Two conventional insecticides namely, the organophosphate insecticide, selecron and the chitin synthesis inhibitor, match as well as the entomophathogenic bacteria, Bacillus thuringiensis sub variety kurstaki were tested indirect method against the third and fourth instar larvae of the predatory lady bird bettle, Coccinella undecimpunctata. The predator was fed on Aphis gossypii treated with LC50 values (10 ppm for selecron and 15 ppm match) and LC25 levels (5 ppm for selecron and 10 ppm for match), while the predator fed on half and quarters values of the recommended concentrations used for B. thuringiensis. Aphid consumption rates caused by different ages of the predatory insect as well as the resulted predatory adult were determined. The obtained results showed remarkable higher Aphid consumption in case of the 4th instar larvae of the predator than the 3rd instar larvae. Data clearly appeared no significant differences among the pupal duration of the predator which resulted from the larval treatment. Treatments of C. undecimpunctata instar larvae with three tested insecticides caused significant reduction in longevity of the produced males and females. Emerged male and females of the predator from treated larvae with all products had significant reduction in the aphid consumption. |
