Effect of selected essential oil plants on bacterial wilt disease development in potatoes

Abstract

Objective: Bacterial wilt disease caused by Ralstonia solanacearum is a major constrain to production of potatoes (Solanum tuberosum). Control of bacterial wilt is very difficult as there are no effective curative chemicals. This study was aimed at investigating the potential roles of essential oil plants in control of the disease.
Methodology and Result: The plants used included: Lippie javanica (Sage brush), Ocimum suave (Cambodia) and Tarchonanthus camphorates (Camphor brush).Experiments were conducted with potatoes grown in greenhouse condition. Freshly harvested leaves, stems and flowers from L. javanica, O. suave and T. camphorates were chopped into small portions that were soaked in water for one hour then applied in the inoculated experimental plots. Each plot was planted with disease-free potato tubers and disease development observed and recorded for a period of two months. Plots treated with T. camphorates had significantly low bacterial wilt incidence (P< 0.05) having been reduced by more than 90%.Treatment with the other two plants, O. suave and L. javanica reduced the disease by 38% and 21% respectively and were not significantly different from untreated plots.
Conclusion and Application of Results: This finding shows that use of essential oils isa potential approach to bacterial wilt disease management. It can be concluded that essential oils plants possess antibacterial activity that is effective in control of R. solanacearum. Application of these essential oils can volatilize with increase of temperature. The application can be done by burying chopped essential oil plant parts in the soil during the time of land preparation just before planting. Further studies on the mode of action of these essential oils particularly those of T. comphrates in the control of R. solanacearum are suggested.

Keywords: Essential oil plants; Potatoes; Ralstonia solanacearum; Wilt incidence