DDT is the generally used abbreviation for the compound which has been given the official name of dicophane. One of its first practical applications was in controlling the spread of TYPHUS. This disease is transmitted by the louse, one of the insects for which DDT is most effective. Its toxic action against the mosquito has also been amply proved, and it thus rapidly became one of the most effective measures in controlling malaria. DDT is also toxic to house-flies, bed-bugs, clothes-moths, fleas, cockroaches, and ants, and active against many agricultural and horticultural pests, including weevils, flour beetles, pine sawfly, and most varieties of scale insect.