Banana bunchy top virus spreads in Nigeria

Researchers have raised the alarm over the increasing spread of Banana Bunchy Top Virus (BBTV) across West Africa with more farms in Nigeria, Wst Africa’s second largest producer, being ravaged by the disease.

“If not checked the virus will devastate banana farms, and jeopardise the livelihoods of millions of farmers who earn their livelihoods from the crop,” says Lava Kumar, virologist at the International Institute of Tropical Agriculture, during a visit to farms ravaged by the disease in Idiroko, a border town in Ogun State, on Monday, at farmers’ Field Day.

Charles Onyeani, head of the Post-Entry Quarantine, Nigeria Agricultural Quarantine Service (NAQS), has also warned against the movement of banana planting materials from infected areas to uninfected areas to check the spread of the disease.

First discovered in 2012 by IITA in collaboration with the University of Ibadan and the NAQS, the disease is now widespread in Ilashe, Odan-Itoro, Ido-Ologun, and Igbogila, in Ogun State.

“Systematic studies on yield losses have not been done but empirical observations indicate 50 percent to 90 percent loss in the affected region,” Kumar adds, stressing “there is a severe shortage of clean planting material. Urgent management actions are required to prevent further spread and also help farmers in the affected areas.”

Nigeria produces 2.74 million tons of banana annually, according to the Food and Agriculture Organisation, making the crop one of the important staples in the country.

Devastation by BBTV on banana fields will have a negative impact on the country’s economy, and thwart efforts towards food security.

Caused by a virus called, Banana Bunchy Top Virus, BBTV is a serious threat to banana in Sub-Saharan Africa. The disease has been recognised in 14 countries in Africa; 13 of these are in Sub-Saharan Africa which represents a combined banana production area of 2.28 million ha, contributing 19.75 million tons of fruit per annum (FAO 2011). The disease is known to occur in all the major banana production regions in DRC, Congo Brazzaville, Burundi, Rwanda, Malawi, Gabon, Equatorial Guinea, and Zambia. Whereas, disease spread is limited to a few regions in Angola, Benin, Cameroon, and Nigeria.

BBTD was first reported in the continent in 1901, however extensive spread into new production areas were observed during the last two decades. The disease has very recently invaded the Bénin (first reported 2011) and Nigeria (first reported in 2013) in West Africa.

“The virus is also spread through an insect, banana aphid (Pentalonia nigronervosa), which is widespread in all the banana and plantain-producing areas in Nigeria and many parts of the world, says Rachid Hanna, entomologist at IITA.

Infected banana plants become progressively smaller and stand more erect giving the plant a bunchy appearance. Plants infected early in their growth do not produce fruits resulting in total loss of yield, while plants infected at later stages may produce deformed fruits. The plant may eventually die, but often remains with its lateral shoots which serve as a source of infection for further spread.

The spread of the disease into new areas can initially remain undetected, complicating timely eradication work and prevention of new outbreaks. Once the disease is present in a region, it is extremely difficult to eradicate.

No durable sources of resistance have yet been identified. Eradication of infected plants and planting healthy planting material is the best available solution.