Assessment of Urdbean Disease Incidence in Rice Fallow Systems of Krishna District, Andhra Pradesh

Abstract— This study focuses on the surveillance of major diseases affecting urdbean (blackgram) cultivated in rice fallows within the Krishna district of Andhra Pradesh. The research is driven by the significant yield losses caused by major diseases in this region. The primary objective is to assess the impact of these diseases on crop yields to develop effective management strategies. A roving survey was conducted in farmers' fields during the rabi 2022-23 season, with data collected on disease incidence and severity for various pathogens, including Yellow Mosaic Virus (YMV), leaf crinkle, leaf curl, stem canker, leaf spots, and powdery mildew. Results from the Rabi 2022-23 survey revealed varying levels of disease prevalence across different villages and crop stages. The incidence of Mungbean Yellow Mosaic Virus (MYMV), measured on a 1-9 scale, ranged from 1 to 5. The percentage of leaf crinkle incidence varied from 1.63% to 11.54%. Leaf spots were rated on a disease scale of 1-9, with scores ranging from 3 to 6. Powdery mildew severity, assessed on a 0-5 scale, ranged from 2 to 3. The percent incidence of leaf curl was found to be between 0% and 2.81%, while stem canker incidence ranged from 2.18% to 27.73%. The findings of this research indicate that diseases such as powdery mildew, Corynespora leaf spot, leaf crinkle, MYMV, and stem canker are all contributing to yield losses in blackgram.