The Sterile Insect Technique as a component of area-wide integrated pest management against selected tsetse fly populations in Africa: past successes and future prospects

Poverty remains widespread in most rural communities of sub-Sahara African countries. Hunger and chronic undernourishment can be reduced through the introduction of productive livestock as a source of milk, meat, manure for crop production, traction and transport. The presence of a number of tsetse fly species and the disease trypanosomosis it transmits is considered a major barrier to the development of more efficient livestock production systems. African farmers lose three million cattle every year to the disease and annual direct economic losses are estimated at US$ 600 to 1200 million. The most desirable way of containing the disease trypanosomosis is through the elimination of entire populations of the vector (the tsetse fly) from delimited geographical areas using an area-wide integrated pest management (AW-IPM) approach. Despite the availability of efficient control tactics, only a few examples exist where the elimination of tsetse flies has proven to be sustainable, e.g. the elimination of Glossina pallidipes Austen from South Africa in the 1950’s, of Glossina austeni Newstead from Unguja Island of Zanzibar in the 1990’s, and of G. morsitans centralis from Botswana by 2003. Although the reasons for these limited successes are numerous, the decentralisation of the tsetse control efforts, the shift from large-scale eradication approaches to localised tsetse suppression efforts, the growing economic crises and political instability have most likely contributed to the decline of tsetse control efforts. We argue that the sustained removal of the tsetse fly over large geographical areas, which would result in enormous economic benefits for the rural farmer community, is feasible provided certain prerequisites are being met. Opportunities exist in the Southern Rift Valley in Ethiopia, KwaZulu Natal in South Africa-Mozambique, and in Western Senegal.