. The fact that glyphosate is widely used and that these effects are not widely reported makes me think the claim is not justified. But I am open to the possibility that further research may uncover some issues in the future. If that happens, adjustments will be made to incorporate the new information into our decisions. New information is always welcome. The farmers I work with have not seen any adverse affects of glyphosate use. Most of the production problems we deal with can be clearly identified as to causes (that doesn’t mean fixing them is all that easy).


Roundup is killing the bees: The study that is commonly cited uses a methodology that really doesn’t fit real world conditions.  In this study bees were fed a sugar solution laced with levels of glyphosate expected to be found after a typical field application. Hardly real world conditions. The EPA has done many studies and have found no toxic effects on bees. In a post at there is a quote with references that states “there is no strong evidence that the spraying of Roundup or generic glyphosate herbicide is directly causing significant bee mortality.  However, Drs. Jim and Maryann Frazier have legitimate concerns about the effect of some adjuvants—especially the organosilicones [27], [28]. ” Glyphosate is rarely sprayed on flowering crops and the majority of the time you are spraying it on small weeds before they bloom so it isn’t likely bees would be picking up much glyphosate in pollen, even at field applied levels. Probably the biggest problem with glyphosate and bees is more of an issue of it working so well that now there are no weeds for them to supplement their nutrition. The Scientific Bee Keeping post touches on that as well. But European honeybee colonies used to pollinate crops are actually starting to increase which suggests that the increased use of glyphosate is not damaging their populations. Those that would like to find some kind of link to glyphosate and bee decline have now pointed to wild bumblebee decline and the lack of weeds these species have to forage on. But new research suggests that climate change may be the issue of declining bumblebee populations.

I’m sure there will still be many people who don’t like “Roundup”, Monsanto or GMOs. The sure volume of false information and poor science that is out there for those that want to ingest it pretty much ensures a steady diet for those who have their minds made up. As for me, I have crops to care for and farmers that need to produce those crops to earn a living and feed a growing population. Glyphosate is an inexpensive, effective tool so lacking any good scientific reason not to continue using it, I’ll continue to recommend it where it is needed, when it is needed and in line with good Pest Management practices.

Do you have a question about crop protection practices or a topic you would like me to explore? Leave me a comment or, if you are on Facebook, you can post a question on the public group Pesticide Myth Busters and let the community there help you find a answer.