Insecticide resistance in anophelines in eastern Saudi Arabia.

In 1953, the fifth year of a malaria control programme with DDT in Eastern Saudi Arabia, the resting of Anopheles stephensi on recently sprayed surfaces suggested the development of resistance in this species to DDT, and this suspicion has been confirmed by tests carried out from 1955 to 1958.DDT was replaced by dieldrin in 1955 and malaria rates, which had been rising, were again reduced. No dieldrin-resistance has been found in local.