In order to struggle efficiently against the phytophag Ceratitis capitata (Wied) that is the cause of many important damages on several fruits which partially attacks the citrus fruits, it necessary to know its bio-ecology in our region as well as its natural parasitism, to propose a mean of an efficient struggle with a perfect correlation with its circle of development and its dynamic of population. The importance of this spoiler attacks seem to be influenced by different ecological, biotic and abiotic factors, like the variety, the date of observation, the orientation and finally the tree which have been tested in order to estimate the impact. The adult trappings have permitted to know their dynamics and their breeding which have permitted to obtain the adult to know the sex-ratio, the time of development, the amount of survival and the nature of parasite and its amount of parasitism. Ceratitis capitata (Tephritidae): Host, Parasite; Opius concolor (Braconidae): Parasite. Ceratitis capitata: Hymenopteran parasites, Opius concolor, Recorded, Plant hosts, Citrus sinensis, Ecology, Cultivated land habitat, Citrus orchard, Algeria, Tlemcen; Opius concolor: Dipteran hosts, Ceratitis capitata, Recorded, Cultivated land habitat, Citrus orchard, Algeria, Tlemcen. Arthropods; Hymenopterans; Insects; Invertebrates; True Flies. none2008checked