Killing Off the Monarchs

Story at-a-glance

  • A PBS documentary covers the amazing 2,000-mile migration of Monarch butterflies from Canada to the highlands of Mexico
  • The North American Monarch butterfly population has fallen by more than 90 percent as their primary food source and breeding habitat are decimated by glyphosate
  • Your help is urgently needed to help save the Monarch butterfly; specific action steps are provided


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

The Monarch butterfly population in North America is in serious trouble. Their numbers are shrinking at a staggering rate because so much of their habitat, the milkweed plant, has been destroyed by destruction of grasslands for the purpose of growing pesticide resistant corn and soy.

Milkweeds are critical to the Monarch’s survival because they’re the only food source for Monarch larvae. The Monarch and the milkweed plant evolved together over the centuries.1

Not only are milkweeds the primary source of food for these butterflies and their young, but a bitter toxin in the milkweed actually protects them from predators throughout their lifespan, and Monarchs lay their eggs on milkweed leaves. Fewer milkweeds mean fewer Monarchs.

Milkweed is very susceptible to being killed by glyphosate, the chemical in the herbicide Roundup that’s used prolifically on Monsanto’s Roundup Ready™ genetically engineered crops.

Milkweeds that used to abundantly line the Monarch’s flight path have been largely eradicated by modern agriculture.2  Not only are chemicals killing the milkweeds, but prairies are being replaced by cornfields, and roadsides are being mowed where milkweeds previously grew wild.

Experts estimate the North American Monarch population has plummeted by 91 percent over the last two decades. In 1996, the wintering habitats of Monarchs covered some 50 acres of the Mexican highlands, but last winter they occupied a paltry 1.66 acres—the lowest on record.3

At the population’s peak, in winter of 1996-1997 there were one billion Monarchs, but only 35 million remain today. These magnificent insects can only be saved by protecting their critical habitat, and unless we act quickly, they face certain extinction.

The Amazing Butterfly Migration

The PBS documentary, The Incredible Journey of the Butterflies, chronicles the remarkable 2,000- to 3,000-mile annual migration of these iconic insects from Canada to a tiny microclimate in the highlands of Mexico. Only North American Monarchs make this migration.

Their destination is an area of only 60 square miles in central Mexico's Transverse Neovolcanic Range. The timing couldn’t be more precise—the butterflies leave Mexico around March 21st each year and begin trekking north on September 21st—timed with the equinoxes!

This schedule is so predictable that their arrival is a highly anticipated event for the Mazahuan people of Mexico who believe the butterflies are the returning souls of their ancestors. Their arrival even marks a Mexican holiday, Dia de los Muertos or “Day of the Dead.”

The migration is a marvel of nature, especially for a small creature with such fragile wings. Scientists are still puzzling over how they are able to navigate thousands of miles—whether by Earth’s magnetic field or the angle of the sun or by some other mechanism—and how they have such finely tuned internal clocks that they can arrive en masse in one location on the same day each year.

They can only fly when conditions are perfect... too hot, they overheat. Too cold, they get sluggish and can’t flap their wings. Rainstorms can be deadly.

They must cross miles of open water—the Great Lakes—in constantly shifting winds, when they can’t see across to the other side. They must cover 50 miles a day with predators lurking everywhere. Danger also awaits them in Mexico, where their forest habitat continues to shrink from illegal logging.

Since all North American Monarchs overwinter in a highly confined region, one major winter storm could wipe out the entire species. For example, during one winter when the population was much more robust, a single storm killed off 75 percent of the Monarch population. We can’t control winter storms, but we CAN curb pesticide application.

Restoring Native Grasslands is Critical for All Life on Planet Earth

Nearly a billion pounds of Monsanto’s glyphosate-based herbicide Roundup is dumped on fields and our lawns each year.

The documented harmful effects of glyphosate extend not just to critical pollinating insects, but also to soil, plant, animal, and human health. It's becoming increasingly clear that glyphosate is doing FAR more harm than anyone ever expected.

Last winter marked the lowest Monarch count on record at a time when other pollinators such as honeybees, native bees, birds, and bats—vital to US agriculture and therefore the nation's economy—also are facing serious decline.

Monarchs do their fair share of pollination, especially on corn.4,5,6 Genetically engineered (GE) corn now accounts for 93 percent of corn grown in the US,7 so you can see how these butterflies can no longer avoid Monsanto’s path of ruin. GE crops are typically the most heavily sprayed, as “Roundup Ready” crops are designed to withstand otherwise lethal doses of this chemical.

This corn also produces its own insecticide, Bt, which is also toxic to insects. Many equate modern farming techniques with “progress,” when in fact many of our technological advancements are now threatening to destroy us right along with the entire planet.

There are major differences between industrial farming and regenerative agriculture, and the foods produced by the former cannot be equated to the foods produced by the latter. GE plants and industrial farming contributes to every form of environmental devastation, while organic farming methods support, restore, and rejuvenate the ecosystem.

Monsanto or Monarchs—Which Will It Be?

Bill Freese of the Center for Food Safety advocates restricting the spraying of glyphosate late in the growing season, when milkweed is flowering and more likely to be killed.8

Freese also supports measures to restore some milkweed plants to farmland, noting that farmers and weed scientists have not found milkweed to be much of a problem.

Of course, representatives of Dow Chemical and Monsanto disagree.  Monsanto spokesperson Charla Lord is quoted as saying, “To a farmer, milkweed is a weed that competes with crops in the field for water, soil, and nutrients.”9 They will defend their chemicals to the bitter end.

Fascination with the Monarch is not enough to save the species—you must take action. The remainder of this article will discuss several ways you can help save our precious pollinators.

Action Step #1: Petition for Classifying the Monarch as 'Threatened'

The outlook is so grim for Monarchs that in August of 2014, the US government embarked on a major campaign to save them. Scientists from several organizations, including the Center for Food Safety, filed a petition10 urging US Fish and Wildlife Service to classify Monarch butterflies as “threatened” under the US Endangered Species Act.

This dovetails with a 2014 White House memorandum11 calling for a federal strategy to promote the health of honeybees and other pollinators, by way of a multiagency Pollinator Health Task Force. The petition also urges the Environmental Protection Agency (EPA), US Department of Agriculture (USDA), and President Obama to protect the Monarchs' breeding habitat by halting the approval of Monsanto Roundup Ready™ and other glyphosate-resistant and pesticide-promoting GE crops. As noted by the Los Angeles Times:12

"Since federal glyphosate rules were last updated a decade ago, its use has spiked tenfold to 182 million pounds a year, largely due to the introduction and popularity of corn and soybeans genetically modified to resist the herbicide... ‘The tenfold increase in the amount of glyphosate being used corresponds with huge losses of milkweed and the staggering decline of the Monarch,’ said Sylvia Fallon, an NRDC senior scientist. 'We are seeking new safeguards desperately needed to allow enough milkweed to grow... The good news is that butterflies are resilient and can rebound quickly... All they need is milkweed on which to lay their eggs.”

Sign Petition

Action Step #2: Ask Retailers to Stop Selling Pesticide-Treated Plants

If you live in the US, I would also encourage you to contact your local Lowe’s store, either by phone or in person, and ask them to stop selling bee-killing pesticides and neonicotinoid-treated plants. Neonicotinoid pesticides are a newer class of chemicals that are applied to seeds and taken up through the plant’s vascular system as it grows, where it’s expressed in the pollen and nectar that pollinators consume. For contact information, see Lowe’s Store Locator page.

Action Step #3: You Can Support Bee and Butterfly Populations from Home

To avoid harming bees and other helpful pollinators that visit your garden, swap out toxic pesticide and lawn chemicals for organic weed and pest control alternatives. Even some organic formulations can be harmful to beneficial insects, so be sure to vet your products carefully. Better yet, get rid of your lawn altogether and plant an edible organic garden. Both flower and vegetable gardens provide good honeybee habitats. It's also recommended to keep a small basin of fresh water in your garden or backyard, as bees actually do get thirsty.

In order to support the Monarch butterflies, consider planting a locally appropriate species of milkweed in your garden, on your farm, or wherever you manage habitat. You can use the Milkweed Seed Finder to locate seeds in your area. Whatever you choose to grow, please avoid purchasing pesticide-treated plants. Cut flower growers are among the heaviest users of toxic agricultural chemicals, including pesticides, so if you must buy cut flowers, make sure you select only organically-grown and/or fair trade bouquets.

Ideally, you'll want to grow your own pollinator-friendly plants from organic, untreated seed, but if you opt to purchase starter plants, make sure to ask whether or not they've been pre-treated with pesticides. Keep in mind that you also help protect the welfare of all pollinators every time you shop organic and grassfed, as you are actually “voting” for less pesticides and herbicides with every organic and pastured food and consumer product you buy. You can take bee preservation a step further by trying your hand at amateur beekeeping. Maintaining a hive in your garden requires only about an hour of your time each week, benefits your local ecosystem—and you get to enjoy your own homegrown honey!


By continuing to browse our site you agree to our use of cookies, revised Privacy Policy and Terms of Service.