Abstract
The toxicity of five insecticides and their mixture : Karate , Decis , Karate & Decis (Pyrethroid ) , Dizinon , Lorsban, Diazinon & Lorsban ( Phosphoric ) and Sevin (Carbamatic) have been evaluated against the southern cowpea weevil Callosobruchus maculatus ( Fab.) after 1 & 24 hours of treatment for the egg stage. The results were taking after 5 days of treatment which showed that the effect of the insecticides depending on the relative toxicity were as follows : Karate > Karate & Decis > Diazinon> Diazinon &Lorsban > Decis > Lorsban > Sevin . The egg stage was also depting for 1 minute in 5 concentrations of the extracts of the diethyl ether of four plants :Garlic, Horsemint, Sweet bacil & Rue. The results after 5 days showed that the relative toxicity were as follows : Horsemint > Garlic > Sweet bacil > Rue. Horsemint extract showed high relative toxicity giving a percentage of hatching 5.2 % only, while that of Rue gave 25.2 % . The adults of the pest were also treated with the different concentrations of the chemicals , depending on the L.D.50 values and relative toxicity the insecticides were in the following descending order : Karate > Diazinon > Karate & Decis > Diazinon & Lorsban > Decis > Lorsban > Sevin . The results of adults treated with the four plant extracts depending on the basis of L.D.50 and relative toxicity showed that Garlic extract was the highest one ,its L.D.50 value was 315.3 mg/L. and its relative toxicity was 61.6 % . While L.D.50 of Rue was the lowest reached 1744 mg/L. and its relative toxicity was 33.6% , for the 24 hours of treatment.
