Researchers at North Carolina State University have developed portable technology that allows farmers to identify plant diseases in the field. The handheld device, which is plugged into a smartphone, works by sampling the airborne volatile organic compounds (VOCs) that plants release through their leaves.
“All plants release VOCs as they ‘breathe,’ but the type and concentration of those VOCs changes when a plant is diseased,” says Qingshan Wei, an assistant professor of chemical and biomolecular engineering and corresponding author of a paper on the work. “Each disease has its own signature profile of VOCs. So, by measuring the type and concentration of VOCs being released by the plant, you can determine whether a plant is diseased and – if it is diseased – which disease it has.
“Our contribution here is the creation of a device that can be plugged into a smartphone and used to make those VOC measurements quickly in the field,” says Wei, who is also a faculty member in NC State’s Emerging Plant Disease and Global Food Security cluster.
Current disease identification techniques rely on molecular assays, which take hours to perform and – most importantly – have to be done in a lab. Getting a sample to the lab, where the sample may have to wait to be tested, can delay disease identification by days or weeks.
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Image: Researchers at North Carolina State University have developed a handheld device that can be plugged into a smartphone so that farmers can identify plant diseases in the field. The handheld device, which is plugged into a smartphone, works by sampling the airborne volatile organic compounds that plants release through their leaves. If a farmer suspects that a plant may be diseased, he or she can take a leaf from the relevant plant and place it in a test tube. The test tube is then capped for at least 15 minutes to allow the relevant VOCs to accumulate. After this incubation period, the cap is removed and the farmer uses a narrow, plastic tube to pump the VOC-laden air into a "reader" device connected to a smartphone. The air is pumped into a chamber in the reader that contains a paper strip. The paper is embedded with an array of chemical reagents that change color when they come into contact with a specific chemical group. By evaluating the resulting color pattern on the strip, users can determine the nature of any plant disease that may be affecting the plant. (Credit: Zheng Li, NC State University)