EFFECT OF ESSENTIAL OILS IN THE CONTROL OF THE Clavibacter michiganensis SUBESPECIE michiganensis IN TOMATO (Lycopersicum esculentum L.) PLANTS

Plants produce compounds with antimicrobial properties that can be used to control diseases of horticultural products, for this reason, the aim of this study was to enlarge the knowledge on the effect of essential oils as an alternative for control for bacterial canker Clavibacter michiganensis subsp. michiganensis (Smith) (Cmm). Essential oil of Lippia palmeri was obtained by hydridestillation from plants collected in Sonora, Mexico. Essential oils of Origanum vulgare, Thymus vulgaris and Cinnamomum zeylanicum were obtained from commercial stores in Hermosillo, Sonora, Mexico. To evaluate the effect of the essential oils on the bacterium Cmm, direct applications in two concentrations (1: 1 and 1: 5 (v/v)) on tomato plants foliage were carried out. Then, plants were inoculated with 1x10-7 CFU/mL of the bacterium and observed for 12 days. The evaluated parameters were incidence and severity. The essential oils and chemical compounds of Origanum vulgare and Thymus vulgaris had effect against Clavibacter michiganensis subsp. michiganensis up to 9 days after application in a 1: 1 (v/v) concentration and up to 12 days after application with the 1: 5 (v/v) concentration. The essential oil of Lippia palmeri only had effect until six days after the application with both concentrations; that is to say, only these three types of essential oils had bactericidal properties, since with the essential oil of Cinnamomum zeylanicum the inhibition of Cmm was very limited, both in incidence as in severity.