How Does DDT Kill Insects?

DDT, dichlorodiphenyltrichloroethane, was a commonly used insecticide used to kill and repel mosquitoes during and after World War II, according to Duke University. DDT is still used in some less-developed areas of the world, as a control chemical for malaria-carrying mosquitoes, although the majority of countries have banned the use of DDT because of concerns over human health.

  1. History

    • DDT was first discovered in 1873 when it was produced in a laboratory environment. The chemical was first synthesized into a pesticide by Dr. Paul Muller in 1939 when it came into use as an insecticide. Along with mosquito control, the chemical was used in agricultural environments as a control for insects, such as potato beetles, coddling moths, corn earworm, cotton bollworm and tobacco budworms. During the 1960s, the build-up of DDT in the cells of living organisms, and the possible health problems caused by DDT, led to a ban in the U.S. in 1972, and remains in place in 2011, the Environmental Protection Agency reports.

    Insects

    • The application of DDT for malaria-carrying insects is done in interior areas by spraying the white powder onto walls in small quantities. When airborne and crawling insects come into contact with the chemical, they are killed by the DDT; flying insects that enter the building are repelled by the DDT and often leave without attempting to feed on humans or animals in the building, according to Malaria. Crops and exterior areas are also sprayed with the chemical to kill insects in the area, and repel those attempting to enter the sprayed areas. DDT is capable of killing insects resistant to other insecticides.

    Food Chain

    • DDT binds itself to fats within the bodies of animals it comes into contact with, making large animals at the top of the food chain particularly susceptible to storing large quantities of DDT in their bodies. DDT was found to be prominent in the bodies of animals such as fish, household pets, and livestock. The spraying of small amounts of DDT for interior insect protection reduces the amount of DDT finding its way into the environment, compared to exterior crop spraying, according to Malaria.

    Health

    • The banning of DDT was completed because of possible links discovered between the chemical and the health of people who operated DDT sprayers. The dangers of DDT include links to liver damage and the cause of certain cancers. DDT is found in small amounts in the majority of living things in the environment, according to the EPA.