Abstract: The world’s most destructive plant pathogens and pests evolved to survive in a niche fully exposed to intense UV light from the sun. Most possess biochemical repair mechanisms that fix the damage that UV causes to their DNA as fast as it occurs. The repair mechanism is powered by blue light, so it runs at maximum speed during daytime. We use that evolved defenses against them by exposing them to small bursts of UV during night hours. This evades the repair mechanism and kills many pathogens and insect pests without harming the host. Our group, including colleagues from Norway, Belgium, and several states in the USA has conducted trials on grapevine, hops, strawberry, cucurbits, apples, beets, and many other crops.
The UV treatments are highly effective against powdery mildews and mites, but also suppress
a diverse group of pathogens that continues to expand as we conduct more trials. The
technology is relatively simple to apply, and can be constructed by anyone with basic
mechanical, fabrication, and electrical skills. There are also companies that provide autonomous robotic devices that apply UV to crops without involvement of a human operator. Risk to crops with appropriate dosing is minimal, and resistance to UV in pathogens is highly unlikely as the technology has been in use in microbiological applications without resistance occurring for over 75 years. Proper protective clothing and eye protection is required, but is generally less onerous than that required for pesticide applications.