Abstract
Canker is the most devastating threat of citrus being caused by Xanthomonas axonopodis pv. citri (Xac). A trail was conducted in the citrus pathology Laboratory, Department of Plant Pathology, University of Agriculture Faisalabad. Nine antibiotics Levofloxacin, Streptomycin, Ampicillin, kanamycin, Erythromycin, Ciprofloxacin, Clarithromycin, Azithromycin, Amoxicillin were tested against Xac by using inhibition zone technique under Completely Randomized Design (CRD). Three concentrations (300, 500 and 700 ppm) were tested. Out of these nine, Levofloxacin expressed best result by producing 14.22 mm mean inhibition zone followed by Ciprofloxacin (13.18), Ampicillin (6.89), Kanamycin (6.64), Clarithromycin (6.01), Azithromycin (5.24), Streptomycin (4.98), Amoxicillin (4.79), Erythromycin (4.29) mm respectively. In interaction between treatments and concentrations, Ciprofloxacin expressed maximum inhibition zone (15.06 mm) at 700 ppm while in interaction between treatments and time, levofloxacin exhibited maximum inhibition zone (15.00 mm) after 36 hours. In conclusion, Ciprofloxacin and Levofloxacin expressed best results at 700 ppm after 36 hours.