Abstract
In the present study, an assessment was conducted on the susceptibility of three rose varieties most commonly used in the landscaping of Astana (Rosa hybrida, Rosa spirea, Rosafloribunda) to the powdery mildew pathogen under controlled inoculation conditions. The aim of the experiment was to identify differences in the manifestation of disease symptoms, as well as to determine the influence of climatic factors on the development of pathogenesis.The results revealed significant varietal differentiation in response to infection. In Rosa hybrida, a pronounced white powdery coating developed on the upper side of the leaves seven days after inoculation, accompanied by tissue blanching and reduced turgor, indicating active disease progression. Rosa spirea exhibited minimal symptoms: slight darkening of the central leaf area and a barely visible coating, suggesting a possible resistance to the pathogen. Rosa floribunda proved to be themost susceptible, with severe leaf infection observed as early as the fifth day, reaching 70% by day seven, followed by tissue blackening and necrosis.Additional analysis of climatic data (April 2024 –April 2025), obtained from open sources of the Kazhydromet Center, indicated that moderate temperatures and high relative humidity provide optimal 65conditions for the development of powdery mildew. Thus, the findings highlight the importance of considering both varietal specificity and weather conditions when planning sustainable urban landscaping