International, multi-stakeholder alliance continue to tackle banana bunchy top disease in Africa

Up to 16 African countries have now experienced the banana bunchy top disease (BBTD), caused by the banana bunchy top virus (BBTV), which threatens the livelihoods of 70 million vulnerable banana farmers. The virus is also endangering the diversity of banana varieties grown by these farmers. The CGIAR Research Program on Roots, Tubers and Bananas (RTB) is combating the virus through the Alliance for Banana Bunchy Top Disease Control in Africa.

The BBTD Alliance convened international, multi-stakeholder teams fostering cutting-edge research for development (R4D) to establish practical solutions so farmers can once again produce bananas for food and income. The Alliance has collaborated with national programs, building their capacity to detect, surveil, and control BBTD.

Fresh banana plants exhibiting subtle Bunchy top symptoms. (Photo: L. Kumar/IITA)

This disease stunts the plant, stopping fruit production, sometimes causing total crop loss in a single season. Farmers are advised to eliminate infected banana mats and replace them with healthy suckers. However, smallholders hesitate to destroy large parts of their banana gardens, especially if some of their plants still bear bunches.

BBTD increases the demand for clean planting material but makes it more challenging to find the seed of local landraces, threatening the diversity of well-adapted landraces. Farmers need to act collectively to prevent the disease from spreading to their community or reinfecting after replanting.

Since the disease was first reported in the Democratic Republic of Congo (DRC) in the 1960s, the virus has invaded several countries across sub-Saharan Africa, spreading through planting material and an insect vector—the banana aphid.

Because BBTD can easily cross borders, management requires international cooperation. In 2011, RTB set up the BBTD Alliance, coordinated by IITA, the Alliance of Bioversity International and CIAT, CIRAD, and national research partners in Benin, Burundi, Cameroon, Congo Brazzaville, DRC, Ghana, Malawi, Nigeria, and Zambia. Other partners include the FAO, the Inter-African Phytosanitary Council (IAPSC), and research partners from Australia (University of Queensland), Asia, Europe, India, Kenya, UK (University of Cambridge), and the USA.

The BBTD Alliance develops new knowledge and management technologies, facilitates training and information exchange, and supports national partners and farmer organizations. Seed entrepreneurs, extension agents, farmers, and plant health inspectors are learning to diagnose the disease in the field, identify rogue infected plants, and produce clean planting material. In 2020, RTB developed an online training course on disease recognition and eradication.

Getting ready for surveillance and eradication of BBTV infected banana plants. (Photo: L. Kumar/IITA)

Trials conducted in Benin, Burundi, and Malawi have effectively maintained BBTD levels below 1%, supporting the production of low-risk seed for expansion. Farmers learned to multiply clean seed and were linked to tissue culture and other sources of healthy planting material.

Early detection of BBTD and the virus’s eradication in Togo is the first case for halting the spread of an invasive virus in sub-Saharan Africa. Demonstrations and hands-on training helped Togolese partners eliminate the disease. Farmers, extension workers, policymakers, and donors also saw how BBTD was managed in Benin, Cameroon, Malawi, and Nigeria.

BBTD Alliance studies also examined gendered access to information and resources in Benin, Cameroon, and Nigeria. In Cameroon, men had more influence in decision-making over farm resources and information services, even when women were more involved in actual seed and site selection. Men also had greater access to clean seed than women. “Getting healthy planting material is crucial for managing bunchy top, and if women cannot access clean seed, they are at a disadvantage. Projects across Africa will have to ensure that women have equal access to healthy planting material,” said Lava Kumar, Virologist and Head of IITA’s Germplasm Health Unit.


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