Studies on the Insecticidal Effect of Vaporized Pyrethroid on Cockroaches

In order to evaluate the insecticidal effect of permethrin and phthalthrin vapor on cockroaches, an apparatus was invented to keep constant the pyrethroids' concentration in air and provide a pyrethroid vapor or mist strong enough to knock down cockroaches. A relationship between the pyrethroid concentration in the air and KTX50 obtained by using this apparatus revealed a certain curve which has a point of inflection at a concentration around 100 μg/l. These relation curves gave a vivid account of the characteristic of each insecticide. Phthalthrin's remarkable KD effect upon cockroaches occurred in its higher concentration in ari, while permethrin showed prominent kill and KD effects through a wide concentration range. In all of these tests male cockroaches were more susceptible than female.