<2>Pesticides are chemicals that are intended to protect food plantsagainst insects and blight from disease. One of the first, and mosteffective, modern pesticides is calledDichloro-Diphenyl-Trichloroethane, better known as DDT. It wasdeveloped during World War Two and originally used against mosquitoesthat carried malaria, as well as other diseases spread by insects.

     Afterthe war, DDT began to be widely used as an agricultural insecticide.It was extremely effective and its popularity grew. After a while,however, some problems appeared. Many species of insect developedresistance to DDT, and the chemical was also discovered to be verydangerous to fish. It ran off from the land and poisoned many rivers.

    RachelCarson, in her 1962 book SilentSpring, gave a starkwarning about the dangers of using DDT. The book questioned theabundant use of chemicals before their effects on vegetation,wildlife, and human health are fully understood. Many people wereinfluenced by Carson's book. Her views were eventually accepted, andDDT was banned in the United States in 1973. Most other countriesfollowed, and it has rarely been used since.

    Now,some critics of the ban point out that malaria kills two millionpeople a year in Africa. Continuing to ban DDT, they say, endangerslarge numbers of people who are not fortunate enough to live inmalaria-free countries. A recent article in a medical journal arguesthat efforts to control malaria should include greater use of DDTbecause it is the cheapest and most effective method.