The parasitoids of the olive fly Dacus oleae (Gmel).
Notes are given on 5 species of parasitoids (Eupelmus urozonus, Eurytoma martellii, the eulophid Pnigalio mediterraneus [P. agraules], the pteromalid Cyrtoptyx latipes and the braconid Opius concolor) attacking Dacus oleae on olive in Italy. Most of them were not exclusive to the tephritid, and none of them controlled it sufficiently well for natural or augmented populations to be used as the sole means of control. However, in the Umbria region, careful studies of the yields of olives at different degrees of infestation have permitted the compilation of tables of economic thresholds for different olive varieties that can be used to determine the effectiveness of parasitism at a given time and the best timing of chemical treatment once the economic threshold has been exceeded; by this means the number of chemical applications can be reduced to 3-4/year. Research is recommended into possible baits to be applied in sprays in order to attract parasitoids in larger numbers to Dacus-infested olive trees.