The inhibitory effects of secondary metabolites of Sclerotium cepivorum against itself were studied both in vitro and in vivo. The highest inhibition of fungal growth and a 98.6 % reduction in the number of sclerotia was obtained with 50 % culture filtrate. No sclerotial germination was observed on media amended with culture filtrates at 10, 25 and 50 %. Methanol extract of mycelia and sclerotia, and ethyl acetate extract of culture filtrate both exhibited over 90 % inhibition of S. cepivorum growth at 1200 ppm. A chloroform extract of culture filtrate resulted in 71.1 % inhibition at 1200 ppm. All extracts completely suppressed the formation and germination of sclerotia at 400, 800 and 1200 ppm. In greenhouse experiments, no disease was observed with the ethyl acetate extract when onion seedlings were dipped in the extract for 4 or 8 h. The GC-MS analysis revealed 28 compounds in the methanol extract. The methanol extract contained mainly hexadecanoic acid methyl ester (31.16 %), whereas 5-hydroxymethylfurfural, HMF, (36.40 %) was the main constituent of the ethyl acetate extract. These results suggest that the secondary metabolites of S. cepivorum are potential and promising antifungal agents for the control of onion white rot. These results can be also applied to reduce the incidence and severity of other diseases in different crops.

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Three entomopathogenic fungal secondary metabolites of Metarhizium anisopliae, Paceliomyces fumosoroseus and Trichoderma longibrachiatum were extracted using two different organic solvent and thoroughly investigated as bio-insecticide against nymphs and adults of onion thrips, Thrips tabaci using spraying method technique. The toxicity index of LC 50 values revealed that T. longibrachiatuom secondary metabolites extracts (chloroform and ethyl acetate) were the most effective against the two developmental stages (nymph stage and adult) of T. tabaci followed by M. anisopliae extracts and the least toxic one P. fuosoroseus extracts after 7days of treatment. The chemical composition of the most promising extracts in each entomopathogenic fungi were analyzed using GC-MS technique. Thirty-five compounds belonging to six different classes of natural products were characterized.

Culture filtrates and organic solvent extracts of Sclerotium cepivorum liquid cultures were evaluated for their antifungal activities against the same fungus. Filtrates at 50% taken from 30 to 45-day-old cultures have reduced S. cepivorum growth by 51.9%. This treatment has also caused a reduction in the number of sclerotia by 98.6%. No sclerotial germination was observed on the media amended with the culture filtrates at all concentrations tested (10, 25 and 50%),.Among all organic solvent extracts, methanol extract was the strongest growth inhibitor against the fungal pathogen; it inhibited S. cepivorum growth by 82.2, 93.3, and 93.6% when used at concentrations of 400, 800, and 1200 ppm, respectively. At the same concentrations, ethyl acetate extract exhibited high inhibition to the fungal growth i.e., 85.56, 88.89, and 90.56%, respectively, while chloroform extract was the least effective in this regard causing 71.11% mycelial growth inhibition when used at concentrations of either 800 or 1200 ppm. All organic-solvent extracts completely suppressed the formation and germination of sclerotia at all concentrations. Further studies are needed to isolate different bioactive compounds from secondary metabolites of S. cepivorum.