<p>This monograph can be divided into three parts. The first part is the classification and identification of fungi. It describes in detail the morphological characteristics of more than 200 species of pathogenic fungi in 76 genera, covering Ascomycetes and Basidiomycetes, focusing on the analysis of newly recorded species of the Erysiphaceae family, such as Erysiphe cichoracearum f. Morphological variation and host specificity of saussurea. The second part is about the distribution and ecology of fungi. Based on field survey data from 1951 to 1960, the distribution laws of fungi in different ecological areas (desert grasslands, mountainous forests) were revealed. It was found that the dominant bacterial groups in arid areas were powdery mildew and Aspergillus., while rust is more abundant in high-altitude areas, and the impact of temperature and precipitation on the spread of fungi was discussed. The third part is disease control and economic impact. For fungal diseases in agricultural crops (such as wheat and alfalfa) and economic forests (such as apples and poplar), chemical control (sulfur mixtures, copper preparations) and biological control (antagonistic microorganisms) are proposed. The strategy is combined, and the loss rate of the disease on crop yield (such as powdery mildew causes wheat production to be reduced by 15%-20%) is also evaluated. The full text provides basic data for the study of plant diseases in arid areas of Central Asia and has important agricultural science and ecological value. </p>