Paraskakis, M., Neuenschwander, P., & Michelakis, S.E. 1980 Saissetia oleae (Oliv.) (Hom., Coccidae) and its parasites on olive trees in Crete, Greece.. Zeitschrift fur Angewandte Entomologie 90(5): 450-464.

Notes: Studies were carried out in Crete, Greece, between 1975 and 1979 on the biology of Saissetia oleae (Ol.) on olive trees by recording monthly population numbers, parasitisation rates, climatological data and effects of insecticide applications. Outbreaks of the pest were frequent, mainly in humid regions of the island. Differences in the scale density between the minimum in spring and the maximum in the following winter were in the order of 100 times. The olive variety Tsounati was preferred by the pest as a food-plant to Koroneiki. In all areas, populations increased during a cool and humid summer. The population collapses during the following year were reinforced by hot, dry weather, but basically the cyclic population changes were attributed to the changing condition of the food-plant. Parasites of S. oleae (of which the most numerous were Metaphycus lounsburyi (How.) and M. helvolus (Comp.)) exhibited a delayed density-dependent reaction in several localities. Density dependence was alsofound when the parasitisation rates of different areas were compared at the same time. Parasite activity was reduced in the mountainous regions. Overall, the cyclically changing scale populations were larger in an area where parasitism was reduced because of insecticide drift from nearby plantations of table grapes. Parasitisation rates were also lower in areas sprayed from the air against Dacus oleae (Gmel.), as compared with orchards which were treated from the ground and/or where insecticide applications were reduced. A total of 8 primary and 6 secondary parasites was reared from S. oleae. The hyperparasites accounted for only 1.1% of the total parasite population. Some released exotic parasites became established but had only a small impact on the S. oleae population.