author(s)
Meddich Abdelilah and Boumezzough Ali

abstract
The present study illustrated the impact of Potosia opaca larva as devastating of two species Phoenix Canariensis and Phoenix dactylifera. We examined the possible relationship between the health status of palm trees and the soil quality of plantations. This study was performed on oases of Marrakech and Errachidia during the period of 2014-2016. The present study results showed that the larvae found belong to Potosia opaca var. cardui Gyllenhal. Chemical and mineral analyses showed that the level of organic matter was higher in soil of Marrakech palm grove (2.06-3.62%) than in Errachidia (1.51%). Levels of available phosphorus (6.98 ppm) and total nitrogen (0.05%) were very low in soils of Errachidia palm groves. K, Cl, Fe, Zn and Cu contents were high in the planting soils of P. Canariensis without exceeding the anomaly thresholds. Lead concentration was found to be low in the studied soils (< to 16 ppm). Phytopahtological analyses show the presence of saprophytic fungi in particular the Dimaties and genus Fusarium with a non-virulent strain. Finally, the present study proposed a strategy to control the larvae of Potosia Opaca to limit its risk of contamination of Moroccan oases.