Cover crops to stop the spread of superbugs

A western corn rootworm crawls through corn silks. (Sarah Zukoff/flickr)


Cora Bern-Klug | August 24, 2016

Despite seed producers’ research, superbugs are still making their way into Iowa farmer’s crops. Companies like Monsanto and DuPont have been selling genetically modified seeds since the 1990’s that are designed to thwart insects. Yet pests like rootworms have become resistant to the deadly bacteria in the seeds.

Rootworms are small yellow to green bugs that mate from late summer to early fall. The female deposits her eggs in the ground near corn. When rootworm larvae emerge in May the hungry larvae devour corn roots. This stunts the corn’s growth and according the the Wall Street Journal stunted American farmers’ bottom line by 2 billion dollars in 2015.

In February of 2016 the Environmental Protection Agency (EPA) released new requirements that address the corn rootworm’s resistance to a strain of corn known as Bt Corn. The EPA stated that it is “concerned that if the resistance continues, it will lead farmers to use more synthetic chemicals to thwart the bug, creating environmental risks.” Bacillus thuringiensis (Bt) is a bacteria that creates a natural insecticide and has been used for decades by organic farmers. Seed producing companies and labs have genetically modified corn seeds to have Bt incorporated in their genetic code. The companies can then have a pesticide that is designed solely for that seed. Making farmers rely on the company for seed and their pest control.

Screen Shot 2016-08-22 at 10.09.26
Graph provided by the Wall Street Journal

Aside from modified seeds and their related pesticides, another option for farmers is to plant cover crops. A cover crop keeps nutrients from leaving the soil and stops weeds from growing over winter. A cover crop is usually oats or alfalfa. In the case of rootworm prevention, farmers are planting cover crops to get rid of the rootworm larvae. If there is no corn to munch on, there are fewer or no rootworms the following year. The downside to planting oats or alfalfa is the yield price. Oats are worth significantly less than corn, but it may be worth the cost to get rid of the pesky pest.

Through more research and more cover crops, we may see a decrease in rootworms. As farmers get on the cover crop bandwagon we’ll be seeing more and more oats and alfalfa growing in our local Iowan fields.

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