Efficacy of Chemicals Against Xanthomonas Axonopodis Pv. Citri Under In-Vitro Condition

Citrus canker, caused by the bacterium Xanthomonas axonopodis pv. citri, is one of the most devastating diseases hampering worldwide citrus production, including in Nepal. Citrus canker is a significant threat to all citrus-growing regions because of its rapid spread, high potential for damage, and impact on export sales and domestic trade. The study was to solve the major problem associated with citrus canker by identifying and evaluating the in vitro efficacy of different chemicals available in the local market. The pathogen was isolated from the diseased plants, and a pure culture was obtained. In vitro efficacy of streptomycin, Bordeaux mixture, kasugamycin, and copper oxychloride was assessed by paper disc technique. The efficacy of different chemicals was compared based on the formation of a zone of inhibition (ZOI). After 48 hours of inoculation, diameters of zones of inhibition were measured in each, and statistical analysis was performed. Streptomycin (100 ppm) was statistically more significant than all other treatments and formed the highest zone of inhibition, followed by kasugamycin (100 ppm). Copper oxychloride (0.3%) and Bordeaux mixture (1.5%) were least effective and found statistically at par. The results revealed that there was a significant difference between different chemicals inhibiting the growth of Xanthomonas axonopodis pv. citri. The study recommends the use of streptomycin (100 ppm) among the chemicals for effective management of the disease. Keywords: Citrus canker, Streptomycin, Xanthomonas axonopodis, Zone of inhibition