FUNGISTATIC EFFECTS OF MELIA AZEDARACH L. AGAINST EARLY BLIGHT OF POTATO

Abstract

The antifungal activity of Melia azedarach L. was evaluated against Alternaria solani Sorauer. the causal agent of early blight of potato (Solanum tuberosum L). Screening bioassays with methanolic leaf and fruit extracts were performed in vitro against A. solani. Results obtained from this bioassay showed that leaf extract of M. azedarach, exhibited strong antifungal activity over the fruit extracts, as 5% concentration retarded the A. solani diameter by 90%. Due to high antifungal activity of leaf extract, this part of M. azaderach was used for further bioassays. Leaf extract was partitioned between n-hexane, chloroform, ethyl acetate and n-butanol. The minimum inhibitory concentration (MIC) of isolated fractions and a commercial synthetic fungicide Metalaxyl + Mancozeb, 72 WP was investigated against A. solani. Different concentrations of fungicide and isolated fractions ranging from (0.19 mg to 100 mg mL^-1) were used in MIC bioassay, and data was recorded after 24, 48 & 72 hrs incubation period. n-hexane fraction of the methanolic extract of M. azaderach leaves and synthetic fungicide were found highly effective against A. solani  with MIC value of 0.19 mg mL^-1. All tested fractions showed less antifungal activity.