Climatic Influence on the Growth and Severity of Powdery Mildew Fungi: A Review of Regional and Crop Specific Studies

Abstract Powdery mildew is a widespread foliar fungal disease caused by several obligate biotrophs in the order Erysiphales, affecting economically important crops and wild plants worldwide. Unlike most foliar fungi, powdery mildew thrives in dry yet humid conditions and is highly sensitive to climatic variables such as temperature, relative humidity (RH), and sunshine. This review synthesizes published studies on the relationship between climate and powdery mildew incidence across various agro climatic zones, with special reference to India. The results show that morning RH above 60%, moderate temperature (18–28°C), and low rainfall favor conidial germination and disease severity. Extremely high RH (>90%) or rainfall tends to inhibit disease development due to spore lysis or physical wash off. Studies also show variability among host species and regional responses. Understanding these interactions is essential for forecasting disease outbreaks, guiding fungicide application timing, and preparing climate resilient crop disease management strategies. Uniquely, it thrives under dry but humid conditions and is highly influenced by climatic factors such as temperature, relative humidity (RH), and rainfall. This review compiles and analyzes findings from numerous regional studies, especially in India, to elucidate the impact of climatic variables on the development and severity of powdery mildew across different crops. Conversely, excessively high RH or intense rainfall may inhibit disease progression by disrupting spore viability. Variability in pathogen behavior across crops and climatic zones highlights the importance of localized disease forecasting and climate-resilient management strategies. This synthesis provides crucial insights for timing fungicide applications, adjusting cropping patterns, and developing predictive models under evolving climate conditions.