Local initiative to manage coffee wilt disease

One of the longest-surviving crop diseases in Uganda is the Coffee Wilt Disease (CWD), a fungal infection that wiped out more than 12 million robusta coffee trees in central and western Uganda regions towards the end of the 20th Century.
The hardest-hit sub-regions by CWD—which erupted in Uganda in 1993—were Buganda, Ankole, Bunyoro, Tooro, parts of West Nile and Busoga.
And, in the Buganda sub-region—Luweero District registered one of the highest tolls visited on some of the country’s largest robusta coffee plantations found in Bamunanika and Katikamu counties.
The CWD, whose scientific name is tracheomycosis or vascular wilt disease, is caused by a fungus (Fusarium xylarioides).
Previously, the disease occurred sporadically in Africa but in the last decade or so, it has become virulent, sweeping across Cameroon, the Congo and into Uganda.

How I overcame
Adams Byaruhanga, a resident of Kikasa village, Bukalasa Parish in Wobulenzi, Katikamu County, Luweero District, is a smallholder coffee farmer who has experienced a hard time with CWD. He decided to engage in an intensive search for the cause, effects and possible solution to the CWD menace, within his limits.
He says with two acres of coffee, he used to earn good money every season of harvests and sales, until around 1993-4 when CWD invaded the area.

“Ever since I settled in that area in 1977 while working for the agriculture department, I found Bukalasa Agricultural College—near his home – a vibrant beehive of agricultural activities with healthy demonstration gardens mainly of coffee that were highly inspiring.
“I took up coffee and within a short time I had established a coffee shamba on the two acres of land I had bought. The late 1970s through to the early 1990s, my coffee farming and business boomed,” he recalls with nostalgia.
“But with the emergence of the disease, which we did not know by name and cause a scare and fear begun to grip us [farmers] and swept across the sub-region like a wildfire.

Motivation
“Remember the area had hardly emerged out of war (that ended in 1986—seven years earlier), and families that were under resettlement, had just rehabilitated their over-grown coffee shambas, and were beginning to earn from their sweat, then came the disease,” says Byaruhanga, adding that the Ministry of Agriculture [whose political head was Dr Wilberforce Kisamba-Mugerwa], was issuing warnings about a new coffee disease called coffee wilt disease. That is when we learnt that it was a fungal infection that spread very fast through the soil and farmers were advised to uproot the affected/infected trees and burn them.
“By the time information spread via extension workers and Radio Uganda (now Uganda Broadcasting Corporation [UBC] Radio), many farmers did not know what had happened to their source of wealth, he goes on.

He embarked on close to 10-year research. “Through studies and close observations, we in Biodiversity Management Training and Research Organisation (BMTARO) have discovered that the primary cause of the coffee wilting is abiotic stress (global environmental warming)-induced impacts on coffee growth and yields.
“This is due to too much, temperature/heat, water/moisture or nutrients stress and shortages. Abiotic stress includes, severe nutrient shortage, nutrient imbalance, soil compaction, moisture-stress, extreme drought and water-logging,” the 63-year-old farmer says.

He argues that the fungal infection, Fusarium xylarioides, is just a secondary cause or opportunistic infection that takes advantage of environmental damage already done to a crop.
“Among all these factors, prolonged extreme temperature/drought-induced stress has the biggest impact on coffee growth and yield.
“Its intensity and duration and the physiological stage of the coffee, are key factors that influence the susceptibility of the crop to pests and disease infection and infestation like Fusarium xylarioides,” Byaruhanga further argues.

Abiotic stress, he insists, weakens coffee predisposing it to biotic (pests and disease) stress factors (‘secondary invaders’) which is mainly fungal in nature.
He says BMTARO research studies found that the subsequent root-cause of crop-mortality (death) is an interaction of the combined stresses (abiotic and biotic).

Interventions
There is no magic strategy that can control crop mortality, says Byaruhanga, adding that production of high quality organic coffee (grown without spraying pesticides/fungicides and without industrial fertilisers etc) necessitates addressing all potential stresses simultaneously and holistically.
He says, “We’ve realised that we have to stem the loss of nutrients in soils by introducing charged-carbon (charcoal dust) over the soils, that will ensure long term-water and nutrient availability under charcoal dust.

“We are promoting what we call the Carbon Negative Climate-Smart Organic Agriculture (CANCSOA) strategies, deliberately aimed at controlling the root cause of the problem, to save the remaining crop.
“And we have also established permanent soil-cover with vegetative (lima beans, velvet beans, jack beans) or dead mulch of plant leaves and compost manure,” he contends.

“Additionally, BMTARO is promoting minimum/no tillage of soils; modified implements and establishing hedge-rows,” adds Byaruhanga. Todate, CWD has caused an estimated loss of more than 200 million coffee trees, according to joint findings by National Agricultural Research Organisation and the Agriculture Ministry.
Since then, Naro through NACORI has been developing resistant coffee varieties, something they achieved around 2006 with a breakthrough of seven new CWD-resistant conventionally-bred lines now being mass-propagated via tissue culture and supplied via the Naads and Operation Wealth Creation.

According to the Uganda Coffee Development Authority (UCDA), the wilt has mainly affected the native, lowland robusta variety which coffee accounts for over 90 per cent of Uganda coffee output and export. And, since 1993 Coffee Wilt Disease has destroyed more than 12 million plants.

Arabica coffee only accounts for 10 per cent of production. The National Coffee Policy (2013) also takes cognizance of the adverse effect of the CWD of coffee output. In its 2.2.1 sub-section on Coffee production and productivity, the Policy states, “… In Uganda, coffee production has stagnated at three million bags per year over the last 40 years. Smallholder farmers dominate coffee production with average holdings estimated at 0.33ha per household. There is limited estate production….. This is attributed to inadequate funding for research to enable the development and dissemination of new technologies, poor agronomic practices (low input-low output farming system), inefficient research-extension-farmer linkages, incidence of CWD on Robusta, which destroyed more than 50 per cent of the old Robusta trees among other causes…”

The National Coffee Policy under section 2.4 on Emerging issues, further identifies one of the main emerging issues including climate change, “… it has implication on changing production patterns and increased incidence of pests and diseases.” In a bid to strengthen and expand coffee research and development in Uganda, Naro in 2014 upgraded its former coffee research centre (COREC) at Kituza in Mukono, to a fully-fledged National Coffee Research Institute (NaCORI) status. The President Uganda National Farmers’ Federation (UNFFE), Charles Ogang, also welcomed the move. “I’m very pleased to hear that COREC is now a national institute. Uganda suffered massive losses and suffering from coffee growers ever since the Coffee Wilt Disease (CWD) broke out more than 20 years ago. The upgrade of COREC to national status for us means widening its mandate to improve and speed up research, and deliver a more disease-resistant, higher-yielding and a better-quality crop.

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