New Disease Halo Blight Threatens Michigan Hop Production

Jun 09, 2021

If you’re a beer drinker, you’ve noticed that hoppy beers have become increasingly popular. Most of the nation’s hops come from the Pacific Northwest. However, commercial hop production regions have expanded significantly. In Michigan hop production nearly tripled between 2014 and 2017 and in 2019, Michigan growers harvested around 720 acres of hops.

Michigan hop growers contend with unique challenges as a result of frequent rainfall and high humidity during the growing season. In 2018, growers approached Michigan State University researchers and the Michigan State University’s Plant & Pest Diagnostics lab with concerns about a leaf blight they had never seen before. This was followed by reports of hop cones shattering during harvest and yield losses in fields with the affected leaves.

Michigan State University scientists, including Doug Higgins, investigated, observing a fungus growing in the symptomatic leaves. They set out to determine if the fungus was causing the symptoms and if the leaf and cone symptoms were linked to the same pathogen. They also wanted to determine how far the disease had spread in Michigan.

They determined that the fungus was the same on both the leaves and the cones. “The fungus was shown to infect and cause disease in healthy hop plants,” said Doug Higgins. “Interestingly, genetic testing showed that DNA from the fungal pathogen did not match DNA from other known fungal species. We concluded that it is novel species and for now called it Diaporthe sp. 1-MI.”

As this novel fungal pathogen causes yellow margins to form around leaf lesions and the browning of cones, Higgins and colleagues named the disease “halo blight.” Their surveys indicated that halo blight is widespread in Michigan, and that other production regions with similar climatic conditions might also be at risk.

“In Michigan, hop is a niche crop used by many local breweries. A disease outbreak could impact the supply of local hops to many small and independent businesses,” explained Higgins. “Additionally, cone discoloration can alter hop quality and may have downstream implications on beer quality.” Higgins recommends that additional research be conducted to understand how the disease moves and develop management strategies.

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Video: Why Invest in Canada’s Seed Future? | On The Brink: Episode 3

Darcy Unger just invested millions to build a brand-new seed plant on his farm in Stonewall, Manitoba so when it’s time for his sons to take over, they have the tools they need to succeed.

Right now, 95% of the genetics they’ll be growing come from Canadian plant breeders.

That number matters.

When fusarium hit Western Canada in the late 90s, it was Canadian breeders who responded, because they understood Canadian conditions. That ability to react quickly to what’s happening on Canadian farms is exactly what’s at risk when breeding programs lose funding.

For farmers like Darcy, who have made generational investments based on the assumption that better genetics will keep coming, the stakes are direct and personal.

We’re on the brink of decisions that will shape our agricultural future for not only our generation, but also the ones to come.

What direction will we choose?

On The Brink is a year-long video series traveling across Canada to meet the researchers, breeders, farmers, seed companies, and policymakers shaping the future of Canadian plant breeding. Each week, a new story. Each story, a piece of the bigger picture.

Episode 3 is above. Follow Seed World Canada to catch every episode, and tell us: Do you think the next generation will have the tools they need to success when they takeover? How is the future going to look?