The paddy fields in the alluvial plain of the Yellow River Region are the important breeding places of two major vectors of diseases in China, Anopheles sinemis and Culex tritaeniorhynehus and their control in'such vast areas remains an unsolved problem in the eradication of malaria, filarisis and Japanese encephalitis. The recent development in the management of rice culture, known as "Wet-irrigation" method offers a promising approach to the problem. A small scale experiment in 1974-1977 showed that the l...