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.

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“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 hdoa.hawaii.gov/pi/ppc/new-pest-advisories/.

“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.”

Rain percolates in Kona coffee belt, not so much elsewhere

Hawaii Tribune-Herald
By John Burnett

For much of May, most of Hawaii Island’s rain gauges were measuring near- to below-average amounts of rainfall, as the National Weather Service in Honolulu predicted in its dry season outlook for May through September.

There was one notable exception — the Kona coffee belt, which experiences its wet season in the summer. That said, it was even wetter than usual.

And one coffee belt gauge, Kealakekua, posted its highest May rainfall total on record, 12.86 inches, 240% of its average May rainfall total, and over 3 inches more than the previous May record, 9.76 inches.

“It didn’t just squeak by on the record; it was a significant margin, so it’s pretty notable,” Kevin Kodama, NWS senior service hydrologist, said Thursday. “And it wasn’t just that site. All of the gauges in that area picked up a pretty good amount. You look at the percent of averages, it was all at, above, or just below 200% of average.”

Kealakekua also had the Big Island’s highest one-day rainfall total of 2.28 inches on May 3.

The other three official coffee belt gauges Kodama referred to are: Kainaliu, which registered 10.57 inches, 204% of its May norm; Honaunau, which measure 9.33 inches, or 196% of average; and Waiaha, which had 7.94 inches, 170% of its usual May.

One unofficial leeward gauge, at Holualoa, in upslope North Kona, tallied 14.99 inches.

“May is just getting things started. Actually, the peak doesn’t occur until later,” Kodama said of the summer wet season for leeward slopes. “So it’s pretty early to be ramped up like this. Overall, we’ve had some instability, but they’ve been getting rain, like, everyday — and in decent amounts.”

Not all Kona locations shared in the rainfall bounty, however.

Ellison Onizuka Kona International Airport at Keahole, where tourists on the tarmac are almost always greeted by sunshine, registered just 0.9 inches for the month, 45% of its usual 2 inches. Puuanahulu was even drier at 0.77 inches, just 34% of its May average of 2.25 inches.

Windward monthly totals were mostly in the range of 60% to 100% of average. Glenwood, in the upper Puna rainforest, had the highest monthly total of 13.74 inches, 86% percent of average.

The rain gauge at Hilo International Airport tallied 6.17 inches, just 76% of its May average of 8.12 inches. Due to a wetter-than-average rainy season, however, the airport’s year-to-date total of 69.56 inches is 134% of its average for the year’s first five months, 51.91 inches.

Piihonua, in the foothills above Hilo town, hit double-digit rainfall in May, checking in at 10.78 inches, 80% of its May norm of 13.48 inches. Piihonua also has the distinction of being the first official NWS rain gauge on the Big Island to crack triple digits for the year, with 100.98 inches of rain, 31% above its year-to-date average.

“The trades have been there most of the month but it’s not been super wet. It’s been kind of what we were expecting,” Kodama said. “… The way drought manifests itself on the windward side of the Big Island, windward slopes, anyway, is you’ll get rain every day or almost every day. But it’s just that the amount of rain is lower than what you’d expect normally. And that’s what’s been occurring.”

And while most of East Hawaii has remained green, so far, other parts of the island are slipping into drought conditions. In his last drought statement, dated May 8, Kodama wrote “With the exception of the Kona slopes of the Big Island, leeward areas of the state may see increasing drought conditions during the summer.”

That assessment is borne out in the numbers.

The Waimea Plain gauge received just 0.91 inches for the month, just a third of its usual 2.61 inches, bringing it to 8.8% for the year, just 40% of its norm of 22.08 inches. And Honokaa also got about a third of its normal May rainfall, 2.3 inches, bringing its total for the year to 40.13 inches, almost 20% drier than normal.

“It’s been creeping along in leeward Kohala and up in the Pohakuloa region it’s been drying out,” Kodama said. “I just found out (Thursday) that even the Honokaa area is drying out. Parts of (Hawaii Volcanoes) National Park are getting dry, too — the windward side not so much, but more in the lee of Kilauea volcano it’s been drying out.

EPA approves fungicide for coffee leaf rust

The Maui News

The U.S. Environmental Protection Agency will allow Hawaii coffee growers to use a fungicide to fight coffee leaf rust, a devastating pathogen found on Maui, Lanai, Hawaii island and Oahu.

The state Department of Agriculture was notified Wednesday that the EPA had approved its request for farmers to use Priaxor Xemium, a fungicide not currently labeled by the EPA for specific use on coffee plants but allowed for controlling fungi on leafy vegetables, strawberries, tomatoes, soybeans, wheat and other crops. In March, the department filed a request for an exemption to use the fungicide on coffee plants. The emergency exemption approval will allow the fungicide to be used for up to one year or until use on coffee plants is added to the product label by EPA and the fungicide’s producer.

Coffee leaf rust was first detected on Maui and Hawaii island in October and on Oahu and Lanai in January, leading the board to restrict the movement of coffee plants from these islands.

“Hawaii coffee growers now have an added method to combat the coffee leaf rust, which is extremely difficult to manage,” said Phyllis Shimabukuro-Geiser, chairperson of the Hawaii Board of Agriculture. “Other efforts to minimize the damage and spread of coffee leaf rust include quarantines on the movement of coffee plants and associated material, the import of disease-resistant coffee plants and the development of integrated pest management strategies.”

Under the emergency exemption, coffee growers must:

• Inform the state Department of Agriculture Pesticides Branch at least seven days prior to using Priaxor Xemium by emailing hdoa.sec18@hawaii .gov.

• Wear personal protective equipment as required by the label.

• Follow all directions on both the container label as well as the dealer-provided Section 18 label.

• Report all use/application to the Pesticides Branch within 10 days of application.

For more information, Maui County growers can call Mitchell MacCluer of the Pesticides Branch at (808) 873-3078.

Two webinars on the use of the fungicide are being planned in June.

For more information on coffee leaf rust and the coffee industry, visit www.hawaiicoffeeed.com or hdoa.hawaii.gov/ pi/files/2021/01/NPA-20-03-Coffee-leaf-rust1-21.pdf.

Webinars Scheduled For Coffee Growers On Possible Fungicide Use

State of Hawaii Department of Agriculture

Two free webinars have been scheduled in April to help inform Hawai`i coffee growers on the potential use of a fungicide to combat the coffee leaf rust (CLR). Earlier this month, the Hawai`i Department of Agriculture (HDOA) filed a request for emergency exemption with the U.S. Environmental Protection Agency (EPA) to allow the use of a fungicide, Priaxor® Xemium, on coffee plants in Hawai`i. The fungicide is approved for use on other agricultural crops, but EPA approval is needed to allow its use specifically on coffee plants.

In anticipation that EPA may approve the request by the end of April, the University of Hawai`i – College of Tropical Agriculture and Human Resources (UH-CTAHR) and HDOA will be hosting two Zoom webinars to help educate coffee growers on the safe use of the fungicide.

The webinars have been scheduled for:

  • Thursday, April 1st and Thursday, April 8th from 4:30 p.m. to 5:30 p.m.
  • Registration is required and may be completed at: HawaiiCoffeeEd.com/priaxor
  • Webinars are free.
  • For more information on the Zoom webinars, contact UH-CTAHR Associate Extension Agent Andrea Kawabata at andreak@hawaii.edu or call (808) 322-0164

Hawai`i researchers believe that if approved by EPA and used properly, Priaxor has the ability to inhibit the CLR spore germination and growth on the coffee plant leaves, unlike currently approved contact fungicides that kill CLR spores on the outside of the leaf.

CLR has been detected on Maui, Hawai`i Island, Lana`i and O`ahu and is a serious threat to the state’s $56 million coffee industry.

CLR is a devastating coffee pathogen and was first discovered in Sri Lanka in 1869 and can cause severe defoliation of coffee plants resulting in greatly reduced photosynthetic capacity. Depending on CLR prevalence in a given year, both vegetative and berry growth are greatly reduced. There are multiple long-term impacts of CLR, including dieback, resulting in an impact to the following year’s crop, with estimated losses ranging from 30 percent to 80 percent.

For more information on CLR and the Hawai`i coffee industry, go to:

  • Coffee Education Website – UH-CTAHR: https://www.HawaiiCoffeeEd.com/
  • HDOA Coffee Leaf Rust Advisory: https://hdoa.hawaii.gov/pi/files/2021/01/NPA-20-03-Coffee-leaf-rust1-21.pdf
  • CLR Field Guide: https://hdoa.hawaii.gov/pi/files/2020/12/CLR-Public-field-guide-with-form11-20.pdf
  • 2020-2021 Hawai`i Coffee Season Statistics (National Agricultural Statistics Service): https://www.nass.usda.gov/Statistics_by_State/Hawaii/Publications/Fruits_and_Nuts/Coffee-01-26-2021.pdf

CTAHR Mid-December 2020 Events & Announcements

View Completer CTAHR Newsletter in your Browser

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UH CTAHR Cooperative Extension Offices will be closed on the following day:
Friday, December 25th, in observance of Christmas
Friday, January 1st, in observance of New Year’s day

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TODAY! 12/18 @ 2:30 pm – Maintaining Soil Health While Treating for Coffee Leaf Rust
From: Joan Obra
Vice President: United Ka’u Farmers Cooperative
Partner: Rusty’s Hawaiian and Isla Custom Coffees

RE: Zoom Meeting on Soil Health
Date and Time: Friday, Dec. 18, 2020, at 2:30 pm.

Since the arrival of Coffee Leaf Rust (CLR) in Hawaii, farmers have been told that maintaining healthy trees is key to fighting this pest. But tree health depends on soil health — and the copper-based fungicides for CLR pose certain challenges to our soils.

What’s a farmer to do? Join us for this Zoom webinar to discover good-management practices for copper fungicide use. You’ll hear a review of scientific literature about these fungicides and their residual effects. And you’ll learn about SOLVITA soil-respiration test kits, a tool that measures chemical and biological soil parameters. Your instructor is Dr. Melanie Willich, The Kohala Center’s Director of Applied ʻĀina-Based Agriculture.

Register in advance for this meeting:
https://us02web.zoom.us/meeting/register/tZUsdeGtpjksHdfoVQpeR4ZEmnxOVcxCPHr0

After registering, you will receive a confirmation email containing information about joining the meeting.

Thank you,
Joan

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Dr. DeFrank’s Air Layer Workshop Recording
Dr. DeFrank provided the Waimanalo Farm Crew with a hands-on air layer workshop on 12/10/20 and has provided a URL link below to 2 videos (classroom and hands-on training) and pdf of slides that details this air layer method and includes sources for various materials used. The mango and guava at the Waimanalo Station were at the perfect stage for air layering and the same may be true for your locations. He has been successful with mango, guava, cacao, longan and native Koa root suckers.

Air layer hands-on workshop at Waimanalo on 12/10/20:
https://www.ctahr.hawaii.edu/defrankj/NON_HOMEPAGE_PAGES/Air_layer_UH_Farm_121121020.htm

Dr. Joe DeFrank
Ph: 808-225-1765
email: defrenk@hawaii.edu

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Kau Coffee Virtual Festival and Coffee College Webinars
Visit https://www.kaucoffeefestival.com for all festival activities. These events will take place the weeks of Dec. 21 and Dec. 28.

The Coffee College presentations are being organized and additional information will be available at the link above.

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Intro to Beekeeping Virtual Workshop – Saturday, January 16th, 9:00 am – 12:00 pm
Interested in learning about beekeeping or know of someone that might but does not know where to start? NOW is the time of year to begin planning and becoming prepared looking forward to the upcoming beekeeping season! The California Master Beekeeper Program (CAMBp) OC Bee Team will be offering VIRTUAL Beekeeping Classes throughout 2021.

The first of the series of SEVEN knowledge building science-based beekeeping classes, presented by the California Master Beekeeper Program OC Bee Team, is Beekeeping 001 Exploring Beekeeping beginning on January 16th. Follow the CAMBp website cambp.ucdavis.edu as new classes in this series will be listed.

BONUS: a 10% discount will be applied to individuals who sign up for the entire series!

Register: for this class https://registration.ucdavis.edu/Item/Details/694

More information at: https://cambp.ucdavis.edu/

Questions? Email: camasterbee@gmail.com

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ADSC Holiday Schedule
Aloha,

The Agricultural Diagnostic Service Center will be operating with a skeleton crew from Monday, December 21st through Thursday, December 31st. Analysis results that are normally available within 7-10 working days will be slightly delayed. We apologize for any inconvenience.

Happy Holidays from the Agricultural Diagnostic Service Center!

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Coffee Samples for UH ADSC Submission
Per Hawaii County Administrator, Susan Miyasaka, NO coffee plant samples NOR soil from coffee farms will be shipped to UH Manoa ADSC [for diagnostics] – there is an inter-island quarantine.

Please contact UH Hilo to submit coffee leaf and soil samples.
https://hilo.hawaii.edu/analab/

For nematode, disease and insect IDs from coffee farms, and other questions or concerns, please contact Susan at (808)969-8258 or miyasaka@hawaii.edu.

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Mahalo – 1215 Virtual Invasive Pest Mini-Conference
Aloha,

Thank you for attending 1215 Virtual Invasive Pest Mini-Conference 2020. It’s my pleasure to have you all in this meeting with some valuable talks on current invasive pest concerns, rapid responses and management efforts, and status updates/ new detections. Special thanks to the speakers – Teya Penniman, JB Friday, Kaili Kosaka, Koki Atcheson, Jane Anderson, Nate Dube, and Kevin Hoffman.

Here is the link to the mini-conference video https://vimeo.com/491793219/c913595d6b just in case if you have missed this meeting. A chat note is also attached.

Announcement – Save a date for 02182021 Virtual Invasive Pest Mini-Conference on Feb 18 (Thursday), 2021. Please let me know if you are interested to give a talk in the 0218 Mini-Conference.

Wishing you a wonderful New Year!!

Sincerely,

Roshan

Coffee Leaf Rust Webinar

JOIN US FOR A LIVE
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

9:00-10:30am
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

11:30-1pm
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

COFFEE LEAF RUST CONFIRMED ON HAWAI`I ISLAND

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: https://hdoa.hawaii.gov/blog/main/pqmtgs/.

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: https://hdoa.hawaii.gov/pi/ppc/new-pest-advisories/

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:

https://www.hawaiicoffeeed.com/clr.html
http://www.extento.hawaii.edu/kbase/crop/Type/h_vasta.htm

Or, the HDOA Field Guide at: https://hdoa.hawaii.gov/pi/ppc/new-pest-advisories/

Coffee Leaf Rust Tentatively Found On Maui

State of Hawaii Department of Agriculture

HONOLULU – Coffee leaf rust (CLR) has been tentatively identified on coffee plant samples collected on Maui. The Hawai`i Department of Agriculture (HDOA) this afternoon received preliminary results from University of Hawai`i, College of Tropical Agriculture and Human Resources (UH-CTAHR) identifying the fungus on plants collected from managed and wild coffee in the Haiku area. Samples have also been sent to the U.S. Department of Agriculture National Identification Services on the Mainland for official confirmation of this federally regulated pathogen.

CLR is one of the most devastating pests of coffee plants and is established in all of the other major coffee growing areas of the world, but had not previously been found in Hawai`i.

On October 21, 2020, leaves from managed coffee in the Haiku area of Maui displaying CLR symptoms were turned in to the Hawai`i Department of Agriculture (HDOA) on Maui. Subsequent surveys in the area found plants with symptoms at three additional locations, two of which were in wild coffee. HDOA has sent a memo to members of the coffee industry throughout the state to alert them to the situation. Currently, HDOA is continuing its efforts to survey on Maui and is extending those efforts statewide as well.

“It is unknown at this time how the rust got to coffee plants on Maui or how long it has been there,” said Phyllis Shimabukuro-Geiser, chairperson of the Hawai`i Board of Agriculture. “We appreciate the assistance of the multiple agencies that are helping us to determine the extent of this infestation and how coffee leaf rust may have been introduced into the state.”

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.

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.

Coffee leaf rust, 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:

https://www.hawaiicoffeeed.com/coffee-leaf-rust—nko.html
http://www.extento.hawaii.edu/kbase/crop/Type/h_vasta.htm