Devastating Coffee Plant Disease Threatens Hawaii's Famed Kona Region

Suzanne Shriner remembers the moment she heard that coffee leaf rust had been spotted on the island of Maui, just around 100 miles from her farm on the Kona Coast on the island of Hawaii. It was a Friday in October—seven months into the pandemic—and Hawaii had just re-opened to tourists.

"I got the text and my stomach dropped," recalls Shriner, who serves on the board of the Kona Coffee Farmers Association. Shriner had been trying to prepare herself for the moment for a long time. "We'd hoped we would have a few more years," she said.

Coffee leaf rust, or Hemileia vastatrix, was first identified in Sri Lanka in the 1860s and has impacted nearly every coffee-growing nation in the world since then. It's a fungus that debilitates and destroys coffee trees; it thrives in warm, wet conditions, and travels on the wind. It's also one of the biggest factors most scientists point to when they say that climate change is coming for your morning cup of coffee.

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After the news broke, Shriner and other farmers began turning over the waxy green leaves on their trees, scanning for transparent dots and splotchy circles of orange spores. And, within weeks, they found them.

Coffee has been central to the agricultural economy of Hawaii since the 19th century and the bulk of the beans are grown in Kona, where a unique variety of tree (Kona Typica) along with the volcanic soil and mild temperatures contribute to a unique flavor profile that fetches upward of $60 a pound.

The state has already been hit hard by the impacts of invasive species and climate change. Now, farmers, scientists, and lawmakers in Hawaii are scrambling to prepare for the onset of coffee leaf rust—and the $50 million industry could be permanently changed. Although no one can predict just how much damage it will do, rust will a likely result in loss of production, changes to the flavor of the coffee, and a rise in prices.

Because addressing rust can be an expensive endeavor, experts also worry that many of Hawaii's roughly 800 small producers—whose mostly family-scale operations are located along the mountain roads that have been there for over a century—could exit the business. And for those farming organically, the odds look even worse.

"It's really going to change everything we know about coffee in Hawaii," says Shriner.

Rust Moves Fast

In 2015, Andrea Kawabata, an extension agent with the University of Hawaii's College of Tropical Agriculture and Human Resources, took a trip to Brazil to learn about another climate-related pest that has impacted Hawaii—the coffee borer beetle (CBB). While there, she heard from growers who had been struggling with rust. Now, she's helping Kona farmers identify rust on their farms.

Time is of the essence. If farmers find rust before it's on more than 5 percent of the coffee leaves on their farms, Kawabata says they have been able to control it by spraying preventative fungicides made with copper and bacillus, a bacteria found in soil. But, Kawabata added, "if they were past that 5 percent threshold, the disease seems to progress quite quickly."

The cost of managing coffee rust on top of CBB will likely get passed along to consumers—creating a less predictable flavor for a higher cost. "All that additional labor is going to have to come out somewhere," Shriner told me.

Melissa Johnson a research biologist at the Daniel Inouye Pacific Basin Agricultural Research Center (PBARC) has also been visiting farms and surveying the quick progression of the disease in Kona since December.

"We found it all the way up and down the coast," says Johnson. By January, she had surveyed 25 coffee lots and about 65 percent of those had coffee leaf rust on about 5 percent of their leaves. In February and the average rate of infection had jumped to nearly 10 percent and some trees had started to lose their leaves.

The Role of a Changing Climate

Lisa Keith, a research plant pathologist at PBARC, is running a series of trials to quickly learn as much she can about how the rust behaves in Hawaii's specific climate. But she admits that it's going to be difficult to control because the typica variety is one of the most susceptible varieties there.

When I spoke with her in February, Keith said most farmers were able to manage the disease because the weather was still relatively cool. "It's in the latent phase and it has the potential to build up," she added.

Coffee leaf rust grows well in wet, warm, and humid climates. It thrives at temperatures that are between 70 to 77 degrees Fahrenheit, says Keith, and that range is more and more common up in the cooler mountainous regions of Hawaii as the climate shifts.

"You're finding it at elevations which would have been too cool in the past. And that's not just coffee leaf rust. Unfortunately, that's what is being seen with a lot of pathogens and pests. They're moving into areas where they weren't observed previously, as temperatures are changing," said Keith.

Lawmakers on the island declared a state of climate emergency in 2019 and are currently drafting a climate action plan. According to the National Oceanic and Atmospheric Administration (NOAA), average annual temperatures increased 2 degrees since 1950 and while they have leveled off in recent years, "historically unprecedented warming" is projected by the end of the 21st century. Extreme rainfall events have also become more common on the island of Hawaii, and 2020 was an exceptionally wet year for most Kona farms.

Lessons from Latin America

Farmer and biologist Arturo Ballar was a child growing up in Costa Rica when coffee leaf rust hit his family's farm in the 1980s. Now he consults with Kona coffee farmers about their growing practices.

He remembers seeing his extended family grapple with the impacts of rust at his grandmother's kitchen table as a child, and being tasked with going out into the fields to find coffee leaves infected with rust—or la roya in Spanish—to bring back to their parents. At first, it was a competitive hunt that took skills, but it quickly became easier.

In Costa Rica, he says, the disease typically has three phases: it would start off as dots on the leaves and would remain somewhat dormant in the cool season. Then, when warmer temperatures arrived, the leaves on the trees would turn from green to yellow. Finally, many trees would lose their leaves and coffee berries altogether. When this happened, it typically took at least two years for the trees to be productive again—and that was if farmers had put time and attention into controlling rust with fungicides and improving the health of the soil.

The farmers who made it through that initial window of production loss adjusted to the new reality, and soon plant breeders developed varieties of coffee that were resistant to rust, which helped them maintain somewhat productive orchards.

Then came 2012. "In Central America, Mexico, and South America, we saw a very, very severe case of rust. It was very aggressive," recalls Ballar. That year, none of the coffee-producing regions were spared, but some had it especially bad. Nearly 70 percent of the coffee acres in Guatemala were impacted by rust, for instance. In El Salvador it was almost 74 percent of the land.

"They had massive tree deaths and loss of yield throughout the entire South American region. It created a huge humanitarian crisis for those farmers and was partly responsible for why we had a wave of immigration: Farmers had to leave their farms," says Shriner.

Since then, Ballar says some Costa Rican farmers have been able to get a handle on the disease, but many have lost crops, money, and ultimately their farms.

"It's like Charles Darwin said, they had to adapt or disappear," says Ballar, "and that's what is going to happen in Kona." Ballar is stressing the role of "prevention over cure" and encouraging farmers to improve their soil.

Some farmers will take that route; others are awaiting permission to begin using a new, more powerful fungicide. The Hawaii Department of Agriculture is moving fast to try to get a systemic fungicide—which can be taken up into plant tissues and kill fungal matter from the inside—called Priaxor approved via an emergency exemption from the Environmental Protection Agency. State lawmakers have also advanced a bill that would subsidize its use for coffee farmers impacted by rust.

And while it would give farmers a much stronger tool to fight rust, it could also have adverse impacts on the local ecosystem. Pyraclostrobin, the key ingredient in Priaxor, has had adverse effects on aquatic ecosystems. One study found that it poses a high risk to amphibians such as frogs and toads, for example.

Importing rust-resistant coffee varieties from Latin America is another option many farmers are exploring, but new resistant varietals likely won't have the same flavor as the Kona Typica—and that worries growers and others hoping to maintain the Kona coffee brand moving forward. There's also is a quarantine period of a year required for new trees. "A lot of growers may not have a year before they start losing production," says Johnson.

The Challenges for Organic Growers

Robert Barnes has been growing organic coffee with his wife Dawn in an idyllic area of South Kona, backed up against a forest reserve, for 15 years. The Barneses had just invested in a brand-new coffee mill and planted 12,000 trees, nearly doubling the size of their orchard when they heard that rust had arrived on the island.

Now, like other farmers in Kona, the Barneses are concerned that the organic treatments won't be enough to fight off rust once the temperature rises this spring. So, they're up against a difficult decision: use Priaxor or run the risk of losing their trees

"We could do nothing and hope for the best, but that would be a real crapshoot," he says, comparing the decision to treating cancer with chemotherapy. "If the chemicals are the only way to save your life, you might have to do it."

The week I spoke with Robert, he described Dawn sitting in their orchard, crying about the impending impact on the trees they've been nurturing for years. "They're like her babies. She gets really emotional about it. And I don't know how our customers are going to take it because they love the [fact that we're] organic," he says.

Melissa Johnson doesn't know whether or not organic coffee farms will be able to maintain their certification in the coming years. She studied eight farmers in Kona as they dealt with CBB and two of them were certified organic. "Both have moved to conventional. So, I expect we might see more drop in organic producers again. Hopefully it will be temporary," she said.Plant pathologist Lisa Keith is optimistic that organic farmers will eventually have options for treating rust, even if the timeline is unpredictable.

But it's not just organic farmers who are at risk of dropping out of the industry. Johnson says she's concerned for all small-scale farmers, who are already facing mounting labor and input costs and are afraid of the unknown. "It's really stressful, and understandably so. I think a lot of them feel kind of helpless," she says.

UH's Kawabata says farmers are exploring alternative crops and talking about getting out of farming. "I haven't heard of any farmers just completely giving up yet. But, that could be next," she said. Kawabata points to the fact that the median age of farmers in Hawaii was 60 in 2017 (the last year the USDA conducted an ag census), and many older farmers don't have a transition plan in place.

A large, mainland-owned corporation moved in and set up a farm a few years back and many of the existing independent farms are already managed by large farm-management companies that oversee the labor on 20 to 50 farms. Together, these shifts represent a big step away from the smallholder model that put Kona on the map, says Suzanne Shriner. "[Under the large management companies], the farmer essentially does nothing. He just turns over the land to them. So, we're losing some of the individuality that our farms had for years," she says.

Keith stresses that what's on the line is more than a really good cup of coffee. "It's people's livelihoods," she says. "It's about the community and about helping the families and working together to try to make the best out of this unfortunate situation."

This story was originally published by Civil Eats.