Researchers at Iowa State University are using unmanned aerial vehicles (UAVs) commonly known as drones for disease surveillance at experimental plots and agricultural fields.  

This technology will boost disease related research via collecting a large amount of data within a short period of time. It will also enable scientists to proficiently process, analyze and store this large amount of information to answer various complex and unanswered questions. Hence, more effective disease management strategies could be designed in near future.  

These drones have started playing the role of plant doctor, and are capable of detecting many kinds of stress plants might be under within the field. They could also save farmers from over-spending on management.  

Diseases are one of those common factors which can stress plants and negatively impact plant health and yield even before any detectable symptoms like yellowing or burning become apparent. However, these stresses are undetectable to the human eye. But, special filter equipped Hyperspectral cameras on the drones can detect these unseen changes in plants and help farmers manage disease outbreaks.  

Now, researchers from the Department of Plant Pathology and Microbiology at Iowa State University are using drones mounted with Hyperspectral cameras to scout experimental and farmers’ fields for diseases.  

Dr. Daren Mueller, an associate professor and extension plant pathologist at Iowa State University, whose lab has recently started using drones to scout diseases, said: “One of the first things we recommend folks to do is to look at the big picture of the field(s) before they start looking at problems in detail”.  

“Prior to UAVs, farmers relied on hilltops, standing on their trucks, finding the high points in fields, downloading maps off Google Maps, or lining up imagery from satellites or aerial photographs,” Mueller said. “Now, they have the ability to use UAVs to assess the big picture patterns in a field. This can give them clues to what is going on or can direct them where they should ground truth scouting.”

The technology could provide farmers with a handy tool to detect stress due to the disease at early stages, hence they can take judicious measures to save their crops from damage.   

Students from Daren’s lab are taking images of experimental plots as well as large soybean fields on a weekly basis using this advanced imaging technology mounted on a drone.  

They hope to detect areas with poor plant growth by studying the images obtained from camera, and the amount of light reflected by the plants.  

A plant’s canopy reflects near-infrared (NIR) light when struck by sunlight. The more NIR light is reflected, the healthier the plants are.  

Hyperspectral cameras use special filters to capture reflected light from selected regions of the electromagnetic spectrum. Stressed plants typically display a “spectral signature” like in the form of low reflectance that distinguishes them from healthy plants.

Hence, parts of field emitting low reflectance could be seen in images and may reveal plants with diseases. For now, these parts of fields need to be scouted (ground truth) to confirm what is affecting the plants, which is the first step for implementing effective targeted management practices.  

Scouting diseases with drones will help researchers in their basic research into plant pathogens.

“And like farmers, we want to gather extra information about our research plots that may better explain the results of our experiments” Daren added.  

These large amounts of field data can help researchers to better study the response of plants to stresses caused by pathogens at the molecular (cell) level. If researchers successfully understand the underlying mechanisms, this could help them breed future crops with better resistance against diseases.  

“Images from UAVs may help us identify plots or parts of fields that may be part of a larger pattern (influence) in a field, so may affect how we interpret our research results. We may also be able to correlate our disease ratings to some of the data collected from the sensors we are using on the UAV”, Daren said. 

Using these special sensors mounted drone technology, researchers can gather large amounts of data in a short period of time and draw more precise conclusions. Not only will this technology save money, but it will also be more time efficient.    

While talking about the future of this technology, he said, “The use of UAVs in agriculture is in the early stages, hence technology and usefulness will improve. And with the number of really smart, motivated people using these tools, I imagine dramatic new development over the next few years. And our lab hopes to provide some science to several of these improvements”. 

Daren also added that “this is an exciting time in agriculture. I love seeing the influx of engineers coming into the agronomy and Integrated Pest Management space. It is exciting to see the technologies and tools that will come from these partnerships.” 

Researchers will be producing “Big Data” using this technology, which they will be able to work on and analyze while working with experts from other walks of life in near future to answer complex questions. It is an established fact that “working hand in hand will not only boost up research but also help to rapidly improve agriculture techniques for the farming community”.