UV Light Treatment Could Put Plant Pathogens in the Dark

UV Light Treatment Could Put Plant Pathogens in the Dark

UV-lit strawberry field in Florida

A global group of scientists is studying how to use ultraviolet illumination to knock the lights out of maladies like powdery mildew. Applications at night appear to be effective. Photo by Tyler Jones, UF/IFAS

Plant diseases like powdery mildew can leave strawberry growers seeing red. Researchers are trying to shed a light – ultraviolet light – on problematic pathogens and find potential new crop protection solutions.

Natalia Peres, a Professor of plant pathology at the University of Florida, is working with researchers from Rensselaer Polytechnic Institute (RPI), Cornell University, Norwegian University of Life Sciences, the Norwegian Institute of Bioeconomy, and the USDA Grape Genetics Research Unit on novel uses of light to suppress pathogens in several specialty crops.


Thus far, the team has developed a tractor-drawn machine with several UV lamps. According to Peres, a breakthrough in the research recently took place when Norwegian researchers discovered that treatments were more effective when applied at night. She explained that the mildew pathogen evolved to survive natural UV in sunlight. But part of that adaptation to sunlight resulted in the pathogen not being able to defend against natural UV light at night. So, nighttime UV applications bypass the natural defenses of the pathogen.

The new technology has been tested at UF/IFAS Gulf Coast Research and Education Center’s strawberry fields and at Wish Farms in nearby Duette, FL.

Similar trials are being conducted across North America and Europe by the research collaborators on grapes, hops, and cucumbers.

The research has been supported by grants from the USDA Specialty Crops Research Initiative, the USDA Organic Research and Extension Initiative, the Norwegian Research Council, and state and regional commodity groups.

While UV lamps are widely used in water purification and microbiological sterilization, they’re not yet commonly used for plant pathogen suppression.

“UV treatments applied once or twice weekly were as effective as the best available fungicides applied on similar schedules for control of strawberry powdery mildew,” Peres stated in a prepared news release. “It’s not a one-time fluke. The trials have been repeated successfully for three seasons now.”