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Agriculture AgTech Precision Ag Research

UV light may replace chemicals in fungus fight

Everywhere grapes are grown, growers have to worry about powdery mildew. A typical grape grower spray chemical fungicides for powdery mildew management between 10 and 15 times each year. The fungicides used are costly and environmentally unfriendly, plus the fungus typically adapts to the fungicides within a few generations, requiring heavier applications or changing formulas.

An international consortium of scientists known as the Light and Plant Health Project, led by David Gadoury, a plant pathologist at Cornell AgriTech in Geneva, N.Y., has developed an inexpensive answer.

“Research in using UV light to kill the powdery mildew pathogens is not new. But it has accelerated with the discovery that UV is much more effective when applied at night.”

David Gadoury, Plant Pathologist, Cornell AgriTech

An international consortium of scientists known as the Light and Plant Health Project, led by David Gadoury, has refined the science and applied technology behind using ultraviolet (UV) light to kill the fungi that causes powdery mildew (PM), opening the door for the technology’s use to control other plant pathogens.

UV light damages the DNA of many organisms, but mildew have developed biochemical defenses against this damage, using a repair process that requires the blue light component of sunlight. At night, the pathogens don’t receive blue light and the DNA repair mechanism isn’t working. The researchers are then able to exploit this weakness, exposing fungi to a small amount of UV light at night – killing the pathogen without harming the plants.

Gadoury and his team have found that mounting UV lights on tractors or sending self-driving robots into the vineyards at night can scramble the mildew’s DNA and kill it faster, safely and more efficiently than costly fungicides.

Researchers at Cornell AgriTech in Geneva have partnered with SAGA Robotics in Norway to develop the first commercial robotic units. The initial assessment is that an autonomous vehicle will make UV light application far less expensive than the current application of organic sulfur via tractor and sprayer with operator.