Effect of Plant Essential Oils on Ralstonia solanacearum Race 4 and Bacterial Wilt of Edible Ginger

Palmarosa (Cymbopogon martint), lemongrass (C citratus). and eucalyptus (Eucalyptus globulus) this were investigated for their effects on Ralstonia solanacearum race 4 and then potential use as biofumigants for reducing bacterial wilt disease of edible ginger (Zingiber officinale) Three concentrations of the oils (0.04, 0.07, and 0.14% vol/vol) were evaluated by culture amendment assays, epifluorescence microscopy, and studies in potting medium In culture amendment assays with palmarosa and lemongrass oils at 0.04%. both oils significantly reduced the growth of the bacterium compared with the control. and at 0.07 and 0.14% they showed complete inhibition of bacterial growth Epifluorescence microscopie observation; showed cell deterioration in 95 to 100% of the cells at all concentrations of palmarosa and lemongrass indicating its bactericidal properties Eucalyptus oil treatments at 0.04 and 0.07, had bacterio-static effects on the cells The pathogen was not detected in R solanacearum-infested potting medium after treatment with palmarosa and lemongrass oils at 0.07 and 0.14% in any of the experiments Bacterial wilt incidence on edible ginger was significantly reduced when planted in essential oil-treated potting medium None of the essential oil treatments reduced the growth or yield of edible ginger grown for 180 days in 5-liter pots