Phytobiocidal management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith) Yabuuchi

Abstract

Phytobiocides are a good alternative to chemicals in managing bacterial diseases including bacterial wilt of tomato caused by Ralstonia solanacearum. In the present research study, finely ground dried powders of seven widely available medicinal plants/weeds species viz., Peganum harmala (esfand or wild rue), Calotropis procera (sodom apple), Melia azedarach (white cedar), Allium sativum (garlic), Adhatoda vasica (malabar nut), Tagetes patula (marigold) and Nerium oleander (oleander) were assessed for their anti-microbial activity, both in-vitro (10% w/v) and in-vivo (10, 20, 30, and 40 g/kg of potted soil) against R. solanacearum. Aqueous extracts (prepared as 10% w/v, soaking for 48-72 h and filtering) of C. procera, A. vasica, and T. patula inhibited the in-vitro growth of the bacterial pathogen over 60% of that produced by the standard antibiotic streptomycin. A. sativum, N. oleander and P. harmala aqueous extracts were less effective while M. azedarach showed no effect against R. solanacearum. The higher dose (40 g/kg of soil) of C. procera, A. vasica and T. patula decreased disease severity quite effectively and increased yield and plant growth characters as much as the standard antibiotic did. No phytotoxicity of medicinal plants powder was observed on tomato plants. Alkaloids, flavonoids, tannins, saponins and terpenoids were detected in the aqueous extracts of T. patula and A. vasica whereas C. procera was found to have only alkaloids, flavonoids, tannins and saponins. Our data suggest that dried powders of T. patula, C. procera and A. vasica (40 g/kg of soil) could be used as an effective component in the integrated disease management programs against bacterial wilt of tomato.

Antibacterial activity of medicinal plant extracts against <i>Ralstonia solanacearum</i> (Smith) that causes bacterial wilt in hot pepper (<i>Capsicum annuum</i> L.)

“…The bacterium isolated from infected C. annum plants was identified using cultural, biochemical characters and pathogenicity test. White creamy colored, irregularly round and non-transparent colonies were formed on CPG medium which matches with the reports of Alemu, Lemessa, Wakjira, and Berecha (2013), Popoola et al (2015) and Din et al (2016). According to the Gram staining test, the isolate was found to be Gram negative.…”

“…The differences among the remaining species extracts were nonsignificant. The methanol leaf extract of M. azedarach did not show growth inhibition against R. solanacearum at all test concentrations, which agrees with the result of Din et al (2016) against the same pathogen. 10.50 ± 0.09 aC 9.82 ± 0.21 bB 9.67 ± 0.16 bB 9.42 ± 0.03 bB 9.29 ± 0.03 bB L. camara 10.50 ± 0.09 aC 9.89 ± 0.11 bB 9.59 ± 0.07 bcB 9.51 ± 0.08 bcB 9.36 ± 0.06 cB R. communis 11.54 ± 0.10 aB 11.36 ± 0.07 abAC 11.18 ± 0.09 bAC 11.29 ± 0.03 bA 11.22 ± 0.11 bA…”

Sustainable and Ecofriendly Approach of Managing Soil Born Bacterium Ralstonia solanacearum (Smith) Using Dried Powder of Conyza canadensis

“…Other researchers also reported similar results for the management of bacterial wilt in tomato as well as other plant disease. For example, using dried powder (40 g kg −1 potted soil) of A. vasica and Calotropis procera suppressed BW significantly and enhanced plant growth and yield in tomato plants [37]. Mulching of flowering-stage of Brassica species released thiocyanates, isothiocyanates and nitriles which infected population of R. solanacearum in soil [38].…”

“…Likewise, release a volatile compound thymol in soil by decomposition of Thymus plants was effectively managed BW of tomato [39]. Dried powders [37,[40][41][42] as soil organic amendments prepared from plants with bio-active compounds have been demonstrated to be effective against different plant diseases. A correlation was found between the decrease in nematode population in tomato roots and increasing plant material doses [41].…”

Bioefficacy of Some Aqueous Phytoextracts Against Clavibacter Michiganensis Subsp. Michiganensis (Smith), the Cause of Bacterial Canker of Tomato

“…Pathogenicity of the bacterium was confirmed by injecting the bacterial suspension (10 8 cfu/ml, OD600 = 0.5-0.7) (Xiulan et al 2010) into stems of four-week old tomato plants, variety Rio Grande (Din et al 2016). Control plants were injected with sterile distilled water.…”