Thyme and Suico essential oils: promising natural tools for Potato Common Scab Control.

•Potato common scab is a worldwide disease mainly caused by Streptomyces scabiei. It seriously affects potato crops by decreasing tubers quality. Essential oils (EOs) are natural products with recognized antimicrobial properties. In this research, the antibacterial activities of thyme, oregano, suico and mint EOs against S. scabiei were analyzed. •Infected tubers and soil samples were used for bacterial isolation; the obtained isolates were genetically identified. The chemical composition of the EOs was determined by GC-MS. The broth microdilution method was used to analyze antibacterial properties of EOs. •Thirty-one bacterial isolates were obtained. An isolate chosen for antibacterial assays was morpho-physiologic and genetically identified as S. scabiei. Thyme EO was mainly composed by thymol and o-cymene, suico EO of dihydrotagetone, trans-tagetone and verbenone, oregano EO of trans-sabinene hydrate, thymol and ɣ-terpinene, and mint EO of menthone and menthol. All the EOs tested were effective against S. scabiei, but thyme and suico EOs were the most successful ones, with a minimum inhibitory concentration of 0.068 g/L and 0.147 g/L, respectively, and a minimum bactericidal concentration of 0.137 g/L and 0.147, respectively. Scanning electron microscopy analysis showed similar damage by both thyme and suico EOs in the bacterial envelope. Total phenolic content of EOs was not related to their antibacterial activity. •Thyme and suico EOs are effective antibacterial agents against S. scabiei, impeding bacterial viability and disturbing their cell envelope. These EOs are promising tools for potato common scab control.