The development of sustainable, effective, eco-friendly compounds for containing and counteracting the development of pathogens is one of the goals being pursued by phytopathological research to identify natural molecules or compounds that are effective in control. There are several research activities in the bibliography on extracts and/or compounds of plant origin that are effective in counteracting pathogens and pests that have subsequently been used in the open field in integrated pest management programs. The present study researches the possible efficacy of plant extracts, organic and aqueous, for the control of E. amylovora, which was evaluated under in vitro and in vivo conditions. Four plant extracts, pomegranate, onion, eucalyptus, and garlic, were used in this research and collected from different areas in Algeria. From the results obtained, it was found that pomegranate ethanolic extract showed increased and remarkable antimicrobial activity against the pathogen during the biological test (disk diffusion test, well diffusion test and agar paper test) and bioassay (immature pear fruit and detached pear leaves) on the Algerian E. amylovora isolates used in this study. Pomegranate extract contains a high concentration of bioactive compounds, and chemical studies are underway to identify compounds that played a role in this antimicrobial activity by Nuclear Magnetic Resonance (NMR) spectroscopy.