Posted on 01/14/2025 6:52:26 AM PST by Red Badger
A fungus causing powdery mildew in blueberries has spread from the U.S. to continents like Europe and Asia, threatening crops and increasing fungicide dependence. NC State researchers found that blueberry powdery mildew has spread globally in two strains, costing the industry up to $530 million annually. A new tool now helps farmers identify and manage the disease.
A new study from North Carolina State University has traced the global spread of a fungus that causes powdery mildew in blueberry plants—a disease that lowers crop yields and increases reliance on fungicides. These findings could help blueberry growers better predict, monitor, and manage the spread of powdery mildew.
The research reveals that over the past 12 years, the fungus Erysiphe vaccinii has expanded from its original range in the eastern United States to several continents.
“We’re watching this global spread happen right now, in real time,” said Michael Bradshaw, assistant professor of plant pathology at NC State and the corresponding author of a paper describing the research.
Powdery mildew covers a plant, stealing nutrients and limiting photosynthesis. Credit: Michael Bradshaw, NC State University
The Nature of Powdery Mildew Disease
As its name suggests, powdery mildew disease causes a white, powdery substance to cover host plants, stealing nutrients and retarding photosynthesis while keeping the host alive. Different species of this fungus affect different plants; wheat, hops, grapes, and strawberries, among other plants, have been detrimentally affected by powdery mildew.
“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,” Bradshaw said.
In the study, Bradshaw and his colleagues examined historic and modern plant leaves plagued by powdery mildew. The collection includes 173 samples from North America, Europe, Africa, and Asia; one sample analyzed from a North American herbarium was collected over 150 years ago, while the foreign samples were all collected within the past five years. In this study, powdery mildew was first spotted outside North America on a farm in Portugal in 2012, as noted by a co-author of Bradshaw’s who was employed by a major berry company.
The researchers performed genetic testing on the fungal samples to trace the history and spread of powdery mildew disease. Interestingly, none of the old specimens have the same genetic makeup, or genotype, as the specimens currently spreading throughout the world.
Two Distinct Global Strains
The study showed that the disease originated in the eastern United States and was set loose globally in two different introductions. One strain of E. vaccinii found its way to China, Mexico, and California, while a different strain wound up in Morocco, Peru, and Portugal. Bradshaw thinks humans are responsible for the spread as nursery plants traveled to foreign shores.
“This is a hard organism to control,” Bradshaw said. “If you’re sending plant material across the world, you’re likely spreading this fungus with it.”
Interestingly, the study also showed that the E. vaccinii fungus found in blueberries in other countries appears to solely reproduce asexually; both sexual versions of the fungus are not required in reproduction, whereas the fungus reproduces sexually and asexually in the United States.
The study also worked with a large company and farmers to provide an estimate of the global cost of powdery mildew to blueberries, reflecting the cost of spraying fungicide to prevent or reduce powdery mildew. The study estimates a cost range of between $47 million and $530 million annually to the global blueberry industry.
Warning for Vulnerable Growing Regions
Finally, the study provides some early warning signals to important blueberry-producing areas, like the U.S. Pacific Northwest. Conditions there are ripe for powdery mildew to take hold and spread, but the disease has not found its way there yet.
“Disease spread could also be impacted by agricultural conditions,” Bradshaw said. “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.”
Bradshaw added that the researchers utilized a useful tool that can help identify E. vaccinii strains to aid farmers and other researchers.
“It’s difficult to identify the fungus that causes powdery mildew in blueberries, so we input our data in a public database developed at NC State by a co-author, Ignazio Carbone. This platform allows growers to enter their data and learn which specific strain is in their fields,” Bradshaw said. “That’s important because understanding the genetics can warn farmers about which strain they have, whether it is resistant to fungicides, and how the disease is spreading, as well as the virulence of particular strains.”
Reference:
“An emerging fungal disease is spreading across the globe and affecting the blueberry industry”
by Michael Bradshaw, Kelly Ivors, Janet C. Broome, Ignazio Carbone, Uwe Braun, Shirley Yang, Emma Meng, Brooke Warres, William O. Cline, Swarnalatha Moparthi, Alejandro K. Llanos, Walter Apaza, Miao Liu, Julie Carey, Mehdi El Ghazouani, Rita Carvalho, Marianne Elliott, David Boufford, Tiaan Coetzee, Johan de Wet, James K. Mitchell, Luis Quijada, JamJan Meeboon, Susumu Takamatsu, Uma Crouch, Scott LaGreca and Donald H. Pfister,
8 January 2025, New Phytologist.
DOI: 10.1111/nph.20351
The paper appears in New Phytologist. Funding was provided by the National Science Foundation under award numbers 2315953, 2200038, 2031955 and 2308472. The work was also supported by the Novo Nordisk Foundation under grant numbers NNF19SA0059360 and NNF19SA0035476.
““Disease spread could also be impacted by agricultural conditions,” Bradshaw said. “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.””
And Georgia. Where my mother-in-law lives there are blueberry farms for miles....................
Masks will help. In fact, they are essential.
I grew up in Maine, and there were blueberry patches for miles and miles, many times along powering pathways. Maine is big on blueberries. Most kids worked raking them to earn summertime money. Xpent many many hours gathering them with the family as a child.
Doh, along power lines i meant
Bad news for Jersey. Ranks 6th in blueberry production.
The best blueberries, and the healthiest in terms of antioxidant content, are the organic wild blueberries from trader Joe’s. Highly recommended.
And 6 feet between bushes.................
Crap! My favorite fruit.
That must be why there is no unfrosted blueberry pop tarts available.
😁😎🙄..................................
https://en.wikipedia.org/wiki/Gymnosporangium_juniperi-virginianae
For some reason, reminded me of cedar apple rust.
When farmers figured this out, cedar tree were eliminated from the landscape. Now the govt promotes cedar trees.\
In the Midwest we used to have a rotation. Corn sb alfalfa to control disease.
“..Most kids worked raking them to earn summertime money....”
Yep. I was one of those kids waaay back in the 1960s. Growing up in a large family that was pretty much dirt poor in eastern Maine, it was the only way to make enough money to buy new school clothes and shoes. Cutting lawns all summer just wasn’t enough to do it. Raking blueberries paid $2.25/bushel after winnowing out the sticks & leaves. That was the going rate back then, and anyone that’s ever done it knows that it takes a lot of hard, back-breaking work to garner up a bushel. It definitely taught me the value of a dollar back then. We’d even fight over the better sections of the field to try and increase our portion...LOL. Man, that was ages ago.
FWIW, they’ve since gleaned almost all the big boulders and rocks out of the fields and primarily use some pretty sohphisticated mechanical harvesting methods to garner the crop now. They can harvest a good-sized field in a manner of hours compared to several days by doing it manually the old fashion way. There is still some secondary manual raking performed to clean up the corners of the field or around where boulders were just too huge to move., but it’s nothing like it was back in the day.
The SciTech Daily is over dramatizing this issue. I don’t usually read this kind of stuff but for some reason it intrigued me (probably because of the attack on the food industry). Bottom line from the study which was conducted from an economic impact point of view, mainly gathering data from the last five years: the fungus is mainly found on plants that are grown indoors, and it is found in localized groups or areas (those who grow indoors). The data doesn’t show a rapid spread, but They “theorize” that it may spread more.
Oh....I also forgot to mention, I still have my 60-tooth blueberry rake to this day although the blistered hand has long healed up. I kept it as a keepsake and a lifetime reminder or what it used to like to make a dollar bill.
I just had a bowl of blueberries this weekend. They were a little mushy, not crisp. But still good. I hope they save them. And the bananas. And bees. Otherwise it will be impossible to eat yogurt.
Did they find which USDA Bio-lab sponsored it yet?
How many blueberries in a bushel? Did you get 55 cents for a peck?
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