Search

Dieldrin at a rate of 22-45 kg active ingredient/ha (10-20 times the rate used in practice) was applied to strips, each 1·8-3·6 m wide, 3·6-4·5 m away from the edges of four ponds. There were shallow to steep slopes from the treated strips towards the ponds. Dieldrin was found in small amounts in untreated soil on the surface of the slopes between the treated strips and the ponds but none was found in the pond water. Very small amounts (maximum 0·3 ppm) were found in bottom mud of ponds but not when the dieldrin had been thoroughly incorporated into the treated soil after application. In the experiment where the vertical distribution of dieldrin was studied the largest amount below 15 cm was 1·1 ppm at 81 weeks from application. [ABSTRACT FROM AUTHOR]

The activity of the (+)- trans-chrysanthemic acid ester of (±)-allethrolone (Bio-allethrin) is shown to be superior to that of the (±)- cis, trans-isomers (allethrin), against houseflies, two species of grain beetle and larvae of the yellow fever mosquito. The efficiency of the (+)- trans-isomer compares favourably with that of pyrethrins when each is used alone or with piperonyl butoxide. [ABSTRACT FROM AUTHOR]