Genetically modified corn losing resistance to major pest
Bt corn, one of the nation’s most widely produced crops, is thought to be losing its natural resistance to the western corn rootworm, a pest that feeds on the roots of corn and could potentially wreak economic havoc if it continues to spread.
Currently the infestations remain isolated, but concerns have been growing ever since Bt corn infestations have been discovered in four Midwestern states, a sign that the repeated planting of the corn strain – instead of being rotated with other crops – is enabling the insects’ resistance to the crop’s pest-fighting powers. Many farmers are foregoing rotation in order to cash in on the high corn prices.
Bt corn was introduced to farmers in 2003 and allowed growers to bring in bountiful harvests using fewer chemicals because the corn naturally produces a toxin that poisons the common pest.
Because of the corn farmers’ current – and most likely ongoing – practices, some scientists fear it could already be too late to prevent the rise of resistance. In addition, they’re also concerned about the problem becoming more widespread due to the rootworm larvae growing into adult beetles that can fly and migrate into new areas.
If rootworms do become resistant to Bt corn, it “could become the most economically damaging example of insect resistance to a genetically modified crop in the U.S.,” said Bruce Tabashnik, an entomologist at the University of Arizona. “It’s a pest of great economic significance — a billion-dollar pest.”
