A novel biocontrol strain Pseudomonas canadensis FRPC18 against box blight (causative agent Calonectria pseudonaviculata)

Background Recent box blight epidemics caused by Calonectria pseudonaviculata ( Cps ) have created the need for finding eco-friendly management strategies, especially in natural habitats. In the present research, the biocontrol activity of 26 bacterial isolates against Cps was investigated under laboratory and greenhouse conditions in a completely randomized design ( n = 3; P < 0.05). Results Strains FRPC18, FRPF4, and FRPF6 showed the most efficiency in the inhibiting Cps colony by 72.4, 46.8, and 34.2% through a dual culture test, respectively. The superior strain, FRPC18, identified belonged to Pseudomonas canadensis . FRPF6 volatile and FRPC18 non-volatile antifungal compounds resulted in the highest inhibition rate of 27.67 and 59.43%, respectively. Strain FRPC18 could also produce the maximum amount of chitinase, significantly, while the highest amount of siderophores was detected in FRPF4. There were non-significant differences among the bacterial strains in producing protease and pectinase. In the greenhouse, FRPC18 reduced box blight severity by 30% and had non-statistically significant differences with Serenade® as a biofungicide ( P < 0.05). Conclusion The results of this study suggest that P. canadensis may be a new biocontrol agent for controlling box blight in disease hotspots during epidemics in boxwood forests.