In vitro bio-efficacy of different antibiotics and bio-agents against bacterial canker (Xanthomonas axonopodis pv citri) of acid lime

Four antibiotics in combination with antibacterial chemicals and two bio-agents viz Pseudomonas fluorescens and Bacillus subtilis, were evaluated in vitro against Xanthomonas axonopodis pv citri (Hasse). The results revealed that among the different antibiotics, in combination with antibacterial chemicals, streptocycline (100 ppm) + copper oxychloride (0.25%) showed higher inhibition zone (10.0 mm) as compared to kasugamycin (0.15%) (8.6 mm) and validamycin (0.2%) + copper oxychloride (0.25%) (8.8 mm). In vitro study of bio-agents by dual culture method revealed that P fluorescence showed maximum inhibition zone (97.2%) followed by B subtilis (92%). In vivo evaluation of antibiotics in combination with antibacterial chemicals and bio-agents revealed that the minimum disease intensity of 19.53 and 19.63 per cent was recorded in streptocycline (100 ppm) + copper oxychloride (0.25%) and streptocycline (100 ppm) + copper hydroxide (0.5%) with 40.41 and 39.46 per cent disease control respectively. Maximum disease intensity was recorded in control (32.50%) with 0.0 per cent disease control followed by B subtilis (5 g/l) (27.41%) and P fluorescence (5 g/l) (26.43%) with disease control of 16.81 and 19.20 per cent respectively.