Populations dynamic of Saissetia oleae (Oliv.) (Homoptera, Coccidae) on the olive tree
1986
Pucci, C. | Dominici, M. | Prosperi, G. | Forcina, A.
德语. This study reports some data periodic surveys of vegetation in a typical Umbrain olive grove (Central Italy) over a two-year period, 1983-84. The descriptive analysis of the data shows that: - the insect population present on leaves in always higher than that on twigs, - the ratio between the number of living and dead insects increases with the age of the coccid even if the ratio depends on how long the coccid remains in a particular instar or stage of development, - the extent of parasitization was rather modest, - the insect winters mainly in the form of 3rd instar larva or, less frequently, as 2nd instar larva or young female. A statistical model was formulated based on the assumption of constant birth, mortality and drop rates between two successive surveys. This model can be used to estimate the extent of the birth, mortality and drop rate in a sample unit of vegetation. In particular the application of the above model showed that: - mortality is highest for 1st instar larvae and it is associated with periods marked by high temperature, - the extent of drops increases with instar stage and is most intense in the rainy periods
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