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The Fungus Affecting Potato Crops Across the U.S.

Potatoes are a staple food in the United States. Who doesn’t enjoy warm French fries with just the right amount of salt, a bag of crunchy potato chips, or some creamy mashed potatoes smothered in gravy?

For potato farmers, growing potato crops has become less than enjoyable as a resilient fungus has been running rampant through U.S. soil. The fungus, known as Silver scurf, accounts for 13% of potato crop losses, which not only affects farmers but also has an impact on the potatoes that are available for us to purchase and consume in whatever form we enjoy most.

Silver scurf is a fungus believed to be transmitted through infected seed, resulting in dark skin blemishes. However unattractive potatoes appear, the blemishes do not affect the inside of the potato. However, industry buyers often reject affected potatoes because they do not turn a large profit in farmer’s markets and grocery stores.

To combat the spread of Silver scurf, Plant and Wildlife Sciences graduate students, Erik Kemp and Shae Taylor, have conducted research on antifungal bacteria strains from the streptomyces bacteria genus. If strains show high inhibition rates, it could be a game-changer not only for potato crop yields, but for the environment overall.

Erik Kemp and Shae Taylor have been conducting important research on a strain of bacteria affecting potatoe crops across the United States.
Photo by Kalicia Bateman

Using bacteria to combat pathogens can be more environmentally friendly than pesticides and fungicides. Additionally, pathogens will be less likely to develop immunity to the bacteria than pesticides, which has been a problem up to this point and a leading cause in the predominance of the Silver scurf fungus in U.S. soil.

In the lab at the BYU College of Life Sciences, Kemp and Taylor have been testing streptomyces strains from all over the country on petri dishes to observe how they interact with Silver scurf. This is a process of trial and error, but when a bacteria strain is seen to inhibit fungal growth, it is an exciting success.

Bacterial strains have been tested on petri dishes.
Photo by Kalicia Bateman

“It’s pretty fun because you set up the experiment, but then you have to wait a few days for it to grow,” Kemp says. “When I come into the lab in the morning, I go check the plates right away to see if anything’s happened. Half the time it’s not good, but the other half of the time shows that you’re making progress.”

Much progress has been made, and recently up to 80% inhibition has been seen in petri dish tests. The next step will be taking successful bacteria strains into the field to determine if they will show similar inhibition rates in an uncontrolled, natural environment.