Comparative Efficacy of Aloe vera (Linn) and Aloe schweinfurthii (Baker) Powdered Leaf Extracts in the Control of Some Plant Fungal Pathogens

ABSTRACT

Evaluation of the relative efficacy of powdered leaf extracts of Aloe vera(Linn) and Aloe schweinfurthii(Baker) in the control of some plant pathogens was undertaken in this work. Antimicrobial activities ofthe extracts obtained using cold water, hot water and ethanol were tested against four fungal spp., namely, Alternaria solani,Colletotrichum lindemuthianum, Sclerotium rolfsiiand Trichophyton rubrum. The phytochemical screening of the leaf extracts of the two aloe species revealed the presence of bioactive compounds such as alkaloids, tannins, saponins, flavonoids, cardiac glycosides, phytates and oxalates. The extracts were observed to exhibit varying inhibitory effects on the selected fungi. Ethanolic extract of A. veraat 50mg/ml and 100mg/ml had the greatest impact on A. solaniand C. lindemuthianum respectively.Similarly, cold water extract of A. schweinfurthiiat 100mg/ml was the most effective against S. rolfsiiandT. rubrum.However, hot water extract of A. vera wasleast effective against C. lindemuthianum. Also, the efficacy of cold water extract of A. schweinfurthii at 50mg/mlwas very low against T. rubrumand A. solani. The hot water extract of A. schweinfurthii at 20mg/ml also showed the least effect against S. rolfsii. Consequently, extracts from both Aloe species can be recommended in the management of the four fungal pathogens evaluated in this study. It is hoped that in no distant future, botanical fungicides would be developed from the two Aloe species