Herbicide Blamed For Monarch Declines

The Natural Resources Defense Council (NRDC) is urging EPA to review the impacts of the herbicide glyphosate, also known as Roundup, on monarch butterflies. In a petition filed on Feb. 24, the environmental group claims that widespread use of glyphosate has led to large-scale loss of milkweed, the sole source of food for monarch larvae. Although other herbicides also kill milkweed, glyphosate has “contributed to significant habitat loss along monarch migratory paths,” the petition says. EPA is scheduled to review the rules for glyphosate next year, but “given the rapid decline in monarch numbers, EPA should take immediate steps to review and restrict glyphosate’s uses,” NRDC argues. Monsanto, maker of Roundup products, says it is “eager to join efforts to help rebuild monarch habitat along the migration path.” The company claims that multiple factors are leading to the decline of monarch butterflies, including loss of habitats in Mexico, strong storms, and extreme climate changes.