Fire blight of pear trees is a devastating disease which is caused by the bacterium namely as Erwinia amylovora (Burrill 1882). Current chemical control methods employed for fire blight disease are periodic applications of copper compounds and streptomycin, especially when environmental conditions are favorable for the infection. Silver nanoparticles (SNPs) are nanoparticles of silver with 1–100 nm size, which are synthesized via different chemical and biological methods. They have been shown to have antibacterial activity against many human and animal pathogens. In this study, silver nanoparticles (SNPs) with an average size of about 25 nm were de- termined using quince petal aqueous extract. The physicochemical properties of the resulting SNPs were char- acterized using UV–Vis spectroscopy, X-ray diffraction technique (XRD), transmission electron microscope (TEM), energy dispersive X-ray (EDAX) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and dy- namic light scattering (DLS). The SNPs inhibited the growth of E. amylovora in culture media and in-planta. The disease severity was reduced by 80 % and 74 % in pear blossoms and immature fruits treated with 100 μg/mL SNP solution, respectively. This work demonstrates that Cydonia oblonga petal extract is a feasible medium for the synthesis of silver nanoparticles which can be used for the control of fire blight disease.

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