Introduction: Fire blight is a dangerous calamity for Apple, Pear and Quince gardens. Bio-control is a good way for control of this calamity. In this way, carrier has an important role for surviving of microorganisms. The aim of this study was evaluation of different compositions as carrier for Pseudomonas fluorescens and Erwinia herbicola that use as bio-controlling agents in Iran.
Methods: Different compositions were prepared as carrier including peat, bagasse, perlite, bagasse-perlite, bagasse-perlite-charcoal, bagasse-charcoal and LB broth medium with 1/3 concentration. The carrier s were sterilized and inoculated with bacteria and achieved final concentration approximately 108 CFU/g. Inoculated carrier s were stored in room temperature and 4oC for 6 months. In the first day and every 14 days until 180 days, the viable of bacteria and pH were measured, in carrier s.
Results: Carrier is a good composition that can to keep bacteria without significant increasing of viable count for 6 months. According these criteria, all of solid carriers were good as carrier at 4°C. In room temperature, bagasse was the best carrier, because the number of bacteria was changed from 8.5 × 107 CFU/g in first day to 1.5×109 CFU/g after 6 months for Pseudomonas fluorescens and from 2.5 × 108 CFU/g in first day to 1.2 × 108 CFU/g after 6 months for Erwinia herbicola. The pH variation was not sensible in bagasse.
Conclusion: According to the role of carrier in bio-controlling of Fire blight, we can to use of bagasse as suitable carrier. Bagasse is very cheap in Iran and harmless in nature.