Finding better ways to fight superweeds

[abovesobelow]

"At a time when soil erosion is recognized as one of the biggest threats to the world's ability to continue feeding itself, it's disturbing to now see U.S. weed scientists suggesting tillage to address invading "superweeds."

There is no question addressing the lengthening list of weeds that have developed resistance to glyphosate must be a top priority for researchers and extension agronomists advising conventional farmers.

As reported by Reuters, resistance to glyphosate has now reached the point where row-crop farmers in the Midwest are unable to control weeds such as Palmer amaranth infesting their fields, prompting weed scientists to suggest farmers resort to tillage.

These weeds were a problem limited to the deep south a few short years ago, forcing farmers in Arkansas to resort to hands and hoe to bring them under control. They are now "exploding" in the Midwest, Dallas Peterson, a weed specialist with Kansas State University, was quoted in a Reuters article.

http://www.winnipegfreepress.com/opinion/columnists/finding-better-ways-to-fight-superweeds-270572991.html

Roundup Herbicide 125 Times More Toxic Than Regulators Say

"The Test Method and Results

In order to ascertain the toxicity of various chemical formulations and their ingredients, the researchers used embryonic (HEK293), placental (JEG3), and hepatic (HepG2) human cell lines, "because they are well characterized and validated as useful models to test toxicities of pesticides, corresponding to what is observed on fresh tissue or primary cells." They noted, "these cells lines are even in some instances less sensitive than primary cells, and therefore do not overestimate cellular toxicity."

The researchers describe the their method of determining toxicity:

We assayed their mitochondrial succinate dehydrogenase (SD) activity (MTT assay) after 24h pesticide exposure, which is one of the most accurate cytotoxicity assays for measuring the toxicity of pesticide adjuvants such as surfactants [26]. Cytotoxicity was confirmed by the measurement of apoptosis and necrosis, respectively, by caspases 3/7 activation [27] and adenylate kinase leakage after membrane alterations [28]

The results of the study were clear. Except for one pesticide (Matin), "All formulations were cytotoxic and far more toxic than their APs [active principles]."

Key findings included:

On human cells, among the tested products, fungicides were the most toxic (Figure 1), being cytotoxic from doses 300–600 times lower than agricultural dilutions, followed by herbicides (except Matin) and then insecticides.
In all cell types, fungicides were the most toxic (mean LC50 12ppm).
The herbicide Roundup (LC50 63ppm) was next in toxicity to fungicides, twice as toxic as Starane, and more than 10 times as toxic as the 3 insecticides, which represent the less toxic group (mean LC50 720ppm).
"

http://www.greenmedinfo.com/blog/roundup-herbicide-125-times-more-toxic-regulators-say

[BrotherIvan]

1. Who could have known??????

You have to admire these plants' remarkable ability to adapt. It took scientists decades of effort to figure out how to modify crops to have resistance to herbicides. It took only a few years for nature to accomplish the same thing, albeit helped by farmers whose repeated use of the same products created intensive selection pressure.

But, but, but Science!