Deciphering Weather Disease Interactions and Epidemiological Drivers of Early Blight in Tomato (Lycopersicum esculentum L.) Caused by Alternaria solani

Abstract

Early blight of tomato, caused by Alternaria solani, is a major disease in tropical and subtropical regions. It survives in soil and plant debris and is strongly influenced by temperature, humidity, and rainfall, which favor its spread and severity, leading to significant yield losses. The present investigation was undertaken to assess the relationship between weather parameters and the development of early blight disease in tomato during the Rabi seasons of 2022–23 and 2023–24. The disease incidence was first observed on 5th February (90 days after transplanting), progressed rapidly from early to late March, and declined by the first week of April. Correlation analysis indicated that maximum temperature had a significant positive association with percent disease intensity, whereas relative humidity (both maximum and minimum) and rainfall exhibited positive but statistically non-significant relationships during both years of study. Multiple regression analysis revealed that the combined influence of temperature, relative humidity, and rainfall played a significant role in disease progression. The coefficient of determination (R²) ranged from 85.54% to 89.90% in 2022–23 and from 64.15% to 73.23% in 2023–24, suggesting that a substantial proportion of disease variability was explained by these environmental factors. Overall, the findings highlight the importance of meteorological parameters in predicting early blight dynamics and support the development of effective disease forecasting and management strategies.