Exploring In Vitro Inhibition of the Causal agent of Banana Xanthomonas Wilt by Medicinal Plant Extracts sourced from North Kivu province, Eastern Democratic Republic of Congo.

Abstract

Abstract Banana Wilt caused by Xanthomonas vasicola pv. musacearum (Xvm), has emerged as a significant threat to food security in eastern DR Congo (Kivu). Currently, the only means of combatting this biotic constraint is through best agricultural practices. The aim of this study was to evaluate the effectiveness of medicinal plants used in Kivu in inhibiting of Xvm. Three in vitro experiments were conducted at Uganda's National Agriculture Research Organization (NARO) laboratories and the International Institute of Tropical Agriculture (IITA) in Kivu. The bacterial samples were collected in banana cultivated in Kivu and isolated on Yeast Extract Peptone Agar (YPGA). Pure Xvm colonies were used for identification via Polymerase Chain Reaction (PCR) and greenhouse inoculation trials. A completely randomized design was used for the inhibition tests (1) on Mueller Hinton Agar (MHA) using disc diffusion with 10 extracts, (2) in liquid YPG Broth, and (3) on MHA using disc diffusion with 19 extracts. The first two trials used ten plant species extracts diluted in petroleum ether, while the third trial used 19 plant extracts diluted in methanol. After maceration, filtration, and solvent evaporation, 10mg of extract was diluted in 80 µl of distilled water + 10µl of Dimethylsulfoxide (DMSO). Ten µl of this solution was impregnated on perforated discs of Whatman filter paper. Zingiber officinale (ginger) and Ricinus communis (castor) were the most effective plant extracts in suppressing Xvm. Of the thirteen plant species identified as effective against the pathogen, the Myrtaceae and Euphorbiaceae families were the most represented.