Viral diseases pose a major challenge to banana production worldwide. While clean propagation techniques such as tissue culture could almost completely eliminate bacterial, fungal and nematode infections, and pests, they have not been successful in keeping virus at bay.
Once infected, banana plants carry the virus all their life transmitting them to suckers hence perpetuating the infection ad infinitum. Viral infections can also be transmitted from plant to plant by insect vectors.
Five viruses have been identified and documented as causing disease in banana. They are the cucumber mosaic virus (CMV), banana bunchy top virus (BBTV), banana streak virus (BSV), banana mild mosaic virus (BanMMV), and banana bract mosaic virus (BBrMV).
The most effective way of controlling viral diseases lies in preventing infection from the outset, rather than trying to cure it. This means the initial banana planting stock must first be virus-free before it is multiplied for cultivation.
Viruses differ in where they are found, their biological properties, and how they are spread. They even differ in how they manifest in different parts of a plant necessitating tailored control measures.
This calls for careful identification and description of viruses causing disease in bananas to create a comprehensive virus index that will aid disease surveillance and serve as a quick scientific reference for prompt diagnosis and treatment of viral diseases.
Africa Harvest is undertaking a banana virus-indexing project in eastern Africa to build knowledge and capacity on management of the region’s key viral threats in order to develop and maintain a completely disease-free supply of banana plantlets. This project is:-
• Helping the national agricultural research centers in Uganda, Tanzania and Kenya to establish virus indexing facilities
• Helping laboratories in the region set up quality control systems for banana plantlets to ensure farmers get the highest quality tissue culture plantlets possible for improved banana production
• Advocating for formal government certification of tissue culture banana plantlets produced by private companies as a way of increasing quality assurance
• Campaigning for institutionalization of the developing virus index to ensure proper supervision and management in both public and private sectors
A good virus index is able to monitor quality of materials coming into and going out of a country, as well as providing comprehensive management information on various diseases.