A devastating disease has put the multibillion dollar global blueberry market, along with its four-year 6.2% CAGR growth projections, at risk as experts warn crops could eventually be wiped out.
Erysiphe vaccinii, a fungus that causes a powdery mildew to form on blueberry plants, originated in North America. It is now spreading rapidly across major blueberry-growing regions, including China, Morocco and Mexico, jeopardising the fruit’s future.
The disease’s spread has quickened over 12 years from the States to several continents, researchers from North Carolina State University tracking Erysiphe vaccinii have said.
What disease is killing blueberries?
“We’re watching this global spread happen right now, in real time,” says Michael Bradshaw, assistant professor of plant pathology at North Carolina State University.
The fungus damages blueberry plants by covering them in a white, powdery mildew substance, which takes nutrients from the plant and prevents photosynthesis. Other variants of the fungus also affect other plants, including wheat, hops, grapes, and strawberries.
“There are other closely related powdery mildews that affect plants like wild berries or eucalyptus, but these are genetically different from the ones spreading across the world on blueberries,” says Bradshaw.
The study showed the disease originated in the eastern United States before spreading globally through two different introductions. One strain of Erysiphe vaccinii spread to China, Mexico, and California, while a separate strain spread to Morocco, Peru, and Portugal. Bradshaw believes humans are responsible for the spread as nursery plants travelled to foreign shores.
“This is a hard organism to control,” says Bradshaw. “If you’re sending plant material across the world, you’re likely spreading this fungus with it.”
The team also noted that disease spread could be impacted by agricultural conditions.
“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.”
What is Erysiphe vaccinii?
Erysiphe vaccinii is an emerging powdery mildew species, which affect blueberry plants.
Once confined to North America, Erysiphe vaccinii is now spreading rapidly across major blueberry-growing regions, including China, Morocco and Mexico.
Blueberry availability could be impacted
The spread of Erysiphe vaccinii has the potential to cause significant damage and cost to the blueberry and food and beverage industries.
The researchers worked with a large food and beverage company and farmers to provide a cost estimate. It included the cost of spraying fungicide to prevent or reduce powdery mildew and ranged from $47m to $530m annually.
Blueberries could become a rare and costly commodity if the disease were to continue its global spread, as supplies could become severely limited.
Blueberry suppliers are already struggling to meet demand. It’s estimated the 1.86m metric tonnes currently grown must double over five years to meet anticipated demand, according to Produce Report.
What are the benefits of eating blueberries?
Blueberries are packed with fibre, Vitamin C and K, and are one of the most nutrient-dense berries available.
They are claimed to be high in antioxidants. The main antioxidant compounds in blueberries belong to a family of polyphenol antioxidants called flavonoids. Studies have also linked blueberries to health benefits, including lowering blood pressure.
Source: An emerging fungal disease is spreading across the globe and affecting the blueberry industry
Published online: 8 January 2025
DOI: 10.1111/nph.20351
Authors: Michael Bradshaw, Kelly Ivors, Janet C Broome et al.
