Studies on The Possibility of Using the Three Biological Control Agents; The Predator Ccoccinella undecimpunctata L., the Predator, Hippodamia convergens Guer. and the Aphid Parasitoid, Diaeretiellarapae (M'Intosh), Against the Legume Aphid, Aphis craccivora Koch.

In Egypt, the faba bean plants (Vicia fabaL.) is considered as one of the most important field crops that are continuously and extensively grown year after year, representing a popular local feeding and market crop for the Egyptian people. This crop is subjected to attack by the legume aphid, Aphis craccivora Koch. (Homoptera: Aphididae), which cause obvious damage to the resulted faba bean crop.The obtained results indicated that the faba bean plants that were cultivated in the greenhouses of the two tested released cases of the ladybird beetles ; Ccoccinella undecimpunctata L. and Hippodamia convergens Guer. (Coleoptera: Coccinellidae) when were compared with that case of the unreleased control 1 were as follows: for the unreleased control 1, the mean total number of the legume aphid, A. craccivora individuals per the period of experiment 1 was 2360.92±419.77(100-5189) individuals. While, in there leased case of the ladybird beetle C. undecimpunctata, the corresponding mean total number of the legume aphid, A. craccivora individuals per the period of the experiment was 715.30±235.30 (100-2861) individuals and the percentage of the reduction in the total number of the aphid individuals per the period of the experiment was 69.70%.But, for the released caseof the ladybird beetle, H. convergens,the mean total number of the legume aphid, A. craccivora individuals per the period of the experiment was 933.00±247.47 (100-2975) individuals and the percentage of the reduction in the total number of the aphid individuals per the period of the experiment was 60.48%.However, in experiment 2, the mean total number of the legume aphid A. Craccivora individuals in the aphid parasitoid, Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae) releasing case was 1380.76±248.84 (100-2711) individuals, in comparing with the unreleased control 2 cases (1672.79±313.10 (100-3582)). The total number of the mummies of the aphid parasitoid, D. rapae increased at the end of the experiment in the release case of the aphid parasitoid, D. rapae. This indicated that the D. rapae adultsˈ parasitoids were emerged from the parasitized aphid mummies and began to parasitize newly aphid individuals and thus the total number of the aphid mummies were increased at the end of season (successful parasitism of the aphid parasitoid, D. rapae has occurred). Therefore, the obtained results revealed the important role of the two predators (the ladybird beetles; C. undecimpunctata & H. convergens) and also the aphid parasitoid, D. rapae, as three effective biocontrol agents (representing a major component of the biological control techniques) against the legume aphid, A. craccivoraon the faba bean plants. As a result, they can be released in the faba bean fields and/or other related fields that suffer from the pest attack. They must be included in the Integrated Pest Management (I.P.M.) strategies, for decreasing the undesirable effects of using the chemical control methods