Application of biorational pesticides against Ralstonia solanacearum (Smith) on tobacco

The different biorational pesticides were evaluated against R. solanacearum (Smith) both in vitro and in vivo conditions. In the in vitro assay using spread plate method, fermented vegetables applied at the rate of 1ml/L of water showed a high degree of efficacy against the bacterial pathogen at one, two, and three days after incubation (DAI) with average inhibitory zones of 2.15 mm, 1.74 mm, and 1.44 mm, respectively. Under in vivo conditions, the inoculated tobacco plants manifested symptoms typical of bacterial wilt due to R. solanacearum (Smith). However, a comparable percent wilt incidence was noted on plants applied with fermented vegetables and other biorational pesticides. Moreover, the growth parameters of tobacco such as plant height, leaf length, fresh leaf weight, and the total number of harvested leaves per plant were not affected by the application of biorational pesticides. The results indicate that fermented vegetables are effective against R. solanacearum (Smith) under in vitro conditions, but did not show significant difference with the other treatments under in vivo conditions. published by the Journal of Biodiversity and Environmental Sciences (JBES)