extracts against Xanthomonas campestris Pv vesicatoria isolated from diseased African nightshade (Solanum scabrum)

Abstract

Solanum scabrum Mill is widely cultivated for consumption as a leafy vegetable, for medicinal purposes and as a source of income. Its productivity is faced with many challenges as farmers in Kenya have been recording low yield ranging between 1-3 tones/ha due to low soil fertility, pests and diseases. Bacterial leaf spot disease caused by Xanthomona scampestris pv vesicatoria accounts for 40-70% loss of yield of Solanum species including Solanum scabrum. The disease is controlled by application of synthetic chemicals which have adverse environmental effect. The aim of this study was to determine the antimicrobial effect of water and ethanol extracts from B. pilosa and E. hirta on Xanthomona scampestris pv vesicatoria. Leaves and roots of Bidenspilosa and Euphorbiahirta were obtained dried and used to make different treatments for water and ethanol extracts. Disc diffusion technique was used to determine antimicrobial activity of the extracts. Extracts from B. pilosa and E. hirta leaves and roots significantly inhibited the growth of Xc. pvvesicatoria. Euphorbia hirta extract was more effective than B. pilosa extracts in inhibiting bacterial growth. Root extracts had higher antimicrobial activity compared to leaf extracts. Higher concentrations for both water extract (100%) and ethanol extract (200mg/ml) significantly inhibited growth of Xc. pv vesicatoria than other lower concentration. The results obtained confirmed the use of B. pilosa and E. hirta in control of plant pathogens