Cross-tolerances of dieldrin-resistant flies and mosquitos to various cyclodiene insecticides.

Nineteen cyclodiene insecticides incorporating major and minor structural variations of the chlorinated bridged bicycloheptene structure were evaluated against susceptible and dieldrin-resistant houseflies, and against larvae and adults of susceptible Culex pipiens quinquefasciatus Say and dieldrin-resistant Anopheles albimanus Wied. Determinations of LD(50) or LC(50) values demonstrated cross-resistance to all of the cyclodienes studied. This cross-resistance was very marked for most compounds, but was least in all cases for octachloro-endomethano-tetrahydrophthalan (Telodrin), which was also very toxic to the susceptible insects.