Some Powdery Mildew fungi distributed in Zarafshan National Nature Park

Abstract

The tugai forests of the Zarafshan National Nature Park represent a unique ecosystem currently facing various environmental stressors. Among the biotic factors affecting these forests, powdery mildew fungi (Erysiphales) play a significant role in compromising plant health and forest stability. This study provides the first systematic analysis of the species composition of powdery mildew fungi within the park. Morphological characteristics, including mycelial structures, conidia, and chasmothecia, were analyzed for taxonomic classification. Disease prevalence and severity were assessed using Dementova’s 5-point scale across 19 species of higher plants from 9 families. The investigation identified 13 species, 8 forms, and 4 variations belonging to three primary genera: Erysiphe , Leveillula , and Uncinula . Significant findings include the identification of key pathogens such as Erysiphe alphitoides (on Quercus robur ) and Erysiphe platani (on Platanus orientalis ). The study notes that while these fungi inhibit photosynthesis and lead to plant desiccation, the teleomorph stage of E. platani is infrequently observed under local environmental conditions. Furthermore, anthropogenic factors like receding water levels and gravel extraction were found to exacerbate plant vulnerability. The research establishes a critical mycological map and biological cycle data (e.g., overwintering patterns) necessary for timing conservation interventions. These findings serve as a scientific and practical framework for protecting the biodiversity of the Zarafshan River basin and regulating economic activities to preserve the ecological integrity of tugai forests.