Wednesday April 30 2014

Scientists in joint, effort to check, banana disease

A banana market in Kampala. Uganda is a leading

A banana market in Kampala. Uganda is a leading banana producer, so any threat to the crop is taken seriously. File photo 

By Peter Wamboga-Mugirya

Ugandan agricultural scientists have raised an alarm about a new virulent banana disease, known as Tropical Race 4 (TR4) that has invaded Africa via Mozambique, months after it first erupted in Central America, Asia and Jordan in the Middle East.
The TR4, which rapidly spreads through infected soil, has been labelled as being many times more deadly than banana bacterial wilt (BBW), according to Dr Andrew Kiggundu, head of the Banana Research Centre, under National Agricultural Research Organisation (Naro).
He says TR4 disease could potentially enter East Africa, if not checked in time, and smallholder/subsistence farmers would be the most threatened.

Steps being taken
“We are highly concerned about this fungal disease, which is very lethal and already on the African continent. It was first detected in Mozambique in October 2013 where it reached from Asia. Since it invaded Mozambique, it has remained confined on a farmer’s plantation. Scientists and the Mozambican Government are ensuring nothing [produce nor planting materials] leave the plantation,” Dr Kiggundu said an interview.

He revealed that TR4 mainly attacks the Cavendish banana variety—which is a dessert banana closely related to bogoya (Gros Michel)—a widely grown, consumed and traded variety in Uganda and across East Africa.
Bogoya and ndizi (apple bananas) are the most exported dessert bananas by Uganda. They are also widely consumed locally.

On steps so far taken to wade off the spreading of the TR4 disease, Dr Kiggundu said scientists under a consortium, which was formed to fight the outbreak, linked up with the Chinese Academy of Tropical Agricultural Sciences (CATAS) to undertake tests of African cooking and dessert banana varieties, to determine if they are also susceptible to TR4 infection.

“The first observation is that our bananas seem tolerant to TR4 disease, although they instead succumbed to Chinese weevils in the trial fields,” he explained.

“We shall repeat the trials against TR4 disease during which we shall control weevils. This will be a second test in our first series of steps to understand TR4 effects on purely African bananas.”

International cooperation
He is a member of the anti-TR4 international consortium, which comprises the Katholek University of Leuven (KUL), International Transit Centre (Belgium), Wageningen University (The Netherlands), and Stellenbosch University (South Africa), in addition to other Asian, African, Latin American scientists and institutions.
Meanwhile, a team of South African scientists led by Prof Altus Viljoen (Stellenbosch University), are working to ensure TR4 disease on a Mozambican banana farmer’s plantation does not spread elsewhere in that country or out of it.
South Africa—Mozambique’s neighbor to the south—grows and consumes bananas, hence the concern and interest in TR4 control.
The UN’s Food and Agriculture Organisation (FAO), says following its spread to Africa and the Middle East, the fusarium wilt, TR4, increases the risks to livelihoods and banana markets.
It has warned countries to step up monitoring, reporting and prevention of one of the world’s most destructive banana disease.
Banana is the eighth most important food crop in the world and the fourth most important food crop among the world’s least-developed countries, according to FAOSTAT, the data-gathering and analysis service.

Avoid worst-case scenario
“Any disease or constraint that affects bananas is striking at an important source of food, livelihoods, employment and government revenues in many tropical countries,” said Gianluca Gondolini, Secretary of the World Banana Forum (WBF), whose secretariat is based at FAO headquarters in Rome, Italy. It promotes sustainable banana production and trade.

“The spread of Fusarium wilt banana disease could have a significant impact on growers, traders and families who depend on the banana industry,” Fazil Dusunceli, a plant pathologist at FAO, said. “Countries need to act now if we are to avoid the worst-case scenario, which is massive destruction of much of the world’s banana crop.”

FAO and its partners, including the World Banana Forum (WBF), the scientific community and the banana industry are among those making efforts to increase awareness of the inherent threat of TR4.

The issue will be on the agenda of a series of upcoming meetings in Kenya, South Africa, and Trinidad and Tobago, with the aim of addressing a range of issues related to TR4, including developing action plans for its prevention, monitoring and containment.

The banana crop is vulnerable to a number of diseases in various parts of the world, including the Black Sigatoka disease, Bananna Xanthomonas Wilt or Banana Bacterial Wilt (BXW or BBW), Bunchy Top Disease (BBTD) and Fusarium Wilt, but Fusarium’s soil-borne nature makes it especially challenging.
The UK-based The Independent says TR4 has spread dramatically after it was announced in recent weeks that it has jumped from South-east Asia, where it has already devastated export crops, to Mozambique and Jordan.

Great damage
“The FAO warns: In view of the challenges associated with control of the disease and the risk posed to the global banana supply, it is evident that a concerted effort is required from industry, research institutions, government and international organisations to prevent spread of the disease.”
The world’s banana crop is worth £26b (about $43b) and a crucial part of the diet of more than 400 million people. And TR4 disease could destroy up to 85 per cent of the world’s banana crop by volume.
Prof Rony Swennen, a banana expert based at Leuven University in Belgium, who supported genetic modification of bogoya, the Ugandan Gros Michel against another fungal disease (Black Sigatoka) in 2004, says:
“If the [TR4] is in Latin America, it is going to be a disaster, whatever the multinationals do. Teams of workers move across different countries. The risk is it is going to spread like a bush fire.”


Africa, where one-third of the world’s bananas are consumed, is a significant exporter of bananas.

Bananas and plantains are a major food crop for many African countries. There are two major banana production systems in Africa: East African highland cooking (matooke) and beer bananas; and the plantain production systems in West Africa.

Scattered in some countries are the dessert banana systems. In East Africa, Cavendish banana is the main dessert in Kenya, and constitutes a large of chunk of exports.