Preliminary results for the eνaluation of the action of Saissetia oleae parasites in Corfu.

Abstract

The action of parasites of Saissetia oleae (Oliv.) (Homoptera-Coccidae) is studied in Corfu from 1980 in the framework of an ongoing project on the population dynamics of Saissetia oleae.Results obtained during the period 1980-1983 from 17 experimental sites indicate the following: a) the population of S. oleae increased in 1981 but from 1982 it declined to very low levels; following the overall decline of the host population, parasitization rates of third instar larvae (mainly by Metaphycus helvolus Comp.) were relatively low and ranged from 2.1 % to 6.7% for the autumn period and from 14.6% to 29.4% for the spring period; this does not minimize the possibility that Metaphycus helvolus plays an important role on the regulation of 5. oleae populations; b) a considerable proportion of females of S. oleae is attacked during summer by Metaphycus lounsburyi How. (an internal parasite on preovipositing females), Moranila calif arnica How. and Scutellista cyanea Motsch. (egg predators), but their significance upon the population system of 5. oleae is not expected to be great. The action of Metaphycus lounsburyi in spring, when the peak of the suitable stage occurs (i.e. fourth instar larvae), appears to be very low, at least for these three years. Its action is delayed and most of the specimens of this parasite emerge from ovipositing females in early summer. Among the species attacking S. oleae females, M. californica (recently introduced in Corfu) was the most abundant and it might be worthy to be introduced to other parts of Greece too.

Flight period of some parasitoids and a predator of the olive black scale (Saissetia oleae Olivier) on Corfu island

“…and Moraniia californica (Howard) (Hymenoptera: Pteromalidae), and Chilocorus bipustulatus (L) (Coleoptera: Coccinelidae) (a predator of the first larval stage) were determined. These parasitoids are the main natural enemies of the olive black scale on Corfu island (Stratopoulou and Kapatos 1984, Stratopoulou et al 1981, Viggiani et al 1975, Viggiani 1978.…”

Population dynamics of Saissetia oleae. II. Life-tables and key-factor analysis

“…Stratopoulou andKapatos 1984). Direct measurements of all mortalitv factors or separation of stage mortality into specific morta lities from various causes of death would allow the construction of multiple decrement life-tables and the evaluation of every single mortality factor (Morris 1959, Cameron and Morrison 1977.…”

Population dynamics of Saissetia oleae. Ι. Assessments of ροpulation and mortality

“…(Homoptera-Coccidae) is one of the most important pests on olives in Greece and other Mediterranean countries. The biology and phenology of S. oleae on olives in Greece has been studied in detail (Argyriou 1963, Viggiani et al 1975. Stratopoulou and Kapatos 1984 and in Corfu it is mainly univoltine.…”