Study of the level of infestation by the white cochineal Parlatoria blanchardi Targ.1868 (Homoptera, Diaspididae) on the principal varieties of date palm in the valley of Oued Righ (South East of Algeria)

Abstract

In the palm groves of the region of Oued Righ, the density of white cochineal varies according to several factors. We quote the variety, the age of the palm tree and the foliar crown. The variety Deglet Nour is more infested with regard to Ghars and Degla Beida with respectively 23.25; 9.06 and 1.57 cochineals / cm2. Concerning the foliar crown, the infestation is higher at the level of the lower crown with 41.65 cochineals / cm2 for Deglet Nour, 15.61 for Ghars and 2.21 for Degla Beida. On the other hand, the low infestation is registered at the level of the superior crown with respectively 5.35; 2.13 and 1.03 cochineals / cm2. As for the age of palm trees, the young palm of Deglet Nour are more affected with regard to the old palm trees with respectively 24.11 and 22.39 cochineals / cm2.