Quick Test For Plant Disease

Quick Test For Plant Disease Plant disease tests that currently take days or even weeks can be completed in 20 to 30 min. with technology developed at North Carolina State University (NCSU). The rapid test uses chemical reagents that change color when they come into contact with diseased tissue. The research behind it was funded by grants from the USDA’s Animal and Plant Health Inspection Service. “We’re using molecular detectors,” explains Jean Ristaino, NCSU plant pathology professor. “They allow us to do in-field diagnostics and confirm a disease.” Ristaino was the founding director of the Emerging Plant Disease and Global Food Security cluster of researchers who have developed the technology. It measures volatile organic compounds (VOCs) that plants release through their leaves. When a plant is diseased or attacked by insects or even damaged mechanically, the type and concentration of the VOCs change. Each disease or plant impact has its own unique VOC profile. For example, tomatoes release hexenal when attacked by late blight. Traditional methods of measuring VOCs often involve expensive equipment, such as gas chromatography, and require time-consuming sample preparation. These factors lead to high costs and preclude portability. Until now, real-time tests have not existed. Over the past several years, the research team has developed several variations of real-time VOC testing devices. One that’s still being developed is an electronic wearable patch. It can be attached to the underside of a plant leaf to continuously monitor for different pathogens. It incorporates other sensors that monitor for temperature, humidity, salinity and more. “Right now, the wearable sensors are too large,” says Ristaino. “We’re working on making them smaller. We’ll be testing them in greenhouses. You can’t put them on a plant in an open field, as there are too many things happening there.” A second device uses reagents embedded in strips of paper that indicate the presence of a disease when exposed to the VOCs. The device plugs into a smartphone to display results. Ristaino and the team are working on a third device that uses reagents in a tube. The solution also contains a fluorescent dye that can be visualized with a smartphone. “We add a tissue sample to the tube and the colors in the tube change from purple to blue,” she says. “We can use a smartphone or a commercial device to interpret the change.” The test is so effective that, in some cases, it can detect the disease before symptoms appear. The research team has developed the test to detect multiple pathogens, including those that cause blight in tomatoes and potatoes, as well as diseases affecting forestry. NCSU is working to patent the device. Ristaino hopes to license it for commercial production. Verdia Diagnostics is an NCSU spinout startup that’s building on the research to develop real-time tools. Co-founder Qingshan Wei, Ph.D., is a member of the NCSU research team. The company’s goal is to build sensor technology that helps farmers protect yields and reduce input costs. “I expect that diagnostic labs will be the first to adopt the tests,” says Ristaino. “I don’t see growers using the technology unless we get the wearable version fully developed.” This past year, Ristaino took the test tube device to Ireland during a sabbatical. “I demonstrated it in tree plantations and ran the test tube assays in 20 min.,” she says. “The test tube version has potential for crop consultants.” Contact: FARM SHOW Followup, Dr. Jean Ristaino, 840 Oval Dr., Campus Box 7625, NC State University, Raleigh, N.C. 27606 (ph 919-515-3257; Jean_Ristaino@ncsu.edu; https://ristainolab.cals.ncsu.edu) or Verdia Diagnostics Inc. (www.verdiadx.com).

To read the rest of this story, download this issue below or click here to register with your account number.