Screening of Fungicides and Drug Resistance Analysis for Xanthomonas axonopodis pv. citri

Citrus canker is an critical bacterial disease in the world. Chemical control is one of the most important measures for the disease. In this study, the sensitivities to eight kinds of bactericides on 21 strains of Xanthomonas axonopodis pv. citri (Xac) mainly from Guangdong and Jiangxi Province were tested by using bacteriostatic experiment in the plate. The results showed that bismerthiazo (1 000×)， new phytomycin (2 800×) and oxytetracyclini hydrochloridum (1 300×) had few effects on 21 bacterial strains. Streptomycin, zhongshengmycin，peracetic acid，copper hy-droxide ziram and bouillie bordelaise had different levels of bacteriostatic action, while streptomycin had the best effect on Xac. However，some Xac strains showed different resistances to these fungicides. In addition, streptomycin and zhongshengmycin showed better control effects on citrus canker disease in the field.