author(s)
Kemayou Christelle Flavie Mbieji, Nono Carine Temegne, Stéphane Martial Kamtchoum, Valteri Audrey Voula, Ibrahim Nchoutnji and Jean Kuate

abstract
The study of the bio ecology of black scale insects Parlatoria ziziphi (Lucas, 1853) was carried out for one year (2018) in a citrus orchard of Foumbot on three varieties of mandarin including two exotic (Beauty and Emperor varieties) and one local (Obala variety). The method used consisted of removing two leaves with twigs and counting all of the living mealybugs using a binocular magnifier. It turns out that the climate influenced the global dynamics of living populations. In the Obala variety, mealybugs were more accentuated and distributed evenly in the west, north, south and center of the tree. They pullulated more and equally in the East, South and Center directions for the Beauty variety and more colonized the North side of the Emperor variety. Furthermore, scale insects preferred to settle on the lower parts of the leaves, and did not colonize the twigs. It would be advisable to whosoever wishing to establish orchards to put the improved varieties more and to accentuate the treatments in the dry season by spraying the leaves, especially the lower parts and the most shaded cardinal directions.