Effect of Some Plant Leaf Extracts on Mycelia Growth and Spore Germination of Botryodiplodia Theobromae Causal Organism of Yam Tuber Rot

Abstract

Water and ethanol extracts of leaves of Cassia alata L., Azadirachta indica A. Juss., Citrus aurantifolia (Christm.) swingle and Anacardium occidentale L. were studied for in vitro activity against mycelia growth and spore germination of Botryodiplodia theobromae Pat, causal organism of yam tuber rot. The phytochemical screening of the extracts of the plant species revealed the presence of alkaloids, flavonoids, glycosides, saponins, tannins, phytobatannins and terpenes. The water and ethanol extracts showed varying degrees of fungitoxicity with the ethanol extracts being more effective. Mycelial growth of B. theobromae was significantly (P < 0.05) reduced by ethanol extracts of C. aurantifolia (60.37 – 73.83%), A. indica (51.44 – 60.46%) and C. alata (50 – 58.51%) during the period of incubation. Spore germination was also significantly (P < 0.05) reduced by ethanol extract of C. aurantifolia (59.68%), A. indica (48.69%) and C. alata (47.19%). The present study showed the potentials of extracts of some plant species to control B. theobromae in yam.

Keywords: Botryodiplodia theobromae, yam tuber rot, Cassia alata, Azadirachta indica, Citrus aurantifolia, Anacardium occidentale