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Background: The Alternaria blight of pigeonpea is considered as an important foliar disease and poses threat to the pigeonpea cultivation due to change in the climatic condition, cultivation practices and variation in pathogenic character. Though the disease is noticed in an alarming proportion after the post rainy season and causing economic yield, little is known about the severity of disease and its impact on crop production. The current study is aimed to study the disease severity and variability of the pathogen and which would helps us to understand the biology of the pathogen to develop suitable management strategies. Methods: In the field and laboratory investigations during 2015 and 2017, different localities of Northern Karnataka were surveyed. Twenty sampling localities were selected based on geographical situation. In the laboratory, collected diseased samples were isolated and determined morphologically and culturally based on taxonomic and molecular characters. Result: Our investigations revealed the varied disease severity in surveyed districts, Vijayapura district recorded the maximum disease severity with a range of 38.67 to 49.33 and this might be due to variation in pathogenic character, rainfall pattern and climatic conditions and also disease severity varied with varieties indicating the source of resistance. The present study contributed for identification of geographical distribution of the disease and its severity in different varieties and places of Northern Karnataka and their genetic and morphological variations.

Six antibiotics, two antibacterial chemicals and five bio-agents were evaluated by in vitro against Xanthomonas axonopodis pv. citri (Hasse). Among the different antibiotics and antibacterial chemicals, Streptocycline (10.84 mm) and copper oxychloride (7.50 mm) showed maximum inhibition zone followed by K cycline (9.68 mm). Among the bio-agents, Bacillus subtilis was effective with the inhibition zone of (16.16 mm) followed by Pseudomonas fluorescens (14.63 mm). The fungal bio control agents viz., Trichoderma viride and Trichoderma harzianum were found totally in effective against the pathogen.How to view point the article : Badiger, Nagaraj, Yenjerappa, S.T., Naik, M.N., Patil, M.B. and Patil, M.G. (2016). Evaluation of antibiotics, antibacterial chemicals and bio-agents against citrus canker caused by Xanthomonas axonopodis pv. citri (Hasse). Internat. J. Plant Protec., 9(2) : 566-569,

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