Business Monday: Kona coffee farms head into this year’s festival with healthier crops

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Suzanne Shriner, owner of Lions Gate Kona coffee, points out one of the older coffee trees at her Hōnaunau farm on Nov. 1, 2023. (Tiffany DeMasters/Big Island Now)

It’s not hard to tell the difference between a healthy coffee tree with its glossy green leaves and one that’s been affected by Coffee Leaf Rust. Brown-speckled leaves have fallen off the trees overtaken by the fungus.

Last year, Coffee Leaf Rust was widespread throughout coffee farms in the state.

“Trees were just sticks,” said Suzanne Shriner, owner of Lions Gate Farm in Hōnaunau. “They had no foliage. It was pretty horrendous to look at as a farmer.”

In 2022, her three farms covering 13 acres on the Big Island produced only 3,000 pounds of coffee cherries per acre compared to a normal yield of 6,000 pounds. And at $2.57 per pound, half a crop is a huge economic loss.

For Tom Greenwell, who said last year was his worst coffee crop since he took over Greenwell Farms in 1992 from his parents, the problem was drought.


In 2021, Greenwell said he saw the worst bouts of drought consecutively in October, November and December. Going into 2022, the lack of water resulted in the trees not having enough energy to produce the coffee cherries.

Suzanne Shriner, owner of Lions Gate Kona coffee, shows Coffee Leaf Rust has impacted some of her own trees at her Hōnaunau farm. (Tiffany DeMasters/Big Island Now)

But this year, entering the 52nd annual Kona Coffee Cultural Festival that runs through Nov. 12, farmers are celebrating higher yields and healthier crops throughout the Kona region due to more rain and better management of the killer fungus.

The festival will hold its first Kona Coffee Expo on Nov. 12 during which coffee farmers will gather to share their expertise in the industry. Presentations include a variety of live Kona coffee demonstrations and lectures on how to create a quality cup and how to properly clean a green bean.

Knowledge also will be shared about Coffee Leaf Rust, which was found on the main Hawaiian Islands in October 2020 and attacks the foliage of coffee trees. Shriner said if a leaf is 30% infected by the fungus it will fall off. The tree feeds itself through photosynthesis in the leaves and with the leaves gone, the tree dies.

The only way to protect a coffee plant from dying is to ensure it has healthy soil. Shriner said her farm boosts the health of that soil using fertilizer that includes micronutrients.


Shriner said she expects to return to her baseline crop production this year because more is known about how to stop Coffee Leaf Rust.

Sharon Hurd, chairperson of the Hawai‘i Board of Agriculture and director of the state agriculture department, said Coffee Leaf Rust has been treated as a priority since the breakout with funding provided to care for the plants.

“They were horrible, devastating infestations to the state, but we banded together and there’s light at the end of the tunnel,” Hurd said.

But, Hurd said the state likely will always have to battle the fungus and cherry borer beetles – a pest that bores into coffee cherries resulting in premature fall of young berries and reducing both yield and quality – because they exist on wild coffee trees.

“We need to remove them so they don’t impact the private industry,” Hurd said.


While the 2021-22 numbers posted on the Department of Agriculture show a rise in crop yields, Shriner said that was not the case at Kona farms, with some only having a 20% yield from their average.

“Kona is the most valuable crop in the state,” Shriner said. “While the yield went up statewide, the value was down, and that’s because the Kona yield was down.”

Coffee beans on a tree at Lions Gate farm in Hōnaunau. (Tiffany DeMasters/Big Island Now)

Shriner and Greenwell see crop yields up across Kona farms so far this 2022-23 season, but the National Agricultural Statistics Service for USDA is forecasting a 9% drop in coffee production from last year.

According to the report, the bearing acreage totaled 6,500 in the state, which was down by 700 from last year. However, the average yield, at 4,000 pounds of coffee cherries per acre, was up 50 pounds from the previous year.

While Kaua‘i produces the most coffee in the state, Kona coffee is the face of coffee for the state, as a result of good marketing and its smooth flavor. The Kona coffee farms also have drawn visitors who want tours, with the Kona brand known worldwide.

Greenwell said Kona coffee has been in the world market for 150 years, with his family taking Greenwell coffee to the World Fair in Vienna, Austria in 1873.

Matthew Loke, with the state Department of Agriculture, said Kona coffee cherries are hand-picked for ripeness and consistency. It is also graded more rigorously. 

“Today, coffee cherries in other regions are machine-harvested,” Loke said. ” This method conserves labor resources but may compromise the quality of fruit harvested.”  

To help combat Coffee Leaf Rust statewide, the Synergistic Hawaiʻi Agriculture Council, a nonprofit organization founded to better market Hawai‘i commodities, like coffee, to foreign and domestic markets, was awarded a four-year federal grant.

The $6 million funding is going toward research that analyzes different fungicides used on coffee trees to prevent Coffee Leaf Rust, how much should be used, and when it should be used, said Shriner, who is also the executive director of the nonprofit.

Industry leaders say a fungicide called Priaxor is effectively killing Coffee Leaf Rust.

Zhiqiang Cheng, professor at University of Hawai‘i in the Department of Plant and Environmental Protection Sciences, is leading two field research programs that are currently being conducted in Kona.

Scale and coffee bags used to pick coffee at Lions Gate farm in Hōnaunau. (Tiffany DeMasters/Big Island Now)

The field research looks at systemic fungicides, which are made of synthetic chemicals and biological control fungicide, which are biological products that are readily used on organic farms when registered.

Cheng said the research is testing seven systemic and two biological fungicides.

The state also helped purchase coffee trees from Central America to test their immunity to the fungus. While most of the plants are still in quarantine to ensure no new pests or funguses are introduced to Hawai‘i crops, there is evidence that some are resistant to the Coffee Leaf Rust.

Whether the beans roasted from those plants are up to Kona Coffee standard is yet to be determined.

“We have the best coffee in the world,” Greenwell said. “It’s mellow, smooth, rich and it’s got a nice aroma all at the same time. It’s just such a sweet coffee.”

For the past couple of years, Shriner said farmers have primarily been battling Coffee Leaf Rust with a decrease in cherry borer beetles due to fewer beans.

Greenwell said the lack of rainfall was what doomed his crops last year. Lower-elevation coffee farms are dependent on rainfall to water their crops as they don’t have irrigation systems.

“This season we’ve had a year’s worth of rain by June,” he said. “Give me an inch of rain a week and I’d be a happy farmer.”

But Greenwell’s farm hasn’t been immune to Coffee Leaf Rust. He has done what he can, including using enriching soil and fungicide, to protect his 200 acres of trees across 11 South Kona farms from the fungus.

Driving around South Kona, Greenwell said it’s common to see the brown-splotched leaves on coffee trees. Every time he sees them, he wishes he could stop to take care of them.

“It’s really sad when a tree drops its leaves,” Greenwell said. “I wish farmers that had CLR took care of their crops a little better.”

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