Monsanto Loses to a Tiny Foe: Corn Rootworm

That clever little pest, the western corn rootworm, is outsmarting the genetic engineers inserting a Bt protein into corn plants. Apparently Monsanto‘s attempts to kill off the beasties has just made them hungrier.

That is more than a little problematic since corn is a popular ingredient in almost everything, and genetically engineered crops account for 88 percent of all the corn planted in the U.S. You probably ate some GM corn today. If you ate any of these foods you almost surely did: corn meal, tortilla chips, yogurt, bread, breakfast cereals, “honey” roasted nuts, salad dressings, canned fruits, jams, barbecue sauce and ketchup.

The rootworm infestation is a triple blow to farmers. They were already struggling for survival in the face of massive drought and new superweeds. Now hungry pests are delivering a knock-out punch.

A 2011 study by Iowa State University’s Department of Entomology was the first to raise the alarm after finding corn rootworm in some fields. The honeymoon was over, but the extent of the problem did not seem like a reason for farmers to divorce Monsanto corn. Some changes in farming practices could bring it under control.

Then in August 2012 a University of Illinois study confirmed the Iowa State findings. Monsanto’s Bt-corn was losing its effectiveness against corn rootworm. In an article in the Daily Illini, entomology professor Mike Gray called it, “an unfortunate consequence of the overuse of good technology.”

Farmers in the Midwest had been enjoying high profits from their Bt-corn. They had not been planting refuge strips and had fallen into the practice of planting the same crop in the same field year after year. That was a boon for Monsanto but also for the corn rootworm, which evolved to resist the toxin.

Next: Monsanto goes on the defensive

Monsanto was quick to respond to the studies and to the U.S. Environmental Protection Agency’s (EPA) concern over “mounting evidence” their corn was no longer living up to its promise. Bloomberg Businessweek reported:

The studies of rootworms in Illinois and Iowa don’t confirm resistance in the field, Kelly J. Clauss, a spokeswoman for St. Louis-based Monsanto, said in an e-mail. More data is needed to prove resistance and the company is working with the EPA to investigate and respond to fields where rootworms cause “greater-than-expected damage,” Clauss said.

While Monsanto works with the EPA to figure out the extent of the problem and how to deal with it, the company has reason for concern. According to Bloomberg Businessweek, U.S. farmers planted the company’s Bt-corn on nearly 40 percent (37 million acres) of their cornfields. That is a major contribution to the company’s profits.

The biotech industry will respond the way it always does, by developing more chemical fixes to address the problem. Pete Riley of GM Freeze pointed out in November 2011 why that is the wrong direction to take:

Strategies to prevent pests becoming resistant are either not being correctly implemented, are failing, or are suffering from a combination of both. The result is more pesticide use rather than less. Throwing more GM at the problem may work in the short term, but the history of artificial pest control in agriculture has repeatedly shown the pests will win over the longer term.

The sooner we switch to agroecological farming techniques, such as avoidance of monocultures, long rotations and the use of natural predators to control pests, the better.


Related Care2 Stories

Genetically Modified Corn and Soy Breed superweeds

Genetic Engineers Blast GM Crops

Monsanto Corn at Farm Markets?


Photos of adult and larval stages of corn rootworm via Wikimedia Commons


Jim Ven
Jim Ven2 years ago

thanks for sharing.

Fred Hoekstra
Fred Hoekstra5 years ago

Thank you Cathryn, for Sharing this!

Wendy Schroeder
Wendy Schroeder6 years ago

Good. Monsanto is an evil company.

Elaine A.
Past Member 6 years ago

Elizabeth M. you could not have said it any better!!!

Winn Adams
Winn A6 years ago


Elizabeth M.
Elizabeth M6 years ago

It figures - they have developed super weeds - now super bugs.
When will man (& Big Corps.) realize that nature looks after itself?

Nils Lunde
PlsNoMessage se6 years ago

Absolutely, excuses for using GMO fall on its own. Dangerous for human is one thing, the other thing is how insect`s can adopt and make things far more dangerous......

Grace Adams
Grace Adams6 years ago

Same problem as super-germs developing resistance to antibiotics because we overuse antibiotics. Overuse almost anything and it fails you. Back to hygiene and isolation and better nutrition to raise the ability of the domestic plant or animal or human to withstand the hazards of the pest species.

Elaya Raja
Elaya Raja6 years ago


Huber F.
Huber F6 years ago

Could it really be that bad?