Malaria control operations. Stearman biplane spraying an insecticide as part of malaria control operations. Stearman biplanes, introduced in 1934, were used extensively after the Second World War in the USA to spray crops. One of the insecticides commonly used, until it was banned, was dichlorodiphenyltrichloroethane (DDT). Mosquitoes are the vector for malaria transmission. Preventing mosquitoes from breeding is one of the ways used to control the spread of malaria. Photographed in Savannah, Georgia, USA.