Editorial: Saving the majestic monarch means preserving the modest milkweed

California has an official insect, the dogface butterfly, which is found only in the Golden State. If the North American continent had one, however, it might well be the iconic, majestic monarch.

Millions upon millions of the orange-and-black insects move between Canada, the United States and Mexico in an epic and mind-boggling multigenerational migration. California has a special place as a winter home to enormous clusters along the southern and central coasts.

But monarchs are in danger. Their population has been sharply declining over the past 20 years, and environmental advocates think they know why: the widespread use of an herbicide called glyphosate, more commonly known by the brand name Roundup.

The Natural Resources Defense Council, a Washington, D.C.-based environmental organization, last week filed a petition with the Environmental Protection Agency asking for new restrictions on the use of glyphosates. The chemical was approved for use in 1993 and has become ubiquitous in the last two decades, including “Roundup-ready” farming – crops that are genetically engineered to withstand the herbicide – and residential landscaping.

Sylvia Fallon, a biologist and director of the NRDC’s Wildlife Conservation Project, said last week that the group is not seeking a ban, just limits on the use of glyphosates next to highways and public easements where weeds like to grow, and in areas around crops. It’s a reasonable request considering the herbicide’s apparent effect on monarchs.

It’s not glyphosate itself that is the problem, Fallon said. The problem is that the herbicide is so effectively killing the plant that monarchs depend on for survival – milkweed.

This unlovely, hardy plant is the main food for monarch larvae and is where the butterflies lay their eggs. But since the widespread adoption of glyphosates in agriculture in the last two decades, the amount of milkweed has plummeted, according to a 2012 study by scientists John Pleasants and Karen Oberhauser. They found that between 1999 and 2010, milkweed in the Midwest declined by nearly 60 percent. During the same time, the population of monarchs declined by more than 80 percent.

That’s worrisome enough, but the Midwest is not the only place with crops or herbicide use. And observations in Mexico, where most monarchs spend their winters, are even more alarming. Before 1993, an estimated 1 billion monarchs migrated across North America to Mexico each year. Last year, only about 35 million showed up. At that rate, the monarchs could disappear altogether in a few years.

California has also noticed declines in individual winter clusters, though not as dramatic as the much larger population that winters in Mexico.

This decline of the monarch has been alarming enough that during a summit among leaders of Mexico, the United States and Canada last month, they took some time to discuss the plight of the monarch. “We have also agreed to work on the preservation of the monarch butterfly as an emblematic species of North America which unites our three countries,” Mexican President Enrique Peña Nieto said. The EPA limits would be a natural first step.

Why should anyone care about this one bug?

If a world without monarch butterflies isn’t reason enough, consider the bigger concerns about environmental degradation and the stress on the all-important pollinators. “It’s symptomatic of bigger problems we are causing by the way we are managing our landscapes right now,” Fallon said.

Government agencies work slowly. The NRDC asked for a response from the EPA within six months. But individuals, businesses and local and state governments don’t have to wait for the feds to take action. Backyard gardeners can certainly help by going easy on the application of weed killer this spring or even planting milkweed to attract monarchs. And everyone can push local and state agencies to limit their use of weed killers on public land.

The monarchs don’t need much, just a weed to call home. With fewer spritzes, we can do that.