Effect of some extracts on Colletotrichum gloeosporioides AND Alternaria sp. FROM Jatropha curcas

Abstract

"Varied concentrations of cold, hot water and ethanol extracts of four tropical plants (Verno11ia amygda/i11a,Azadiracl,ta i11dica, Carica papaya and Zingiber officina/e) were evaluated for their in vitro inhibitory effects on ,Jatropha leaf spot pathogens; Alter11aria sp. and Colletotric/,um gloeosporioidel·, Leaf samples (200g) and rhizomes (l00g),werc washed, dried at 28-30° C and pulverized to obtain extract concentrations of 1, 5, 10, 15 and 20 % (w/v). Agar pairing metbod was used to determine inhibitory effects of extract Etbanol extracts of V. amygda/ina induced the highest inbibition of Alter11aria sp. (83.0%) and C. gloeosporioides (94.5%) at 20% (w/v) concentration. Hot water extracts of A. indica and C. papaya was effective against Alternaria sp. at 10% concentrations. Ethanol extract of C. papaya completely inhibited mycelial growth and spore germination of Alternaria sp. and C. gloeosporioides atg/oeosporioides at concentrations ~ 20 and 10 % (w/v) respectively. Phytochcmical screening of extracts showed · the presence of alkaloids, tannins, saponins llavonoids and phenolic compounds with higher amounts recorded in ethanol extraction.