Essential oils for the management of bacterial wilt in tomato plants1

ABSTRACT Bacterial wilt, caused by Ralstonia solanacearum, is considered one of the main phytosanitary problems in tomato cultivation. This study aimed to evaluate the efficacy of essential oils on the in vitro inhibition of R. solanacearum, as well as their ability to reduce the pathogen in the soil and decrease the severity of bacterial wilt, in addition to verify their effects on the growth of tomato plants of the ‘TY 2006’ hybrid, under greenhouse conditions. The chemical composition of the oil with the greatest efficiency in controlling the disease was characterized and the effect was correlated with the main bioactive constituent. The clove essential oil (0.14 %), among the other tested essential oils, promoted the in vitro inhibition of bacterial colonies, as well as a significant reduction in the soil bacterial population and lower incidence, severity, and progression of the disease, in addition to promote tomato plant growth. The bactericidal activity was attributed to eugenol acetate, the major compound of the oil.