Influence of Weather Parameters on Cabbage Alternaria Leaf Spot Disease

Alternaria leaf spot of cabbage caused by Alternaria brassicae is the economically one of the most important and widespread disease in India and the world. As the rate of disease increase is dependent on weather factors, weather-based forewarning system enable to guide farmers to take protection measures timely. The field experiment conducted during the period of 2023-24 in the Department of Plant Pathology, College of Agriculture, VNMKV, Parbhani, Maharashtra. The objective of this experiment was to find out the influence of weather parameters on the initiation and spread of the Alternaria leaf spot of cabbage disease and develop a suitable weather based disease forewarning equation. Correlation data analysed revealed that the Alternaria leaf spot disease development was negatively correlated with rain fall (-0.144), minimum temperature (-0.368), bright sunshine hours (-0.393) and wind speed (-0.612). Whereas maximum temperature (0.642), morning relative humidity (0.562), evening relative humidity (0.271), and evaporation (0.644) were positively correlated. Co-efficient of determination R² value (0.61) represent that 61 per cent influence on the intensity of Alternaria leaf spot by two independent variables viz., minimum temperature (°C) and bright sunshine hours (hr).