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.
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Introduction
Urdbean [Vigna mungo (L.) Hepper], also known as blackgram is a short-duration pulse crop often grown in rice-fallow systems in many parts of Asia. Urdbean is suitable for rice fallow situations due to its ability to thrive in residual moisture and its short duration. Specifically, sowing urdbean immediately after rice harvest, potentially with an increased seed rate, can be an effective strategy for maximizing yields and profitability in these systems. Despite immense scope, the extensive use of rice fallows for pulse cultivation is mostly restricted because of several biotic, abiotic and socio-economic constraints (Pande et al., 2000). Among the biotic constraints, several fungal, viral diseases, insect pests and nematodes constraint both cool season and warm season pulses production in rainfed rice fallow lands (Pande et al., 2012).
Krishna district, located in the coastal region of Andhra Pradesh, is recognized for its fertile lands and extensive rice cultivation. Consequently, urdbean is a major rabi (post-monsoon) crop in the district, thriving in the black cotton soils that retain moisture effectively. In rice fallow areas urdbean and mungbean are susceptible to Mungbean Yellow Mosaic Virus (MYMV), besides they are susceptible to powdery mildew, cercospora leaf spot and also to leaf curl virus (Narendra et.al., 2018). An in-depth understanding of disease incidence is critical for enhancing urdbean (Vigna mungo) productivity, particularly within the rice fallow pulse systems of Krishna District, Andhra Pradesh. This research helps in reporting the findings of a survey conducted to identify and assess the prevalence and severity of major diseases affecting urdbean cultivated under rice-fallow conditions in Krishna district, Andhra Pradesh during rabi 2022-
Conclusion
The survey confirms that several major diseases, including MYMV, Leaf Crinkle, Powdery Mildew, Leaf Spots, and Stem Canker, significantly affect urdbean yields under rice-fallow conditions in Krishna district. These fungal, bacterial, and viral diseases are considerably contributing to yield reduction. The results suggest that continuous monitoring of these diseases could aid in developing a disease forecasting system that farmers could adopt for timely management of diseases.
