Abbreviation for dichloro-diphenyl-trichloroethane (ClC6H5)2CHCHCl2) insecticide discovered 1939 by Swiss chemist Paul Müller. It is useful in the control of insects that spread malaria, but resistant strains develop. DDT is highly toxic and persists in the environment and in living tissue. Its use is now banned in most countries, but it continues to be used on food plants in Latin America.