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Mint Research

November 01, 2023

Throughout the past decade, University of Idaho Extension nematologist Saad Hafez has researched ways to protect mint farmers from a nasty pest and disease combination that can wreak havoc on their yields.

Harmful nematodes can cause mint crop losses of up to 30%, but they also open wounds in plant roots, potentially enabling a devastating fungal disease, verticillium wilt, to take hold.

Hafez, who is based at the U of I Parma Research and Extension Center, acknowledges progress against verticillium wilt has been elusive, and the issue demands further research. He’s had some recent successes, however, in his efforts to find new nematicides for mint farmers to add to their arsenals of crop protectants.

About a year ago, his work resulted in the Bayer broad spectrum fungicide and nematicide Velum Prime getting a special-needs label for use in mint. He recently sent the mint industry preliminary data toward getting a special-needs label to use an additional nematicide, Salibro by Corteva Agriscience.

The mint industry has clearly taken notice of Hafez’s efforts on their behalf. In January, Hafez received the Service to the Industry Award from the Mint Industry Research Council in appreciation of his outstanding service to the North American mint industry. Hafez was also inducted into the Idaho Mint Hall of Fame in 2019.

Furthermore, the Idaho Mint Commission has pledged funds toward construction of a microbiology laboratory located within the new Idaho Center for Plant and Soil Health at the Parma Research and Extension Center. The Idaho Mint Commission will be granted naming rights for the microbiology laboratory.

The 9,600-square-foot center, which is scheduled to open in October and will be dedicated next February, will also house laboratory space for research related to nematology, pomology, plant pathology and hops quality.

Idaho’s mint industry started in the late 1940s. Idaho mint farmers now raise about 17,000 acres of mint annually, which produces 1.8 million pounds of mint oil. The state ranks No. 2 in U.S. peppermint production, with 1,000 acres, and No. 4 in U.S. spearmint production, with 16,000 acres.

“The mint industry has been very good to me and has supported me for all of these years,” Hafez said.

In 2017, James Woodhall, a UI Extension plant pathologist based in Parma, was the first to characterize a specific strain of the fungal pathogen Rhizoctonia solani in mint. A grower requested that Woodhall test mint from a stand that was in decline based on concerns that verticillium wilt was the culprit.

“That’s the good thing about testing at a university laboratory instead of a testing laboratory. They wouldn’t have gone on and characterized it, but we found the true cause,” Woodhall said.

The new facility will be far more spacious and will provide faculty with state-of-the-art technology. Idaho Mint Commission Chairman Tony Weitz, who farms in Caldwell, anticipates the new Parma facility will help U of I attract talented new faculty, who will continue conducting important research to aid mint producers.

“I’m happy to see they’re improving the facilities over there. We’ve had a lot of research done there and hope to continue that,” Weitz said.

Published in Catching Up with CALS

Mint research continues at the Parma Research and Extension Center.

About the University of Idaho

The University of Idaho, home of the Vandals, is Idaho’s land-grant, national research university. From its residential campus in Moscow, U of I serves the state of Idaho through educational centers in Boise, Coeur d’Alene and Idaho Falls, nine research and Extension centers, plus Extension offices in 42 counties. Home to nearly 11,000 students statewide, U of I is a leader in student-centered learning and excels at interdisciplinary research, service to businesses and communities, and in advancing diversity, citizenship and global outreach. U of I competes in the Big Sky and Western Athletic conferences. Learn more at


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