LAUSR

The potential of finely ground dried powder of different parts (leaves, succulent shoot and stem) of the desert medicinal plant, Withania coagulans, (L) Dunal to control bacterial wilt (BW) of tomato was explored using four different doses (0 g, 10 g, 20 g, and 30 g Kg−1 soil) and three different (0 days before transplanting DBT, or 10 DBT and 20 DBT) application timings. Both, in-vitro and in-vivo experiments were conducted. In in-vitro studies, each of the three concentrations (5%, 10%, and 20% w/v) of aqueous extracts of leaves, succulent shoot and stems inhibited the growth of the BW pathogen, Ralstonia solanacearum. The aqueous extract (20% w/v) of dried powder of leaves produced the maximum zones of inhibition (ZI) (20.8 mm) followed by that of succulent shoot (19.2 mm) and stem (16 mm) while the minimum ZI (11.2 mm,) was produced by the aqueous extracts of (5% w/v) stem powder. Consistent with the in-vitro results, the effect of the ground powders of the medicinal plant was found to be dose- and plant-part-dependent in in-vivo studies as well. Dried powder of leaves performed better than those of succulent shoot and stems. Leaves powder used at 30 g kg−1 soil under in-vivo conditions, reduced area under disease progress curve (AUDPC) by 37.54%, pathogen population g−1 of the infested soil by 45.04%, enhanced shoot length by 37.45%, root length by 63.36%, and plant fresh biomass by 38.62% as compared to untreated inoculated control plants. Dried powder of succulent shoot (tender shoots plus leaves) used at 30 g/kg soil, ranked second in terms of controlling bacterial wilt. It reduced AUDPC by 32.33%, pathogen population g−1of soil by 32.66%, augmented shoot and root lengths by 35%, and 62.39%, respectively and plant fresh biomass by 38.41% as compared to control plants. Lower doses of dried powders of all parts of the medicinal plant gave inferior results. Similarly, the application time of 20 DBT was found to be better than 10 DBT and 0 DBT. It achieved a reduction of 32.91% in AUDPC, and an augmentation of 41.32%, 54.42%, 54.53% in shoot length, root length and plant fresh biomass, respectively in comparison to untreated inoculated plants. Therefore, it is concluded that dried powder of leaves or succulent shoots of W. coagulans applied at the rate of 30 g kg−1 soil, 20 DBT, can be included as an effective component of integrated disease management (IDM) against BW.