Selection of Effective Antibiotics and in vitro Monitoring of Sensitivity in Xanthomonas campestris pv. campestris Isolated from Highland Kimchi Cabbage (Brassica rapa subsp. pekinensis) in Korea

다국어 초록 (Multilingual Abstract)

Black rot, caused by Xanthomonas campestris pv. campestris (Xcc), is a major threat to highland Kimchi cabbage in Korea. Due to a lack of registered pesticides, antibiotics labeled for other cruciferous diseases are often used, raising concerns about resistance. This study evaluated the susceptibility of 11 Xcc strains (8 field isolates and 3 reference strains) to five antibiotics. Oxytetracycline (OTC) and oxolinic acid (OA) exhibited the greatest antibacterial efficacy, displaying a steep dose-dependent inhibition profile starting from 10 ppm. In contrast, kasugamycin (KAS) and validamycin A (VA) exhibited significantly lower activity, particularly within the field application range (50–300 ppm). These findings suggest a decline in the field efficacy of KAS and VA and highlight the urgent need to register OTC and OA for effective Xcc management in Korea.