Cavendish dessert bananas are widespread in southern Africa. This high-yielding export variety dominates production in countries such as Mozambique, South Africa, Malawi and Zimbabwe. But smallholders in Africa also grow many other local banana varieties for eating fresh, cooking and brewing beer – varieties that are unique to Africa.
In eastern and central Africa, particularly in eastern African highland countries such as Tanzania and Uganda, local cooking banana varieties are essential to food security. More than 100 million people rely on them as a primary source of carbohydrates and nutrient-dense calories, with an average of more than 300 kilograms being consumed per person a year.
A new ACIAR-funded project is investigating the risk that banana production systems in eastern Africa face from Fusarium wilt tropical race 4 (TR4; also known as Fusarium wilt or Panama disease). This is a soil-borne fungal disease that is impacting Cavendish bananas in major production areas outside of Africa.
The fungal pathogen that causes the disease, Fusarium oxysporum f. sp. cubense, affects a wide range of other banana varieties; the project will assess if Africa’s local banana varieties are also vulnerable.
The project focuses on two countries. The first is Mozambique in southern Africa, where Fusarium wilt TR4 was first detected in 2013. The second country is neighbouring Tanzania in eastern Africa, the continent’s second-largest producer of bananas and, so far, free of Fusarium wilt TR4, although feared to be at high risk of infection.
The TR4 pathogen is moved from place to place in infected plant material, contaminated soil or water. There is no treatment and infected plants eventually die.
Leading the project for ACIAR are Stewart Lindsay and Ingrid Jenkins from the banana production systems team at the Queensland Department of Agriculture and Fisheries.
Mr Lindsay said most existing biosecurity and management resources regarding Fusarium wilt TR4 have been developed for Cavendish plantations and do not necessarily reflect the inherent risks in smallholder production systems in Africa, or for local African bananas.
Mapping production systems
Globally, Cavendish is commonly grown in monoculture plantations, but in Africa it is often part of a mixed crop system. Most smallholders farm less than one hectare and grow several crops at once, such as bananas, coffee, beans, yams and vegetables.
Researchers will work directly with smallholders in Mozambique and Tanzania to identify what aspects of their production systems present the greatest risk of TR4 infection. The researchers also aim to develop practical and culturally appropriate biosecurity practices to help reduce the risk of infection.
Mr Lindsay said his experience with a previous ACIAR-supported project in the Philippines in 2014 highlighted the importance of taking local cultural and social conditions into account. This required working with not just smallholder farmers, as originally planned, but also the corporate organisations they supplied. ACIAR now has a follow-up project underway in South-East Asia working across the supply chain.
Overseeing the new project in Africa is Professor Altus Viljoen, a plant pathologist at Stellenbosch University who verified the first known outbreak of TR4 in Mozambique in 2013.
Professor Viljoen said surveillance in Mozambique and neighbouring countries, based on visual inspections of plantations and tissue samples, has not found any further spread from the 4 plantations initially infected. ‘But we are extremely concerned about this,’ he added.
‘The ACIAR-supported project will help by trying to bring some biosecurity measures not for commercial growers, but for smallholders, who dominate banana production in Africa,’ said Professor Viljoen.
‘I think the technologies and the approaches we develop through this project will be applicable beyond the borders of the two countries.’
In Mozambique, there are about 70,000 hectares planted to bananas, of which about 6,000 hectares are larger commercial plantations. Tanzania has more than 550,000 hectares of bananas and millions of smallholder farmers. Cavendish makes up a substantial portion of total production, but it is the local bananas that form the basis of daily diets across the region.
Project partners in Mozambique include the Ministry of Agriculture and Rural Development, and the Mozambique Institute of Agricultural Research. In Tanzania, partners include the International Institute of Tropical Agriculture, the Ministry of Agriculture and the Tanzania Agricultural Research Institute (TARI).
Support for local farmers
TARI’s national banana research coordinator Dr Mpoki Shimwela said with the threat of TR4 on the border, the emphasis is on raising awareness among farmers, especially along the border with Mozambique.
‘We want to train farmers on how to identify the disease, because most of them don’t know what it looks like, and to help identify biosecurity measures they can apply.’
As there are many women farming in Africa, Dr Shimwela highlighted the importance of ensuring that women farmers are involved in mapping farm systems, creating awareness of the disease and developing biosecurity practices.
The project will also increase the capacity of project team staff and organisations in technical aspects of Fusarium wilt TR4 research and effective biosecurity extension and communication methods. This project is funded through the ACIAR Horticulture Program and runs until the end of 2024.
ACIAR PROJECT: ‘Developing a biosecurity system for small banana growers resilient to Fusarium wilt TR4 in southern and eastern Africa’ (HORT/2020/128)