Green areas are a special element of the urban environment. Trees are essential for healthy communities and people. The state, conservation and development prospects of plantations constitute a whole complex of difficult and important scientific and practical problems. The complex of tree diseases is the most important factor of negative impact in urban plantations. Both infectious and non-infectious types of diseases can be found in green spaces. In park plantings, rot diseases and various infectious lesions of leaves dominate; while in street plantings, non-infectious leaf necrosis and necrosis-cancerous lesions of trunks and branches predominate. The goal of the study was to identify diseases of the most common to the urban area of Chisinau Norway maple (Acer platanoides) and to evaluate the effectiveness of biological con-trol of powdery mildew using a consortium of microorganisms.