RESEARCHES INTO THE BEHAVIOUR OF THE ARTIFICIALLY REARED OPIUS CONCOLOR (HYM. BRACONIDAE) UNDER THE CONDITIONS OF THE DALMATIAN OLIVE GROVES DURING 1972.

Sa？etak The paper gives results of the releases of Opius concolor conducted on the islet of Babac (Pa？manski kanal - Pa？man Channel-near Biograd) and of the studies on the population density of the olive fruit fly on the same islet and on several locations in the Northern and Central Dalmatian Littoral. On the basis of the obtained results it has been concluded that the olive fruit fly can be kept during winter and spring in its adult stage. On the mentioned area, during 1972, the presence of the following larviparasites of the olive fruit fly was recorded: Cyrtoptix dacicida MASI (Hym. Braconidae), Eurytoma martelli DOM. (Hym. Eurytomidae) and Eupelmus urozonus DALM. (Hym. Eupelmidae). The obtained results have shown that the released O. concolor can influence greatly the population density of the olive fruit fty. The economic effect, however, will depend on the age and number of the released individuals, on the density of the olive fly population, on the intensity of its translocational propensities, and also on the right integration of the mentioned biological treatment with the other treatments used in the protection of the olives. According to the obtained results it follows that the released O. concolor can disperse also over larger distances. The degree of its dispersion, however, will depend on the intensity of the attack by the olive fruit fly. When the attack is stronger the dispersion of the released parasites is significantly weaker due to the ensured possibility of its reproduction on a smaller area