Farmers tackle new threat to island coffee trees

The Garden Island
By Scott Yunker

The most-destructive disease known to the coffee plant has arrived on Kaua‘i, putting local growers on high alert.

Less than one year after the state’s first reported case of coffee leaf rust occurred in Maui, the blight’s presence has now been established on all major Hawaiian islands.

Coffee leaf rust, which is caused by the fungus Hemileia vastatrix, can lead to defoliation, reduced fruit size and plant death. Local grower Ben Fitt of Outpost Coffee was the first to report the disease on Kaua‘i while tending to his one-acre orchard on the North Shore in late June.


“I came across some interesting markings on some of the leaves and had a look, and I was pretty certain it was coffee leaf rust,” Fitt said.

Fitt immediately contacted the state Department of Agriculture, which sent a field agent to collect laboratory samples. The results came back as CLR on July 9. However, the fungus had been on Kaua‘i for at least six months prior to Fitt’s discovery, according to a department announcement released last week.

No one will ever know how the rust took hold in Fitt’s orchard, which follows stringent protocols intended to mitigate the risk of infection. In addition, the state has restricted the movement of affected islands’ coffee plants and other potential hosts since CLR’s first appearance in Hawai‘i last October.

Coffee leaf rust was first documented in Africa in 1861, according to the U.S. Department of Agriculture, which claims it was next spotted in Sri Lanka six years later, where it ruined that country’s coffee production within a decade. The disease has since been found in all major coffee-producing countries.

“I can only speculate as to how it got over. We took every step we can to prevent it. It’s just so contagious,” said Fitt, who hopes to destigmatize growers dealing with rust and other agricultural ills.

“There’s been a lot of farmers that haven’t reached out about it on the other islands, because they were scared of the repercussions from others,” Fitt explained. “I’d rather create an environment of, ‘The more we let people know and the departments know earlier on, it’s not a reflection on you as a bad person for having it.’”

The general manager of Kaua‘i Coffee Company, the largest coffee-grower in the U.S., appreciates Fitt’s transparency: to be forewarned is to be forearmed.

“We knew it was just a question of time,” Fred Cowell said, drawing a parallel between leaf rust and the arrival of the coffee berry borer, a pestilential beetle, in September. But it took the berry borer a decade to penetrate Kaua‘i following its discovery on Kona in 2010. In contrast, CLR has blown through Hawai‘i Island, Maui, O‘ahu, Lana‘i, Moloka‘i and Kaua‘i in eight months.

Cowell’s team has yet to find rust within Kaua‘i Coffee Company’s approximately 3,000-acre orchard. If it’s discovered, farm-workers will document the findings with a smartphone app connected to a centralized database that allows users to monitor problem areas with pinpoint accuracy. The company, which already utilizes mechanization throughout its operation, may even deploy drones to spray infected coffee trees.

“I don’t need to spray the entire orchard. I just need to spray wherever the hotspot is, either rust or CBB. We can send a tractor out and just do that area,” Cowell said. “But, potentially, in the future, we could launch a drone and it could go from spot to spot to spot and be done.”

Different approaches to fighting disease

Fitt, meanwhile, has taken a more-hands-on approach: He’s hired help to assist him in removing infected trees, and has adopted new pruning techniques. These efforts will increase airflow and sunlight in the orchard, thereby reducing the hot and moist conditions preferred by CLR. He is open to spraying fungicide, but only as a last resort.

“We don’t want to be spraying systemic chemicals on our farm,” Fitt said. “We would rather take a lot of other steps first to make sure that we do everything we can in our power to limit the spread with less-harmful techniques.”

Fitt estimates 3% to 5% of his coffee trees are showing relatively minor signs of rust.

“One of the key factors to how the tree responds to the pest is how healthy it is,” he said. “It’s kind of like humans getting sick: If you’re unhealthy before, you’re going to be affected worse.”

Fortunately for Fitt, that’s not the case here.

“We’re in a lucky position that our trees are super healthy. Our soil is very healthy, too,” Fitt continued. “Even though we are seeing signs of it, the trees aren’t really being affected that much.”

Cowell agrees: Soil affects everything, from the trees’ hardiness to the quality of consumers’ morning brew. Nurturing Kaua‘i Coffee Company’s land with cover crops, compost and other sustainable techniques will go a long way toward mitigating damage caused by rust.

CLR hasn’t gotten to Kaua‘i Coffee, yet

“With leaf rust showing up now and us having begun, five years ago, a journey toward better soil health and better sustainability, I think we’re going to have a pretty good chance of fighting it,” Cowell said. “There will be challenges, we don’t doubt it. It’s not here yet, but I have to assume that it will show up.”

CLR does not pose an existential threat to the Hawaiian coffee industry, according to Cowell, who said the product won’t disappear from supermarket shelves. However, it may bode ill for small orchards and hobbyists unable to invest the time, money and effort required to fight the disease.

“I think — for the state, anyway — it isn’t that CLR is going to chase them out of the business. It’s just a question of how much are they going to put up with?” Cowell said. “Exactly how difficult will it get before I finally just say, ‘You know what, I’m going to put in a few orange trees’ or ‘I’m just going to mow my field.’ That’s the long and short of it.”

Fitt is asking residents to report any suspected cases of coffee leaf rust to the state Department of Agriculture. Contact information and a CLR sampling form is available online at

“Coffee prices are going to go up because there’s a lot more labor involved in making sure this coffee leaf rust doesn’t destroy people’s trees,” Fitt said. “Production will go down with coffee leaf rust. I think the biggest thing that the average person can do to support their local farmers is to buy Hawaiian coffee.”

Pesticide Rotation on Onion Thrips and Onion Variety Trial in Bulb and Green Onion Crops Webinar

This free webinar is open to all growers in Hawaii

The webinar discussion will cover:

  • Pesticide rotations to control onion thrips: yield and pest pressure
  • Variety trials of green and bulb onions
When: Wednesday, July 27th, 2021, from 4:00 to 5:30 PM
Zoom information will be sent to registrants
Registration is required: RSVP to Rosemary by emailing to


  • Rosemary Gutierrez-Coarite
  • Joshua Silva
  • Kylie Tavares

HDOA Continuing Education Credits:

  • CEUs 1.5 hours
  • Approved categories: Commercial 1a, 9, 10, and Private 1

DOWNLOAD the Webinar Flyer

Open to everyone without regard to race, age, sex, color, or disability. Educational activities are accessible for individuals with disabilities. For more information or to request an auxiliary aid or service (e.g., sign language interpreter, designated parking, or material in alternative format), contact Rosemary Gutierrez-Coarite at (808) 244-3242 or via email at seven days before the activity/event.

Rosemary Gutierrez-Coarite Ph.D.
Assistant Extension Agent, Edible Crops
Department of Tropical Plant and Soil Science
UH CTAHR Maui Cooperative Extension Service
310 Kaahumanu Ave., Bldg. 214 Kahului, HI 96732
808-244-3242 ext. 232
" No task is too big when done together by all"

Help is on the way: Funding to assist ranchers in battling two-lined spittlebug

West Hawaii Today
By Laura Ruminski –

Help is on the way for Big Island ranchers fighting an invasive bug decimating pasture land in North and South Kona.

Franny Brewer of the Big Island Invasive Species Committee said the two-lined spittlebug (TLSB) could fit easily on a fingernail, looking innocuous and almost pretty with its orange-on-black stripes. But for Big Island ranchers, the sudden appearance of this insect in South Kona 2016 was anything but welcome. Since then, this tiny insect has spread prolifically, destroying more than 175,000 acres of pasture in the few short years since its arrival.

“The impact this little bug is having on pastures … is catastrophic,” said Mark Thorne, University of Hawaii Cooperative Extension Service State Range and Livestock Extension Specialist. Thorne and his team have been working since 2016 to find and track TLSB, all while searching for solutions. So far, they have found few strategies for mitigating the damage.

“We have seen the impact zone of this pest increase by about 35,000 acres per year, it’s spreading and it is very, very difficult to control,” Thorne said.

Already, affected ranchers have been forced to reduce herd sizes as the TLSB threatens Hawaii’s $65 million cattle industry. In response, the 2021 state Legislature approved $350,000 funding from the American Rescue Plan to support affected ranchers and fund ongoing research into mitigating the damage. The funds will be directed to the state Department of Agriculture to be used in responding to the invasive spittlebug.

“Hawaii’s food sustainability and resiliency depends on our ability to produce nutritious, affordable, healthy protein,” Hawaii Cattlemen’s Council Managing Director Nicole Galase said, adding that she hopes to work closely with the state Department of Agriculture to ensure the money has the greatest impact on the long-term sustainability of the ranching industry on Hawaii Island.

Keith Unger, who manages McCandless Ranch in South Kona, said the entity has yet to see the invasive bug in its pastureland.

“We’re not affected by it so far, but our next door neighbor is, so it’s just a matter of time,” he said. “It is a scary situation. The Legislature has definitely realized the potential devastation of this insect and that it could go further than just affecting the ranchers at the point that it affects watershed and erosion. If all of a sudden all these grasses disappear and you have nothing but bare ground or weeds, and all of a sudden you have flooding issues, you have soil retention issues.”

Even though the bug has been contained in the Kona region, Unger said the concern obviously is it spreading out of Kona and up into North and South Kohala, where Parker Ranch, one of the largest private owned ranches in the nation is located.

“The cattlemen there and on the other islands are definitely keeping an eye out on this and are participating in educational outreach just to make sure we can contain as best we can,” Unger said. “McCandless only has Guinea grass and akoa, and so far, spittlebug does not affect those feed sources. But anyone who has kikuyu or pangola in particular seems to be mostly affected.”

Roy Wall said Wall Ranch in Kealakekua was not so lucky.

“We started seeing the spittlebug back in 2016 around the same time that a few other Kona ranchers started seeing it,” said Wall. “By 2020, we had seen 100% of our kikuyu and pangola pastures decimated. Invasive weeds have moved in with no grass cover to hold them out.”

Wall said the ranch was forced to reduce its cow heard on those pastures by 50%.

“I feel like we are past the disaster phase and are moving in to the recovery and rebuild phase,” he said. “We have been working on trying to find resistant grasses — and some look promising — but its’ going to take years to recover. I’m hopeful that this bug will run through its initial explosion and find a balance.”

Brewer, with the Big Island Invasive Species Committee, said the team at the University of Hawaii’s College of Tropical Agriculture and Human Resources Cooperative Extension Service, CTAHR-CES, has been testing some TLSB-resistant grasses that could be used to reseed pastures. However, unlike the broad open plains where these grasses have been successfully deployed in North America and Brazil, Hawaii pastures range over thousands of feet in elevation and multiple climactic zones, all over diverse substrates, including lava rock, that make reseeding difficult.

“No single grass can solve the problem,” said Carolyn Wong Auweloa, USDA Natural Resources Conservation Service State Rangeland Management Specialist.

More research is crucial, she insisted, to help ranch lands recover. She pointed out that TLSB has completely killed forage in the heavily infested areas, effectively reducing productivity to zero and leaving behind a desolate swath that quickly fills in with invasive, toxic, and unpalatable weeds that in turn threaten the native forests that border the pastures.

“These grazing lands will not recover their productive potential without significant inputs to suppress weeds and attempt to re-establish forage species that can withstand the bug,” Auweloa said. “A lot of people don’t realize the important role ranchers play in maintaining the health of our watersheds.”

According to the state Department of Agriculture’s Statewide Agricultural Land Use Baseline study, grazing lands occupy over 760,000 acres in Hawaii.

“Healthy grazing lands have healthy, deeply rooted plant communities that cover the soil and help rainwater infiltrate to recharge our aquifers,” Auweloa said. “The funding from the Legislature will help to make these lands productive again, so they can continue to provide valuable ecosystem and social services, while feeding our livestock, our people and our economy.”

McCandless Ranch’s Unger said the help from the department is appreciated, but biosecurity at airports and ports needs to be beefed up because it’s becoming “one infestation after another.”

“We can and should spend more money at out ports and airports to stop these (invasives) from coming in,” he said. “Here we are, now spending hundreds of thousands and into the millions fighting on the back end. If you are going to talk about more ag sustainability you are right back to biosecurity for the State of Hawaii. Hopefully we can kickstart it again.”

Big Island residents are being asked to be alert about their lawns and pastures. Patches of dead grass that cannot be explained by other environmental factors should be reported right away to the state by visiting, calling (808) 643-PEST (7378) or using the 643-PEST mobile application for iOS and Android. Residents must also practice extreme caution in not transporting the insect out of its known infestation area.

A short documentary aimed at highlighting the plight of the ranchers and the impacts of TLSB in the hopes of raising awareness about the extreme threat to Hawaii’s agriculture can be found at

“This infestation is by far the worst thing I’ve seen in my 40-plus years of ranching in Kona but I’m confident that we will find a way to survive,” said Wall.

2021 University of Hawaii Turfgrass and Landscape Pest Management Webinar Series

Webinar series is free of charge, brought to you by UH Manoa Turfgrass and Landscape Pest Management Program, and CTAHR Cooperative Extension Service with the support of the HGCSA. –

Download the Flyer

4:00 – 5:00 pm on Tuesdays in April 2021 –

Live on Zoom: Webinar Zoom link will be provided to registered participants.

Certified Educational Units

  •  1.0 HDOA Pesticide CEU for categories: Private 1 and Commercial 1a, 2, 3, 6, 9 &10.
  • 1.0 LICT CEU.
  • 0.10 GCSAA points (0.10 each for April 06 and April 13 webinars).
  • 1.0 ISA CEU (1.0 each for April 20 and April 27 webinars).
    * CEUs pending confirmation from HDOA, LICH, GCSAA, and ISA.
April 06, 2021Management of several important turfgrass and golf course pests in Hawaii: take-all patch, mini ring, frit fly, and rover ant. Dr. Zhiqiang Cheng, UH Manoa.
Registration link (by April 02, 2021):
April 13, 2021Grassy weed control at West Loch golf course, case history with 200 gallon sprayer with 20ft. boom. Dr. Joseph DeFrank, UH Manoa (retired).
Registration link (by April 07, 2021):
April 20, 2021Management of several important landscape pests in Hawaii: lobate lac scale, Ficus stem and leaf gall wasps, and hala scale.
Dr. Zhiqiang Cheng, UH Manoa.
Registration link (by April 14, 2021):
April 27, 2021Research update on chemical and biological control of coconut rhinoceros beetle in Hawaii.
Dr. Zhiqiang Cheng, UH Manoa.
Registration link (by April 21, 2021):

Organized and hosted by:
Zhiqiang Cheng, Ph.D.
Associate Professor and Extension Specialist
Dept. of Plant and Environmental Protection Sciences, CTAHR, UH Manoa

Questions or for additional info, please contact: Dr. Zhiqiang Cheng (


Melon Fruit Fly Management Webinar – Wednesday, December 16th, 2020

Aloha Dear Growers,

You are invited to participate in this free webinar event.

This webinar is open to all growers on Maui County and it will cover:
– Melon fly monitoring
– Roosting host areas
– Control strategies and
– New pesticides

Wednesday, December 16th, 2020, 4:00 PM-5:00 PM

Robin Shimabuku
Kylie Tavares
Rosemary Gutierrez-Coarite

RSVP to Rosemary by emailing to

Please CLICK to download the flyer.

Best Regards

Rosemary Gutierrez-Coarite Ph.D.
Assistant Extension Agent, Edible Crops
Department of Tropical Plant and Soil Science
UH CTAHR Maui Cooperative Extension Service
310 Kaahumanu Ave., Bldg. 214 Kahului, HI 96732
808-244-3242 ext. 232
” No task is too big when done together by all”

UH develop rapid test to detect bacterial wilt in Guam

University of Hawai’i News

Bacteria wilt is a problem affecting numerous trees in Guam. Under a grant from the United States Department of Agriculture (USDA), a University of Hawaiʻi at Mānoa assistant researcher and graduate students have helped to develop tests to rapidly distinguish the bacterial strain attacking the plants.

The USDA’s Priority Pest List for 2021 includes Ralstonia solanacearum race 3 biovar 2, a bacterium better known as a bacterial wilt. It infects through the roots and is deadly to plants, and is the subject of new grant funding for the University of Guam under the USDA’s Plant Protection Act.

Assisting with the characterization of Guam’s bacterial wilt strains are Mohammad Arif of UH Mānoa’s College of Tropical Agriculture and Human Resources Department of Plant and Environmental Protection Sciences and graduate students Sujan Paudel, Dario Arizala and Diksha Klair. Paudel and Shefali Dobhal recently developed rapid assay tests that can accurately and quickly distinguish the race 3 biovar 2 strain from the R. solanacearum species complex.

“With these diagnostic assays in hand, we can rapidly detect the bacteria directly from crude host tissue sap. We are now responsible for understanding how bacteria interact inside the host tissues, as well as mapping out endophytic communities associated with ironwood decline through microbiome studies,” said Arif.

“We’ll also study genetic variability among Ralstonia strains found associated with ironwood decline, and how this bacteria has evolved,” he added. “These objectives will enhance our understanding of this pathogen and disease, toward the development of effective disease-management strategies.”

Plant containment greenhouse to safeguard Hawaii plant imports

horti daily

After 2.5 years of planning and construction, the statewide Hawaii Tropical Fruit Growers (HTFG) boasts a new state-of-the-art containment greenhouse. Approved by the Hawaii Dept. of Agriculture (HDOA) last week, the facility is situated in South Kona.

The $263K greenhouse, funded mainly by the state’s Grants-in-Aid program, will provide fruit growers with insect and disease-free plant resources imported from around the world.

“The greenhouse enables us to bring in, effectively isolate and safely propagate fruit we believe will be productive in Hawaii,” explains Mark Suiso, HTFG president. “Hawaii did not evolve naturally with fruit. This facility has technology that will allow us to efficiently introduce desired plants and evaluate them to assure they can safely be released and grown in our state.”

To ensure introduced plants don’t bring in any unintended problems, the 30 X 30-foot greenhouse is surrounded by a five-inch moat and 15-foot concrete barrier and further secured by an electric fence and security system. Specialized USDA-approved micro screen walls will prevent any insects from gaining access and limited staff entry to the greenhouse is through double doors. A solid, specialized plastic roof tops the greenhouse and interior halls between the greenhouse’s eight rooms are blackened with insect traps in each room and hallway.

Ken Love, HTFG executive director, says greenhouse waste water will be treated with bleach before released into a holding tank and finally a septic system. “There is always a concern that water passing through growing media could contain bacteria that might have been missed in the initial plant inspections,” he details. “The bleach treatment will kill any bacteria or virus that travels from the dirt to the drains and into the holding tank.”

According to Love, all chosen imported plants will go through five stages of inspection: by HTFG on-site at exporting farm, by country of origin’s Dept. of Agriculture, by USDA upon arrival in Honolulu, by HDOA in Honolulu, and finally by HTFG before entering greenhouse. Imported plant stock will arrive as small, bare-root trees or cuttings.

Once the seedlings are received at the Kona greenhouse, they will be potted in a sterile and organic nursery mix.

HTFG members will decide what plants to import and clone and they will be quarantined in the 900-square-foot greenhouse over a two-year period before released. The project’s six rooms can each hold about 1,000 trees and two, small tube pot rooms can hold up to 4,000 seedlings.

Love shares virtually unknown fruit like sweet-sour tampoi has “great economic potential” for Hawaii growers as does the creamy, sweet and savory durian, which can currently be exported from Hawaii to the U.S. Mainland.

“We have already arranged to bring in 500 hachiya persimmons from Japan and 1,000 durian from the Philippines,” adds Love. “Other trees are being grown out for us in Borneo, Queensland and India.”

In addition, the specialized containment greenhouse enables HTFG to apply for a specialized Controlled Import Permit to bring in new varieties of citrus and mango. This more restrictive permit is required as Hawaii is already growing citrus and mango and prevention of introducing new pathogens to existing crops is crucial.

Once plants are settled in the greenhouse, smart monitoring systems will result in little interaction between plants and people as the goal is to minimize exposure between the confines of the greenhouse and the outside world.

To nurture seedlings in a controlled setting, the greenhouse has a timed irrigation system that controls misting, fogging and spraying to mimic ideal growing conditions, including those of the equatorial rainforest. Each growing room has Wi-Fi sensors for monitoring and recording temperature and humidity readings.

“The precise production of desired growing conditions will produce healthier plants more quickly,” notes Love. “This includes cuttings from most citrus, Chou ume plum and any desired local plants like those in the mountain apple family.”

The new greenhouse is a sister project to HTFG’s existing statewide fruit tree repositories where trees are available for sharing among organization members, plus to the public at periodic sales. Love says distribution of the greenhouse’s resources will be similar.

“Ultimately, we want to see a diverse selection of fruit grown productively throughout the state and with little dependence on importing it from outside the state,” adds Suiso.

“HTFG especially appreciates the funding efforts of state legislators Mike Gabbard, Richard Creagan, Donovan Dela Cruz and Nicole Lowen. Mahalo to Phyllis Shimabukuro-Geiser, Sharon Hurd, Lance Sakaino and Clare Okumoto of the HDOA; Mike Scharf, Matthew Goo, Peter Follett and Dorothy Alontaga of the USDA; Dr. Robert Paull and Andrea Kawabata of the University of Hawaii; and Kenneth and Ader Takaki of Ken’s Masonry, Mark Dixon Construction and Diamond Sprinklers.”

“Thanks also to HTFG members statewide, especially Brian Lievens, Greg Garriss, Chuck Cope, Shinobu Doucette and Xavier Chung.”

For more information:
Ken Love
HTFG President Mark Suiso

Coffee Leaf Rust Webinar

Coffee Leaf Rust Webinar
Thursday, November 19, 2020

This webinar is provided as a free resource for our association members and the broader community. It is designed to provide important updates on the Coffee Leaf Rust disease recently discovered in Hawaii. The webinar will consist of two sessions and have a Q&A session at the end of each.

The webinar will have two sessions. Please see the schedule below and register for each session individually.

IMPORTANT: Please ensure you are notifying all farm staff, including seasonal pickers who may work on multiple farms, of new sanitation protocol to mitigate the spread of this fungus. We also encourage you to share this webinar information with your farm staff.

Webinar Schedule
Thursday, November 19

Short Term Strategies
with Jacques Avelino of CIRAD* and Andrea Kawabata of University of Hawaii CTAHR

Jacques will discuss the biology of the causal agent of coffee leaf rust: the fungus Hemileia vastatrix and some epidemiological considerations. He will explain how meteorological variables, topography, coffee tree characteristics, natural enemies and management, particularly nutrition and shade, affect coffee rust development. This knowledge can be used to improve coffee rust management at farm and regional levels.

Andrea will provide updated information on approved fungicides for coffee in Hawai’i to help combat Coffee Leaf Rust, including application protocol. She will also cover necessary general farm practices, hygiene, and sanitation protocol that producers should be implementing on their farms immediately to avoid spreading CLR spores.

*CIRAD is the French agricultural research and international cooperation organization working for the sustainable development of tropical and Mediterranean regions.

Register for the Short Term Strategy Session

Research, Resources & Regulation
with Kevin Hoffman of HDOA and Lisa Keith of USDA and PBARC

Kevin will provide an update to attendees on the most current information available to HDOA including new quarantine restrictions.

Lisa will focus on the pathology of coffee leaf rust in Hawaii, including what we know, what we don’t know, and short and long term research efforts to manage CLR in Hawaii.

Register for the Research, Resources & Regulation Session


State of Hawaii Department of Agriculture

HONOLULU – Coffee leaf rust (CLR) has been confirmed on coffee plants on Hawai`i Island by the U.S. Department of Agriculture National Identification Services. The samples were collected by a grower on a farm in the Holualoa area, south of Kailua-Kona, on Hawai`i Island on October 31, 2020. Samples from Hilo, mentioned in an earlier news release, were negative for CLR. Earlier in October, CLR was detected and confirmed in the Haiku area of Maui. CLR has not been detected on other islands.

CLR is one of the most devastating pests of coffee plants and is established in all major coffee-growing areas of the world, but had not previously been found in Hawai`i prior to its recent discovery on Maui and Hawai`i Island.

“Coffee is one of Hawai`i’s signature crops, of which production was estimated to be $54.3 million in 2019,” said Phyllis Shimabukuro-Geiser, chairperson of the Hawai`i Board of Agriculture. “As surveys continue across the state, the Hawai`i Department of Agriculture is preparing to establish interim rules that will hopefully prevent the spread of the fungus to uninfested islands.”

The Hawai`i Department of Agriculture (HDOA) Advisory Committee on Plant and Animals has scheduled a meeting on Friday, Nov. 13, 2020 at 1:30 p.m. to consider an interim rule to restrict the movement of coffee plants and coffee plant material from islands found to have CLR to islands on which the fungus has not been detected. Information on the meeting via Zoom is available at:

CLR can cause severe defoliation of coffee plants. Infected leaves drop prematurely, greatly reducing the plant’s photosynthetic capacity. Vegetative and berry growth are reduced depending on the intensity of rust in the current year. Long-term effects of rust may include dieback, which can have a significant impact on the following year’s yield, with some researchers estimating losses between 30 percent and 80 percent.

The first observable symptoms are yellow-orange rust spots, appearing on the upper surface of leaves. On the underside of the leaves, infectious spores appear resembling a patch of yellow- to dark orange-colored powder. These young lesions steadily increase in size with the center of the lesion turning necrotic and brown, with the infection eventually progressing up the tree. CLR may also infect young stems and berries.

HDOA’s Plant Pest Control Branch has prepared a field guide to aid in the detection and reporting of possible CLR infections. The field guide maybe found at:

While there are fungicides that may be used to help control the fungus, one of the key factors to any pest management program is good sanitation practices. Regular pruning and training of the coffee tree helps to prevent over-cropping and maintain a healthy field. These practices help to improve air circulation and also to open up the canopy to allow proper fungicide spray coverage. Good weed control is an important factor as it keeps competition for vital nutrients low, thereby reducing the susceptibility to the rust.

CLR, Hemileia vastatrix, was first discovered in Sri Lanka in 1869 and is now found in the major coffee-growing regions of the world, including Southeast Asia, Africa, and Central and South America.

Hawai`i has strict importation rules requiring all imported green coffee beans for roasting and associated packing materials be fumigated prior to entering the state to ensure beans are free of pathogens and insect pests. These rules also subject coffee plants and propagative plant parts to strict quarantine requirements if imported to Hawai`i, including a quarantine on all imported coffee plants for a minimum of one year in a state-run quarantine facility.

To report possible coffee leaf rust infestations on any island, call HDOA’s Plant Pest Control Branch at (808) 973-9525.

For more information on coffee leaf rust go to the UH-CTAHR webpages at:

Or, the HDOA Field Guide at: