A research study at North Carolina State University has pinpointed the worldwide spread of a fungus that infects blueberry plants with powdery mildew.
The study shows that the fungus, Erysiphe vaccinii, has spread from its point of origin in the eastern U.S. to multiple continents in the last 12 years.
“We’re watching this global spread happen right now, in real time,” Michael Bradshaw, assistant professor of plant pathology at NC State and the corresponding author of research paper, said in a university news report.
Powdery mildew causes a powdery substance to cover host plants and steal nutrients and slow photosynthesis. Different species of fungus infect different plants. Powdery mildew can infect grapes and strawberries, among others.
Bradshaw examined historic and modern plant leaves infected with powdery mildew from North America, Europe, Africa and Asia. Researchers discovered the first infection of powdery mildew outside North America on a farm in Portugal in 2012. The study traced its spread, with one strain of E. vaccinii in China, Mexico and California, and another strain in Morrocco, Peru and Portugal.
The research team attributes the spread from nursery plants.
“This is a hard organism to control,” Bradshaw told the university. “If you’re sending plant material across the world, you’re likely spreading this fungus with it.”
The research team estimates the blueberry industry invests between $47 million to $350 million annually to reduce powdery mildew.
The researchers said there is an imminent threat of powdery mildew in blueberry-producing regions such as the Pacific Northwest, where conditions favor the fungus.
“Disease spread could also be impacted by agricultural conditions,” Bradshaw told the university. “Some areas that grow blueberries in tunnels, or enclosed areas, seem to have worse disease outcomes than areas that grow blueberries outdoors without any covering, like in North Carolina.”
