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Protecting Genetically-Modified Corn Crops with Proactive, High-Tech Monitoring

EPA researchers and collaborators are developing remote observation techniques for monitoring genetically modified crops.

Drawing of a plane and satallite over a corn field

For decades, pest infestations in agricultural fields across the country were met with a similar strategy: the application of pesticides, often from low-flying, crop duster aircraft. Although the target of such actions has been European corn borers, rootworms, and other crop-destroying insect pests, the impact of the pesticides didn’t necessarily stop there.

Traditional pesticides are broad spectrum in nature, meaning they can affect not only to the pests they are intended to control, but pollinators and other insects, wildlife, and even people, as well. Residues can remain in the local environment, in soils and waterways, and on fruits and vegetables eaten by consumers.     

Over the last 15 years, the practices of agricultural pest control have begun to experience a revolution, tapping advances in environmental monitoring, bioengineering, integrated pest management (IPM), and other emerging fields. One promising example: incorporating genes from the bacteria Bacillus thuringiensis (Bt)—which produce toxins lethal to the European corn borer and corn rootworm—into corn plants.   

Sixty-three percent of the total U.S. crop now consists of genetically modified (GM) plants.

But challenges remain. Infestations have been discovered in GM cotton in India and GM corn in Minnesota. Such problems raise concerns beyond lost crop yields, because they may also signal that pests have developed resistance to the traits incorporated into the crops. 

“A major concern is to ensure the optimal productive life for the biotech crop due to the expected environmental benefits,” says EPA scientist John A. Glaser, Ph.D. Glaser is working with collaborators from National Air and Space Administration (NASA)6 and the U.S. Department of Agriculture (USDA) to develop ways to use patented imaging technology to serve as an early warning system of pest infestations in GM corn fields.

“The question is:  How sustainable are the GM crops, what is their weakest element,” explains Glaser. “Their weakest element is the trait that, added through genetic modification, makes the plant pest resistant.  That trait assists the grower to avoid using broad-spectrum pesticides. But insects can develop resistance, leading to the loss of the GM corn variety.”

Glaser and his partners are using imagery obtained from an aircraft-mounted hyperspectral sensor camera to monitor color changes in GM corn.  Color changes detected as differences in reflected light from plants indicate pest infestations and other environmental stressors. 

Image of the corn monitoring equipment

The hyperspectral sensor used by EPA scientists was inducted into the Space Foundation's Space Technology Hall of Fame.

The technology allows farmers to monitor much larger areas efficiently, and to identify subtle changes in plant health significantly earlier than they could from the ground.  Early identification can mean better harvests and the related economic gains to the grower. And because crop infestation begins as a local phenomenon, pinpointing problem spots before field failure occurs is critical to obtaining the optimal life of a GM crop strain.  

In addition to providing an early warning system for pest infestation, developing such a monitoring system will help farmers meet EPA requirements for GM crop production, including Agency specifications under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA).

The monitoring approach Glaser is developing with high-tech imaging technology involves three layers. First, satellite images are used to identify hotspots of potential infestation across a large area, Then, aircraft equipped with hyperspectral cameras fly over suspected areas at about 7,000 feet, pass over same crops at strategic times across the growing season. Finally, the images taken from the aircraft are transferred to a computer system that can analyze the digital imagery to distinguish conventional and GM corn, as well as infestation effects and environmental stressors such as dehydration, nutrient imbalances, and grazing. 

If infestation is suspected, insects are collected in the field and tested for resistance in the lab.  Farmers then would have the option of changing their pest-fighting strategy before harvest. 

“In a nut shell, this technology offers a monitoring system capable of detecting pest infestation across the 90 million acres of the U.S. corn belt,” states Glaser.

Keeping an eye on such a large area could provide lots of benefits. In addition to monitoring pest resistance, the new technology will also supply key data for use in use in such things as modeling land-use changes and productivity estimates for crops involved in biofuel applications, the precise application of fertilizer, and computing carbon exchange estimates for global climate change assessments.

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