Ecological and Biological Studies on Some Predaceous Mites in Qalubia Governorate

Abstract

Population density of phytophagous mites; scale insects and predacious mites was studied during two years in two regions at Qalubia governorate Population dynamics of Brevipalpus californicus has one annual peak of seasonal abundance in June on leaves of Navel orange during two successive years. The population dynamics of Phyllocoptruta oleivora, and Eutetranychus orintalis also, has annual peak of seasonal abundance in December and August on leaves, respectively. The population density of the three phytophagous mites was positively correlated with average temperature. The population dynamics of scale insects, data indicated that scale insects have one peak in August during two successive years. The predacious mites, Typhlodromus athiase; Cheyletogenes ornatus; Agistemus exsertus and Saniosulus nudus were surveyed on navel orange trees. These predators play an important role in controlling phytopha ous mites and scale insects. The population dynamics of predacious mites showed negative correlation with average temperature and it was positive correlation with relative humidity. Also, biological studies were canied out on the predator Agistemus exsertus to study the effect of four kinds of food and five degrees of temperatures on biological aspects on this mites. Results indicated that the optimal temperature was 28°C and

the suitable food was the eggs of

' Tetranychu

s urticae. While in the

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case of Saniosulus nudus the optimai temperature was 30°C and the suitable food was the eggs of Lepidosaphus beckii. In case of T. athiase the optima temp. degree was 28°C and the suitable food was eggs of Tetranychus urticae.