To the editor:
I’m glad to see the interest triggered by your recent article on glysophate (the active ingredient on Monsato’s herbicide Roundup) for removing knotweed in our area.
Along with many others, I have great concerns about the use of this chemical. Specifically, I question the claim from Will Marlier that there is “overwhelming evidence” that glyshophate does not cause cancer. There are, in fact, many studies and lawsuits claiming otherwise. For example, this June 2025 article out of George Mason University’s College of Public Health states: “A comprehensive carcinogenicity study on the world’s most used herbicide, glyphosate, involving scientists from Europe and the U.S., has found that low doses of the controversial weed killer cause multiple types of cancer in rats.” (And such studies historically indicate a relatively high probability of similar results in humans.)
In addition, that International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO) of the UN, declared in 2015 that glysophate is “probably carcinogenic to humans” based on limited evidence of cancer in humans and sufficient evidence in experimental animals, (linking it, in particular, to non-Hodgkin lymphoma.)
This is personal for me. My mom died at age 66 of a non-Hodgkins lymphoma. I hate to admit it, but my mom, like many others in the 1960s and 1970s, used Roundup often. There is a lot here that we don’t yet know for sure. But it seems to me that much more research is needed before any potential use of glyphosate is practiced in these local pilot projects, especially since they are very close to water sources, though I would add any substance that would go straight into the earth that has not yet been proven to be safe, should be avoided.
Finally, the link below, aligns closely with my way of seeing the unknowable or unseen realms of our world, one that leaves space for the Great Mystery and for wonder, especially if we slow down enough to listen. This link also contains some valuable insights about the possible use of knotweed to treat Lyme disease, and other healing gifts from our Mother Earth. Perhaps it’s time to look at where the real, more serious invasiveness comes from.
https://sacredgardener.ca/japanese-knotweed/
Nancy S. Riege
Greensboro
