Detection of bacterial microflora antagonistic to Erwinia amylovora on apple, pear and quince trees

Naturally occurring epiphytic bacteria were isolated from apple, pear and quince trees from forty five fire blight occurring orchards in the Isparta province of Turkey. The immature pear fruit assay was used to screen the epiphytic bacteria for antagonism against Erwinia amylovora. All antagonistic bacterial isolates were differentiated according to some biochemical properties and tested in-vitro for antibiotic production against Erwinia amylovora, and also screened for copper sensitivity. Fluorescent pseudomonads and yellow bacteria antagonistic to Erwinia amylovora were more frequently isolated from apple than pear and quince trees. Two gram positive isolates, fifteen fluorescent pseudomonads and three yellow pigmented bacteria produced antibiotics in vitro. The minimum inhibitory concentration of antagonistic isolates differed from 0.08 mM to 0.8 mM CuSO4.