The authors carried out two series of field test to determine the basic lines of DDT and Dieldrin susceptibility of Anopheles sinensis at Andong(1961) and Yoju(1962), where malaria endemicity is relatively high in Korea. Tests were performed in accordance with the standard method established by the World Health Oraganization(1960).

The results were summarized as follows:

1. The LC-50 of DDT for A. sinensis caught at Andong as 1.5%, while for the same species in Yoju was 1.3%.

2. The LC-50 of Dieldrin for A. sinensis caught at Andong was 0.075%, while the LC-50 for the same species at Yoju was 0.07%.

These results therefore indicate Anopheles sinensis, as the malaria vector species in Korea, is susceptible to DDT and Dieldrin.