On www.eurekalert.org on March 2, 2020, McGill University published an article titled: “Widely used Weed-killer Harming Biodiversity.” The article’s subtitle states that glyphosate-based herbicides comprise the class of weed-killers most commonly used by the world’s crop growers. According to Canadian scientists at this Montreal-based institution, this most widely used group of ag chemicals can spawn loss of biodiversity, making ecosystems more vulnerable to pollution, disease, and climate change.
Let’s define “biodiversity.” Greenfacts.org defines the term as follows: “The variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species, and of ecosystems. Biodiversity forms the foundation of the vast array of ecosystem services that critically contribute to human well-being.” Complicated definition? Yes. But let me give you an uncomplicated example of lost biodiversity — namely, the southern corn leaf blight of 1970 and 1971.
Approximately 85% of corn hybrids planted in the U.S. then shared major amounts of gene pool that lacked resistance to Race T of the fungus Bipolaris (Helminthosporium) maydis. Economic losses from southern corn leaf blight disease totaled about 1 billion dollars.
Presently, widespread use of glyphosate on farms sparks concerns over potential health and environmental effects globally. Since the 1990s use of that herbicide has boomed, as farmers adopted glyphosate-tolerant genetically modified crop seeds that are resistant to the herbicide. “Farmers spray their corn and soy fields to eliminate weeds and boost production, but this has led to glyphosate leaching into the surrounding environment. In Quebec, traces of glyphosate have been found in Montérégie rivers,” said Andrew Gonzalez, a McGill biology professor.
Using experimental ponds to expose phytoplankton communities (algae) to the herbicide, scientists tested how freshwater ecosystems respond to environmental contamination by glyphosate. “These tiny species at the bottom of the food chain play an important role in the balance of a lake’s ecosystem and are a key source of food for microscopic animals. Our experiments allow us to observe, in real time, how algae can acquire resistance to glyphosate in freshwater ecosystems,” said post-doctoral researcher Vincent Fugère.
The researchers found that freshwater ecosystems experiencing moderate glyphosate contamination became more resistant when later exposed to very high levels of the herbicide. They describe this phenomenon as a type of “evolutionary vaccination.” They believe that the results are consistent with what scientists call “evolutionary rescue.” Previous experiments by the Gonzalez et al. demonstrated that evolutionary rescue can prevent the extinction of entire populations, when exposed to severe environmental contamination by a pesticide. But researchers also noted that the resistance to the herbicide came at a cost of plankton diversity: “We observed significant loss of biodiversity in communities contaminated with glyphosate. This could have a profound impact on the proper functioning of ecosystems and lower the chance that they can adapt to new pollutants or stressors. This is particularly concerning as many ecosystems are grappling with the increasing threat of pollution and climate change.”
The researchers point out that it is still unclear how rapid evolution contributes to herbicide resistance in these aquatic ecosystems. They do know that some weeds have acquired genetic resistance to glyphosate in fields sprayed heavily with the herbicide. Finding out more will require genetic analyses currently being worked on by Gonzalez and Fugère. These authors acknowledge support and operating funds from the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Fonds de Recherche du Québec.
Last month marks the fifth anniversary of a televised interview between French investigative journalist Paul Moreira and a spokesman for corporate biotech agriculture. (I wrote about this interview in Crop Comments shortly after the televised 45-second dialogue that took place on French TV.) Here’s some background information leading up to the March 27, 2015 interview between Moreira and his guest.
In late February 2015 the Journal Lancet Oncology published an article spotlighting peer-reviewed documentation of the human carcinogenicity of the herbicide active ingredient glyphosate. Moreira scheduled a live-telecast interview with an American spokesperson for ag biotech interests. An on-line summary following the interview between the two gentlemen opened as follows: “(Ag Chemical) Lobbyist Refuses to Gulp Carcinogenic Glyphosate After Calling it Safe to Drink.” That spokesman stressed how safe glyphosate was: “You can drink a whole quart of it and it won’t hurt you.” He stormed out of the interview, when the Canal Plus TV journalist, Paul Moreira, offered him a glass of glyphosate to drink. “I’m not stupid. I’m not an idiot,” the biotech enthusiast retorted to Moreira. With his bluff just called, he abruptly ended the interview, calling his host a “complete jerk”. The journalist did, in fact, have a bottle of glyphosate, having brought it back from on-location interviews in Argentina. In that South American nation, he had interviewed field workers (who extensively handled glyphosate) who were experiencing 300% higher-than-normal frequencies of Non-Hodgkin Lymphoma (NHL, the disease being targeted by Lancet Oncology writers). Okay. Why call it a wooden anniversary. With some effort I learned that fifth anniversaries are celebrated with wooden gifts.
What’s happened in the 60 months since that March 27, 2015? Within very few months glyphosate became ineffective against many agronomically significant weeds. Also, the herbicide dicamba — accompanied by crops genetically altered to tolerate this chemical — has become to “go-to” weed control program of choice. Unless farmers grow crops in regions with warm enough summer nights to volatilize unmetabolized chemicals… which then often drift onto neighbors’ “conventional” crops. Over two years ago, federal courts began awarding huge multi-million dollar damage awards to documented NHL victims. As of last month, none of the first three victims has receive dollar one for their sickness, pain, and suffering.