Epidemiological Factors Influencing the Development of Bacterial Blight in Clusterbean in Semi Arid Eastern Plain Zone –IIIA of Rajasthan, India

Background: The bacterial blight caused by Xanthomonas axonopodis pv. cyamopsidis is the most destructive disease of clusterbean causing tremendous losses in yield and quality under severe conditions. Methods: The effect of environmental factors on the development of bacterial blight disease of clusterbean on susceptible cultivar RGC-936 on experimental field at RARI, Kharif 2018 and 2019. The seeds of susceptible cultivar RGC-936 were sown by staggered sowing at 10 days interval initiated from 10th July, 20th July, 30th July, 9th August and end with 19th August in field conditions. The plot size was 3 x 2 m2 and spacing 30 x10 cm between row to row and plant to plant, respectively. After sowing, 30 days old plants were inoculated by spray inoculation method with a bacterial suspension (2.5x108cfu/ml). Results: The maximum bacterial blight disease severity was recorded during the period between 36th to 37th standard meteorological weeks (3rd Sept. to 16th Sept.). Hence, the first fortnight of September to the second fortnight of September can be considered as window period for bacterial blight disease.