Soaring use of the weed-killer glyphosate, first marketed as “Roundup,” is devastating monarch butterfly populations, and new safeguards should be put in place immediately to save the iconic species from further decline, the Natural Resources Defense Council said Monday.
In a petition filed with the U.S. Environmental Protection Agency, NRDC said current uses of glyphosate are causing “significant ongoing harm” to monarchs, the unique orange-and-black butterfly species that migrates through the United States, Canada and Mexico as part of its annual lifecycle.
The use of glyphosate, a broad spectrum weed-killer, has led to large-scale suppression of milkweed, a native plant that is the sole source of food for monarch butterfly larvae.
While many herbicides can kill milkweed, it is the current application of glyphosate that has “contributed to significant habitat loss along monarch migratory paths,” the petition says.
Recent figures show the monarch numbers in their Mexican wintering ground have plunged to just 10 percent of their recent annual average, and “the pervasive use of glyphosate has contributed to the monarch’s decline,” the petition said.
Because each monarch lives only a few weeks in the summer, it takes several generations of butterflies to make the round-trip from Mexico to Canada and back.
The petition asks the EPA to conduct an urgent review of the rules for glyphosate and consider the cumulative impact on butterflies from glyphosate and other weed-killers.
Since the glyphosate rules were last updated in 1993, its use has soared tenfold to 182 million pounds a year, following the introduction and rapid spread of “Roundup Ready” corn and soybeans.
Developed by Roundup’s creator, ag-biotech giant Monsanto, these crops are genetically modified to resist the weed-killer. Transgenic soybeans and corn now dominate Midwest farms and glyphosate has become the most widely used herbicide in the United States.
New herbicide-tolerant crops are in the pipeline, raising new threats to monarch habitat.
Although EPA is scheduled to complete a new review of glyphosate rules next year, “given the rapid decline in monarch numbers, EPA should take immediate steps to review and restrict glyphosate’s uses,” the petition says.