Diagnosis and recommendations for management of trees and shrubs in green squares in Warsaw based on research on fungal diseases

Key message Comprehensive management of urban greenery is a key approach to control fungal diseases of trees and shrubs to avoid the deterioration in their health status. Preliminary investigations on the health status related to fungal diseases of trees and shrubs growing in four green squares in Warsaw were conducted in 2017-2019. The examined plants were affected by diseases that are commonly identified in urban greenery, e.g., powdery mildew (causal agents: Sawadaea tulasnei, S. bicornis, Podosphaera leucotricha, Podosphaera sp., Erysiphe alphitoides, E. magnifica, E. berberidis, E. flexuosa and E. adunca), rusts (Gymnosporangium sabinae, Melampsora laricis-populina), apple scab (Venturia inaequalis), tar spot of maple (Rhytisma acerinum), and oyster mushroom (Pleurotus ostreatus). The causal agents of the diseases were identified based on their morphological (macro- and microscopic) features. Preventing and managing fungal plant diseases and reduction of their effects are the key tasks in conscious management of urban greenery. To address this issue, the study presents basic guidelines based on the application of various recommended actions and good practices, which constitute a comprehensive and sustainable strategy for integrated protection of trees and shrubs against these diseases. The implementation of the strategy for complex management of urban greenery is a crucial measure aimed at maintenance of a high health status of urban plants.