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Coffee home - From crop to cup - Coffee Plant Diseases

Coffee Plant Diseases



Coffee Plant Diseases
MAJOR DISEASES

HEMILEIA VASTATRIX; Leaf Rust:A fungus. Spores are very light and spread by winds or passing animals. Simply touching the diseased tree will attach spores the toucher and will flick spores into the atmosphere. Spores move from the ground up to the leaves during rain periods. Spores will also move up the plant from rain. Spores last a long time on the ground. An area affected by Hemileia Vastatrix may never recover.

This disease is temperature related. The spore gets on the leaf, germinates, and sucks nutrition out of the leaf. This turns the leaf brown, thus, the term leaf rust. At colder temperatures, the germination process is slow. At higher altitudes, the temperature and humidity is such that the spores germinate so slow that the leaf dies of natural causes before its life is sucked out of it. The plant then replenishes the leafs before the leaf dies of the disease.

Generally speaking, leaf rust affects arabica coffea and not robusta coffea. Leaf rust is prevalent in many areas around this world. This disease is similar to that which affects wheat, and has many different races.

A particular survivor plant, of arabica type was found on a plantation owners crop which was wiped out by this disease, but this particular plant wasn't affected. The owner was named Mr. Kent, and hence the name, Kent's coffea. This plant has been sent to India, East Africa and many other areas where Hemileia Vastatrix is a problem. It was found that Kent's coffea is resistant all but two of the varieties of Hemilea Vastatrix.

MYCENA FLAVIDA; American leaf spot: This is a fungus. The process which kills the plant is faster than leaf rust. Defoliation can be swift and sever. The particular disease is prevalent in the Americas. There are regions in Mexico, Guatemala, Costa rica, Colombia, and Brazil which whole plantations have been wiped out because of this disease. The spores will live indefinitely in the ground and make the area permanently troubled.

This disease will kill other crops as cacao and citrus. In general, it affects only the arabica variety and not the robusta variety.

The only effective method of control is choosing the correct environment. Perenox, Captan, and the concoction of 2 pounds of copper sulphate, 2 pounds of lime, in 40 gallons of water sprayed in a mist works to retard the disease.

COLLETOTRICHUM COFFEANUM; Coffee berry disease:This is a fungi belonging to the genus Colletotrichum and generally considered an active race to the above fungi. The difference is it tend only to attack the berries. And, it attacks at various times, such that it is believed to be caused something lacking in the environment.

Coffee berry disease attacks the green tissues at the beginning stage of berry development and often penetrating into the interior of the berry destroying the bean. It appears at the base berries then moves up the stalk. The berry will have brown patches which seem to have small punctures. Lesions form on the darker areas of the berry and in time the berry turns ash gray.

Coffee berry disease has caused sever losses in Kenya and the Congo. Varieties of coffea such as Jamaican Blue Mountain show inherited resistance to this disease.

Control of this disease is again by choosing the right environment. This disease is a cold temperature disease and may be avoided is the temperature never drops below 65 degrees fahrenheit. Perenox spray and other copper fungicides in four applications during the year tends to reduce the affects.

FUSARIUM XYLORIOIDES; Tracheomycosis wilt: This is a microbe disease which is in the soil and enters a low surface wound or a shallow root. The disease spreads up through the stem into the vascular strands. Symptoms are yellowing and collapse of the leaf.

This disease affects plants in dry warm soils of Africa's equatorial areas. It attacks robusta coffea and has wiped out 100,000 acres at a time.

Once this disease has been diagnosed, it is contained by fire. Pull the affected plant, the plants around the affected plant, water the ground to keep down dust, dig up about 3 feet deep of ground from all the area, take the whole pile somewhere else and burn it to fine ash, throw some gas on the dirty ash and burn it some more.

ROSELLINIA BUNODES; Collar-rot: This disease affects forest planted coffees. It is accompanied by fungus growth and internal discoloration of the roots. Its symptoms are wilting of the leaves.

The disease has attacked coffee all over the world. It will attack rubber tree too. It will also kill the shade trees Leucaena glavca. Apparently, Leucaena glavca seem to act as centers of infection.

To prevent this disease, one must properly prepare the soil. Remove any dead stumps and their roots. In area where trees are to be removed, it means ring-barking a year in advance in order that the dead tree's roots are exhausted of all nutrients. This disease is easier to prevent than to eradicate.

ARMILLARIA MELLEA; root rot: It is a widespread occurrence in the world. It attacks many orchard crops. It starts with dead or dying stumps and roots. It is a common saprophyte in forest soils and spread by the wind easily. Generally does not affect strong healthy plants but weak plants are susceptible and get it started. It then becomes aggressive.

It becomes a toadstool, rhizomorphs, which drives a strand of mycelium into the soil for a considerable distance.

Symptoms on the coffee plant are yellowing and wilting of the foliage followed by death. Symptoms on the ground are toadstool clusters of pale yellow.

To prevent this disease, one must properly prepare the soil. Remove any dead stumps and their roots. In area where trees are to be removed, it means ring-barking a year in advance in order that the dead tree's roots are exhausted of all nutrients. This disease is easier to prevent than to eradicate.

MINOR DISEASES

RHIZOCTONIA BATATICOLA or RHIZOCTONIA SOLANI; Damping-off disease: A faily common disease caused by over watering, over crowding, over shaded or sitting on continually damp ground. Generally occurs to seedlings soon after germination. Symptoms are the seedling collapses. A compound of 2 ounces of copper sulphate, 11 ounces of ammonium carbonate, in 26 gallons of water poured at the seedlings base.

RHIZOCTONIA LAMELLIFERA; Root disease: This is an ant and termite transported disease. It starts at the thinner roots and spreads to the base of old trees. Trees should be burnt and the soil deeply cultivated, in a year or so, the space may be replanted with some success. This is somewhat a mysterious disease. That is to say, plants mysteriously die and the generally have these insects around them.

Although, not a formal solution, kill the insects before they destroy the plant.

RHIZOCTONIA; Tip die-back: A sudden die-back progressing from the tip of the upright branches downwards. Dense shade and humid conditions are predisposing factors. Prune away affected tissues well beyond the diseased area and burn immediately.

CERATOSTOMELLA FIMBRIATA; Trunk and shoot canker: Affects arabica coffea much more than robusta. Generally believed to be a physical wound, possibly by insects, animals, or humans gnawing, cleaving, or scraping the trunk. The bark grows gnarly, develops cracks like being hacked with a machete.

All diseased parts should be cut and burnt. The remaining plant be treated with a 10 percent solution of formalin. Afterward, a paste made with copper sulphate and calcium carbide be applied to that affected areas.
Prevention by proper training of labor and proper animal and insect control.

HELICOBASIDIUM COMPACTUM; Root-collar disease: This disease occurs when coffee plants are growing near tea plants. It is believed to be a disease of Java, and the coffee plant is the host. Young trees wilt and die at the start of the dry season. In India it is known as violet root rot because of the mycelium which grows on the stem. Wet or alkaline soil predisposes the attack. The cure is to improve growing conditions, add acidity to the soil, and eliminate diseased material.

FOMES LAMAOENSIS; Brown root rot: It is a fungus said to be caused by FOMES NOXIUS. It is common in Mysore India, and is often attacks rubber trees too. It occurs in Java, Malaya, and the Philippines.

FOMES LIGNOSUS; White root rot: It is a fungus generally associated with rubber plants. However, it has been found in the Congo where there are no rubber plants. It is spotted when the root area has mycelium threads of yellowish-white.

XYLARIA THWAITESII; Black root rot: It also is a fungus spread from rubber trees.

Nutrient disorders: Like all plants, too much or too little of the right nutrient causes poisoning or starvation. Typical nutrients are nitrogen, phosphorous, potash, iron, and boron, etc. Numerous symptoms from yellowing of the leaves, whitening of the leaves, browning of the leaf, either the whole leaf or just at the tips. Some trace elements if totally devoid in the soil will also cause problems. The cure or prevention is proper fertilization.

Berry and leaf fall: Excessive shedding of berries and leaves if not caused by insects is caused by too alkali soil. Proper pH must be maintained by fertilization.

Die-back: The five general causes of a plant just dying off is either too hot or too cold, or not giving time for the plant to build up its strength before it bears fruit, or bad lighting or bad watering. These plants can be fried from the sun and get sun burn in a single day if for some reason the atmosphere does not filter the light right. For example, a bunch of years the humidity is high and there is light clouding, then one day the humidity drops to zip and there isn't a cloud in sight, wake up in the morning and a lot, if not all, the plants are gone. Let it drop below freezing and it is just that fast. Let the subsoil dry out real good and the plant starts to die right now too.

Virus Blister and ring spots have been known to be caused by various viruses. Generally, viruses are carried by insects, such that eradicating the insect, eradicates the virus. The coffee plant has a good immune system toward viruses and when the fresh source of viruses is removed, the plant recovers.

PEST DISEASES

The word pest covers mites, aphids, caterpillars, slugs, snails, beetles, flies, moths, butterflies, nematodes, bugs, rats, monkeys, grazers, and humans.

There are many more pests which will not be mentioned here. These are the worst. Some of these pests have been responsible for wiping out whole plantations.

DIARTHROTHRIPS COFFEAE; TAENIOTHRIPS XANTHOCEROS; Coffee thrips: These are small active insects usually found underneath the leaves. They suck the life out of the leaf so a symptom is dying leaves. The are sucker type insects that like dry draughty periods. Proper mulching which keeps the humidity up generally thwarts their appearance. A small amount of these pests can do a large amount of damage. An 18 percent strength solution sprayed on leaves from underneath tends to inhibit the thrips.

ANTESTIOPSIS LINEATICOLLIS; ANTESTIOPSIS FACETA; The variegated coffee bug: They feed voraciously by piercing the fruit and sucking the inner juices. They tend to feed on young green berries but will eat ripe berries. Symptoms are a good deal of berry shedding, or when the fruit is pulped, there is no bean or badly shaped beans. The bugs are so ferocious that two or three on a tree can wipe out the berries. When there are no berries, the adult insect will attack the buds, shoots and the leaves.

No amount of pruning will bring the trees back to normal until this bug is eradicated. 5 percent aldrin powder and a 6 percent solution of pyrethrum in 40 gallons of water sprayed on the tree then powdered will kill this bug. However, more troublesome bugs as leaf miners are usually present in areas antestopsis is, so killing leaf miners takes out these things too.

LEUCOPTERA; Leaf miner: This moth is the problem with insects affecting coffee plants. The larvae of the moths do the damage by tunnelling into the leaf and resides between two leaf surfaces. Hence the name 'miner.' Because it resides inside the plant, it is hard to kill.

Natural insect control by parasites has been accomplished in some areas. However, organo-phosphorus spays give sufficient penetration for control. Parathion, Methyl-Parathion, or Diazinon are some chemicals sprayed in low volume which do the job.

PLANOCOCCUS; FERRISIANA; Mealybugs: Mealybugs are generally kept under control of other parasites and larger animals. Birds, reptiles, and mammals all eat these things. But, from time to time, an ant colony starts to protect and propagate these bugs, in which case, they get out of control. They simply eat the plant.

Many countries promote the concept of banding the tree such that ants can't get into it. This seems to work. But killing the ants works to. Dieldrin or Chlordane into the soil does the job.

COCCUS; Green scale: This insect encourage a black sooty fungus to grow which kills the plant. This insect is spread and protected by ants. Banding the plant tends to control this insect, thus controlling the fungus. Dieldrin, Diazinion, Malathion, or Parathion sprayed on the plant kills the insect. Dieldrin or Chlordane into the soil kills the ants.

ASTEROLECANIUM COFFEAE; Star scale: This is a pest in Kenya. It is controlled by trunk banding with a brown tar oil solution. Diazion also kills this bug.

STEPHANODERS HAMPEI; Coffee berry borer: A minute beetle which is capable of immense damage as an adult and as larvae. A small dark brown, almost black beetle which bores into the fruit. Symptoms are small holes in the fruit and the fruit has discoloration. When the fruit is pulped, it has varying quantity of beans. It is a ground beetle which likes weedy areas. Generally, an infestation is caused by poor ground keeping. The beetle itself eats the berry and the larvae eats the berry.

Natural parasites may hold the pest in control. The best prevention is proper grounds care. Dieldrin sprayed twice during harvest tends to control the pest.

XYLOTRECHUS QUADRIPES; White stem borer: An insidious pest of older coffee trees. It is a beetle with long antennae curving over their back. They lay their eggs under the bark of the thicker main stems. The grubs, white colored, tunnel into the wood and progressively burrow their way around in the tree. Symptoms are small amounts of woody waste around small holes in the trees. Unfortunately, once deep inside the tree, the larvae are hard to kill. If not stopped early, this pest can kill whole areas of trees.

Dieldrin spray mixed with Methylene and blue dye is applied to the trunk and main stems of the tree with a brush to kill these best when outside the tree. This concoction should be applied once or twice a year, just before it rains. For plants that the larvae has already penetrated deep into it, there isn't much that can be done. Uproot and destroy the tree.

APATE; Black stem borers: These beetles like a single tree or small group of trees. The tend not to do extensive damage but can affect the small group of trees. This is a boring type beetle and to kill it, one pushes a think steel wire into the hole and stabs it. Generally found in Africa but have been seen in other areas.

BIXADUS SIERRICOLA; Stem borer: Another African beetle which generally is a sign of poor husbandry and unsuitable environment. This beetle generally resides in shade trees and attacks the coffee tree from them. Constant spraying with Dieldrin or several other type chemicals will control this pest.

XYLEBORUS; twig borers: These type of insects and other like it are generally small suckers. They can be controlled by proper pruning and spraying with Dieldrin or several other type chemicals.

HABROCHILLA; Lace wing coffee bug: Several species generally found in Africa. These bugs live off the leaf and suck the life out of the leaf. Found in Uganda and Kenya although have been know to frequent other areas. This pest is usually depressed by other insects, but when the other insects which do damage are killed off, these flourish. Malathion or Parathion controls these pests but applications must be made more often because these pests generate fast.

EUXOA; Cutworms: These are sluggish caterpillar like larvae which curl up just under the soil. Fat greenish or brownish crawlers which feed on young tender shoots near the ground. Easily controlled by a deep manure cover crop just before planting. Dusting the soil with Aldrin at regular intervals until young plant have gotten large and tougher.

THLIPTECERAS; VIRACHOLA: Moths and Butterflies: There are many types of moths and butterflies who's larvae attack the coffee plant. Generally speaking, these larvae are caterpillars. These buggers both eat the leaf and the berry. An infestation can be controlled with Diazinon.

MANY SPECIES; Flute-holing and shot-holing beetles: There are many of these pests which tend to flourish when their predatory feeders are killed off. These bugs larvae bore into the branches and lay eggs inside the plant on the bark. Constant spraying with Dieldrin, Malathion, Parathion, and Diazion is advise. So, this is the age old story, when the bigger pests are killed off, those of lesser known nature take over.

MANY SPECIES; Nematodes: Generally worms or worm-like pests which eat the roots of the plants. These are usually the result of killing off the higher order predators as birds and grubbing type animals by eradicating an insect with a poison.

Everything else: Many other minor pests from red spiders to weeds choking the plants can be a problem. It is the same with every crop; if there isn't one thing it's another.



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