COFFEE LEAF Past, Present and Future in the RUST Fight Against Fungus

THE LASTING IMPACT of COFFEE LEAF Past, Present and Future in the Fight Against Fungus RUST By Chris Kornman UCKY" is not likely to be the first descriptor “L you’d hear from coffee farmers when discussing their careers. Successful coffee production isn’t the result of chance. The job takes skill, dedication, intuition and resilience. Yet coffee is fickle, and prone to innumerable afflictions; even the most fastidious farmer’s trees fall victim to disease. One of the vilest afflictions known to coffee is a fungus known as rust. Among the coffee producers I’ve been privileged to meet is a subset of proactive conservationists and forward- thinkers. Their fields were not immune to recent epidemics of coffee leaf rust (CLR, or roya in Latin America) sweeping through the coffeelands. They were unlucky, like the rest, but they were quick to learn and adapt. CONTINUED ON PAGE 24 Coffee leaf rust in Guatemala. | Photo by Lily Kubota July | August 2019 23 THE LASTING IMPACT of COFFEE LEAF RUST | Past, Present and Future in the Fight Against Fungus | CONTINUED One such producer is Alejandro Solis, who facing these days. With unpredictable and unstable weather, manages his family’s farms, Finca Injertal the risks of producing coffee have increased. Flowering, and Finca Huixoc, near the cities of San Pedro planting, fertilizing, harvesting and all other labors are greatly Necta and La Democracia in Huehuetenango, influenced by weather—as is, of course, quality. So, I think this Guatemala. A third-generation farmer, Solis has topic is always important for everybody to learn.” the privilege of running large and successful On Huixoc, at 130 hectares, farm management is no small operations blessed with abundant spring water. undertaking. The farm crosses a wide range of elevations, Even so, he has also observed climatic changes from 1,150 meters to nearly 1,700 meters, and in recent years it over the years. He is a conscientious coffee has experienced rather dramatic average high temperature caretaker, and it became apparent to him that increases. “During our rainy season, which lasts between five investment in climate technology throughout his and six months,” Solis explains, “there are ample conditions farms would provide his family, his farm and his for outbreaks, especially when temperatures rise and there is employees with security to continue growing enough humidity.” On Huixoc, rains begin as early as February, coffee into the future. usually peak in April, May and June, and can extend through His gathered climate data has been used August. These wet summertime conditions—warm and damp to help predict temperature and rainfall, and weather—are ripe for roya. contributed toward an impressive scientific Solis’s approach to containment must be clinical to be report led by Dr. Peter Baker at Climate Edge, a successful on a farm at his scale. U.K.-based firm that aims to empower farmers “We have implemented an integrated management system with predictive weather and temperature models. to manage [rust] and keep it below levels which would not Not long ago, Solis confided in me that affect our productivity too much,” he says. “We do careful Alejandro Solis, manager of his family’s farms, Finca Injertal and Finca Huixoc, in Huehuetenango, Guatemala. | Photo courtesy of Royal Coffee roasters “need to know what coffee farmers are CONTINUED ON PAGE 26 Coffee leaf rust in Guatemala. | Photo by Lily Kubota 24 July | August 2019 25 THE LASTING IMPACT of COFFEE LEAF RUST | CONTINUED monitoring every month. We regulate our shade trees in very moist areas. We try to provide the best nutrition possible, and we have replanted some specific areas where rust is more prevalent with rust-resistant varieties. We have also opened our row spacing in some areas. We also use fungicides to keep inoculum at low levels. If you let the rust level get too high, there is nothing you can do to stop it.” He elaborates, “After the rust outbreak in 2012–2013, we have seen how the rust fungus adapts to higher altitude and moist climates, where we have most of our coffee planted. We know we are never going to eradicate it.” That word “never” hangs in the air, thick like smoke. Coffee’s most recent rust crisis was an alarm bell for a fire that’s been smoldering for more than a century. Without a deep knowledge of rust’s history and behavior, and the preventive measures in which roasters can participate, I fear we’re just fanning the flames. Let’s take a deep look at the interaction between rust, coffee and ourselves as we prepare for the next steps into an uncertain future. GROUND ZERO On November 6, 1869, a three-paragraph report with three footnotes and an illustration ran in The Gardeners’ Chronicle and Agricultural Gazette. Written by Reverend M.J. Berkeley and his assistant C.E. Broome, the notice identified a newly described species on the island of Sri Lanka (called Ceylon at the time). It was not a coffee species, or even a plant, but a fungus. “We have recently Image courtesy of Missouri Botanical received from our Garden, Peter H. Raven Library excellent friend Mr. Thwaites a specimen of a minute fungus which has caused some consternation amongst the coffee planters in Ceylon, in consequence of the rapid progress it seems to be making amongst the coffee plants,” reads the first sentence (biodiversitylibrary.org/page/33107926). Berkeley and Broome proposed Hemileia vastatrix as its scientific name and classified it under the order of rust fungi. Somewhat coy in their description of “consternation,” the CONTINUED ON PAGE 28 26 July | August 2019 27 THE LASTING IMPACT of COFFEE LEAF RUST | Past, Present and Future in the Fight Against Fungus | CONTINUED pair buried the lede in the translation of the Dutch at the turn of the century, were Coffee leaf rust was impossible to circle of life by feeding on decomposing throughout Africa, the Middle East and Asia. coffee tree. Those trees lucky enough to the species name. The Latin word vastitas populating plantations at a fever pitch, contain in Sri Lanka. The fungus jumped matter found on the dead, rust fungi are The most obvious symptom of any survive typically lose the fruit from both the means “devastation.” establishing their first coffee farm in 1825. from island to mainland and back, on the not so easily satiated. The 8,000 identified rust infection is the presence of colorful infection season and that of the following Coffee leaf rust fungus had also been The boom and bust of Sri Lanka trade winds and on travelers, and utterly rust species are “obligate biotrophs,” which yellowish or reddish spores that cluster year. noticed a few years earlier in western coffee plantations is shocking both in its decimated coffee production throughout means they require a living host to survive. together; on a coffee leaf the circular The burnt orange blemishes, called Kenya, near Lake Victoria, sometime in magnitude and brevity. By 1840, just 15 the Eastern Hemisphere. Coffee leaf They are parasites. splotches are immediately recognizable, urediniospores, represent just one of 1861 per Talhinhas, et al., in their article years after the first plantings, coffee was rust spread throughout the Indian and Rust fungi are ancient, likely evolving like the curse of a fungal evil eye. The rust’s natural life stages. These spores are “The Coffee Leaf Rust Pathogen Hemileia the island’s leading export commodity. Pacific oceans, India and Indonesia, the around the same time as the first flowering affliction eventually causes the leaves clones, rapidly reproducing and infecting vastatrix: One and a half centuries around In 1873, exports peaked at over 111 million Philippine Islands (once fourth in global plants on Earth. Other than CLR, one of the to drop off the plant, incapacitating the CONTINUED ON PAGE 30 the tropics,” published in Molecular Plant pounds (more than 840,000 bags), enough arabica production behind Ceylon), and most familiar species, Puccinia graminis, Pathology in 2016. Many Ethiopian farmers to place it third in global production the Hawaiian Islands; even Bourbon trees known as “stem” or “black” rust, affects have been aware of its existence for years, volume at the time, trailing only the on Réunion Island were not spared. Sri wheat. without much noting significant problems stalwart Dutch colonial coffee mainstay Lanka’s coffee leaf rust outbreak would In ancient Mesopotamia, a sweeping it may have caused—likely the fortuitous of Java and 19th-century breakout super- pull the linchpin in an unprecedented epidemic decimated wheat crops around result of having abundant genetic producer Brazil (Kushalappa, Ajjamada, shift of arabica production to the Western 1300 B.C. Without the knowledge of diversity in their country’s montane C. & Albertus B. Eskes. Coffee Rust: Hemisphere in the span of less than 30 microorganisms, farmers called the disease forests. Epidemiology, Resistance, and Management. years. “red barley sickness” and had little option The monoculture coffee plantations CRC Press, Inc. (1989) 178). Yet by the late for respite other than prayers to the gods across the Arabian Sea, however, would 1890s, there would hardly be a tree left of harvest. Most scholars denote this as not be so lucky. On Sri Lanka, where on the teardrop of India, all dead—or KNOW YOUR ENEMY the first recorded rust outbreak in human farmers had little knowledge of the uprooted and replaced—because of rust history. disease or its treatment, the infection (Ukers, William Harrison. All About Coffee. Coffee leaf rust is a member of a vast In fifth-century southern Europe, rapidly spiraled out of control. The British, Tea and Coffee Trade Journal Company order of problematic fungi.

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