Tsetse fly
David Hines was employed in Dar es Salaam, Tanganyika (now Tanzania) by the Colonial Office to develop farming : even by the early 1950s, there were over 400 co-operatives operational, despite vast areas of central and southern Tanganyika being plagued by Tsetse fly, making them unsuitable for agriculture and cattle raising. Previously, farmers had sold their produce to Indian traders at poor prices. The farmers gained more favourable prices for their crops by banding together in co-operatives and selling their produce in bulk.