To develop biocontrol agents for the control of kiwifruit bacterial canker, we isolated a strain CXG2-5 with inhibitory activity against Pseudomonas syringae pv. actinidiae (Psa), the pathogen of kiwifruit bacterial canker, from the rhizosphere soil of kiwifruit by the plate confrontation test. The strain was identified by morphological observation, physiological and biochemical tests, and molecular biological methods. The indoor control efficacy of the strain was determined by the inoculation of the strain into detached branches with wounds and into leaf discs by vacuum infiltration. The ability of the strain to expand and colonize leaf veins was determined by fluorescent labeling and scanning electron microscopy. Subsequently, the strain was prepared into microcapsules, the field control efficacy of which was evaluated. The strain CXG2-5 was identified as Pseudomonas benzenivorans. It demonstrated good antagonistic activity against Psa, with an inhibition zone diameter of 22 mm and an inhibition rate of 72.7%. The preventive effects of the strain on kiwifruit bacterial canker were better than the therapeutic effects on both detached branches and leaves, with the preventive effects reaching 65% and 92.4%, respectively. The control effect of microcapsules of this strain in the field reached 60.89%, which was slightly lower than that of 20% kasugamycin and higher than that of Bacillus subtilis wettable powder. In conclusion, strain CXG2-5 serves as a candidate for the control of kiwifruit bacterial canker, and the prepared microcapsules have good value for development and application.
Actinidia/microbiology* ; Plant Diseases/prevention & control* ; Pseudomonas syringae ; Pseudomonas/isolation & purification* ; Capsules ; Antibiosis ; Biological Control Agents ; Pest Control, Biological/methods*