THE OLIVE FLY (DACUS OLEAE GMEL.) IN CRETE, GREECE

The olive fly is the most important olive pest in Crete. Experiments for studying this insect were carried out in different areas. In the plains of Crete the olive fly adults are active all the year round with the maxima of catches in spring, in June-July and during autumn. In highlands the olive fly catches start in March-April with a maximum in May-June and then they continue until October. The percentage of the mature females is very much reduced during the period from end of May until the beginning of July. The fruit infestation starts end of May in the plains. Comparing the population structure and phenology between olive fly populations in olive groves with those on different species of other fruit trees, ornamentals and wild plants growing nearby to the olives, it was found that the population structures (sex ratio, sexual maturity of females) and phenologies are virtually identical in the two situations. The fly density is always higher in the olive groves but captures on other trees are sometimes important especially during periods when the host plant lacks olive fruits. Among the olive fly parasites most important are the chalcid ectoparasites Eupelmus urozonus Dalm, and Pnigalio mediterraneus Fer. et Del. as well as the braconid endoparasite Opius concolor Szepl.