The present study aims to locate possible foci of infections of fungal and bacterial origins in the olive tree in the Tadla-Azillal region and to estimate the rates of infestation based on a symptomatological diagnosis. Surveys carried out in 11 municipalities and villages (February-April 2017), allowed us to identify the presence of three diseases of microbial origin, two of which are of fungal origin, namely verticillium wilt, and olive scab (Peacock’s eye) and one of bacterial origin, olive knot disease. The importance of scab in the region is 91.30%. The orchards of Beni Mellal, Tagzirt, Mghila and Sidi Jabber, are the most affected by this disease. As for verticillium wilt, one of the most serious diseases of the olive tree, represents 65.21% in the region, particularly in the orchards of Fquih Ben Salah (75%) which are the most affected, followed by Beni Mellal and Azillal with 66.67% and 55.56%, respectively. The importance of bacteriosis in olive groves is around 13.04%. 2 out of 6 (33.34%) douars and the visited municipalities of Beni Mellal region are touched by the disease. In the Azillal region, no sign of this disease is encountered. The assessment of the knowledge of 103 agriculture in the region regarding phytopathologies diseases and wrestling methods reveals that 82.82% with knowledge of the presence of pests and microbial diseases, including the peacock’s eye, psyllid, verticillium wilt which are the most mentioned. However, only 48.52% of these farmers declare the adoption of phytosanitary treatment against these phytopathologies.