Vegetos

Abstract

Citrus canker disease caused by Xanthomonas axonopodis pv. citri is one of the most devastating diseases that affects many kind of commercial citrus varieties. Citrus canker is a disease affecting citrus species caused by the bacterium Xanthomonas axonopodis. Infection causes lesions on the leaves, stems and fruit of citrus trees. While not harmful to humans, scanker significantly affects the vitality of citrus trees, causing leaves and fruits to drop prematurely; a fruit infected with canker is safe to eat, but too unsightly to be sold. The main symptoms of citrus bacterial canker are hyperplasia type lesions on leaves, fruits and a stem which is severe infections can cause leaf abscission, twig dieback and premature fruit drop. Attempts have been made to device an effective and economic method for its control including use of antibiotics, but partial success has been achieved due to their various limitations. Xanthomonas axonopodis is a rod shaped gram - negative bacterium with polar flagella. The observed that the bacterium was gram negative, rod shaped and showed positive results in KOH solubility test. A bacterial suspension of each specimen was then cultured on YDCA media, suspected colonies were transferred onto YDCA media and incubated at 28°C for 2–3 days. The Xanthomonas axonopodis pv. citri colonies grown on YDCA media were yellow and mucoid. For identification Gram s staining was performed to determine the size, shape, arrangement and gram reaction of the isolates. KOH test identified the biochemical characterization of the bacterium Xanthomonas axonopodis pv. citri. To confirm Koch s postulates, bacteria were re-isolated from the infected area