Treatments of antagonists and commercial biological products to control blossom infections by Erwinia amylovora.

Abstract

Fire blight is the most serious bacterial disease of rosaceous plants. Erwiniaamylovora, causes severe infections in blossoms. Since copper compounds arephytotoxic at blooming stage and antibiotics are restricted in Turkey, investigationof alternative control strategies is&nbsp; important while plant trees are bloomed.Biological control of fire blight using commercial biological products provides aneffective disease management on blooming period. In this study, the efficacy ofcommercial biological products (Blossom Protect, Serenade Opti) and 99individual antagonists (92 bacteria and seven yeasts) isolated from natural florasof five district provinces (Adana, Amasya, Mersin, Osmaniye, and Siirt) in Turkeyduring 2014 and 2015 were investigated for their antagonistic effects on blossominfections by Erwinia amylovora&nbsp; using apple blossom tests under semi&nbsp; in vivoconditions with three replicates. Antagonistic microorganisms suppressed diseasedevelopment among 8,33-58,33% on apple blossoms. The most effectiveantagonistic bacterium suppressed pathogen development by 58,33%, eventhough the efficacy of this antagonist was higher than streptomycin and testedcommercial biological products. However, while the disease pressure of anotherantagonistic bacterium was similar to streptomycin and Blossom Protectcontaining the fungus, Aureobasidium pullulans by 41,67%, Serenade Opti whichcontains the antagonistic bacterium, Bacillus subtilis was 50% effective inreducing disease development. According to results, 10 antagonists werepromising in fire blight disease control. These antagonists will be treated toevaluate their ability of disease control on the apple orchard in spring of 2017 asfurther studies. This study was financially supported with Project numbers FBA-2016-5287 and FUI-2016-6563.&nbsp;</p