Biology of Scaeva albomaculata (Macquart) and evaluation of its efficacy on almond aphid Brachycaudus helichrysi (Kalt.)

Scaeva albomaculata is one of the most important natural enemies of Brachycadus helichrysi. Its larva has predatory behavior and much of predation belonging to third larval instar. The biology of larva was investigated in laboratory condition. In 22 ± 2 °c and 45 ± 5 R.H. ‘ the longevity of 1st. to 3rd larval instar were 61.6 ± 5.399, 37.6 ± 3.86 and 103.2 ± 4.54 hours respectively and the eggs were hatched in 52.8 ± 5.3 hours. In the same condition the 1st. , 2nd. and 3rd larval instar were ate 21.7 ±1.95, 35.1 ± 2.8 and 613.2 ± 41.2 nymph respectively and each larva had eaten 670 ± 41.8 nymph in its life stage. The handling time of 3rd larva instar was investigated on nymph stages of B. helicerysi. The average time of allocation to each of instars were 21.5 ± 5.06, 46.25 ± 28.92, 76.52 ± 17.75 and 110.72 ± 34.76 second. The adults flying from 1 March to 10 May, 25 may to 21 June and 1 September to 14 October. This predator has several generations in a year that 3 distinct generation was seen on almond aphids, 2 in spring and 1 in autumn. The most population of larva was seen in first generation on B. helichrysi. The predator larva was collected from aphid colonies on the other plants including Prunus armeniaca (Rosaceae) , Prunus persica (Rosaceae), Prunus domestica (Rosaceae) , Prunus malus (Rosaceae) , Juglans regia (Juglandaceae) , Tragopogon orientalis (Compositae), Chrysanthemum segetum (Compositae) , Echinophora platiloba (Umbelliferae), Triticum sativum (Gramineae) , Hordeum vulgare (Gramineae) , Brassica napus (Cruciferae) , Medicago sativa (Legominosae) , Euphorbia sp. (Euphorbiaceae). The third larva instar after completing of feeding was coming to the ground and penetrating to the soil under the tree and finally pupated in 3 to 5 centimeter of soil depth. Two parasitoids were collected from pupae, Diplazon laetatorius T. (Ichneomonidae) and Dothriothorax sp. (Encyrtidae). D. Laetatorius was came out from 36% of pupae. The crown was digging and searching soil and eating the pupae. The ants collecting eggs and first larva instar and moving them to their nest.