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As monarch butterflies plummet, it's time to rethink the widespread use of our nation's top weedkiller

Sylvia Fallon

Posted February 24, 2014

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Today NRDC is calling on EPA to re-examine the widespread use of glyphosate, commonly called Roundup, in light of its impacts on monarch butterflies.  Glyphosate was last approved by EPA in 1993 before the adoption of genetically modified crops that are tolerant to its use, known as “Roundup Ready” crops.  Now, however, Roundup Ready corn and soy dominate the agricultural system and the use of glyphosate has skyrocketed tenfold to 182 million pounds annually.  As a result, milkweed – which is the sole food source for monarch butterfly larvae – has all but been eliminated from farm fields across the Midwest. 

monarch larvaeAt the same time that spraying of glyphosate has soared, the monarch butterfly population has been plunging.  This winter the population at their Mexican wintering grounds fell to just a tenth of its running average, to 33.5 million, and a calamitous drop from a high of one billion monarchs in 1997, the year after the first Roundup Ready crops were introduced to the market.

Because of this alarming decline, researchers this year declared the monarch’s migration is at “serious risk of disappearing.”  This means we are in danger of losing, in just a few short years, a marvel of nature that has existed for millennia. The monarchs’ annual flight from a tiny area of Mexico to as far as Canada and back, all in a single season and spanning several generations, is a unique phenomenon still mysterious to science.

 Although other factors like temperature and drought also affect the monarchs, researchers broadly agree that the widespread use of glyphosate in association with genetically modified Roundup Ready crops has been a major contributor to the decline of the monarch population.  With glyphosate, says leading monarch expert Karen Oberhauser of the University of Minnesota, “We have this smoking gun.”

 Now that we know that glyphosate is having a devastating impact on one of the world’s most spectacular natural wonders, it’s time to restrict the pervasive use of this and other weed-killers. 

The EPA has the authority to conduct an urgent review of any herbicide and impose restrictions to address its adverse impacts.  That’s why NRDC has filed a petition asking the EPA to undertake such a review of glyphosate and develop measures that would reduce its impact on monarch populations.  Some of the measures we propose include preventing use of glyphosate and other weed-killers along highways and power-line rights of way where milkweed, a relatively short plant, could grow freely without interfering with maintenance or emergency crews – and  requiring farmers to establish herbicide-free safety zones in or around their fields,  or create other milkweed-friendly habitat.  And we encourage the agency to explore other safeguards to protect monarch habitat from glyphosate and other herbicides.

The devastation of the monarchs is a disheartening example of the many unintended consequences we suffer from the industrialization of the agriculture system.  By taking steps to save the monarch, we must also take a hard look at the wider impacts of our current land use and farming practices.  There are several other herbicide-resistant crops in line for approval that will only further contribute to the loss of milkweed and other native plants that pollinators depend on unless we build in appropriate safeguards.

Though seemingly delicate, monarch butterflies are remarkably resilient and their decline can be reversed – but for that to happen we must find a way to make a little room for the very plant that they need to survive.

To help NRDC and our partner MonarchWatch plant milkweed please visit our Green gifts.


Photo credit: Kim Starr for Caterpillar and Sherri VandenAkker for Butterfly.

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carolyn berryFeb 24 2014 01:16 PM

This must stop, please outlaw Roundup.

Barbara SadlerFeb 24 2014 01:27 PM

The annual flight of the monarchs is one of the most amazing phenomena in nature. Let's put a stop to the use of glyphosate, and insure these beauties survive.

Pilar GarciaFeb 24 2014 02:40 PM

El ser humano no puede seguir destruyendo su propio hogar y llevarse por delante tantos seres vivos.

Stephanie JohnsonFeb 24 2014 03:15 PM

Stope killing butterfies with weedkiller.

Ava ColemanFeb 24 2014 03:20 PM

We need Bird's, Bee's and Butterfly's too survive....

Bernard LacourseFeb 24 2014 04:02 PM

stop killing butterflies, bees with weedkiller!

karinski oslobodFeb 24 2014 04:37 PM

bees and butterflies are key to our survival.

Joan FaszczewskiFeb 24 2014 06:46 PM

They are beautiful butterflies. I like to watch all butterflies some are very colorful. Stop useing posions on them and even the honey bees. They provide food for us when they pollinate.

Cynthia WrightFeb 25 2014 07:29 AM

The epic monarch migration is in danger of extinction, in large part due to the spraying of Roundup in the GMO crops grown in the fields of the midwest, thus eliminating the growth of milkweed, the only food plant that monarch caterpillars feed upon for survival. Please review the use of glyphosate and develop measures that educe its impact on monarch populations. For example,, prevent the use of glyphosate and other weed-killers along highways and power-line rights of way where milkweed, a relatively short plant, could grow freely without interfering with maintenance or emergency crews – and requiring farmers to establish herbicide-free safety zones in or around their fields, or create other milkweed-friendly habitat. We also encourage the EPA to explore other safeguards to protect monarch habitat from glyphosate and other herbicides.

catherine mattinglyFeb 25 2014 07:32 AM

Monsanto doesn't care if it kills us , too. They are putting it in our food! Save the butterflies & bees- Save ourselves!

Ken TrimbleFeb 25 2014 08:27 AM

Once upon a time not too long ago there were pollinators called butterflies and honey bees. They were amazing and beautiful insects. The end. Goodnight my love.

Marissa TosadoFeb 25 2014 09:09 AM

Please, we need to stop destroying the habitat and the food sources of all those animals. The effects is going to hit us all. We are doing that to bees and now to monarchs. And we are all living right now with the consequences of that. There are other ways to do things without harm those that are necessary to the continuity of life on this world.

Rosemary ThorntonFeb 25 2014 01:30 PM

I was so disappointed last summer when our milkweed grew so heartily, but I could find few eggs. It seemed unbelievable that whereas the summer before I had found dozens, I was finding none or maybe one or two. At our cabin in the sand hills where I always found dozens, I found NONE. I feel sad, but also urgent to do something to change the situation.

Marian ViramontesFeb 25 2014 06:20 PM

Have been trying to help the plight of the monarchs, spent a small fortune on milkweed trying to keep them fed. I am so heartbroken every time one emerges with deformed wings unable to fly and even more so when they don't emerge at all. Can't tell you how often this happens!
Please tell me what else I can do to make a difference!!

Diane carrollFeb 25 2014 07:56 PM

Its time, to think of the furture,its coming real fast!

Marcia KirkleyFeb 26 2014 09:21 PM

Monarchs are the tip of the iceberg. Round-up kills everything in its wake, not just plants but all life in the soil (bacteria, fungi, nematodes, earthworms etc). That soil life provides nutrients to plants...naturally. But we kill them, so our farmers have to feed the crops mechanically with synthetic chemicals...a vicious circle ensues.

ST: we need to stop using synthetic herbicides, pesticides & fertilizers along highways, rail and phone lines. LT: we need to get our farmers to stop using synthetic chemicals and GM seeds, that perpetuate unsustainable farming practices.

Jane PetersMar 1 2014 12:06 AM

It seems like these companies are determined to destroy the earth that we all are dependent on.

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