Growing Resistance, Oregon Hazelnuts Battle Blight

Feb 18, 2013
Originally published on February 18, 2013 6:42 am

Although Oregon is known for many exports — from timber to hipster irony — few people are aware that it's actually the country's leading source of hazelnuts.

Growers estimate that 99 percent of the United States' crop comes from Oregon's Willamette Valley. Just a few years ago, the industry was on the verge of collapse due to a disease called Eastern filbert blight. Now, years of research have brought blight-resistant breeds to fruition.

The disease first hit the region in the late 1980s. Infected trees develop cankers, which gradually kill off the branches.

"It's just like cancer for trees, there's no real answer to it yet," says Tanner Koenig, a young farmer who grew up fighting blight. "It's just some of them have a 20-year lifespan left, some of them, it's five. Some orchards, we're taking trees out already."

Farmers initially struggled with handling the disease. They tried to cut off trees at the base (that actually led to new growth, which was more susceptible to the disease). They also sprayed the trees in the fall with copper-based fungicides --only to later find that the sprays were only effective on new bud growth, which happens in the spring.

The growers' association taxed its members and put the funds into research, which developed a regimen that extended the life of infected trees. But it came at a high cost in terms of manpower, as Koenig explains.

"It's a constant battle. I have four guys who prune every day from the first of November until the end of March," he says. "It takes two guys to stack up all the branches all winter long, and then they spray about four times for it in the springtime."

While farmers struggled to keep trees alive, researchers struggled to find a solution that would save the industry: a blight-resistant hazelnut. Shawn Mehlenbacher, professor of horticulture at Oregon State University, has been working on developing the resistant hazelnuts for more than 25 years.

Creating special breeds is a long process. It takes eight years to grow a hazelnut generation, and each new variety must go through several generational crosses before it's ready for testing.

Even determining whether the strain is resistant takes time. After Mehlenbacher infects a tree with blight, he has to wait 16 months to see if it gets the disease.

Mehlenbacher didn't start his work from scratch. The first cross-pollination to develop trees with blight resistance happened in the late 1970s. Scientists happened upon a blight-resistant pollinator in the fields — with a gene they named gasaway — and began the slow process of breeding trees that shared that resistance, as well as producing prolific, tasty nuts. By the time farmers were really hurting, OSU could offer plants that were not perfect, but had at least some resistance, taking longer to become stricken with blight.

"The first release by the OSU breeding program that really had an impact on the industry was [the Lewis breed], in 1997," Mehlenbacher says. "It was planted quite widely — kept the industry alive for another decade."

These semi-resistant varieties served as bridge for farmers, helping them hang on until fully resistant trees were introduced.

Now, those trees — pioneer breeds like Jefferson, Yamhill, Santiam and others — are all over the Willamette Valley. Admittedly, in tree years, these varieties haven't been around very long. But farmers are putting their hope in them, replacing blighted trees with these new varieties.

Most farmers continue to spray and prune the old trees, trying to keep them going as long as possible.

But some, like Rich Birkemeier, are just cutting the expense. This winter he's pulling up about 1,500 of the semi-resistant Lewis trees that have finally gone under and planting the new, fully resistant trees in their place.

Birkemeier expects to see these new, blight-resistant trees still bearing nuts by the time his grandchildren are working the farm.

Copyright 2018 NPR. To see more, visit


Here in the U.S., farmers in the Pacific Northwest are fighting for the survival of a unique crop. Oregon is where nearly all this country's hazelnuts - also known as filberts - are grown. They're an $80 million crop for the state. But farmers have been losing their trees to persistent fungus.

From Oregon's Willamette Valley, Deena Prichep reports on efforts to combat the blight.

DEENA PRICHEP, BYLINE: Rich Birkemeier farms a few hundred acres of hazelnut trees out in Canby, Oregon. And it was one of the first farms to be struck with Eastern Filbert Blight. That's a fungus that kills hazelnut trees - and almost killed Oregon's hazelnut business.

RICH BIRKEMEIER: A blighted tree will have this sunken tissue here, where you can see the inside. It is dead. As soon as it sets a heavy crop of nuts, it will split in half.

PRICHEP: Birkemeier is still pulling up dead trees.


PRICHEP: Fifteen hundred this winter. But a couple decades ago, he pulled up nearly all his trees. Even when you prune out the cankers, and spray the trees, they still get blight.

Birkemeier's wife Nancy does the farm's books.

NANCY BIRKEMEIER: Well, it was difficult. I mean we sold land, we cut timber, we didn't take a paycheck for about five years, you know.

PRICHEP: It got to a breaking point.

BIRKEMEIER: And I thought to myself, this is not sustainable. I'm never going to have big trees here again. And Dr. Shawn Mehlenbacher, he walked up to me and handed me his business card.

DR. SHAWN MEHLENBACHER: I came to Oregon State University in September 1986.

PRICHEP: Shawn Mehlenbacher is a professor of horticulture.

MEHLENBACHER: And one month after my arrival, Eastern Filbert Blight was found in Clackamas County.

PRICHEP: Mehlenbacher's breeding program has spent years on the best hope for the industry: blight-resistant trees. They discovered a naturally-occurring gene for resistance, and have been trying to breed it into good-producing, good-tasting hazelnuts. It's a slow process.

MEHLENBACHER: Waiting, waiting, waiting.


MEHLENBACHER: We operate on an eight year cycle - that's eight years from seed to seed.

PRICHEP: That means Mehlenbacher cross-pollinates two trees, then waits eight years for the next cross. And then another eight years. Even when he tests the trees by exposing them to blight, he has to wait 16 months to see if they get the disease. But the years of work have yielded trees that don't get blight at all.


PRICHEP: At this year's annual nut growers meeting, Mehlenbacher released the latest blight-resistant variety to about 500 eager farmers, processors, and chocolate-makers. But change doesn't come overnight on a tree farm.

TANNER KOENIG: Those new trees, it's year seven before you make any money on them. So you want to leave the big trees in as long as you can, but you got to take them out and replace 'em at some point.

PRICHEP: Twenty-seven-year-old Tanner Koenig pretty much grew up with blight. He's learned how to manage it, extending the amount of time one of the old trees can survive. And managing comes at a cost.

KOENIG: It's a constant battle. I have four guys that prune every day from the first of November until the end of March. It takes two guys to stack up all the branches all winter long. And then they spray about four times for it in the springtime.

PRICHEP: Other farmers, like Rich Birkemeier out in Canby, have abandoned spraying entirely. He's just taking down trees as they succumb to blight, and planting the resistant ones in their place

BIRKEMEIER: Now frankly, I like working with trees. And now, that we have come through the dark days of Eastern Filbert Blight, the farm is actually doing better every year. Partly because of the new trees, and partly because the market for hazelnuts right now is just very, very good.

PRICHEP: And because of the health of the market - and the health of the trees -Birkemeier hopes Oregon farms will keep consumers in Nutella and hazelnut lattes for generations to come.

For NPR News, I'm Deena Prichep. Transcript provided by NPR, Copyright NPR.