الفهرس 
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Abstract
Scale insects are the most injury pests of orchard crops, shrubs and ornamental trees. During the course of these study, which extended for two years at a farm not treated with pesticides at Agricultural Research Center, Sids of Beni- Suef. Survey of natural enemies of some scale insects and the population abundance were studied. The role of parasitoids in regulating the population of the oriental yellow scale, A. orientalis, the maskell scale, L. pallida and the african scale, L. africana have been studied. Also, biological studies on one hymenopterous parasitoids viz. E. lounsburyi was carried out.
The study revealed that 24 entomophagous insect species parasitized on scale insects were studied, from which, 19 hymenoptrous parasitoids species and 5 predacious insect species were surveyed during this study.
The seasonal fluctuation of population showed that; A. orientalis had 4 annual peaks of abundance and 4 annual generations. However, L. pallida had 4-5 annual peaks of total population and 4-5 annual generations. As for L. africana, it had 2-3 annual peaks of abundance and 2-3 annual generations were observed for the African scale during the two years of study.
The highest percentage of parasitism reached 52 % on A. orientalis during 2008/2009. However, as for L. pallida the percentage of parasitism was 75% in the second year 2009/2010. In case of L. africana the percentage of parasitism was 58% throughout the second year 2009/2010.
The durations of immature stages of E. lounsburyi were 2.75, 2.68, 2.59, 3.16 days for the egg, three larval instars. Also 1.00 and 6.56 days pre-pupa and pupa, respectively.