Exogenous Application Of Bacillus Subtilis And H2o2 Mitigated Fire Pear Blight Bacterial Disease Incidence In Correltaed With Yield And Fruit Quality Improvement

Pear fire blight bacterial disease caused by Erawinia amylovora as biotic stress is one of the most serious diseases that cause great loss of pear crop in Egypt and over world. E. arnylovora pathogen was isolated from pear infected plants and molecularly characterized by PCR using specific primer. Koch's postulates applied to assure the pear fire blight disease that causes high defects in the trees growth and yield. The treatments which used in this research to control the disease were Bacillus subtilis as abio-agent, Huwa San 25 commercial product of hydrogen peroxide (H2O2), oxolinic acid (Starner 20%) and antibiotic streptomycin. In vitro bio-agent such as Bacillus subtilis was able to inhibit the bacterial growth of E. ainylovora. However, H2O2 did not inhibit the bacterial growth as compared to the starner and streptomycin which showed significant inhibition. Under greenhouse disease symptoms and severity of inoculated pear seedlings and treated with B. subtills, H2O2, starner and streptomycin showed significant inhibition and decrease as compared with the control infected only. Under field conditions and natural infection, as a result of application with B. subtilis, H2O2, starner and streptomycin, disease severity, disease symptoms and electrolyte leakage % were decreased significantly. Interestingly that the vegetative growth such as shoot length and diameter were significantly increased with all treatments. Fruit set, yield and quality were improved compared to the control. At the open field, the application of H2O2 gave the best results for the most characteristics followed by Bacillus subtilis, starner and streptomycin respectively.