The Preliminarily Research On Biocontrol Of Kiwifruit Bacterial Canker In Shaanxi

Bacterial canker disease is one of the most truculent diseases on kiwifruit, not only influencing the output of fruits seriously, but also depressing the quality of fruits greatly. In China, several serious results were due to, such as destroying the plants and gardens. Now, it has been taken a place in the China Forestry Plant Quarantine Objects.This research aimed at isolating and screening antagonistic Bacillus with great activity on the pathogen of Kiwifruit Bacterial Canker from the root soil, collected from the healthy plant of 5 gardens in Shanxi; identifying the antagonistic strain; optimizing the fermentation medium and conditions; applying in curing of the field disease with reasonable and effective method, at last.(1) In order to certain the pathogen of Kiwifruit Bacterial Canker, one virulence strain was isolated from the spot tissues, colleted from 5 kiwifruit gardens. According to Koch's principle, morphological, cultural, and physiological-biochemical characteristics of the strain, it was designated to Pseudomonas syringae pv. Actinidiae, as the pathogen of Kiwifruit Bacterial Canker.(2) In the experiment, 115 strains of Bacillus were isolated from 25 soil samples, collected from 5 kiwifruit gardens, heated at 80℃for 10 min.(3) During the selection of Bacillus, a new bacillus strain B56-3, which had strong antagonistic effect on the pathogen, was selected through fermental filtrate plate experiments, single-cell isolations and pot experiments.(4) Based on morphological, cultural, and physiological-biochemical characteristics of the strain B56-3, it was regarded as Bacillus subtilis preliminarily.(5) In the research, the femental medium and conditions was optimized by single factor and complex factor design (orthogonal design) method. The optimum medium was : glucose 1%, sucrose 1%, cornmeal 3%, soybean flour 2%, yeast paste 0.2%, ZnSO₄·7H₂O 0.06%, K₂HPO₄·3H₂O 0.05%; the favorable condition was: temperature 35℃, original pH 7.0, rotation speed 150 r/min, fermention time 36 h.(6) Through the measure of biological antagonistic activity in paltes, the pathogen inhibited table of B56-3 fermentation filtrate was researched. Results showed that: B56-3...