Superweeds surging, survey of farmers finds

Cutting pigweed in Arkansas. Photo from
The Commercial Appeal by Brad Luttrell

The problem of herbicide-resistant "superweeds" continues to grow, with almost half of farmers in a 31-state survey saying their land has weeds resistant to glyphosate, the active ingredient in Roundup, agriculture's main weed killer.

The survey was done by Stratus, an agri-marketing research consultancy. It found that glyphosate-resistant weeds are spreading in just about every way: New regions, more farms and more weed species are involved, Stratus's Kent Fraser reported. Farmers might need to use new crop seeds that are resistant to more powerful herbicides that can kill superweeds, but that will take time for government approval.

Stratus said it surveyed thousands of farmers in 31 states over three years. Its finding that almost half reported glyphosate-resistant weeds on their farms in 2012 was a 34 percent increase from 2011. The South has the biggest problem, with 92 percent of Georgia farmers surveyed reporting glyphosate resistance on their farms. Uther regions are "catching up," Fraser wrote. In Nebraska and Indiana, the number of estimated acres with resistant weeds nearly doubled from 2011 to 2012.

Plants commonly known as horseweed and pigweed were the most commonly reported as resistant, but Fraser said "the problem is getting more complicated" since more farms are reporting having two or more resistant species. Tom Philpott of Mother Jones speculated that companies like Monsanto, which created Roundup and makes "Roundup ready" seeds that allow fields to be sprayed with the herbicide without killing the crops, might encourage farmers to "try out 'next generation' herbicide-resistant seeds—that is, crops engineered to resist not just Roundup, but also other, more toxic herbicides, like 2,4-D and Dicamba," but new seeds would probably not be approved by the Department of Agriculture until at least next year. In the meantime, farmers will likely use more herbicide to curb weeds, Philpott wrote, though another crop to their yearly rotations could decrease superweed growth. (Read more)