An autonomous robot that eliminates downy and powdery mildew overnight
Robot Thorvald has passed its final tests on Chardonnay with flying colours. This spring, it went through the rows of vines and projected its ultraviolet rays on the leaves to eliminate powdery and downy mildew completely autonomously.
To successfully suppress the fungal diseases, it had to work by night. “What makes it possible for us to use UV to control these plant pathogens is we apply it at night,” explains David Gadoury, project leader for Cornell AgriTech in New York State. “At night, the pathogens don’t receive blue light and the repair mechanism isn’t working. Low doses of UV light are enough, killing the pathogen without harming the plant”.
In 2019, the robot had already proven effective in reducing the symptoms of powdery and downy mildew on grape clusters. Vines treated with a weekly dose of 100J/m2 showed 5% powdery mildew symptoms, while the untreated trial showed 15%. “The robot even outperformed conventional fungicide treatments in the fight against powdery mildew”, adds Gadoury. It also suppresses certain insects, including moths.
Production of Thorvald will be scaled up and the robot will be marketed by the Norwegian company SAGA Robotics from the end of the year. It is 2.4 metres long and 1.2 metres wide and moves at a speed of 1.5 metres per second. Its battery allows it to treat vines for 5 hours. Researchers are already working on a second version of the robot, focusing in particular on making it able to modulate its UV doses depending on the level of symptoms occurring on the vines.