Coffee

Description

Crop details

Scientific name: Coffea

Family: Coffea

Genus: Coffea

Local names: Kahawa (Swahili)

Other names:

Spanish: café

French: café

German: Kaffee

Italian: caffè

Portuguese: café

Dutch: koffie

Swedish: kaffe

Norwegian: kaffe

Danish: kaffe

Finnish: kahvi

Russian: кофе (kofe)

Arabic: قهوة (qahwah)

Turkish: kahve

Japanese: コーヒー (kōhī)

Chinese: 咖啡 (kāfēi)

Korean: 커피 (keopi)

General Information

Coffee is grown in over 60 countries in the world, with the majority of the crop being produced in Brazil, Vietnam, Colombia, Indonesia, and Ethiopia. Other major African coffee-producing countries include Uganda, Ivory Coast, Tanzania, and Kenya, with the crop serving as a significant source of income for many farmers and an export commodity for many countries.

The coffee plant has a woody perennial evergreen shrub or small tree that can grow up to 30 feet (9 meters) tall in the wild, although it is usually pruned to a height of 6–10 feet (1.8–3 meters) to make it easier to manage for cultivation. The plant has a straight trunk, elliptical leaves, and small, fragrant white flowers that bloom in clusters. After the flowers are pollinated, the fruit, known as a coffee cherry, develops. Each cherry usually contains two seeds, which are the coffee beans that are harvested and roasted to make the coffee beverage. It takes 2 to 3 years for a coffee plant to mature and start producing berries, and it can continue to produce coffee berries for up to 25 years under good conditions.




Coffee Varieties

The two main coffee varieties are Arabica (Coffea arabica) and Robusta (Coffea canephora).

Arabica is the most widely consumed and accounts for approximately 60% of the world's coffee production. Arabica coffee is grown at high altitudes, typically above 2,000 feet (600 meters) above sea level, and is known for its delicate and complex flavor profile. Its berries have a smoother, sweeter taste, with notes of fruit, berries, chocolate, and nuts. They also have a lower caffeine content compared to robusta beans, which makes them a popular choice among coffee enthusiasts.

On the other hand, robusta coffee beans are known for their strong and bitter taste, higher caffeine content, and lower acidity. The plants can grow at lower altitudes, typically between 900 and 1200 feet above sea level, and are generally more disease-resistant and easier to cultivate compared to arabica. It has a shallow root system and grows as a shrub tree to almost 10 meters tall and has evenly distributed flowers. It takes 10 to 11 meters for the cherries to ripen, though this ripening is determined by the rainfall distribution. Robusta beans are commonly used in espresso blends and instant coffees due to their strong flavor profile and affordability.

In Uganda, a number of varieties have been developed by the National Agricultural Research Organization (NARO), and close to 10 varieties of coffee that are high-yielding and resistant to coffee wilt have been released. These run from KR1 to KR10 (KR is an abbreviation for Kituza Robusta).

Other coffee varieties include:

  • Liberica: A coffee variety that is grown primarily in West Africa and Southeast Asia. Liberica beans have a unique flavor profile that is often described as smoky and woody with a floral aftertaste. They are known for their large size and irregular shape.
  • Excelsa: A coffee variety that is grown primarily in Southeast Asia. Excelsa beans have a tart and fruity flavor with hints of dark
  • chocolate and a floral aroma. They are often used to add complexity to coffee blends.
  • Maragogype: A coffee variety that is grown primarily in Central and South America. Maragogype beans are very large and have a distinctive flavor that is often described as mild and nutty.
  • Catuai: A hybrid coffee variety that is a cross between Caturra and Mundo Novo. Catuai beans are grown primarily in Central and South America and are known for their high yield and balanced flavor profile.
  • Bourbon: A coffee variety that is grown primarily in Central and South America and Africa. Bourbon beans have a sweet and fruity flavor with a bright acidity and are often used in specialty coffee blends.

These are just a few examples of the many different coffee varieties that exist. Each variety has its own unique flavor profile and characteristics, and they are often used in different ways in the coffee industry.




Uses

Coffee has a variety of uses beyond being a popular beverage. It is often used as an ingredient in cooking and baking, adding a rich and complex flavor to dishes. Coffee is also commonly used in the production of chocolate and is a key ingredient in espresso-based drinks like lattes and cappuccinos. In addition to its culinary uses, coffee has non-culinary uses as well. For example, coffee grounds can be used as a natural exfoliant in beauty products or as a deodorizer in the home. The caffeine in coffee is also used in some medications and cosmetics, as it has stimulating properties. Furthermore, coffee has been shown to have a variety of health benefits, including improving cognitive function and reducing the risk of certain diseases. Overall, coffee is a versatile and valuable commodity that has a range of uses beyond just being a beverage.




Climatic, soil, and water conditions

Growing coffee requires specific climatic, soil, and water conditions. It is a tropical crop that thrives in areas with warm temperatures, abundant rainfall, and well-drained soil. The ideal temperature range for coffee growth is between 60-70°F (15-24°C). Heat stress can be caused by temperatures above 86 °F (30 °C), while temperatures below 50 °F (10 °C) can damage the coffee cherries. In terms of rainfall, coffee plants require a lot of water but also need well-drained soil to prevent root rot. The ideal rainfall range for coffee growth is between 1200mm and 1800mm, well distributed over a period of nine months, with consistent rainfall throughout the growing season.

The soil type and quality are also important factors in coffee production. Coffee plants require nutrient-rich soil with good drainage, a slightly acidic pH level (between 5.5 and 6.5), and good aeration. The soil should also be deep enough to allow the roots to penetrate and access water and nutrients. Additionally, coffee plants grow best in areas with high levels of organic matter, which can be provided through the use of compost or other organic fertilizers.

Water is also a critical factor in coffee production. Coffee plants require consistent access to water throughout the growing season, with frequent watering during dry spells. However, the soil must also be well-drained to prevent waterlogging, which can cause root rot and other diseases. In some areas, irrigation systems may be necessary to ensure that the plants receive adequate water.

Overall, the climatic, soil, and water conditions for growing coffee must be carefully managed to ensure a successful harvest and high-quality cherries.




Planting Procedure

The coffee planting procedure typically involves the following steps:

Land preparation: The land must be cleared of any existing vegetation, rocks, and other debris. The soil should then be tilled to a depth of at least 30 cm to loosen and aerate it.

Selection of seedlings: High-quality coffee seedlings should be selected from a reputable nursery or developed from seeds. Seedlings should be healthy, disease-free, and at least six months old.

Digging of holes: Holes should be dug at least 60 cm (2 feet) deep and 60 cm (2 feet) wide enough to accommodate the root ball of the seedling. The holes should be 3 meters apart.

Planting of seedlings: The seedlings should be carefully placed in the center of the hole. The soil in the hole should be uniformly mixed with well decomposed manure to boost growth and root establishment. Pest and disease-free seedlings should be selected.

Mulching:  This is the covering of topsoil between the coffee trees. A layer of organic mulch, such as dry leaves or grass, coffee husks, composted manure, maize stalks, and rice stalks, should be applied around the base of the seedling to help retain moisture and suppress weed growth. Mulching regulates soil moisture, controls soil erosion, and helps retain water.

Watering: The newly planted seedlings should be watered immediately and regularly to ensure that the soil remains moist but not waterlogged. In dry spells or when the rains aren't regular, water bottle irrigation should be used, as this is the cheapest of all.

Pruning:  At a later stage, when the plant has grown, pruning should be done to remove any weak, dead, unproductive, diseased, and broken branches and promote the growth of a strong central stem. Pruning reduces competition for nutrients and sunlight on the stem or plant and removes unproductive parts to help the plant grow vigorously. It should be carried out at the end of the harvesting season, just before flowering takes place.

Fertilization: Regular fertilization is necessary to provide the coffee plants with the nutrients they need to grow and produce high-quality cherries.

Pest and disease control: Pests and diseases lead to reduced production, reduced quality, and losses to the farmer. Some of the pests include the Coffee Twin borer (BCTB), Coffee Berry Borer (CBB), Coffee Mealyburg, Coffee Leaf Miner, Coffee Leaf Skeletonizer, tailed caterpillars and Tailed Ant. Some of the Disease of Coffee include, Coffee Wilt Disease also known as "Fusarium wilt" or "Tracheomycosis spp" (CWD), Coffee Leafrust , Red blister (Cercospora caffeicola) and Root rot or Collar Crack Disease (Armillaria mella). Pests and diseases can be managed to reduce the rate of infection by doing different practices, consulting government extension officers, PlantVillage field extension officers, or seeking knowledge through the PlantVillage Nuru application, which can be downloaded for free from the Google Playstore.

Other maintenance practices: Coffee plants require regular maintenance, including pest and disease control weeding, planting shade trees around the garden, planting cover crops within the plantation, irrigation, and thinning to ensure healthy growth and optimal yields.

The specific planting procedures may vary depending on the location, climate, and soil conditions, but the above steps provide a general overview of the process.




Harvesting

Coffee is typically harvested by hand, which involves picking the ripe coffee cherries from the coffee plants. This can be accomplished through the use of either selective or strip-picking methods.

Selective picking: involves going through the coffee fields and picking only the ripe coffee cherries. This is typically done in several phases, as the coffee cherries do not all ripen at the same time. The picker will gently pull the ripe cherry from the tree, taking care not to damage the surrounding branches or unripe cherries.

Strip picking: Also known as "milking," this is the complete removal of all the berries from the coffee tree at once. It can be done manually with hands or with machinery that shakes the tree and knocks off all of the cherries. However, strip picking is discouraged since it involves mixing mature and ripe cherries with immature and unripe ones, leading to ununiform drying and eventually reducing the taste and quality of the final product.

After harvesting, the coffee cherries are processed to remove the outer layers and reveal the coffee cherries inside. There are two main processing methods, which are dry processing and wet processing.

  1. Dry processing: This is the drying of harvested coffee cherries under the sun. Solar dryers, cement floors, tarpaulins, and raised tables are used. In Uganda, for example, this process takes 2–4 weeks, depending on the weather conditions. The dried coffee is now called "kiboko," and it should be free of dust, mold, and a bad smell with a recommended moisture content of 13–14% before being taken to the milling machine. At the machine, the outer cover is removed from the inner beans. The outer cover is now coffee husks, and the dried beans are now called "clean coffee" or "FAQ," which means fair to average quality. This is then graded to different screen sizes and packed for storage, export, or value addition.
  2. Wet Processing: Coffee processed using this method usually fetches high prices because it's of a higher quality than the one under dry harvesting; however, this process is more complicated and requires specific tools to run it. The processing can be a full wash or a semi-wash. In a full wash, the skin of the freshly harvested berries is removed either manually or using a pulling machine with the addition of water. Mucilage (the sugary coating) is fermented for 2–3 days, and the parchment is washed to remove all the fermented mucilage. The parchment is dried to attain the recommended 12–13% moisture content. To dry 1 kg of fresh berries, 5 to 10 liters of water are required, as well as good management in washing and fermenting to ensure that the flavor is not lost in the process. In a semi-wash, the fresh skin is physically removed using a pulling machine with the addition of water to avoid damaging the fabric. The mucin is then immediately removed with a mucin machine. No fermentation is done here. Once the mucilage is removed, the berries are now ready for drying to attain a moisture content of 12 to 13%. This process is faster than the full wash and uses less water—usually 0.5 to 1 liter for 1 kg of fresh cherries. However, it is not commonly used since a lot of expensive machines are used. It usually takes 7–12 days to dry the parchment coffee. This must be properly dried to avoid the growth of mold, rotting, and aflatoxins. Usually, farmers under this system use raised wire meshes under a shade to avoid direct sunlight from cracking the beans. 12–13% moisture content should be maintained, and the coffee shouldn't be put in bare grounds or dirty environments.



References

Bittenbender, H. C. & Smith, V. E. (2008). Growing Coffee in Hawaii. College of Tropical Agriculture and Human Resources, University of Hawai'i at Mãnoa. Available at: http://www.ctahr.hawaii.edu/oc/freepubs/pdf/coffee08.pdf. [Accessed 13 February 23]. Free to access

CABI Crop Protection Compendium. (2008). Coffea datasheet. Available at: http://www.cabi.org/cpc/datasheet/14791. [Accessed 13 February 23]. Paid subscription required.

DE Foundation. Manual for Sustainable Coffee Production. Available at: http://www.defoundation.org/assets/Uploads/Uganda-Full-Coffee-Manual-DEF-PLAN.pdf. [Accessed 13 February 23]. Paid subscription required.

Kuit, M., Jansen, D. M. & VanThiet, N. (2004). Manual for Arabica Cultivation. Tan Lam Agricultural Product Joint Stock Company & Improvement of Coffee Quality and Sustainability of Coffee Production in Vietnam. Available at:




Common Pests and Diseases

Diseases

Category : Bacterial

Bacterial blight Pseudomonas syringae

Symptoms
Water-soaked spots on leaves which dry out and become brown and necrotic with yellow halos; necrosis of shoot tips which spreads rapidly down branches; leaves turn black and die off but remain attached to tree
Cause
Bacterium
Comments
Disease can be spread long distance by the movement of infected seedlings or within the field by water splash; bacteria can enter the plant through wounds
Management
Protective sprays of copper should be applied to the plants just before the onset of the rainy season and should be continued right through to the short rains

Category :

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Berry Blister

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Coffee Rust Leaf

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Coffee Rust Leaf (underside)

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Coffee Rust Symptom

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Coffee Rust Symptom (underside)

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Healthy Berry

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Healthy Coffee Berry

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Healthy Leaf

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Healthy Leaf (underside)

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Other

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Rust Leaf (topside)

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Rust Leaf (underside)

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Rust Symptom (topside)

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Rust Symptom (underside)

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Unknown

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Category : Fungal

Cercospora leaf spot (Brown eye spot, Berry blotch) Cercospora coffeicola

Symptoms
Brown spots on foliage which enlarge and develop gray-white center and a red-brown margin; lesions may also be surrounded by a yellow halo or may have a burned appearance if lesions are very numerous; infected leaves may drop from plant prematurely; lesions on green berries are brown and sunken and may have a purplish halo; infected red berries may have large black sunken areas
Cause
Fungus
Comments
Disease can be spread by wind, water-splash and through human movement through fields, particularly when plants are wet
Management
Ensure crop is adequately fertilized as nutrient deficient plants are more susceptible to the disease; remove all crop debris from filed after pruning to prevent build up of inoculum; good plant spacing and pruning to open up the canopy promotes good air circulation around foliage and protects against disease; if disease does occur then it can be controlled with the use of copper fungicides where available

Coffee berry disease (CBD) Colletotrichum kahawae

Symptoms
Dark sunken lesions on green berries; berries dropping from plant; mummified berries
Cause
Fungus
Comments
Very serious diseases; can destroy up to 80% of crop
Management
Protective sprays of copper containing fungicides can help to control the disease; any diseased berries should be removed from plants; resistant varieties are available and should be planted in areas where disease is present

Coffee leaf rust Hemileia vastatrix

Symptoms
Small, pale yellow spots on upper leaf surfaces followed by powdery orange-yellow lesions on the undersides of leaves; symptoms commonly develop on lower leaves of plant first and then spread; infected leaves drop from the plant and twigs and branches become defoliated
Cause
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History Origins and spread Coffee originates from high altitude regions of Ethiopia, Sudan and Kenya and the rust pathogen is believed to have originated from the same mountains. The earliest reports of the disease hail from the 1860s. It was reported first by a British explorer from regions of Kenya around Lake Victoria in 1861 from where it is believed to have spread to Asia and the Americas. Rust was first reported in the major coffee growing regions of Sri Lanka (then called Ceylon) in 1867 and the causal fungus was first fully described by the English mycologist Michael Joseph Berkeley and his collaborator Christopher Edmund Broome after an analysis of specimens of a “coffee leaf disease” collected by George H.K. Thwaites in Ceylon. Berkeley and Broome named the fungus Hemileia vastatrix, Hemileia referring to the half smooth characteristic of the spores and vastatrix for the devastating nature of the disease. It is unknown exactly how the rust reached Ceylon from Ethiopia but over the years that followed, the disease was recorded in India in 1870, Sumatra in 1876, Java in 1878, and the Philippines in 1889. During 1913 it crossed the African continent from Kenya to the Congo, where it was found in 1918, before spreading to West Africa, the Ivory Coast (1954), Liberia (1955), Nigeria (1962-63) and Angola (1966). The collapse of the coffee industry in Ceylon In the nineteenth century, Ceylon was one of the largest coffee producing regions in the world, responsible for the export of approximately 42 million kilos of coffee per year. In the 28 years following the arrival of rust, export ceased and production was reduced to less than 3 kg/year. It wasn’t until 1879 that the government of Ceylon set up a commission to investigate the crisis and the British government sent Harry Marshall Ward to the plantations. Ward’s work on the coffee rust fungus would establish him as one of the most important figures in the field of plant pathology. Ward was able to link the collapse of the coffee crop to the Hemileia vastatrix fungus and, identify characteristics of both the fungal spore and agricultural practices that caused such a catastrophic loss. Unfortunately the investigation came too late and the rust epidemic was too far advanced. Ward could do little other than document the complete collapse of the coffee crop, as has been recounted in many histories of the disease (Large, 1940, Carefoot and Sprott 1967, Money 2007). Ward’s observations however, would provide the crucial basis for the development of future control strategies, discussed below. Biology and ecology of coffee rust The collapse of the Sri Lankan coffee industry and Ward’s investigation of the agricultural practices being employed highlighted the problems created by planting coffee at such high densities. The proximity of the plants to one another created optimal conditions for rust transmission over short distances while the reduced genetic diversity resulting from the practice of monoculture meant that once the rust pathogen broke down the inherent host resistance, little could be done to prevent its spread. The pathogen, Hemileia vastatrix, evolved within the forest and adapted to the widely dispersed nature of the wild host by producing highly mobile spores that are capable of travelling large distances via wind currents, water splash and on the bodies of insects. The practice of removing native trees to plant coffee side by side, removed a natural barrier to the movement of the rust spores and helped compound the catastrophic crop losses witnessed in Ceylon. Rust transmission and infection Coffee leaf rust is an obligate parasite and is transmitted when urediniospores (spores produced from the brown-red rust pustules) disperse from one part of the plant to another, or to a new, uninfected plant. The spores are produced on the underside of the leaf from uredinia which make up part of the red/orange pustules on the undersides of the leaves. When the spores erupt, they enter the air current where they can travel a few centimeters to the next leaf, or hundreds of kilometers to another site (spores have been recorded travelling 1,000 m up in the high altitude air streams). The spores are also known to travel over shorter distances by rain-splash, which is a common way for plant pathogens to travel from leaf to leaf of the same tree. There are also documented cases of spores being transported to new sites by small insects such as Thrips and parasitoid wasps. When the spores reach a leaf, they attach to the surface using the spines on their rough side. In order for the spores to germinate, they require the presence of liquid water on the leaves and a temperature of 17 to 25°C (62.6 to 77°F), with 22°C (71.6°F) being optimal. Heavy rains can wash the spores from the leaves and prevent infection occurring. When conditions are favorable, the spores produce a long tubes known as germ tubes which move over the leaf searching for a stomata (tiny openings in the leaf surface where plants breathe and release water). The germ tubes produce appressoria (flattened fungal structures that produce ‘pegs’ to puncture through host tissues) on, or close to the stomata, from which infection hyphae grow and puncture the host cells. The entire infection process is completed in 24 to 48 hours and new urediniospores erupt from the stomatal openings after 10 to 14 days. One rust lesion will produce 4–6 spore crops over a 3–5 month period releasing 300–400,000 spores into the environment to repeat the process. The 2012 Coffee leaf rust epidemic In 2012 there was a major increase in coffee rust across ten Latin American and Caribbean countries. The disease became an epidemic and the resulting crop losses pushed coffee prices to an all time high amid concerns for supply. The reasons for the epidemic remain unclear but an emergency rust summit meeting in Guatemala in April 2013 compiled a long list of shortcomings. These included a lack of resources to control the rust, the dismissal of early warning signs, ineffective fungicide application techniques, lack of training, poor infrastructure and conflicting advice. In a keynote talk at the “Let’s Talk Roya” meeting (El Salvador, November 4th 2013), Dr Peter Baker, a senior scientist at CAB International, raised several key points regarding the epidemic including the proportional lack of investment in research and development in such a high value industry and the lack of investment in new varieties in key coffee producing countries such as Colombia.
Management
Resistant varieties Commercially grown coffee has, through the practice of monocultures, lost much of the genetic diversity of its wild ancestors. Sadly, due to the effects of deforestation, wild coffee has also lost much of its genetic diversity outside of its evolutionary center in Ethiopia. The breeding of crop varieties which are resistant to key pathogens has proven to be a very successful method of controlling diseases and inIn the late 1950s, a natural coffee hybrid was discovered growing wild in East Timor. The plant was found to be a hybrid of C. arabica and C. canephora and was named Hibrído de Timor (HDT). The plant was found to possess full or partial resistance to all known races of the rust pathogen and five genes were subsequently elucidated from the hybrid and from other coffee varieties that were responsible for conferring the resistance Varieties expressing some of these genes have been grown commercially but the the resistance was broken-down after a few years when new virulent races of the rust pathogen emerged. Crosses of the hybrid with other commercial cultivars produced the ‘Colombia’ cultivar which is now widely planted. Colombia managed to reduce its losses during the 2012/13 epidemic because of new plantings. Many Colombian farmers are now replanting with Castillo or Colombia varieties. Fungicides Copper-containing fungicides Copper-containing fungicides remain one of the most effective and economical methods of controlling the rust pathogen in susceptible coffee varieties and during conditions which are favorable to the development of rust. They have the added advantage of being active against a number of other fungal pathogens and have also been shown to increase coffee yields. Examples of copper-containg fungicides used in coffee include copper oxychloride and cuprous oxide which have largely replaced the use of Bordeaux mixture in most commercial plantations. These chemicals are applied protectively with plants being sprayed in advance of infection and work by adhering to the plant and producing a toxic barrier to invading fungal pathogens. They pose limitations due to their need to be reapplied at regular intervals to protect new growth flushes and also pose environmental concerns over the accumulation of copper to toxic levels in the soil. Copper-containing fungicides can be alternated with systemic fungicides to reduce the amount of copper build-up. Systemic fungicides Systemic fungicides used in coffee include pyracarbolids such as triadimefon and propiconazole and strobilurins such as azoxystrobin. Systemic fungicides are transported around the plant in the vascular tissue after application thus requiring lower doses and less frequent application than copper-based fungicides. They can be applied after infection has occurred to treat the symptoms of the disease and eradicate it from the host plant. Systemic fungicides tend to be more expensive and some have been shown to induce severe defoliation of the coffee plant. They have been shown to be very effective at controlling rust when used in combination with copper-containing fungicides. Organic fungicides Only one organic fungicide is widely used in coffee - triadimefon. Triadimefon is a systemic fungicide which is applied to the foliage and works to inhibit the rust infection. It can be alternated or combined with other chemicals and is generally very effective at controlling rust infections. Organically certified control methods Most commercially grown coffee varieties are susceptible to coffee rust fungus and because organic farmers cannot use chemical approaches controlling the rust is extremely hard. (note that in some growing regions copper based fungicides are allowed). Here we discuss a few methods and we encourage others to share knowledge by emailing PlantVillage or answering questions on the forum. i) Planting spore traps. The fungal spore has a rough side that attaches to plant tissue. Wind-break trees can be used to reduce the spore load. Organic coffee is often grown using shade trees which may act to reduce inoculum reaching the coffee plants. ii) Spraying organic formulations that impacts the ability of the spore to germinate or of new spores to be produced. We have heard that some farmers had success with this strategy but we do not know the details. Dr Peter Baker of CABI has reported to us that some farmers are using lime sulphur because of the expense of copper. We will try and find more information. Please contact PlantVillage if you have information. iii) Spraying water. It is feasible that high pressure water can wash the spores from the leaves and reduce the spore load. Heavy rains may also have the same effect. As humidity on the leaves actually promotes fungal growth then washing is best done when the water is likely to evaporate. Biological control Concepts Biological control is the use of one living organism to control another living organism that is considered a pest species. In addition to breeding new and better genetic material and the use of good crop husbandry, the development of an effective biological control strategy could provide another tool to manage coffee rust which would allow for organic certification and the continued use of heirloom varieties. If a suitable agent(s) can be identified in the short term, then this approach would be available in significantly less time than that needed to develop a new variety. CBC of fungi exploits the ability of coevolved fungal natural enemies in order to produce massive quantities of inoculum on the host plant and allow them to spread and propagate continuously within the host population. It offers a sustainable control method but has and has, surprisingly, never been used for crop pathogens (diseases). The concept is simple and follows the enemy-release hypothesis whereby an exotic or alien species increases its fitness, and hence its invasiveness, because it arrives without its guild of co-evolved natural enemies. Examples i) Bacteria Bacteria such as Bacillus and Pseudomonas are known to produce compounds that negatively affect fungal pathogens of plants. Such bacteria evolved in the soil and utilize antifungal compounds to compete with soil dwelling fungi. A number of studies have shown how coffee rust development in greenhouse settings or in the lab can be retarded by Bacillus and Pseudomonas. For example, a study by Haddad et al, 2009 showed for the first time that certain strains of< i>Bacillus and Pseudomonas reduced coffee rust on organic farms in Brazil. In follow up work the same team (Haddad et al 2014) found 17 different bacterial isolates collected from leaves, leaf debris, and soil reduced both the infection frequency and the number of H. vastatrix urediniospores produced per leaf by more than 70%. ii) Other fungi White halo fungus, Lecanicillium lecanii, has been suggested as a potential biological control agent of coffee rust by Prof. John Vandermeer and collaborators at the University of Michigan (Vandermeer et al 2009). White halo fungus has been shown to be hyperparasitic on Hemileia vastatrix in laboratory conditions and it has also been observed attacking the fungus in the field. White halo fungus often infects green coffee scale which feed on coffee. These insects are frequently tended by ants which collect the sugar that they excrete. The ants often create clusters of scale insects on the plants which are infected with white halo disease. It is postulated that white halo fungus may attack and kill the coffee leaf rust fungus or may simply reduce its abundance due to crowding effects or produce chemicals to attack it. Currently, the fungus does not appear be a viable biological control agent because it has not evolved to parasitize the fungi, rather it evolved to infect insects. Promising attempts have been made to culture the fungus and apply it as a topical spray to control the rust fungus. Future prospects Currently, no CBC program has focused explicitly on controlling coffee rust but pathogenic rusts have themselves been used to control other pests. For example, rubber vine is considered to be a major pest plant in Australia as it is highly invasive and causes millions of dollars of damage to agriculture and massive ecological damage. A team led by Dr. Harry Evans, a scientific officer with CAB International, identified a rust called Maravalia (which is taxonomically close to coffee rust) in the center of genetic origin for rubber vine in Madagascar which showed potential for use as a CBC agent. Before the rust could be released in the environment in Australia, it had to be quarantined. This process removed the rust from its natural enemies and had the effect of making the rust fungus extremely pathogenic. Dr. Evan’s stated that the rust went ‘berserk’ and when it was eventually deployed in Australia, it was extremely successful at controlling the rubber vine, even killing off young seedlings. In 2014, another team led by Dr. Evans and Dr. Roberto Barretto of the Federal University of Vicosa in Brazil will begin to explore genetic centers of origin of Arabica coffee with the aim of identifying similar co-evolved natural enemies of Hemileia vastatrix. It is believed that CBC holds great promise for the future control of coffee rust.

Category : Other

Coffee Red Blister

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Pests

Category : Insects

Black twig borer Xylosandrus compactus

Symptoms
Wilting and yellowing of foliage, often at end of twigs and branches (termed "flagging"); o pin sized hole can often be found on the underside of the flagging stems or twigs where the insect has entered the plant; twigs and stems are hollowed out and can be seen by cutting open the affected tissue; the adult beetle is small and black, approx. 2 mm in length and is rarely seen; eggs and pupae are creamy white in color
Cause
Insect
Comments
Damage caused by the beetles promotes secondary infestation by bacteria and other fungi; adult beetles overwinter in the plant
Management
Prune out infested twigs and stems and destroy; flagging branches should be pruned back a few inches from the beginning of symptomatic areas; adequate fertilizer and irrigation to ensure vigorous plants can speed recovery from pruning injury

Coffee berry borer Hypothenemus hampei

Symptoms
Fruit dropping from plants; small holes may be evident on red cherries; when the insect is feeding, debris is pushed out of the hole and forms a brown or grey deposit on top of the hole; adult beetle can be found by cutting open the berry; adult is a tiny black beetle approx. 1.5-2.5 mm in length; larvae are white grubs with brown heads
Cause
Insect
Comments
Female beetle lays clusters of eggs inside the berries; insect undergoes up to 5 generations per year
Management
Removal of dropped berries and debris on plantation floor can help reduce sources of new infections; remove any berries remaining on plants after harvest; insecticide application is only effective if applied when the female beetle is still in the entry tunnel and has not yet penetrated deep into the berry
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