Predatory Efficiency of Eupoedes Corollae (Fabricius)( Diptera: Syrphidae) to Different Densities of Aphis Gossypii and Aphis Nerii

Predatory efficiency of Eupoedes corollae predator's larvae toward densities of 25, 50, 75, 100 insect of Aphis gossypii and of Aphis nerii, a study was carried out of the laboratory in growth chamber with a temperature of 24±1 C◦ and 70 ± 10 % RH and photoperiod 12: 12 hours. The results showed that the predator E. corollae larvae consumption in different percentage according to the prey's species and the number provided, and that 50 density of cotton aphid was the best in the daily and total consumption of E.corollae predator, in addition to the relatively low development period of predator larvae at the same density. The average of consumption of the predator's larvae instars was proportional to the different densities of the aphids 25, 50.75 and 100 insect, as it reached to ( 84.64, 143.16, 170.9 and 217.93) of cotton aphid and (56.23, 110.67, 124.78 and 148.16) insects of oleander aphid , respectively. The average of aphid is estimated at 154.2 and 110.2 insect, respectively, for the two species with significant differences between them.