Isolation and identification of antagonistic bacteria and screening of fungicides against potato scab pathogen

Objective In recent years, potato scab has become increasingly severe in Xinjiang, leading to reduction in potato yield and quality. This study aimed to screen effective and low-toxic fungicides and antagonistic bacteria for controlling the pathogen of potato scab in Zepu County, Kashgar Region, Xinjiang.

Methods The effective and low-toxic fungicides and antagonistic bacteria against potato scab pathogen were screened by plate confrontation method and filter paper method.

Results Among 9 fungicides including prochloraz, dimethomorph, chlorothalonil, etc., 40% prochloraz at the concentration of 700 mg/L showed the largest inhibition zone against Streptomyces acidiscabies, with the diameter of (22.83 ± 1.04) mm. Strain B3 with the best antagonistic effect was screened by plate confrontation method. Based on morphology and 16S rDNA sequence analysis, strain B3 was identified as Bacillus licheniformis.

Conclusion The optimal fungicide against S. acidiscabies is 40% prochloraz at 700 mg/L, and strain B3 with excellent antagonistic effect is identified as Bacillus licheniformis. It can provide resources and basis for green prevention and control of potato scab in Xinjiang.