UI Grad Student Makes Progress in Pythium Leak Study

Published online: Dec 12, 2018 Articles Heather Kennison
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Source: The Times-News 

Andrew Hollingshead estimates he’s ruined 10 to 12 tons of potatoes.

Now in the third year of his research project, the Ph.D. student will continue bruising, battering and dissecting tubers throughout the winter. But these unusual experiments are nothing new at the University of Idaho’s Kimberly Research & Extension Center. The center has been researching potatoes since the early ‘90s.

And it’s largely industry-driven.

“We will tailor our research based on what are the issues,” said Nora Olsen, a professor and potato specialist at the center.

Hollingshead’s research project is focused around Pythium leak, a disease caused by a fungus-like pathogen that lives in soil. Potatoes get infected with it when they have an open wound or bruise.

“We will abuse our potatoes and make them get infected with it,” Olsen said.

So as part of his experiment, Hollingshead has been tumbling potatoes around in a cement mixer for 90 seconds.

“They’re bumping, they’re grinding, they’re getting beat up along the way,” Hollingshead said. “It provides this nice opening so that the inoculum can infect the tuber.”

He inoculates the potatoes a few days later with a liquid culture that includes V8 juice used to grow Pythium. The tubers are stored and inspected each day. Once infected, a potato turns to mush and begins leaking within four days.

This is a big concern for an industry that stocks the majority of its crop in large storehouses. About 60 percent of Idaho’s potatoes go to processors, Olsen said.

And since it’s more efficient to store potatoes fresh than frozen, “we’re going to store 80 percent of the crop at least some of the time.”

In storage, Pythium leak won’t spread to other potatoes. But the seeping potatoes can create a moist environment that allows other pathogens to infect the rest, Hollingshead said.

Through his research, he’s looking for ways to prevent Pythium leak, such as using different varieties of potatoes or changing the storage temperatures.

Hollingshead is originally from New York but became interested in potatoes after doing an internship in Rupert. He earned a bachelor’s degree in landscape management and a master’s degree in environmental science from Brigham Young University. He’s working on a Ph.D. in plant sciences from the University of Idaho.

So far, Hollingshead has found that different varieties of potatoes are more susceptible to leak and bruising, and textural differences in the skin may reveal why.

“There is considerable variety differences both to bruising and susceptibility to Pythium leak,” Olsen said. “(With) some of these new varieties that have come out in the last five years, we’re on a steep learning curve.”

Work at the research center is impacting the industry with its findings.

“We’re trying to drive the whole industry in the right way,” Olsen said.