Tuesday, March 15, 2011
Glyphosate: Are You Using It Or Are You Scared By The Rumors?
Are you familiar with glyphosate? Of course you are. Your entire soybean weed control program and maybe even your corn weed control program are built around glyphosate. You have used so much of it, some of it may even be in your blood (in a figurative sense.) Glyphosate has become the center of great controversy following comments published by a former Purdue staff member who called into question issues that may be best described as “unintended consequences.” However, a broad base of agricultural researchers is challenging those accusations and farmers may find themselves wondering if glyphosate is safe to use.
About the time of year you start to spend thousands of dollars on glyphosate and the seed that is designed to work with it, all of this controversy pops up. It started with Dr. Don Huber, retired Professor of Plant Pathology at Purdue University and the comment “It is well-documented that glyphosate promotes soil pathogens and is already implicated with the increase of more than 40 plant diseases…” Dr. Huber drew a line in the sand and his former colleagues at Purdue were among the first to cross it by saying, “We encourage crop producers, agribusiness personnel, and the general public to speak with University Extension personnel before making changes in crop production practices that are based on sensationalist claims instead of facts”.
At Iowa State University, weed specialist Bob Hartzler looked at some of Dr. Huber’s other research and reported, “Glyphosate is similar to most herbicides in that when it enters the soil it differentially affects soil microorganisms (Kremer, 2005). Thompson and Huber (2007) reported that glyphosate application to GR soybean altered the balance of Mn reducing and oxidizing bacteria associated with soybean roots in a manner that suggested that Mn would be immobilized in the soil. However, published data documenting reduced soil availability of Mn due to the activity of glyphosate on soil microorganisms is lacking.”
The latest salvo to be fired in defense of glyphosate comes from a broad range of crops researchers at Ohio State University. In the recent issue of the Crop Observation and Recommendation Network, a series of reports were filed;
1) Soybean plant pathologist Anne Dorrance said she cannot document any truth in the statement about 40 diseases being fostered by glyphosate. She said numerous allegations in the past had been negated by a number of research studies, “One of these studies was done by a group at Southern Illinois University, which compared round-up ready soybean cultivars with and without glyphosate for the development of SDS. There were no significant differences in the level root infection, SDS symptom development, nor colonization of roots between the sprayed and unsprayed plots of the same variety. Their primary conclusion was that the development of SDS in their region on round-up ready soybeans was due to the lack of resistance to this pathogen and NOT due to glyphosate applications.”
2) Ohio State veterinarian William Shulaw addressed the issue about Roundup Ready alfalfa being approved by USDA, which puts it into cattle feed channels. He says the “new” pathogen supposed to be associated with glyphosate is reportedly a micro-fungal like organism. Shulaw says, “As near as we can determine, this new organism has not yet been described in scientific publications or in oral presentations at scientific meetings. Results from research demonstrating its ability to cause abortions or other negative health consequences in animals have not been presented in these settings either. It is very unusual that preliminary experiments that demonstrate an ability of an organism to cause abortion could already be completed without some description of the organism itself being presented to scientists in written or oral communications.”
3) Weed specialists Mark Loux and Robert Mullen at Ohio State say many soybean growers are beginning to ask if they are misusing glyphosate and causing deleterious effects to their crops. They say the glyphosate critics should be offering scientific evidence of their claims, “A major problem we have with the negative glyphosate story being told is the almost complete lack of appropriately designed and repeated field research studies that validate the concerns that are being raised. The meaning of “appropriately designed” here is that the treatments are designed to accurately assess the effect of one or more factors. This and the treatment replication within studies, and the repetition of studies, is what allow scientists to draw valid conclusions. In our opinion, growers trying to evaluate the glyphosate issue should be asking the developers of the negative glyphosate story to show results of this type of field research.”
4) Mullen, Loux and Dorrance also address the issue with manganese and glyphosate which causes concerns from time to time among farmers who use glyphosate. They say the manganese issue has research support on both sides, “There are published studies that have shown that application of glyphosate can result in decreased manganese concentration in soybean tissue. Conversely, data collected from Ohio over 4 site-years has not shown that application of glyphosate (even at rates well in excess of the labeled rate) has influenced soybean manganese tissue concentration even two weeks after application.”
Summary:
Renewed criticism about glyphosate has recently occurred with statements attributed to a retired Purdue researcher about glyphosate enhancing fungal diseases, abortion in livestock, and problems with manganese uptake and use. Researchers at Purdue, Iowa State, and Ohio State have all refuted the criticism, and say that their research proves the opposite, although there is supporting research on both sides of the issue with regard to manganese.
Posted by Stu Ellis on 03/15 at 12:11 AM | Permalink
Comments
Posted by: Terry Humphrey at March 20, 2011 8:08AM
In my experience, farmers are very sensible, practical people not prone to getting swept up in hysteria, and they are right to require some scientific proof before making changes in their practices. However, Dr Huber may be wise to be concerned about unintended consequences. After all, the true long term effects of heavy reliance on glyphosate, will only be known when it has been tested in America’s croplands for decades. Logic and experience tells us that any chemical that powerful will have effects on the balance of microbes and nutrient uptake of the soil. Personally, I would like to see some serious money put into unbiased research of the proliferation of this “organism” and its effects on the health of plants and livestock.
Posted by: Eugene Sargent at May 12, 2011 6:06AM
“And Monsanto finances how much ag research at the above mentioned schools?”
This is what is referred to as a “circumstantial ad hominem”.
When the misinformed or the dishonest cannot proceed in a debate by sticking to points and facts raised, they immediately begin to divert the argument by suggesting conspiracies committed by connections either real or imagined.
It is possible that such conclusions were scientifically arrived at without the involvement of Monsanto. It is also possible that the conclusions are correct regardless of Monsanto’s Involvement.
Skeptic Guy:
As you would well expect, Monsanto invests research dollars at many universities. Sometimes they get what they expect, other times they don’t. Some researchers are willing to accept funding for research but will not guarantee the results that corporate funders want. It has to be an interesting dance between the researchers and the funders, but because basic research is so expensive, it has to be done at public facilities because private companies can really only afford to conduct advanced research.
You open an interesting argument. Anyone else want to weigh in…?
~Stu
Posted by: ThatSkepticGuy at March 3, 2012 8:08PM
And Monsanto finances how much ag research at the above mentioned schools?
Terry;
Good question. I don’t have the data. It probably is accessible with some diligence and effort. Most of that kind if money is public and has to be accounted for, so the data should be obtainable. I think the researchers were a bit miffed that the critical comments came without the research that they routinely conduct. The issue you raise is one that many farmers also question, but I think if something were seriously wrong with the product, sales would fall off rapidly, despite a cadre of researchers vouching for it.
~Stu