Indoor Residual Spraying (IRS) of houses with insecticides to kill mosquitoes is one of the main methods that have been used to control malaria on a large scale. IRS has helped to eliminate malaria from great parts of Asia, Russia, Europe, and Latin America, and successful IRS programmes have also been run in parts of Africa.
Mud remains a common indoor wall surface in Africa. The effectiveness of IRS formulations on mud surfaces is known to vary between geographic areas and IRS formulations. However, data on how the properties of muds can affect the residual efficacy of insecticides, other than DDT, are lacking, including the most widely used insecticides today. Therefore, it is difficult to rationalize results from bioassays on mud surfaces, and even more difficult to predict how a particular IRS formulation will perform on a particular type of mud.