The food security of some 700 million Africans depends on cassava, but on that continent, there are two viruses that are a dangerous threat to the crop, the Cassava mosaic virus and the Brown stripe virus. To fight these diseases, 28 international institutions, foundations, research centres, universities and NGOs recently joined forces to set up the Pan-African Cassava Surveillance Network (PACSUN). According to scientists from the lead institution, the “centre français de coopération internationale en recherche agronomique pour le développement (CIRAD), Montpellier, the advantage of such an organisation is that it makes it possible to pool and coordinate the very many local initiatives concerning cassava diseases. The launch of PACSUN is the result of an international workshop on the surveillance and control of cassava diseases in Africa in Réunion from 10 to 13 June organised by CIRAD and the IRD (Institut de recherche pour le développement), under the aegis of GCP21 (Global Cassava Partnership for the 21st Century).
As CIRAD notes in a press release, the members of the network will be concentrating on the main two diseases: Cassava mosaic virus, which is found throughout the continent - the virus reduces yields by some 25 per cent by hampering root growth; and Brown stripe virus, which is more insidious, is largely invisible on the leaves but makes the tubers unfit for consumption. The viruses that cause brown stripe have long been known in East Africa, but currently seem to be spreading. PACSUN is a response to a serious threat say CIRAD scientists and add that this is particularly true since in Africa, cassava is increasingly playing a central role in food security, notably following the rise in cereal prices.
The priority for PACSUN is, therefore, to monitor the spread of brown stripe, so as to introduce measures to slow that spread. At the same time, simple, reliable diagnostic tools are to be developed and passed on to the African partners in the network via training courses. The network also plans to set up a website to provide up-to-date information on the geographical spread of cassava diseases.
According to CIRAD, the network will also set-up a disease-free cutting production facility in Réunion, the only zone free from the two viruses. CIRAD scientist Jean-Michel Lett adds that "it will be necessary to take account of the wide variety of cassava cultivars, which are each suited to the tastes and specific uses of various regions in Africa".
The members of the network are: