Study on parasitism of Carpomya vesuviana Costa (Diptera: Tephritidae) by Fopius carpomyiae (Silvestri) (Hymenoptera: Braconidae) in Bushehr Province.

Document Type : Research Paper

Authors

Abstract

Fopius carpomyiae (Silvestri) (Braconidae: Opiinae) is primarily an egg-pupal, larvae parasitoid of  Ber (Konar) fruit fly, Carpomya vesuviana Costa, which is a key pest of several species of genera "Ziziphus" in the south of Iran. In this investigation, eggs, different larval stages and pupae of Ber (Konar) fruit fly were collected from natural areas to evaluate the potential of parasitism of this parasitoid. Each of all stages was counted and allowed to grow separately into Petri dishes contained soft soil, with enough aeration. The percentage of parasitism was evaluated monthly. Some parasitic behaviors were studied by direct observation on establishing wasps on the non-infested and infested Ber fruits in experimental tubes. The research was conducted in a complete randomized design with five replications, with four treatments (Wasp sitting on non infested fruit, Wasp just movings toward on non infested fruit, Wasp sitting and search on infested fruit and Wasp Just movings toward on infested fruit) and carried out for three years by using an alfactometer system. Pre-oviposition period of the wasp was 9 ± 1.6 days. Third instar larvae changed into pupa after 5± 2 days. Pupal period was 6 ± 2 days. Male and female longevity was 15 ± 4 and 22 ± 5 days, respectively. The female wasp with a long ovipositor can parasitize host eggs and young larvae that are completely concealed in fruits. The observations and statistical analysis showed that, at first female wasps attracted towards fruits infested with eggs or larvae of fruit fly, by using some chemicals, which were probably released on Konar fruits at the time of oviposition by fly (F=4.37, df=3,16, P<0.05). The female wasp started to move for searching, found larvae and eggs on the fruits by using probable chemical materials (odor) and antennal searching, then released and established only one egg into the host body after digging a hole under fruit skin. The parasitoid emerged from puparium of host fly after its completing development by killing the host. The statistical data showed differences in parasitism potential of this wasp during different months of the year, as it ranged from 7% in January to 49.6 % in December. The mean percentage of parasitism in the Samal zone of Bushehr Province was estimated 24±3.3% over a three year period.

Keywords