In 1974 when Monsanto first patented the glyphosate-based herbicide they named “Roundup,” it was hailed as an agricultural breakthrough. Previously, the most effective herbicides available were dioxin-based, persistent in the environment, and highly damaging to animal life. Glyphosate was benign by comparison.
However, we’ve made up for this supposed lowered toxicity by using an almost inconceivable amount of this stuff. It’s sprayed everywhere from city ornamental gardens to suburban back yards, and genetically-modified “Roundup Ready” crops like corn and soybeans are sprayed with it during the growing cycle.
Trouble with the “inactive” ingredient
In spite of Roundup’s original “safer than table salt” ad campaign, acute poisoning with Roundup (less than half a cup) can bring on symptoms leading to coma or death.
The tricky part is that Roundup and similar glyphosate-based weedkillers are compounds of many ingredients, and that at least one of those ingredients, the surfactant POEA (polyethoxylated tallowamine) is more toxic to animal life than the glyphosate. Yet glyphosate is the listed “active ingredient” in Roundup, and much of the herbicide’s touted low-toxicity is based upon studies of this ingredient only, disregarding the other “inactive” ingredients that go to make up the compound.
While it’s a rare person who will drink half a cup of Roundup, more pernicious than acute poisoning is the low-grade systemic poisoning that can occur from daily environmental exposure. Some industry studies show that glyphosate in isolation produces fetal malformations in lab animals. There is also evidence that it causes cell death in human embryos, placentas and umbilical cords. In Argentina, some provinces that grow large harvests of GMO soy have found that local rates of birth defect and cancers have ballooned. In one area, childhood cancer rates tripled and birth defects quadrupled after the introduction of glyphosate-resistant GMO crop agriculture.
How it works
The weed killer acts as an endocrine disruptor, inhibiting progesterone production. It may cause genetic damage at even sub-agricultural levels.
Even though Roundup breaks down more quickly in water, frogs and fish are far more sensitive to it than terrestrial animals. Runoff containing glyphosate-based herbicides can cause fish kills.
The compound does not degrade as quickly in soil as Monsanto reported. In loamy, humus-based soils, the half-life of Roundup may be only about three days, but in clay soils—prone to shedding water rather than absorbing it—it may hang around for months or even years.
Additionally, plants that die of Roundup preserve the glyphosate in their dead roots, stems and leaves—and the chemical can be reactivated as this plant matter decays, especially if the soil is subsequently treated with a phosphorus-bearing fertilizer. This is bad news for both gardens and waterways.
Understanding the manner in which glyphosate kills weeds is important: Basically, the chemical disrupts a metabolic pathway inside the plant and disables its immune defenses. Naturally occurring soil pathogens (bacteria and viruses) then move in and quickly kill it off. Weeds grown in sterile soil will not die when treated with Roundup.
A new kind of pathogen?
Glyphosate itself also kills a great many soil microbes—so the ones that survive create a highly unbalanced soil ecology. Pathogens that affect both plants and animals thrive in these disturbed conditions.
Don Huber, emeritus professor of plant pathology at Purdue University caused a huge stir in January 2011 when a letter he wrote to Secretary of Agriculture Tom Vilsack was leaked to the public. Dr. Huber asked Secretary Vilsack to stop deregulating Roundup Ready crops until further research was completed, saying he had found evidence of an overabundance of a new kind of pathogen in feedstock from crops treated with glyphosate, and that this pathogen was apparently implicated in animal miscarriages and infertility. An interview with Dr. Huber and the text of this letter can be found here: tinyurl.com/huberinterview
Selective pressure on an ecosystem always creates adaptation—this is evolution in action. Thirteen states are now reporting weeds resistant to Roundup. There are 15 confirmed glyphosate-resistant weed species, within a group of 63 that have shown to be developing resistance.
Roundup on the rise
The use of glyphosate doubled from 2001 to 2007, according to the EPA. Agricultural use in the U.S. has increased eightfold since 1992. The U.S. Geological Survey reported last August that glyphosate is ubiquitous in the Mississippi River after flooding. “Glyphosate is the mostly widely used herbicide in the world,” says Paul Capel, USGS chemist and an author on the study. “We know very little about its long term effects to the environment.” German scientists report glyphosate in human urine at five to 20 times the rate allowable for drinking water.
Addressing the UK Houses of Parliament this past January, Don Huber referred to glyphosate agriculture as a serious threat to the environment, livestock and human health.
Once considered a silver bullet, Roundup and its knockoffs more resemble a ricochet. It looks like the collateral damage has just begun.
Eternal vigilence is the price of freedom from bindweed
The three great inevitabilities in any gardener’s life are death, taxes, and field bindweed. Convolvulus arvensis, now classed as invasive “pernicious weed,” was brought over from Europe or Asia in the 1700s. The vine is indefatigably vigorous and incredibly difficult to kill: Underground roots store energy in starchy rhizomes and may easily extend downward 20 feet or more in length, as they will continue to grow until they hit the water table. Bindweed out-competes native and cultivated plants, and it is common in gardens, grasslands, riversides and disturbed environments such as roadsides and empty city lots. Bindweed seeds can remain viable in the soil for decades.
Fighting a pitched battle against bindweed can be frustrating in the extreme, especially if you wish to avoid herbicides. The green parts of the plant easily break off the root system, and the plant will regenerate over and over again from the roots. If ever you waffle on the subject of using Roundup, it will likely be in response to an invasion of bindweed.
Diligently weeding new sprouts from an old root system does pay off. Weeding the same patches over a course of years may eventually exhaust the root system.
The best advice is: vigilence and diligence. Pull those pointy little leaves the day they emerge. Know the places it likes to frequent and visit them daily. By all means, wherever you are, if you see a bindweed in bloom, do everyone a favor and rip it out before it goes to seed.
Bindweed is also a meditation—it challenges us to become more process-oriented and aware of our surroundings. Life, like a garden, is never completely under our control—but with patience and attention, we can create a space of restful harmony.
Failing sanguinity, try boiling water or a flame weeder.
Find other organic strategies for combating bindweed here: http://tinyurl.com/bindweedstrategies
Nontoxic home alternatives to the most widely used herbicide in history
Roundup was originally promoted as a way for farmers to cut back on tilling (the standard form of weed control) and curb the problem of erosion. It also helped phase out the pesticides associated with deadly dioxins. Forty years later, it has solidly ingratiated itself into the agricultural sector, with its own line of Roundup-ready grains. It is also, according to the EPA, the second most-used pesticide in the home and garden sector. There is little doubt that glyphosate-based weedkillers are being overused. The truth is that we just don’t need the stuff.
Farmers have serious issues to deal with regarding erosion, weed control and the accompanying genetically modified seed situation. The following practices do not apply to them. These alternatives are workable for the home and garden, however. If we expect people whose livelihoods may be at stake to make healthy choices regarding pesticides and the environment, it behooves us to do the same. Many common weeds can be adequately controlled using organic, non-toxic alternatives:
VINEGAR. Plain old acetic acid—white vinegar—can be sprayed on weeds. It causes chemical burns on the leaves that will kill the plant, but unlike glyphosate, soil microbes readily break it down. Vinegar will affect any plant it touches so be careful where you spray it. Using a paintbrush to apply it directly to selected leaves can eliminate overspray in plant beds. Adding a teaspoon of vegetable-based liquid dish soap to a quart of white vinegar and a quarter cup of table salt creates a systemic organic weed killer that is effective when sprayed at the base of the undesireable plant. This recipe also works well for weeds growing in sidewalk cracks.
ESSENTIAL OILS. Clove, peppermint, tea tree, pine, and citronella can be used just like vinegar, painted directly on leaves. If you add a surfactant (vegetable soap) you may also be able to get the weed to absorb the oil systemically and kill the root system as well. Use these formulations carefully because each oil has its own harms and benefits—remember, the dose makes the poison. Too much tea tree oil is also bad for humans!
SOLARIZING. For a larger area, cover with clear construction-grade plastic after watering. Keep the plastic on at least a month to kill weeds, then replant. What about beneficial soil organisms? According to a UC-Davis report, solarizing increases populations of mycorrhizal fungi and fungi and bacteria that aid plant growth, making them more resistant to pathogens than nonsolarized or fumigated soil. Earthworms are generally thought to burrow deeper in soil to escape the heat.
NEWSPAPER MULCHING. Spread newspapers over the area and then rake a couple of inches of good topsoil over them, dig holes through the topsoil and newspaper and plant into the holes.
FLAME WEEDERS. Available at garden stores and big-box hardware stores. Get rid of your weeds with fire!
RUBBING ALCOHOL. Try a solution of one tablespoon rubbing alcohol to one quart water in a garden sprayer.
BOILING WATER. Right out of a kettle—pour it directly on the weeds, but make sure it doesn’t splatter on you or any plants you want to keep!