Coffee wilt disease still a threat to farmers
SCIENTISTS and researchers recently warned that if the Government does not embark on coffee research, in 15 to 20 years to come, the country will have no coffee because the Coffee Wilt Disease (<i>Tracheomycosis</i>) is wiping out many coffee trees especially Robusta coffee.
By Paul Tentena
SCIENTISTS and researchers recently warned that if the Government does not embark on coffee research, in 15 to 20 years to come, the country will have no coffee because the Coffee Wilt Disease (Tracheomycosis) is wiping out many coffee trees especially Robusta coffee. Arabica coffee is also affected.
Coffee Wilt Disease (CWD) Tracheomycosis
According to Frederick Sewaya, the Principal Research Officer with Uganda Coffee Development Authority (UCDA), the CWD is caused by fusarium xylarioides fungus.
He says: “The fungus attacks the vascular system of the coffee plant, causing blockage of water and nutrient transportation from roots to other parts of the plant.
It causes wilting and eventual death of the affected plant.â€
The disease was first reported in the Democratic Republic of Congo in the 1950s and more recently in the Beni region of the Eastern DRC in 1988.
In Uganda, CWD was first reported in 1993 in Bundibugyo district.
What are the symptoms?
Small brown lesions appear on the young leaves still in the apical bud. The lesions are usually marginal and the necrotic areas do not grow with the rest of the leaf, resulting in the uneven growth and leaf deformation. The affected branches usually have shortened internodes.
Disease detection
Sewaya says the affected coffee tree may start by yellowing and curling of the leaves. With a multi-stemmed coffee plant, stems die in sequence until the whole plant completely dries up.
“When the bark of the affected tree is peeled off, black, brown or violet streaks or bands are seen on the wood underneath. At advanced stages, cracks or cankers usually occur around the collar region of the stems of the affected plant,†Sewaya observes.
Coffee berries ripen prematurely, dry up, but remain attached to the primary branches. The plant remains firm in the ground.
Sewaya says the infected plants do not recover even after pruning or stumping.
Transmission and spread
Erostus Nsubuga, the chairman National Crop Resource Research Institute (NacRRI), fusarium xylarioides is soil borne. Its spores enter the plant tissue through cracks on the stems (collar region) and the root system.
“The disease is spread by wind, running water, movement of infected soil or planting material, movement and use of infected coffee husks (as mulch) and dried plants (as firewood) and use of unsterilised garden tools.â€
Disease control
NacRRI chairman says introduction of overhead shade and windbreakers reduces the incidence of crinkle leaf.
Control measures currently in use aim at reducing disease spread and destruction of innoculum.
Nsubuga advocates for regular field inspections to identify trees infected with CWD. The infected ones should be chopped, uprooted and the whole plant burnt.
Tips to farmers
A coffee tree usually has two or three branches. If one branch is infected, uproot and burn the whole tree even if the other branches have not shown the symptoms.
Coffee branches that dry due to CWD should not be used for firewood because the tools used in cutting down the branches and the act of relocation would aid in the spread of the disease from the field to other plantations.
A coffee field that has been infected by CWD should not be replanted with coffee for at least three years.
Do not use coffee husks from infected berries for mulching coffee gardens.
Spray infected coffee with carbolineum mixture to kill off the plant and the fungal spores, then uproot and burn the already dried coffee.
Do not harvest berries from infected coffee trees. Such berries should be destroyed.
However, scientists and researchers in Kituuza, Mukono district are believed to have developed 25 lines of coffee tree resistant to the CWD.
SCIENTISTS and researchers recently warned that if the Government does not embark on coffee research, in 15 to 20 years to come, the country will have no coffee because the Coffee Wilt Disease (Tracheomycosis) is wiping out many coffee trees especially Robusta coffee. Arabica coffee is also affected.
Coffee Wilt Disease (CWD) Tracheomycosis
According to Frederick Sewaya, the Principal Research Officer with Uganda Coffee Development Authority (UCDA), the CWD is caused by fusarium xylarioides fungus.
He says: “The fungus attacks the vascular system of the coffee plant, causing blockage of water and nutrient transportation from roots to other parts of the plant.
It causes wilting and eventual death of the affected plant.â€
The disease was first reported in the Democratic Republic of Congo in the 1950s and more recently in the Beni region of the Eastern DRC in 1988.
In Uganda, CWD was first reported in 1993 in Bundibugyo district.
What are the symptoms?
Small brown lesions appear on the young leaves still in the apical bud. The lesions are usually marginal and the necrotic areas do not grow with the rest of the leaf, resulting in the uneven growth and leaf deformation. The affected branches usually have shortened internodes.
Disease detection
Sewaya says the affected coffee tree may start by yellowing and curling of the leaves. With a multi-stemmed coffee plant, stems die in sequence until the whole plant completely dries up.
“When the bark of the affected tree is peeled off, black, brown or violet streaks or bands are seen on the wood underneath. At advanced stages, cracks or cankers usually occur around the collar region of the stems of the affected plant,†Sewaya observes.
Coffee berries ripen prematurely, dry up, but remain attached to the primary branches. The plant remains firm in the ground.
Sewaya says the infected plants do not recover even after pruning or stumping.
Transmission and spread
Erostus Nsubuga, the chairman National Crop Resource Research Institute (NacRRI), fusarium xylarioides is soil borne. Its spores enter the plant tissue through cracks on the stems (collar region) and the root system.
“The disease is spread by wind, running water, movement of infected soil or planting material, movement and use of infected coffee husks (as mulch) and dried plants (as firewood) and use of unsterilised garden tools.â€
Disease control
NacRRI chairman says introduction of overhead shade and windbreakers reduces the incidence of crinkle leaf.
Control measures currently in use aim at reducing disease spread and destruction of innoculum.
Nsubuga advocates for regular field inspections to identify trees infected with CWD. The infected ones should be chopped, uprooted and the whole plant burnt.
Tips to farmers
A coffee tree usually has two or three branches. If one branch is infected, uproot and burn the whole tree even if the other branches have not shown the symptoms.
Coffee branches that dry due to CWD should not be used for firewood because the tools used in cutting down the branches and the act of relocation would aid in the spread of the disease from the field to other plantations.
A coffee field that has been infected by CWD should not be replanted with coffee for at least three years.
Do not use coffee husks from infected berries for mulching coffee gardens.
Spray infected coffee with carbolineum mixture to kill off the plant and the fungal spores, then uproot and burn the already dried coffee.
Do not harvest berries from infected coffee trees. Such berries should be destroyed.
However, scientists and researchers in Kituuza, Mukono district are believed to have developed 25 lines of coffee tree resistant to the CWD.