Department of Civil, Construction, and Environmental Engineering

Iowa State University researchers have found a way to identify Asian soybean rust—a deadly, rapidly-spreading fungus affecting soybean crops—without stepping foot in the field. The team—which includes Khalil Ahmad, a graduate student in environmental engineering—uses satellite images of soybean fields and applies remote sensing, Global Positioning System (GPS), and Geographic Information System (GIS) technologies to determine if a crop has the disease. This technology could help create an early warning system to improve crop biosecurity in the United States.

“In plant pathology, researchers go into the field using either visual methods or a handheld radiometer to measure the disease,” Ahmad says. “Now, technology enables us to do the same thing using satellites.”

Ahmad says the research team—which includes Forrest Nutter, Iowa State professor of plant pathology; Neil van Rij, a plant pathologist in South Africa; and John Basart, Iowa State professor emeritus of electrical and computer engineering—has discovered that soybean rust leaves a unique elliptical-shaped footprint, allowing them to accurately identify patches of diseased crops from satellite images.

“We can use the images to get GPS coordinates, and then if necessary, can send someone out into the field to get plant samples and confirm the disease,” Ahmad says.

The research is funded by the U.S. Army’s Telemedicine & Advanced Technology Research Center. With increasing attention on bioterrorism, agencies such as the U.S. Department of Homeland Security (DHS) and U.S. Department of Agriculture also are highly interested in this research.

The DHS could use the technology to help them determine if the disease is occurring naturally or deliberately, says Ahmad.

Because the U.S. economy is heavily based on agriculture, the government is interested in this technology from an economic standpoint, he adds.
Soybeans and soybean byproducts are used in a wide number of products—plastics, cleaning products, alternative fuels, antibiotics, animal feed, and cooking oils, for example. The impact of widespread Asian soybean rust could cost the United States billions of dollars in lost revenue and increased production costs, says Ahmad.

Asian soybean rust has been found in five states this year. Approximately 26 other states were observed for potential signs of the disease. The disease is caused by fungi spread by wind-borne spores, and typically thrives in climates with high moisture and moderate heat.

Ahmad says the research team’s technology could serve as an early warning system for crop biosecurity. Government agencies could monitor soybean crops and the spread of the disease during crop season. If the disease is found, they can pinpoint the location and notify growers and agribusinesses in the affected communities. It also could allow them to monitor the disease in neighboring countries, so that if an infection is moving towards the United States, U.S. officials can alert the appropriate agencies and individuals, as well as inform the neighboring country of the disease’s presence.

Ahmad recently received honors for his research. In April, he was awarded the Best Poster Award for his poster “Development of Early Warning Systems to Improve U.S. Crop Biosecurity” at the Iowa Geographic Information Council. In June, he earned a Student Assistantship Award to attend the ESRI International User Conference in San Diego, California, a conference for researchers using GIS software. And in September, he received second place in a student poster competition at a remote sensing conference at Purdue University.

In the future, Ahmad hopes to apply this research and technology on plant pathogens to water quality research. “I’m interested in applying this research with plants to water quality by using satellite images of lakes or other bodies of water to view and identify contaminants,” he says.

Ahmad’s major professor is Roy Gu, associate professor in environmental engineering.