Citrus Infestation by the Black Scale Parlatoria ziziphi Lucas (Homoptera: Diaspididae) in Tlemcen, Algeria

摘要

The study of citrus infestation by the black scale Parlatoria ziziphi Lucas 1853 (Homoptera,Diaspididae) is realized between 2012 and 2013 on two citrus varieties (Thomson and Portuguese) in El Fehoulstation in Tlemcen in the North-West of Algeria. This study shows that Parlatoria ziziphi is present in bothvarieties and the upper surface of leaves is is always more infested than the lower surfacess. In terms of leavesinfestation rates, it’s very important at the southern exposure and the center of the plot for Thomson varietyand with 100 % in the southern and northern exposure of the Portuguese variety. The rate of fruit fruitinfestation is the most important in the south with 87.9 % for Thomson variety and 79 % for the Portuguesevariety. The infestation rate of the leaves does not change after harvesting the fruit. This species of scale insectis cosmopolitan and it attacks many species of Citrus family. It is also very common on citrus in Algeria.