Biology and population dynamics of Scaeva albomaculata (Diptera: Syrphidae) in almond orchards of Shahrekord, Iran

Biology of Scaeva albomaculata (Macquart) was investigated on Brachycaudus amygdalinus (Schouteden) as a prey in laboratory conditions (۲۰ ± ۲ ºC and ۴۵ ± ۵ % RH). Developmental times were ۲.۵۷ ± ۰.۰۹۸, ۱.۵۷ ± ۰.۰۷۲ and ۴.۳ ± ۰.۰۸۵ days for the first, second and third instar larvae, respectively. The first and second instar larvae of syrphid fly consumed ۲۱.۷ ± ۰.۸۷ and ۳۵.۱ ± ۱.۲۵ the first and second nymphs, respectively, whereas the third instar larvae consumed ۶۱۳.۲ ± ۱۸.۴۳ alate nymphs of B. amygdalinus. Adults of syrphid flies mostly emerged in early morning. Population dynamics of eggs and larvae and larval behavior were studied from emergence time (early March) to late October during ۲۰۰۱-۲۰۰۴ in two regions (Shahrekord and Shorab-Saghir). In natural conditions, the larvae that completed their growth left the almond twigs and pupated at a depth of ۳-۵ cm below the soil surface. The most important natural enemies of S. albomaculata larvae were identified as Diplazon laetatorius (Fabricius) (Hym.: Ichneomonidae) and Dotriothorax sp. (Hym.: Encyrtidae), which parasitized ۳۴% and ۵% of the larvae, respectively. These parasitoids emerged from pupae of S. albomaculata. Another mortality agent was an unknown pathogen, which caused the body content of the pupae to become a milky liquid.